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HomeMy WebLinkAboutSEPA EPIC-196-82 - TSAO & COMPANY - MCNAMARA CONDOMINIUMMCNAMARA CONDOMINIUM PRE-DRAFT 53AVS&KLICKJTAT EPIG196 -82 VNIL4 4, City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 19 09 Gary L VanDusen, Mayor September 22, 1982 Edward McNamara 2367 Eastlake Avenue East Seattle, Washington 98102 The plan review of the drawings submitted for construction of the fifty - four unit condominium project, near 53rd Avenue South and Klickitat has progressed to a point where additional information..is needed. The additional information that is required should be reflected on the drawings or other data. The comments of the departments that are reviewing the project are attached for your.:.: convenience. The attached plan check comments are subject to errors and omissions, and do not authorize any violation of any adopted code or ordinance. If you need clarification of any of the items or additional information please call 43.3 -1849. City of Tukwila Al Pi.e.=r Building Official AP /blk xc: P1 ng. Dir. Public Works- Dep ,t. Planning Dept. Fire Dept. Planning Department Comments 1. Provide *children's play area per. TMC 18.60.200(.lc) and details of equipment to be placed therein. , 2. Provide landscape plan per TMC 18.60.200(.1g). 3. Obtain B.A.R. approval of recreation space plan per TMC 18.60.200(2). 4. Additional site modification may be necessary following outcome of SEPA analysis. Fire Department Comments 1. All buildings to be fully sprinkler.ed.th.roughout. 2. Fire hydrants required per Ordinance #729. 3. Fire lanes required by Ordinance #110 - Asphalt minimum 12' width, 35' turning radius throughout, maximum 15% grade. 4. Fire extinguishers, required per. NFPA 10. 5. Attic separation divided into maximum 9000 square feet. 6. Provide minimum fire flow requirements of I.S.O. & W.S.R.B. 7. In buildings "4 stories" in height, one stairwell shall extend to the roof surface. 8. An approved automatic or manually operated fire alarm system required on Buildings #2 and #3.' 9. Sprinkler systems shall be supervised by an approved central station. 10. Approved numbers or addresses shall be placed on all buildings in a position as to be plainly visible and legible from street. 11. All exitways shall meet minimum class. rIflame spread rating per UBC 42 -B. 12. Provide visual alerting devices in both the sleeping areas and living areas of all handicapped units. • • Building Division Comments 1. Provide handicapped units (.3) per handicapped code. 2. Show method of attic ventilation. 3. Show method of stack framing on all multistory units. 4. Show method of fire blocking per U.B.C. 2517 in all areas where fire blocking is required. 5. Show location and routing of vents for bathrooms and clothes dryers. 6. Show method of routing D.W.V. plumbing, avoiding the excessive cutting of headers, joists, and other framing members. 7. Show method of emergency exit from below grade bedrooms. (9' window wells do not comply.) 8. Show foundation drain details and method of damp proofing foundation walls. 9. Show or call out insulation on rim joists areas. .S 1- �4 City %f Tukwila k z 2 6200 Southcenter Boulevard -o Tukwila, Washington 98188 Public Works Department 433-1850 September 14, 1982 Byron G. Sneva, Director Via Planning Department 6200 Southcenter Boulevard Tukwila, Washington 98188 Mr. Edward MacNamara 2367 Eastlake Avenue East Seattle, Washington 98102 • Re:- 54 Unit Condominium in Tukwila, Washington Dear Mr. MacNamara: The Public Works Department has reviewed your plan submittal for Job No.. 8024A, Plan Sheets C -1, 2, 3. Requested at this time is a resubmittal of your proposed site plans per the following comments: 1. Curb Cut /Access /Sidewalks /Improvements. to the Public Right -of -Way The plan submittal is deficient with respect to defining the necess- ary access onto 53rd Avenue South and improvements to the inter- section of 53rd Avenue South and Klickitat Drive per past staff reviews of TRANSPO GroupA.-s traffic analysis (11/24/81 memorandum by Ted Uomoto, Public Works Director) and public. testimony (Tukwila City Council 4 /15/81). A detailed plan submittal for this project shall include the addressing of concerns of the public, concerns of staff and include the rechannelization of the intersection of 53rd Avenue South and Klickitat Drive to allow for adequate turning movements and lane stacking during peak hour traffic flows. Also, on the plan resubmittal shall be shown access from the develop ment to the existing trail system which is in the City of Seattle Water Department pipeline right -of -way to the south of the project. By this development, required is pedestrian walkway system per the requirements of Ordinance Nos. 1158 and 1233 for sidewalks adjacent to the development on 53rd Avenue South. How the roadway fronting the property is to be developed with curbs and gutters and sidewalks, is necessary as part of this plan submittal. Vehicular accesses shall be completed including delineation of the edge of pavement for the existing roadway in 53rd Avenue South and the proposed edge of pavement for the access points from the develop- ment to 53rd Avenue South including slopes with the pavement, drive- way aprons, etc. 2. Soils Report - The staff review of the soils report (Hemphill Consulting Engineers), requires the following information be addressed as part of the final plan submittal: a. Shown on plans area and approximate depth of unsuitable soils to be removed. b. Provide rockery details and specifications. c. Indicate'how surface and groundwater to be handled from the west of the development. d. Provide assurances by the developer that Mr. Hemphill's recommendations as described in the last portion of his report will be carried out in the construction phase per Item E -11 page 19 of his February 6th, 1982 report (Hemphill Project No. 6290). 3. Water Fire Loop and Water Meters and Services - On Plan #C-3,-General Notes under Note #5 take out the last line, "PVC pipe and fittings may be used if approved by authorities.'' Also, under Note #10 add' all water mains shall be built per Tukwila Municipal Code 14.04.060. All hydrants shall include a hydrant secondary valve three to ten feet from the hydrant. All mains shall be a minimum of ten feet from any building. 4. Storm and Sanitary Sewerage Systems A. Storm Drains: Drainage from this development shall go into surface or sub- surface detention ponds and proceed into the storm drain system but shall not bypass that detention system. Because this development is on a side slope and involves a substantial building program, both sanitary sewer and storm main lines shall be of concrete and not corrugated metal. pipe. A submittal analyzing the downstream storm system is necess- ary unless the development is providing for retention of all storm drainage flows. B. Sanitary Sewers (1) Clean outs are required outside of buildings and at "Ys" and bends. (2) A minimum 2% grade shall be provided on all sewer lines. (3) Class "B" bedding material shall be provided on all sanitary and storm pipes. (4) A 95% compaction shall be provided throughout. .(5) For sanitary sewers, air tests only shall be provided. (PVC pipe no loss is expected). (6) Eighteen inches minimum cover shall be provided for all metal and concrete pipe and 36- inches minimum cover shall be provided for pipe which is PVC. (7) Final plan submittal of the sanitary sewer system shall be provided only after final approvals and criteria have been met by the Val -Vue Sewer District. (8) On Plan #C -3 note #15 eliminate water settlement as a method by which either the foundations or utilities . may be stabilized. • (9) On Plan #C -3 Note #17, elltinate the corrugated' PVC for 6 -inch diameter pipe and substitute with rigid pipe, corrugated metal pipe or concrete. (10) On sheet #C -3, Note #22, water settlement shall be eliminated as a manner by which utilities can be compacted for this development. If you have any questions regarding any of the issues, please do not hesitate to call me at 433 -1856. • Sincerely, Phillip Fraser, Senior Engineer xc: Tukwila Maintenance Shops Al Pieper, Building Official William S. 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SALM _suistwr satiC s __P.. afg Affttam., (pi( , s .60 • Z40 S) eit6 opELs (WM r)%11) MOV I PEP- pLDC DL,pc, LtS: 10 e 40 ) e 40 if DLD4 415 ; 4 6 c_o 1908 • City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 Frank Todd, Mayor 14 September 1982 Thomas M. Walsh Attorney -at -Law 1111 Third Avenue Bldg. Seattle, WA 98101 SUBJECT: McNamara Building Permit Application Dear Mr. Walsh: Enclosed is a copy of the pre - draft scope -of -work which we have developed as a guide to the preparation of a comprehensive Environmental Impact Statement for the McNamara. Project. As previously agreed between your client and the city, a draft EIS will be prepared by a consultant whom you select and who is approved in advance by the Planning Director.. To date, we have not been ap- praised of your choice of EIS consultant. As you wished .to.begtn tne_pr_e -draft consultation process prescribed in WAC- 197 -10 -420 as soon as possible, we ask that you advise us of your schedule for consultant selection and of a probable date on which to meet and discuss the scope of work. Please call me if you have questions on this matter; the telephone number for the Planning Department is 433 -1849. TUKWILA PLANNING DEPARTMENT Brad Collins Director encl. xc: City Atty. EPIC - 196 -82 MC /ibm • • PRELIMINARY SCOPE OF WORK McNamara Condominium Proposal 'Checklist Section 1, Item 11: Plans by Others - Disagree with "no" response: What about the Tukwila 6 -yr. T,I.P.? • How about any plans by Val -Vue sewer? Checklist Section 1, Item 12: Applications - Disagree with "no" response: Building permit and related utility appli- cations will be necessary. Checklist Section 2, Itme 1: Earth. - The preliminary project soils engineering reports are not conclusive as to the ability of soil conditions drainage characteristics necessary vis- a-vis the present scale of the project. Indeed, the soils consultant indicates that a responsible conclusion on this topic is not feasible in advance of actual foundation excavation. No conclusions are offered regarding the cost feasibility, or the degree of disruption of existing site covering conditions necessary to prepare the site for construction based on soils requirements; these topics are appropriate disclosures which should be included in the E.I.S. - Disagree with explanation response to Items lb and lc. Checklist Section 3, Item 3: Water - E.I.S. should amplify and quantify the engineering solution proposed for control and retention of run -off. A complete discussion of existing sub- surface drainage characteristics of the site is also expected. Checklist Section 2, Item.5: Fauna - Vegetation removal /preservation plan required and strategy for replacement of screening value required. • Checklist Section 2, Item 6: Noise - Disagree with "explanation" response: concern is regarding interior noise level compliance with HUD standards resulting from oximit to 1-5 corri- dors as well as off-site noise- impacts produced by tie proseC . Checklist Section 2, Item 8: Land Use - Analysis should be combined with additional elements from Section 11 of PRELIMINARY SCOPE - h' tli; 4ARA CONDOMINIUM PROPOSAL 0 Ordinance 1211 - "Quality of Life " / "Neighborhood Cohesion " / "Sociological Factors ": Currently, there are no multiple - family developments in the incorporated area of McMicken Heights. The proposed project, if imple- mented, represents a significant departure from the prevailing low- density residential land use pattern. The social implications and growth- inducing impacts of this project relative to the policies of the Comprehensive Plan should be analyzed. Checklist Section 2, Item 13: Transportation -Both the TRANSPO study'and theiPubTic Works Department follow -up agree:: that implementation of the McNamara project will entail the need for turn - movement rechannelization and other lane- capacity improvements at Klickitat Drive /53rd Avenue intersection. The exact configuration of these improvements and suitable alternative mitigation should be determined at the Draft E.I.S. stage. Checklist Section 2, Item 14: Public Services - Combine analysis of public service costs with elements 2 and 3 of Section 11, Ordinance 1211: "Tax Base /Economy°: The content should be focused on a. cost /revenue analysis.of extending municipal . services or upgrading existing services to this project site which is located at the urban fringe. Checklist Section 2, Item 16: Utilities - Verify availability. and adequacy of utility infrastructure; discuss any necessary interagency cooperation anticipated in the provision of utility . services, especially storm drainage and sewerage. Checklist Section 2, Item 18: Aesthetics - Construction of the project may impact the visual character of the over story growth of the easterly slope of McMicken Heights as perceived from the valley floor. A view analysis should be conducted in the E.I.S. Checklist Section,2, Item 19: Recreation - Discuss adequacy of on -site recreation opportunity given the anticipated project population level and the lack of nearby public park lands. Also demonstrate compliance with Recreation /Open Space Standards of (old) TMC 18.60.200. • MC /js 1908 City• of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 Gary L VanDusen, Mayor • August 27, 1982 Thomas M. Walsh 1111 Third Avenue Building, Suite 2600 Seattle, WA 98101 RE: Your request for permit application extension Due to the amount of time elapsed since the original application was filed, the change in land use zoning, and various other considerations the City does not feel obligated nor is it appropriate to extend the time period for completion of the application procedure beyond October 18, 1982.. . Therefore, your request dated August 25, 1982, for a 180 day extension per Section 304CC) of the Uniform Building Code is denied. City of Tukwila • Al Pi.e�'-r Building Official AP /bik xc: Ping.. Dir. • AMY L. KOSTERLITZ THOMAS M. WALSH LAW OFFICES OF THOMAS M. WALSH 1111 THIRD AVENUE BUILDING. L UITE 2600, SEATTLE, WASHINGTON 98101 (206) 464 -1560 August 25, 1982 Mr. Lawrence E. Hard LeSourd, Patten, Fleming, Hartung & Emory 3900 SeaFirst National Bank Building Seattle, WA 98154 RE :, McNamara Building Permit Application Dear Mr. Hard: p�(��OdI3 AUG L OF TUF KWILA PLANNING DEPT. Enclosed is a copy of our letter to the City of Tukwila requesting an extension of time for review of our building permit application. Mr. Brad Collins, the Planning Director, has indicated that he will be consulting with you regarding our request. Therefore, I thought it would be appropriate to send you a copy of our letter so that you would be acquainted with the grounds for our request. Needless to say, the decision on our request for an extension is a matter of serious concern to our client. Therefore, we would like the opportunity to discuss this matter with you prior to your issuance of an opinion on the request. It is to everyone's advantage to ensure that all information has been carefully considered before a decision is made on this request. I will be out of town from now until Tuesday, August 31, 1982. I will call you on Tuesday when I return to the office, and I hope that you will give me the opportunity to discuss this matter with you at that time. Thank you very much for your consideration. Very truly yours, )144(elti THOMAS M. WALSH TMW /ehk encl. cc: Mr. Edward F. McNamara AMY L. KOSTERLITZ THOMAS M. WALSH LAW OFFICES OF THOMAS M. WALSH 1111 THIRD AVENUE BUILDING, SUITE 2600 SEATTLE, WASHINGTON 98101 (206) 464-1580 August 25, 1982 Mr. Brad Collins Planning Director City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 RE: McNamara Building Permit Application Dear Mr. Collins: To: A- e'v�-�,y ve= IMME AU G 2 6 1982 L OF TUKWILA t=:.. -:NNING DEPT. This letter will confirm the results of our meeting on Monday, August 23, 1982, at Tukwila City Hall. In response to our letter of August 17, 1982, the City has agreed to omit the threshold determination requirement and move directly to preparation of an EIS in accordance with WAC 197 -10 -300 (2)(a). However, the City has decided to reject our EIS consultant, Hunt, Schultz.& Associates. Regardless of the merits of the City's decision to reject our consultant, the decision has now made it clear that we will not be able to meet the October 18, 1982, deadline for issuance of a building permit. We had invested time in interviewing consultants, selecting Hunt, Schultz & Associates, and negotiating the contract for their services. During this time, Hunt, Schultz & Associates had spent time "clearing the deck" of other work in their office in preparation for working on the EIS, and they had begun reviewing the project documents in preparation for their ,work on this project. Now we must begin this process again. As you have acknowledged to us, there is not sufficient time remaining prior to October.18, to select a new consultant, discuss the scope of the EIS, prepare the draft EIS, circulate it for the required time period, and get final building permit approval. Therefore, in accordance with the provisions of Section 304(c) of the Uniform Building Code (UBC), we hereby request an extension of time for 180 days to complete the building permit application process. This section provides as follows: Mr. Brad Coll • August 25, 1982 Page 2 "The Building Official may extend the time for action by the applicant for a period not exceeding 180 days upon request by the applicant showing that circum- stances beyond the control of the applicant have prevented action from being taken. No application shall be extended more than once." There are circumstances beyond our control that have prevented action from being taken. First, the City's decision to reject our EIS consultant has cost us valuable time as discussed above. We did not delay in advising the City of our selection of Hunt, Schultz & Associates; we notified the City on August 17 which was even before finalizing our agreement with the firm. Hunt, Schultz & Associates is a highly reputable and experienced firm, and the City's decision was beyond our control. Secondly, the Tsao firm's refusal to release vital documents and our subsequent court action to get the documents was time consuming. The decision by the Tsao firm to withhold these documents was beyond our control, and we took prompt action to gain control of that situation through expedited court action. (King County Superior Court Cause No. 82 -2- 10879 -1) This application has not been previously extended. The earlier decision by the City to set a deadline of October 18, 1982, was not an "extension" but merely an administrative interpretation of when the initial 180 day time period began and ended. The City's letter of May 25, 1982 advising us of this deadline, states as follows: "Section 304 C of the Uniform Building Code 1979 edition allows 180 days for issuance of a building permit after receiving application. In this case, review of the application was delayed approximately one year by consideration of the waiver requirement, which was not entirely within the control of the applicant. Accordingly, . the review of this application will need to be completed and a building permit(s) issued by October 18, 1982, in order to be timely." Moreover, Section 304(c) provides that an extension may be granted "upon request by the applicant." This indicates that extensions are involved only when there is a request from the applicant. But here, the applicant did not request an extension. Finally, the intent of Section 304(c) is to allow a maximum of 180 days for building permit review plus an additional 180 days on extension. There was virtually no building permit review activity during the waiver process. Building permit review activity did not seriously begin (AI Mr. Brad Coll August 25, 1982 Page 3 until spring, 1982. Therefore, we are still within the initial 180 day period and an extension period has not yet begun. Thank you very much for your consideration of our request. Ver truly yours, . (.14,0 THOMAS M. WALSH TMW /ehk cc: Mr. Lawrence Hard Mr. Edward F. McNamara 1909 Ask CitySf Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 Gary L VanDusen, Mayor August 24., 1982 Mr. Ed McNamara McNamara Investment Co.,.Inc. 1600 Dexter Ave. N., Suite 1 Seattle, WA 98109 Mr. Tom Walsh 1111 Third Avenue Building, Suite 2600 Seattle, WA 98101 RE: 4- 13 -81, McNamara Building Permit ApplicaUon Dear Mr. McNamara. and Mr. Walsh: In response to your requests at the August 23, 1982, meeting this letter - reiterates information about the City's plan review process and the reason why Mr. John Hunt of Hunt, Schultz & Associates was not accepted to do consulting work on the Environmental Impact Statement (EIS) for your project. I would also like to make it very clear to you again that the City is acting in good faith to process your building permit application. There should be no misunderstanding that the City is and has been ready to review your plans as soon as you provide the necessary materials to the City. You specifically ask again why the City cannot guarantee that the thres- hold determination will result.in a Declaration of Non - Significance. In response, I have said that without reviewing an applicant's Environmental Checklist, whic'h'identifies both impacts and explanation of the signifi- cance of any impact, I cannot make a threshold determination. In your particular case, much discussion of environmental concerns has occurred since your latest application materials submittal with the result that the City is informed about some impact, as well as additional technical studies that may already adequately explain their significanbe or non - significance without doing an EIS. However, the City has not assessed all environmental review items per SEPA, nor has the fee required to undertake the review been received. Until the City has actually completed the SEPA environmental review, a threshold determination, which is the result of such a review, has not occurred, nor my decision made on significance. r ' Mr. Ed McNamara ,- Mr. Tom Walsh L• Au9uSt 24, 1382 With regard to the unacceptance at this time of John Hunt to do consulting work in preparation of the EIS, the City Attorney advised that, since Mr. Hunt was involved in.a:.matter of litigation with the City on another EIS, he should not -be performing .a similar service for the City at the same time. In discussions with Mr. Hunt, I indicated that it was his respon- sibility to inform you and was informed that he had made his involvement in this litigation known to you. Finally, at the meeting of August.23, 1982, 1 believe we had an understanding on the following five points with regard to your request to proceed ahead with an EIS without a threshold determination: 1. The City will accept your reuqest to:proceed with an. EIS without a threshold determination in order to save time which is of the essence and would be spent for the threshold determination. 2. The responsibility to obtain issuance of the . building permit by October 18, 1982, is the applicant's duty. 3. There does not appear to be sufficient time to complete the EIS process prior to October 18, 1982, since it is the City's estimate that without allowing any time for actual preparation time 70 calendar days is the fastest (minimum) time needed to simply process the Draft and Final Environmental Impact Statement. 4. The cost of the EIS will be paid by you with the awareness that the benefits of a building permit cannot be assured nor perhaps expected and, therefore, the value of the ETS may be found in its. use for other similar proposed actions such as a rezone application. 5. On advice from the City Attorney, another consultant will have to be employed at this time to work on your EIS, since Hunt, Schultz & Associates . is currently involved in litigation proceedings with the City on another matter. (Several alternative consultants were dis- cussed and not disqualified.) Furthermore, it is your responsibility to initiate the plan and environmental reviews by submitting previously identified materials. Sincerely, C�d�J■ Brad Collins, Planning Director BC /blk xc: City Attorney Hard Mayor Van Dusen 1 • McNAMARA INVESTMENT CO., INC. 1600 DEXTER AVENUE NORTH • SUITE 1 • SEATTLE, WASHINGTON 96109 • [206] 285 -6646 CERTIFIED MAIL Tune, 4, 1982 Mr. Mark Caughey Associate Planner City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Re: Letter dated May 27, 1982 to Mr. Thomas M. Walsh, Attorney for McNamara Investment Co., Inc. Dear Mr. Caughey: You may expect a complete, updated State Environmental Policy Act checklist for my 54 -unit condominium project shortly. In talking with Mr. Bill Tsao he sees no need for submitting this checklist prior to having the other materials prepared that your office requests. Subse- quently the S.E.P.A. checklist will be submitted along with the additional information and drawings necessary to complete the building permit application. EFMcN /c cc: Mr. Thomas M. Walsh Mr. Bill Tsao Sincerely, MC NAMARA INVESTMENT CO., INC. Edward F. McNamara President City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 27 May 1982 Thomas M. Walsh Attorney at Law 1111 Third Avenue Bldg. Suite 2600 Seattle, WA 98101 SUBJECT: McNamara Bldg. Permit Application • This letter is sent.in regard to. that portion of the building permit ap- plication concerning compliance with the State Environmental Policy Act. Since the proposed project constitutes -a major action within the language of RCW 43.21C.030 (e),--compliance with the threshold. determination po - cess is mandatory. As yet, we do, not have on file .a complete, up -.to -date SEPA checklist.for the McNamara project.. This item will be needed to con- tinue processing by this office of your building permit request. An ex .ception to the required filing.of a checklist is found in WAC- 197 -10 -300 (2) in cases where the applicant and lead agency agree that an E.I.S. is appropriate. So that.we may continue timely:action on your permit appli- cation, we request that you take one of the following actions: 1) Submit a.complete,.up -dated SEPA checklist for the project, including explanation of all "yes" and "maybe" answers con- tained therein. 2) Submit a letter requesting agreement by the lead agency.(City • of Tukwila) that an environmental impact statement for this project is appropriate, per WAC 197 -10 -300. We have discussed the matter of SEPA compliance with Mr. McNamara,'Mr. Tsao and you on several occasions and have explained the procedural options avail- able. In your letter of 20 April, 1982, the application; we ask your help, stated concern that the city ter.as we have. not received a response to� our eprior ecommunications . this Thankt you for your attention and assistance. TUKW PLANNING DEPARTMENT M. Caughey ssociate Planner MC /ib.m xc: P1 ng Dir City Atty Bldg Off \IOLA qs City/ % Tukwila ►•G 3' 1906 6200 Southcenter Boulevard Tukwila Washington 98188 Frank Todd, Mayor May 25, 1982 Mr. Thomas Walsh 1111 Third Avenue Building, Suite 2600 Seattle, WA 98101 RE: McNamara Building Permit Application Dear Mr. Walsh: The application on behalf of Mr. Edward McNamara for building permits to construct a group of residential structures near Klickitat Drive and 53rd Ave. So. in the City of .Tukwila is dated April 13, 1981. The Uniform Building Code Section 304C expires applications by limitation when the application process is not completed. Section 304C of the Uniform Building Code 1979. Edition allows 180 days for issuance of a building permit after receiving application. In this case, review of the application was delayed approximately one year by consideration of a waiver requirement, which was not entirely within the control of the applicant. Accordingly, the review of this application will need to be completed and .a building permit(s) issued by October 18, 1982, in order to be. timely. The material submitted to date by the applicant for review by the City has not been adequate for a complete review. A letter was sent to the applicant on April 27, 1981, explaining many of the deficiencies and,.again on April 23, 1982. As of May 24, 1982, the additional material needed to complete the review process has not been received by the City. City of Tukwila Al Piep Building Official AP /BC /blk cc: Brad Collins, Planning Director Lawrence Hard, City Attorney CITY OF ;TUKWILA C &T;° C = TUKWILA ENVIRONMENTAL CHECKLIST FORM AUG 2 1 t GUIDING DEPT.' This questionnaire must be completed and submitted with the application for permit. This questionnaire must be completed by all persons applying for a permit from the City of Tukwila, unless it is determined by the Responsible Official that the permit is exempt or unless the applicant and Responsible Official previously agree an Environmental Impact Statement needs to be completed. A fee of $50.00 must accompany the filling of the Environmental Questionnaire to cover costs of the threshold determination. I. BACKGROUND 1. Name of Proponent: William S. Tsao & Co., P.S., agents for McNamara Invest - Co. , Inc. 2. Address and Phone Number of Proponent: 324 -8780 2367 Eastlake Avenue E., Seattle, Washington 98102 3. Date Checklist Submitted: / June, 1982 4. Agency Requiring Checklist: City of Tukwila 5. Name of Proposal, if applicable: 6. Nature and Brief Description of the Proposal (including but not limited to its size, general design elements, and other factors that will give an accurate understanding of its scope and nature): 54 unit condominium consisting of 34 Townhouse units, 20 flats, all in 5 buildings plus required parking area (s). 7. Location of Proposal (describe the physical setting of the proposal, as well as the extent of the land area affected by any environmental im- pacts, including any other information needed to give an accurate under- standing of the environmental setting of the proposal): Bordered on west by 53rd Avenue S., on East by Klickitat Dr., 2.69 acres. Site downslopes gradually from S.W. to N.W. Flora is generally underbrush with large shrubs to small or medium size trees. . Estimated Date for Completion of the Proposal: December, 1985 9. List of all Permits, Licenses or Government Approvals Required for the Proposal (federal, state and local): (a) Rezone, conditional use, shoreline permit, etc. YES NO X (b) King County Hydraulics Permit YES; NO X (c) Building permit • • YES X NO Azz,61' Ace Attenzie>2.972,774e/nera C44.4d 11,4 /0/17t1 aladdi aztimiegud tdneeds.t. daza.t 6/2Q.a4 4/nee GI t/5454 aadt. „ a-' Awe "nee .6ll ,, • .0.4P)-2,., D% • • (d) Puget Sound Air Pollution Control Permit YES NO X (e) Sewer hook up permit YESX NO (f) Sign permit YES NO X (g) Water hook up permit YESX NO (h) Storm water system permit YESX NO (i) Curb cut permit YESX NO (j) Electrical permit (State of Washington) YESX NO (k) Plumbing permit (King County) YESX NO (1) Other: 10. Do you have any plans for future additions, expansion, or futher activity related to or connected with this proposal? If yes, explain: NO 11. Do you know of any plans by others which may affect the property covered by . your proposal? If yes, explain: NO 12. Attach any other application form that has been completed regarding the pro- posal; if none has been completed, but is expected to be filed at some future date, describe the nature of such application form: NO • II. ENVIRONMENTAL IMPACTS (Explanations of all "yes" and "maybe" answers are required) YES MAYBE NO 1. Earth. Will the proposal result in: (a) Unstable earth conditions or in changes in geologic substructures? (b) Disruptions, displacements, compaction or overcover- ing of the soil? (c) Change in topography or ground surface relief fea- tures? (d) The destruction, covering or modification of any unique geologic or physical features? — -7- X X YES MAYBE NO (e) Any increase in wind or water erosion of soils, either on or off the site? X (f) Changes in deposition or erosion of beach sands, or changes in siltation, deposition or erosion which may modify the channel of a river or stream or the bed of the ocean or any bay, inlet or lake? X Explanation: lb, c - Minimum amounts of gradning for the siting of structures may have some effect on soil placement. However, the amount of soil to be moved will be non - significant. See soils report by Hemphill dated 2/6/82 & 3/17/82. 2. Air. Will the proposal result in: (a) Air emissions or deterioration of ambient air quality? x (b) The creation of objectionable odors? X (c) Alteration of air movement, moisture or temperature, or any change in climate, either locally or regionally? X Explanation: 3. Water. Will the proposal result in: (a) Changes in currents, or the course or direction of water movements, in either marine or fresh waters? X (b) Changes in absorption rates, drainage patterns, or the rate and amount of surface water runoff? X _ (c) Alterations to the course or flow of flood waters? x (d) Change in the amount of surface water in any water body? ?� (e) Discharge into surface waters, or in any alteration of surface water quality, including but not limited to temperature, dissolved oxygen or turbidity? x (f) Alteration of the direction or rate of flow of ground waters? X (g) Change—in-the quantity of ground waters, either through direct additions or withdrawals, or through interception of an aquifer by cuts or excavations? x -3- • • YES MAYBE NO (h) Deterioration in ground water quality, either through direct injection, or through the seepage of leachate, phosphates, detergents, waterborne virus or bacteria, or other substances into the ground waters? x Reduction in the amount of water otherwise avail- able for public water supplies? x Explanation: 3b - Addition of buildings and parking lots may affect absorption. Surface water runoff will be controlled by means of an on -site runoff control system. (i) 4. Flora. Will the proposal result in: (a) Change in the diversity of species, or numbers of any species of flora (including trees, shrubs, grass, crops, microflora and aquatic plants)? (b) Reduction of the numbers of any unique, rare or endangered species of flora? (c) Introduction of new species of flora into an area, or in a barrier to the normal replenishment of existing species? X X X (d) Reduction in acreage of any agricultural crop? x Explanation: 4a - Some clearing will be required for structures. Most existing trees will be saved, and placement of some additional trees will result in more trees on the site than currently exist. 5. Fauna. Will the proposal result in: (a) Changes in the diversity of species, or numbers of any species of fauna (birds, land animals including reptiles, fish and shellfish, benthic organisms, insects or microfauna)? x (b) Reduction of the numbers of any unique, rare or endangered species of fauna? X (c) Introduction of new species of fauna into an area, or result in a barrier to the migration or movement of fauna? (d) Deterioration to existing fish or wildlife habitat? x Explanation: YES MAYBE NO 6. Noise. Will the proposal increase existing noise levels? x Explanation: During construction some additional noise will be generated. However, this will be limited to normal work hour's. 7. Light and Glare. Will the proposal produce new light or glare? x Explanation: The project when completed will have some outdoor parking area lighting. However, source directed lighting will be used so there will not be glare. 8. Land Use. Will the proposal . result in the altera- tion of the present or planned land use of an area? X Explanation:. ' Presently, the site is undeveloped. jThe pree set ,one is R -1 (single - family; However, this application is made retroactive-7ND the change of zone from RMH (multiple residence high density) to R-1. 9. Natural Resources. Will the proposal result in: (a) Increase in the rate of use of any natural resources? (b) Depletion of any nonrenewable natural resource? Explanation: 10. Risk of Upset. Does the proposal involve a risk of an explosion or the release of hazardous substances (including, but not limited to, oil, pesticides, chemicals or radi- ation) in the event of an accident or upset conditions? Explanation: x x x • 11. Population. Will the proposal alter the location, distribution, density, or growth rate of the human population of an area? YES MAYBE NO X Explanation: New residents in project will increase area population by approximately 134 people. 12. Housing. Will the proposal affect existing housing, or create a demand for additional housing? Explanation: 13. Transportation /Circulation. Will the proposal result in: (a) Generation of additional vehicular movement? X (b) Effects on existing parking facilities, or demand for new parking? X (c) Impact upon existing transportation systems? x (d) Alterations to present patterns of circulation or movement of people and /or goods? x (e) Alterations to waterborne, rail or air traffic? x (f) Increase in traffic hazards to motor vehicles, bicyclists or pedestrians? x Explanation: 13a, b - Vehicular traffic may be increased on and around project by the addition of approximately 80 more vehicles. Demand for new parking will be satisfied by inclusion of sufficient number of on -site parking spaces. 14. Public Services. Will the proposal have an effect upon, or result in a need for new or altered governmental services in any of the following areas: (a) Fire protection? x (b) Police protection? x (c) Schools? x (d) Parks or other recreational facilities? X (e) Maintenance of public facilities, including roads? x -6- • • YES MAYBE NO (f) Other governmental services? Explanation: 15. Energy. Will the proposal result in: (a) Use of substantial amounts of fuel or energy? (b) Demand upon existing sources of energy, or require the development of new sources of energy? x X x Explanation: 15b - As with any new residential development, there may be a moderate need for additional energy for lighting, heating, etc., primarily electrical energy. 16. Utilities. Will the proposal result in a need for new systems, or alterations to the following utilities: (a) Power or natural gas? X (b) Communications systems? x (c) Water? X (d) Sewer or septic tanks? xx (e) Storm water drainage? x (f) Solid waste and disposal? X Explanation: 17. Human Health. Will the proposal result in the crea- tion of any health hazard or potential health hazard (excluding mental health)? Explanation: X • YES MAYBE NO 18. Aesthetics. Will the proposal result in the obstruc- tion of any scenic vista or view open to the public, or will the proposal result in the creation of an aesthetically of- fensive site open to public view? Explanation: 19. Recreation. Will the proposal result in an impact upon the quality or quantity of exist- ing recreational opportunities? Explanation: 20. Archeological /Histroical. Will the proposal result in an alteration of a signifi- cant archeological or his- torical site, structure, object or building? Explanation: CERTIFICATION BY APPLICANT: • I, the undersigned, state that to the best of my knowledge the above information is true and complete. It is understood that the lead agency may withdraw any declaration of non - significance that it might issue in reliance. upon this checklist should there be any willful misrepresentation or willful lack of full disclosure on my part. June 23, 1982 Signature and Title ' Date -8- ;.�.:� _ 17 March, 1982 • SLOPE STABILITY STUDIES;.; 0) z o dl tiq �.° 1600•Dexter Avenue N. .' ' Seattle, Washington 98109 - `' WiU(am ".S:: Tsao zz w Reference: 54 Unit Condominiums to be located in Tukwila, o 0 Works Director, Tukwila, WA . 4 Z - O • • McNAMARA ,INVESTMENT COMPANY z Suite o w' Subject:}" Response to comments from Phil Fraser, Acting Public W o• FQ- W (r' 0 0 W - F Q Q J w 0 z w z z cc cE 0 0 w • • • z z o E I U1 U U1 w Z (13 (7 Z w z FIETENTION STUDIES 0 z z o 1 z o U a J w w Z w 0 a a cc 0 ]D 0 7 0. w • SOIL TESTING -LAB & FIELD The purpose of this report . is to respond to comments and questions presented by Phil Fraser, Acting Public Works Director of Tukwila, WA, concerning the McNamara 54 Unit Condominium project. The following responses refer to questions A through G Fraser's letter. A copy of Mr. Fraser's letter is enclosed end of this letter. Question A: HEMPHILL has studied the drainage system that was installed by the State Department of Transportation during the construction of I -5, and has determined that the drainage system will neither affect the site of the proposed McNamara 54 Unit Condominium, nor will construction activities at the site, or the final completed project, have any affect on the drainage system. Question B: The utilities that exist off the property will not be affected by construction activities at the site, provided that normal precautions are taken. Any interaction with adjacent utilities will be the responsibility of the contractor and the owner of the utilities. Adjacent utilities could effect the site if they should malfunction, but those conditions cannot be anticipated, and would be the responsibility of others. The location of the existing manhole and sewer line in relation to Building 5 will be investigated by the architect, and proper action will be taken in the final design phase of the project. Question C: The site is presently composed of several- different types of soils. Each soil type could be supporting floor slabs and paving, either in an undisturbed condition, or as a structural fill. Imported soils might also be required as structural fill and as backfill. in Mr. at the 1 4812 170th PLACE N.E. e REDMOND, WA.. 98052 • (206) 883 3924 Question D: •any different types of sits can be suitable as structural fill, provide that the moisture.. content can be controlled to achieve proper:._ compaction, therefore availability of the soils, weather, and groundwater conditions-can .each determine the types of soils that will be suitable- for both compaction and drainage. It would be difficult for HEMPHILL to specify any. filter soils, drainage soils, or capillary break soils that would be suitable for use with each of the wide range of soils that would be suitable for use at the site under each of the conditions. Such a list of specified filter and drainage soils would still require a person skilled in soil mechanics to recognize the structural soil. Some man -made materials are also:available for use as filters that, under some difficult situations, can save much construction time. Interaction between the soil engineer and the contractor can benefit the contractor by saving time and making more materials available, thereby lowering construction costs. The contractor can request approval of available soils under . different construction conditions, and can use construction methods that are more suitable to his equipment and knowledge with the approval of the soil engineer. Such flexibility can be of benefit to the owner, and still assure that the intended results are achieved. HEMPHILL has determined that no disturbed soils at the site are suitable bearing soils. Generally the description 'disturbed' soils means soils that have been softened due to the weathering process, such as freezing and thawing, and wetting and drying, that have been loosened by root action, by sliding and sloughing, or by man disturbance. Disturbed soils are generally inconsistent and are considered to be low in bearing and high in compressibility. The only soils permitted by HEMPHILL for bearing are the natural, undisturbed soils described as glacially compacted clays, silts, and sands. Because of the inconsistency of those soils at the site, HEMPHILL cannot specify a consistent depth to the proper bearing soils; also some soils could be difficult for untrained persons to recognize. The other soil type that can be a suitable bearing soil is structural fill. Structural fill can be composed of a wide range of soils that must be placed in a controlled condition that is not HEMPHILL necessarily consistent with afferent soils. • A ro erly designed and constructed a all r :the structural. Structural indicates nowo,.: the physical parameters of the rockery are the rockery can be placed in a specified manner':: within a reasonable range that is exceeded by, the safety factor. The same soil parameters required forethe design design of a rockery wall, except of a reinforced concrete retaining that the rockery is a series of retaining s each with overturn and sliding points intersection of rock. Enclosed is a computer printout of a rockery design. The various parameters used in this program are exactly the same as the parameters wall, would be k used fetai ing wall he data that is wall, and like any r used is only as good as the control of the construction. Question F: The rockery filter system is necessary to prevent the soils behind the rockery from either pushing or eroding through the void spaces .in the rockery. rockery The large crushed rock behind the ue main of finer members prevents the next the rock voids, grained soils from eroding that would creating void spaces behiround the su face and create eventually work to the ground The number of different grain size on t ee vo dusred behind a rockery is dependent size of the structural or the rockery vs the grain fill or natural soils that must ofb the next larger moving into the void spaces can filter material. Filter soils of h sbuyperc also incorporated e es s even into w without drainage drainage. necessary Question : Soil conditions can be highly variable, often times within short distances, and thereforeSoil revealed by the subsurface investigation. Soil properties can also vary greatly weather conditions. Soils are often affected different ways by different construction procedures that are not obvious to the untrained technician. 3 HEMPHILL ons e complexity of soils andOroundwate ncon i iols are such that a soil report that a possible conditions would be extremely complex, and difficult to comprehend, and each range of condition would not be obvious to an untrained technician, therefore the section of the soil report titled, "Recommended Construction Procedures", ny is to phases es allow observe of contstruction control that are co affected by soils and groundwater. There are numerous slopes at the site, and some footings will be placed on slopes. The required depth that a footing would be placed into a slope to resist the lateral uphill pressures is dependent upon the height of soils on the uphill portion' of the footing wall, the type condition of the backfill soils, the strength of the soils on the slope, and the steepness of the slope. Since those conditions can all be variable, and the combination of the those variable conditions could become very complex, then the decision placing onof the contractor, should or be anyone not eci knowledgeable in soil mechanics. Some soil information is sometimes required for design purposes, and estimates of the worst conditions are presented to the structural engineer. That information should not be presented to the contractor to be used at his descretion, or to be used as an indication of exact conditions to be expected throughout the site. Since structural designs are sometimes based on the estimated worst conditions, footings and foundation walls can sometimes be raised with the approval of the soil engineer to the benefit of the owner. Dale C. Hemphill, P.E C Registered Engineer Nb. 14777 State of Washington 4 HEMPHILL Comments received from Phil Fraser, Acting Public Works Director, regarding the soils investigation of 6 February 1982 prepared by Hemphill Consulting Engineers for the McNamara 54 -unit condominium project: A) Page 3, Item S(3), Paragraph 4: The report indicates that extensive excavation occurred on the slopes during construction of Southcenter; however, no mention is made of similar excavation impacts as a result of constructing I -5. The final soils report should evidence coordination with the State Department of Transportation regarding measures taken to mitigate excessive earth removal and drainage problems as a result of these prior slope disturbances. B) Utility Location /Identification: Existing utilities adjacent to and traversing the property should be shown as part of the preliminary soils report so that appropriate conclusions can be reached as to the relationship of surrounding soils to the maintenance of existing utilities. Utilities of concern include sewers, water mains, storm systems and the retaining walls adjoining Klickitat Drive. The manhole near test pit 1 described on Page 5, S(6) paragraph 4 is not, and should be shown on the site analysis drawings. The cautionary note at the top of page 6 is appropriate; however, without adequate research of the existing sewer lines and its location and pur- pose it is difficult to determine whether the sewer line can be relocated as is suggested in the caution note.relative to the location of the building 5 foundation. C) Page 7, Item b: There is an indication that some drainage requirements beneath the project's paving slabs, retaining walls, and foundation walls could require soils of specified grain sizes. Rather than provide the design criteria in this report, it indicates that the requirement should be determined after the excavations have exposed the natural soils and water conditions have been determined. It would seem to me that a report of this nature should provide background data and suggested design criteria to be applied in the final plan. 0) Page 10, Item E(5A), Part 2: While the report references foundation placement techniques in undisturbed soils areas, it should include also a discussion of appropriate techniques for foundation placement on disturbed soils, since the initial text of the dc:ument indicates extensive presence of disturbed soils on this site. E) Page 11, Item E -6: This section is entitled "Retaining Walls" and, in brackets, "rockeries." Rockeries are not retaining walls and have no structural significance; therefore, the equation of rockeries to retaining walls is rejected. F) Figure 9: Per the diagram, Fig. 9, Rockery Filter System, we question whether French drains behind the rockery should be included in the design, con- sidering there was mention of a great deal of seepage through the filters of soil in the area. G) Page 19, Item E -11: It appears that there are several instances wherein the report cannot be used to determine preliminary site design parameters in advance of beginning actual field work. For example, i'n Item 5 of the "recommened construction procedures" it seems that a determination of the project's ability to pick -up subsurface drainage will be finalized in the field since an adequate investigation of subsurface conditions is not provided. We know that the State instituted elaborate improvements to deal with the substantial drainage from the hillsides in this area. Similar, though smaller -scale problems can reasonably be presumed to exist on this site and preliminary design alternatives should be discussed in relation to the scope and nature of anticipated drainage problems prior to the construction phase. The preliminary site plan for the project suggests that some portions of the various condominium buildings will be placed on slopes exceeding 20 %, yet no where in the preceding text is placement of foundations relative to slope steepness discussed. Recommendations 1 and 2 suggest that final footing designs should be left to field investi- gation. While the report discusses standard foundations designed for placement in standard soil conditions, unusual soils conditions as they influence stability and configuration of footing structures is not included. Staff believes that design alternatives based on predictable estimations of slope and soil instability should be included in the report. MC /blk ■ • • • • • • T ZOW w U O W W N Z a- ZO. Z Z Z: 0 W 0 j Q Cr (J) w Z w ° • • • N 0 Z 0 _W w 4 W w 0 rd Z 0 CO J a J WW1 Q 0 Q Z a Q n o 3 p- J 2 W W • • • . FOR THE .McNAMARA INVESTMENT COMPANY DATE: 6 FEBRUARY, 1982 PROJECT NUMBER 6290 PTI-' SE 2467. • 1-3 SCOPE OF INVESTIGATION AND,,REPORT • '• • • • . . 1-4 DESCRIPTION'OF,PROjECT • • • .• -• • • • • • . . . .• - -- • • - • • • . • MPTIONS • : • . • 1-5 1-6 LIMITATIONS.OF,REPORT.. • .7 4.2. - '7.-14-Aki • • • - ';-117Y- • • • • • • • SUBSURFACE:4. INVEST. QATIO. PAGE NO. 1 1 1 1 1 2 S-1 GEOLOGIC RESEARCH....... • •.• • .• 3 S-2 SURFACE.DESCRIPTION. •• • • . • • 3 S-3 EXPOSED CONDITIONSON ADJACENT PROPERTIES. . • • 3 „,,,S-4.,-;SUBSURFAM'STUDIES • • • • A - • • r' ..'• 1. TEST PITJJOCATIONS A. TEST,PIT,LOGS • r:,• • •.. S-4B. FIELD_TESTS • • • .. • S-5 GROUNDWATER OBSERVATIONS S-6 SUMMARY OF SUBSURFACE STUDIES ENGINEERING STUDIES AND RECOMMENDATIONS E-1 EARTHWORK OOOOO ••-••• OOOOOOO •••• E-1A REMOVAL OF UNDESIREABLE SOILS E-1B -STRUCTURAL -FILL -• 1. DESCRIPTION OF STRUCTURAL FILL . • • • a. • 'STRUCTURAL FILL TO SUPPORT STRUC- TURES AND PAVING 4 4 4 4 5 6 6 6 6 6 HEMPHILL { _ � .. STRUCTURAL FILL FOR DONAGE .. . 7 PREPARATION OF SOIL TO. BE USED.FOR FILL 7 .COMPACTION OF STRUCTURAL FILL'.:. 7 _ . .- - .ALLOWABLE.BEARING SOILS AND CAPACITIES . . . . 8 E- 2A ..,ALLOWABLE BEARING CAPACITIES IN UNDISTURBED :SOILS. .. . • - • • • • -.. • • • • • • '. • • 8 ALLOWABLE BEARING CAPACITIES IN STRUCTURAL • FILL . . .. • • . • .• • • 8 -2C • . EARTHQUAKE • AND WIND, LOADS. ...;. ,. E ::.. 8 ,FOOTINGS + .• ..•3'• �._, • `'`,' 8 MINIMUM, ALLOWABLE DEPTH. OF FOOTINGS. • • 8 ▪ FOR FROST . PROTECT ION ; .: . • • • 8 2. FOR BEARING CAPACITY . . . . • • • 8 9 9 9 3. PLACEMENT FOR STABILITY. • • .,. • • • E -3B MINIMUM ALLOWABLE FOOTINGS SIZES . E -3C .PREPARATION OF SUBGRADE FOR FOOTINGS 1. PREPARATION OF SUBGRADE IN..UNDISTURBED SOILS :: 2. PREPARATION OF SUBGRADE IN STRUCTURAL • • • • • . E -4 SETTLEMENT FILL -. . . . • . ^. ..;; • .9 E -5 FOUNDATION WALLS 10 10 E -5A LATERAL DRIVING PRESSURES AGAINST FOUNDA- TION WALLS 10 1. FOUNDATION WALLS SUPPORTING STRUCTURAL FILL 10 2. FOUNDATION WALLS SUPPORTING UNDISTURBED SOILS 10 3. DRAINAGE BEHIND FOUNDATION WALLS . . .11 E -5B LATERAL RESISTING PRESSURES AGAINST FOUN- DATION WALLS 11 SASIVE‘`.. S OIL —RESISTANCE T FICTIONAL RESISTANCE TO SLIDING afi a, `r ri: 1`tl tta � •,+, � ,+_..�� -, >RETAININGW LS (ROCKEIES);. E; 6A SLIDING BETWEEN .'ROCKSz. :,• B .OVERTURNING-BETWEEN..ROCKS. -6C - SLIDINGBETWEEN ROCK .. • • • • • .• AND SOIL. • • '`. • • _fPASSIVE •RESISTANCE TO SLIDING.. SON REISTANCE TO.,SLIDING• Lam, .. 1.`p. - -. _ �t' !1� .Jai '�__i . +:i'tr•n D • -6 E> •.PAC =6F FILTER SYSTEM. ;. • •. • 11 11 12 12 12 E -6G ROCKERY DESIGN OPTIONS E -7 DRAINAGE ..:: !. -d.. • E -7A SITE DRAINAGE E -7B DRAINAGE FOR FOUNDATION WALLS E -7C DRAINAGE - E -8 FLOOR SLABS E -9 PAVINGz • • t, •,_,.,• •,..• • • ,• • Ste• "•• • • .• • • • • • • ' • n �aeklwdSar�it�LL ••. wk E -9A FULL -DEPTH ASPHALT PAVING. • • • • • . . 13 14 14 15 15 ,1.5 17 E -9A1 'FULL -DEPTH ASPHALT PAVING FOR —TRUCK PARKING 17 E -9A2 FULL —DEPTH ASPHALT PAVING FOR CAR PARKING 117 E -9B PAVINGFOR- PARKING AREAS WITH MORE THAN 2 FEET OF STRUCTURALFILL • 17 E -9B1 ...PAVING FOR .TRUCK PARKING-ON STRUC- - - TURAL . FILL 18 E -9B2 PAVING FOR CAR PARKING ON STRUC- TURAL FILL 18 E -9C ALTERNATE ASPHALT PAVING • • 18 >: •,:: FOR HEAVING, TRUCKS. • • • • 18 OR PASSENGER ,CARS... • • • 18 E -9D ,.ROADWAY PAVING . .. . ... . . 18 E -10 RECOMMENDED 'DESIGN PROCEDURES = 19 • . E -11 RECOMMENDED 'CONSTRUCTION PROCEDURES 19 FIGURE 1 2 3 4 6 7 8 9 10A 10B 10C • "11 TITLE OR DESCRIPTION LOCATION'OF SITE PLAN OF PROPOSED SITE PLAN OF EXISTING SITE TEST PIT LOCATIONS TEST PIT LOGS BEARING AND SETTLEMENT FOR FOOTINGS. OPPOSITE PAGE NO. 1 2 3 4 5 8 OVER- EXCAVATIONS..FOR FOOTINGS 9 LATERAL PRESSURES ON FOUNDATION WALLS 10 ROCKERY FILTER SYSTEM 12 ROCKERY DESIGN PARAMETERS 13 ROCKERY THICKNESS VS SAFETY FACTORS 13 ROCKERY THICKNESS. VS TILT -BACK 14 PROTECTION OF FLOOR SLAB FROM CAPILLARY BREAK 15 • • ' FIGURE 1 LOCATION. OF SITE \ \\ \ \ ■ \ \ \ \ N \ A,;.-0:11M.P.t- • • • .; „ • • ! • NN X % N N ■ \ N N krisry-i --tz‘ \• \\•\, • • INTRODUCTION PURPOSE ; of ..REPORT, The purpose of this report is to present the results of the subsurface investigation, and to present recommendations for designing the foundations, floor slabs, retaining walls. drainage, and paving for the proposed 54 unit condominiums for McNAMARA INVESTMENT COMPANY, to be located as shown in Figure 1. I -2., AUTHORIZATION for... INVESTIGATION and REPORT On 14 January, 1981, Tony Mottar, of PITTSBURGH TESTINU LABORATORY .gave a verbal authorization to Dale Hemphill of HEMPHILL CONSULTING ENGINEERS to conduct a preliminary soil investigation at the site of the proposed 54 unit condominiums. On 18 January. 1982, during a meeting at the site. Tony Mottar authorized HEMPHILL to prepare a soil report. I -3 SCOPE of INVESTIGATION and REPORT The request by the client for HEMPHILL to act as soils engineer obligates HEMPHILL to investigate and make recommendations concerning all phases of design and construction that would be affected by soils and foundations. Included in the studies are groundwater" and drainage, bearing capacities and settlements for footings in both undisturbed soils and in structural fill, sub - grade preparation for floor slabs and paving, lateral.: soil pressures for retaining walls and foundation walls, and drainage for groundwater. I -4 DESCRIPTION of PROJECT. The description of the existing site and proposed project are approximately as shown in 18 drawings by William S. Tsao and Co., identified as their Job No. 8024, and dated approximately 6 April, 1981. The project will include 5 buildings with 2 and 4 story condominiums, each located approximately as shown in Figure 2. I -5 ASSUMPTIONS The analysis, conclusions, and recommendations contained in this report are based on the following assumptions: EMPHIL'L o. ore or • w • �#� • oil ,/ or•- (2) • • • 1:-6 • That site conditions will not change due to natural eauSisconstruction operations.at or adjacent to the • -- B. That the subsurface investigation revealed conditions that are representative of subsurface conditions throughout the site. C. That the assumed soil properties are correct, and are representative of all the soils at the, site, and that those properties will be verified by HEMPHILL after the excavations have exposed the true nature of all the bearing ••• _ LIMITATIONS of REPORT A. This report was •prepared for the exclusive use of the owner, the architect, and the engineer to design the project. and to prepare construction specifications. B. The recommendations presented in this report are based on the requirement that the presumptive soil properties, the assumed soil conditions, and the drainage requirements will be verified by HEMPHILL after the soils have been exposed during the excavating process. llIiUIIUIII!!Ii!ItF ".111• Warm ;Ar on MUMMER . .iii 2 MN HEMPHILL OZT 2 ,iii OZ T . ,gay .- ?fir 0 0; • e��� -- 1 f,,i . 1 1 ‘c,070111•1 OZT SZT OCT SCI Ott 1 • • • I • •' • • ••• • ' I `� / / 1 / 1.4;,Da.• . • ,S %es, O. fl , 'T . / .4 6;% • • • • • / ,• • • • • • I 1 I • •' • • / I I I • ss • es. • • 0 I • • ▪ I .' .' • - . �n / I I i I • I -� •• I • 1 • - ,. , i • /'� - ' ' o I -. ! / • D IG d .. ..• .+ • £T • 1 ' . 1 _.' 0'0 i 1 I • / • eat' • .....n.• •nu•.0 n.,r4 SST 09T S9T 53rd AVENUE SOUTH • / . I ■ • 91 t I / .. 0 1 ' • ' l • . , . 1 165 , , ' . / I • • 1 • • o 160'•/% /' . ■ '155, 0 0 t . • -6 150x• �, • 144. `` -f.:0 „. • 1 ” I ' Q r®• ' • - . ,,,. eto...) 1 ....... / \ 03 0:4 14 =t:{ '1' • 101"/ , / , ici O • ®, .'. -•.. •• • 1 % 1 1 '1 • • • • 1 • • • \ • • 140 135 130 125 120 120 SUBSURFA STUDIES' S -4A.;: TESTPITS_ 1.. TEST PIT LOCATIONS 10 test pits were located approximately as shown in Figure 4. The locations were chosen to minimize disturbance of the proposed building areas, but in a manner that would determine the consistency of the soils at the site. Since the test pits and exposed eroded soils revealed similar conditions, and since this report is based on the condition that the soil conditions will be verified after the excavations are completed, then HEMPHILL assumed that further testing within the building areas was not necessary. v. 2. TEST. PIT LOGS Logs of the test pits are shown in Figure 5. The logs show visual descriptions of the soils, depths of changes in the soil types, groundwater observations, and any other pertinent observations or field tests. S -4B FIELD TESTS HEMPHILL conducted field penetration tests and vane shear tests in the test pits to determine the approximate strength characteristics of the soils. S -5 GROUNDWATER OBSERVATIONS The test pits revealed that groundwater is moving in the upper sandy soils on top of the undisturbed, unweathered clays. Some seepage surfaces at lower portions of the site. The source of the groundwater is probably storm -- water infiltration from properties to the west-and-will require an interception system. Additional studies will be required during construction to determine the quantity and source of groundwater. and to determine the required drainage materials and filters. 4 HEMPHILL . FIGURE 5 TEST-:,I0 LOGS DEPTH 0 1 2 3 4 5 6 7 8 9 10 DEPTH 0 1 2 3 4 5 6 7 8 9 TP 1 SEWER BACKFILL HARD GRAY SILT BOTTOM .. TP 6 WEATHERED HARD GRAY a BROWN SILT TP 2 TP WEATHERED DENSE BROWN FINE SAND BROWN VERY DENSE VERY FINE SAND LAYERS HD. GY. SILT TP 7 FILL MEDIUM DENSE TO DENSE BROWN a GRAY COARSE SILT AND V.F. SAND 3 WEATHERED DENSE BROWN V. FINE TO SAND HARD GRAY SILT DENSE GRAY SAND TP 8 • TP 4 TP WEATHERED HARD YELLOW a GRAY SILT. SAND. GRAVEL. a COBBLES TP 9 FILL HARD • BROWN a GRAY SILT • HARD GRAY SILT _ _ ___ OP 5 MEDIUM DENSE FINE TO MED. SAND HARD a DENSE GRAY SILT a SAND' HARD GRAY SILT TP 10 WEATHERED DENSE BROWN a GRAY SILT i SAND DEPTH 0 1 2 3 4 5 6 7 8 9 10 DEPTH 0 1 2 3 4 5 6 7 8 9 6 SUMMARY.• SUBSURFACE STUDIES • Visual observations and test pits conducted at the site reavealed fairly consistent conditions that were similar to exposures on adjacent properties. The glacially compacted clays and silts are very strong, and capable of very high bearing capacities. The sands overlying the clays and silts could be combinations of the original glacially deposited and compacted esperence sands, and sands that have been eroded from uphill seepage zones. The - fill> soils. encountered in the upper portion of the site are•:of poor. quality 'and cannot be used .'for• support of foundations or paving. .The fill soils-can be used for buffer zones or other aesthetic purposes. Test Pit 1 was located near a manhole not shown on the drawings. The manhole appeared to be connected to another manhole nearly directly south and on the adjacent property. The sewer backfill was encountered to a depth of 10 feet. Test Pit 11 revealed backfill, but was not completed to avoid damaging the sewer pipe Because of —the Thigh <;shear strength `.of :`.the, undisturbed soils, deep seated-'slides would be.unlikely. Any instabililty,wouhd -be the result of sloughing of-the upper few feet of weathered soils, or movementwithin any fill deposits which generally exist along the upper portion of the site, or would result from heavy .water 'erosion. Removal of the fill soils, and properly designed drainage, should help to stabilize the upper portion of the site, and will decrease future erosion and instability in the lower portions of the site. 5 H`EMPHILL • '• , - ••:**, . , • • • • •- : • • - - • • -; • ENGINEERING STUDIES and R•OMMENDATIONS Because of the possibility that the present proposed location of Building 5 is over a deep sewer line and questionable backfill, HEMPHILL recommends that the sewer line be located exactly. and that appropriate action be taken. If the sewer line is located as suspected by HEMPHILL, and if Building 5 is not moved, then special footings must be designed to span the excavation, or the backfill must be removed and replaced with structural fill. E -1 EARTHWORK E -1A REMOVAL OF UNDESIREABLE SOILS HEMPHILL.. ,re.commends -that, the 3 .to' . 5 feet :: of sof t Organic . soi1rsat the= proposed 'iodation of the upper level condominiums in the southwest corner of the site be removed, and, if necessary,' replaced with structural fill. Those soils are composed of poor quality fill. and should either be removed from the site, or used as buffer zones, or other aesthetic purposes. E -1B STRUCTURAL FILL 1. DESCRIPTION of STRUCTURAL FILL a. STRUCTURAL FILL TO SUPPORT STRUCTURES AND PAVING Structural fill is defined as any soil that can be properly compacted to have the necessary . physical properties to support foundations, to transmit the loads to the softer soils below, to have minimum compressibility, and to resist attracting capillary water to the underside of the floors and footings. Any of the natural inorganic sandy soils from the site can be used for structural fill, provided the soil is properly compacted. The ability of the existing sandy soils to be compacted would depend on the water content of the soils, as described below. HEMPHILL STRUCTURAL FILL FOR ARINAGE Some drainage requirements, such as beneath slabs, paving, and behind retaining walls and foundation walls, could require soils of specified grain sizes. Those requirements should be determined after the excavations have exposed the natural soils, and the water conditions have been determined. 2. PREPARATION OF SOIL TO BE USED FOR FILL Prior to placement and compaction, all soils to be used for filling should be either wetted or dried to the optimum water content to help to achieve the required compaction. To determine the required compaction and the optimum water content, each soil used for filling should be tested to determine the maximum density that can be achieved in a Modified. Proctor Test (ASTM D 1557, Method D). 3. COMPACTION of STRUCTURAL FILL Structural fill at this site should be compacted to a density equal to or greater than 95% of the maximum density achieved in the Modified Proctor test (ASTM D- 1557). The procedures to achieve the proper density of a compacted fill are dependent on the size and number of passes, of the compacting equipment, the water content of the soils, the thickness of the layer to be compacted, and some soil properties. If it is determined that the laboratory and field testing required to control the compaction of the soils is not warranted at this site, then HEMPHILL recommends that the soils be placed in layers not thicker than 8 inches, and the soils be compacted with several passes of a heavy vibrating type compactor. The soils should not be too wet or too dry during the compaction. Generally. poorly compacted soils are the result of poor workmanship, or soils with a high degree of silt being too wet, or coarse grained soils being too dry. 7 HEMPHILL rn --� rn r 0 33VA ns QN11OJ9 MINIMUM FOOTING SIZE (FEET) V1 4:71 3S6 000 ./ • • • SSA ....f J .1_ • -2 ALLOWAB BEARING SOILS AND CAPACITIES NOTE: HEMPHILL should identify tlt design bearing soils, and should verify their presumed bearing capacities at the time that the excavations for the footings are. conducted. E -2A ALLOWABLE BEARING CAPACITIES in UNDISTURBED SOILS The-:minimum allowable bearing capacity . of natural undisturbed sandy soils between 2 and"5 "feet below the existing ground surface is 2000 psf. The bearing capacity of sand increases with depth below the final proposed ground surface, as shown in Figure 6. Figure 6 can be used to design footings for bearing capacity in accordance with the acceptable settlement. E -2B ALLOWABLE BEARING CAPACITIES in STRUCTURAL FILL Structural fill that is properly placed and compacted to a minimum density of 95% of the Modified Proctor maximum density will have a minimum allowable bearing capacity of-2000 psf. Higher bearing capacities in fill can be achieved if approved by HEMPHILL, or- in accordance with Figure 6. E -2C EARTHQUAKE AND WIND LOADS The allowable bearing capacities can be increased by 1/3 for temporary loadings from earthquake and wind forces. E -3 FOOTINGS E -3A MINIMUM ALLOWABLE DEPTH of FOOTINGS 1. FOR FROST PROTECTION Footings to be adjacent to unheated areas should be placed a minimum of 18 inches below the final ground surface to protect against uplift due to frost expansion, or loss of bearing . capacity due to softening from thawing conditions. 2. FOR BEARING CAPACITY Footings should be placed on the undisturbed soils which exist approximately 2 to 5 feet below the existing ground surface. HEMPHILL FIGURE 7 PROCEINE FOR OVER-EXCAVATING AAPREPARING FINAL GRADE BASE COURSE FOR FOOTINGS • • PLACEMENT FOR STABILITY All footings located adjacent to slopes should be placed at ,a depth so that the slope will not kick out from the footing loads. The required depth of footings placed on slopes should be verified by HEMPHILL at the time of construction. .E -3B MINIMUM ALLOWABLE FOOTING SIZES The minimum allowable. footings:sizes` should.be. 18 inches :f or' °a three, story building, and 15 inches for a 2.;_ st -ory building, in accordance with the requirements of the UBC: E -3C PREPARATION of SUBGR ADEfor FOOTINGS ! All organic soils and.grass or shrubs should be ,..-,,removed from beneath .,any... footing ,locations. If soft soils are encountered at the proposed elevation of any footing, then the excavation should continue to competent soils approved by HEMPHILL. 1. PREPARATION OF SUBGRADE IN UNDISTURBED SOILS The subgrade for footings in undisturbed soils should be prepared by hand cleaning to remove any soils loosened by the excavating process. Fill soils should not be placed into irregularities to smooth the bottom of the excavation. 2. PREPARATION OF SUBGRADE IN STRUCTURAL FILL If any footing is over- excavated" to remove unsuitable soils from beneath the footing, the over - excavation can be backfilled with structural fill compacted to 95% of the Modified Proctor maximum density. The sides of the excavation should extend beyond the edges of the footing by a distance equal to 1 foot for each 2 feet of depth of the over - excavation, as shown in Figure 7. That allows the stresses beneath the footing to dissipate through compacted soils, rather than through the weaker existing soils. 9 HEMPHILL FIGURE 8 LATE.. PRESSURES AND BEND I NG: M•NTS.; ON. FOUNDATION. WALLS ' D E S C R I P T I O N of P R O J E C T PiOJEcT NAME s MCNAMARA CONDOMINIUMS PNOJEcT NUMBER s 6290 LOCATION OF SECTION s FOUNDATION WALLS D E S C R I P T I O N ot S L I D I N G W E D G E A. SHAPE OP WEDGE SLOvE.1 ANGLE of SLOPE - 90 DEG HEIGHT of SLOPE - 14 FT SLOPE 2 ANGLE of SLOPE 0 DEG HEIGHT ot SLOPE 0 PT B. NO SURCHARGE LuADS on WEDGE C. SOIL PARAMETERS UNIT WEIGHT COHESION INTERNAL FRICTION 120 PCP A 9 PSI' 25 DEG HEIGHT TOTAL INCxEMENTAL MOMENT OF LATERAL LATERAL OF SLOPE 1 FORCE FORCE OVERTURN . (ft) (lbs) (LOS) (ft lbs) 0.00 0 1.00 16 16 5 2..0 64 10 41 3.00 144 80 139 4.00 256 112 334 5..0 100 111 657 6.00 576 176 1,140 7.00 785 208 1,816 8.00 1,025 240 2,715 9.01 1,297 272 3,810 10..0 1,601 394 5,314 11..0 1,9.17 336 7,078 12.00 2,306 368 9,194 13.00 2,706 400 11,694 14.00 3,138 432 11,611 SETTLEMENT,; "` Settleme t of footings placed on disturbed soils should be minimal, and will be dependent on workmanship during the preparation of subgrades and placement of concrete for footings. - Settlement of footings placed in structural fill will vary in accordance with the type and thickness of soil placed beneath the footing. Any differential settlement should be 1 inch or less if placed in accordance with the recommendations in this report, and using soils approved by HEMPHILL. .E -5 FOUNDATION WALLS E -5A LATERAL DRIVING PRESSURES AGAINST FOUNDATION WALLS The lateral pressures of soils against the exterior foundation walls will vary with the soil type and condition, the degree of compaction, and the rigidity of the wall. 1. FOUNDATION WALLS SUPPORTING STRUCTURAL FILL HEMPHILL recommends that the soils be well compacted by hand within a 45 degree angle from the base of the wall. Figure 8 shows the anticipated lateral pressures and bending moments that can be developed for each foot of depth for a 14 ,foot- high . backf illed foundation wall. The lateral pressures are for the worst permissible backfill soils that presently exist at the site, and assume no surcharge loads, and no hydrostatic pressures. The backfill soils, drainage materials and filters, and compaction procedures should be approved by HEMPHILL. 2. FOUNDATION WALLS SUPPORTING UNDISTURBED SOILS When foundations walls are adjacent to excavations into the existing undisturbed soils, lateral pressures could be minimal. If the soils are fine grained and hold water by capillary tension, lateral pressures can be as low as 10 pcf equivalent fluid pressure. Such conditions cannot* be anticipated prior to excavating for each foundation wall, and should be approved by HEMPHILL at that time. Any additional surcharge loads should be added to the "at -rest" pressures. 10 HEMPHILL DRAINAGE BEHIND FOUNDAT# WALLS Any drainage materials placed behind foundation walls should be properly filtered to prevent any fine grained soils from eroding into the drainage system. The required filter soils should be determined by HEMPHILL after the undisturbed soils have been exposed, or the backfill soils have been chosen. E -5B LATERAL RESISTING PRESSURES AGAINST FOUNDATION WALLS 1. PASSIVE SOIL RESISTANCE to SLIDING The lateral passive resistance to kick -out exterted by the soils adjacent to the sides of the footings and foundaton walls will vary according to the condition of the undisturbed soils and workmanship. The- lateral-'pressures for the worst conditions will -be approximately equal to an equivalent fluid pressure of 300 pcf. The lateral movement required to mobilize the full value of passive resistance could be damaging to the structure. 2. FRICTIONAL RESISTANCE to SLIDING Frictional forces resisting sliding under the footings will be approximately 0.3° x - -the vertical loads. E -6 RETAINING WALLS (ROCKERIES) The three ways that a rockery can fail are by sliding one rock over the top of the other, by overturning the entire rockery above any section, or by sliding the entire rockery on the soils below. E -6A SLIDING BETWEEN ROCKS The lateral pressures behind the rockery are resisted by the friction forces between the rocks. The friction forces are determined by the weight of rock above. The greater the weight of rock above an intersection between 2 rocks, the greater the friction force that will resist sliding. The resistance to sliding can be increased dramatically by tipping the rockery back so that the upper rock must slide uphill on the lower rock. HEMPHILL FIGURE 9 ROCKERY FILTER SYSTEM - .40 ;4)94 AO .4410 STRUCTURAL F ILL �10��'y'' • oe;�1� -1��I _ .7:41016101104 . _ h (10A-11revt.-- . _ — . .UNDISTURBED SOILS MIN. THICKNESS 6" • The values of friction are fairly consistent, and generally are not dependent on the area of contact between the two rocks, unless the area of contact becomes so small that the total weight of rock above causes the point of contact to pulverize, which then lowers the frictional resistance to sliding. Each rock should be placed so that there is a large area of contact between rocks. E -6B OVERTURNING BETWEEN ROCKS Overturning can occur at any intersection between two rocks. The upper portion of the rockery will rotate at the outermost point of contact. If the outermost point of contact is at the outer edge of the upper rock, then the rocks above have the greatest' resistance to overturning. If the outermost point of contact is somewhere inside the outer edge of the upper rock, then the resistance to overturning will be decreased in direct proportion to the distance from the backside of the rockery to the point of contact related to the distance from the backside of the rockery to the front point of the rockery. When the minimum allowable thickness of rockery at a section is required to resist sliding, then the pivot point of the rockery can be behind the outer edge and still be within the required safety factor. If the required minimum thickness of rockery is to prevent overturning, then a rock should be placed that is in contact at or near the outer edge, or a thicker rock should be placed. E -6C SLIDING BETWEEN ROCK and SOIL: 1. PASSIVE RESISTANCE to SLIDING The soils that will resist the movement of the rockery wall are composed of silty sands. Those types of soils can become stronger with depth if the silt content is small. A conservative value of 300. pcf equivalent fluid pressure was used to calculate the resistance to sliding at the base of the rockery resulting from the weight of the soil in front of the rockery. 2. FRICTION RESISTANCE to SLIDING Also resisting the sliding of the rockery will be he friction forces between the bottom rock and the natural undisturbed soils, which would be approximately 0.4 x the value of the perpendicular, or normal, load. 12 HEMPHILL FIGURE 10A FIGURE 10B D E S C R I P T I ON of S L I D I N G W E D G E REQUIRED WALL THICKNESS for VARYING SAFETY FACTORS (SLOPE of WALL - 25 DEGREES) A. SHAPE OF WEDGE SAFETY FACTOR 1.8 1.5 2.8 2.5 3.8 3.5 SLOPE 1 WALL ANGLE - 65 DEG HEIGHT OVTn SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID SLOPEHEIGHT - 18 DE -_-- ---_ °_- ---- ---- ---- ---- - --- -___ ____ ____ ____ SLOPE 2 18.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 ANGLE - 6 DEG 9.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 5 SLOPE HEIGHT - 8 FT 8.0 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 8. NO SURCHARGE LOADS ON WEDGE 7.8 1. 1.3 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 C. SOIL PARAMETERS 6.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.7 UNIT WEIGHT - 120 PCP COHESION - 8 PSF 5.8 1.) 1.3 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.8 1.5 2.1 INTERNAL FRICTION - 25 DEG 4.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.7 1.5 2.1 1.5 2.5 D E S C R I P T I O N of ROCKERY 3.0 1.s 1.) 1.5 1.5 1.5 1.6 1.5 2.0 1.5 2.S 1.6 2.9 A. ROCKERY DESIGN PARAMETERS 2.0 1.5 1.5 1.5 1.5 1.5 1.8 1.5 2.3 1.6 2.0 1.9 3.3 VERTICAL HEIGHT of ROCKERY - 10 FT MINIMUM THICKNESS AT TOP - 1.5 IT 1.8 1.5 1.5 1.5 1.5 1.5 2.8 1.5 2.6 1.9 3.2 2.2 3.8 SLOPE ALONG BACK of ROCKERY - 25 DEG DENSITY of ROCK - 165 PCP • 1.s 1.5 1.5 1.6 1.5 2.2 1.8 2.9 2.2 3.5 2.6 4.2 % MAXIMUM ALLOWABLE VOIDS - 28 FRICTION FACTOR for ROCK on ROCK - 0.55 -1.8 1.5 1.5 1.S 1.8 1.6 2.5 2.1 3.2 2.5 3.9 2.9 4.6 FR ACTION FACTOR for ROCK on SOIL - 0.48 FRICTION FACTOR for SOIL on ROCK - 8.38 PASSIVE SOIL RESISTANCE - 388 PCP DEP 1.0 1.8 1.8 1.0 1.8 1.8 DESIGN SAFETY FACTOR - 2.00 SAFETY FACTOR MINIMAL INSPECTION - 2.58 DEPF .4 .3 •.- -.3 -.6 -.9 SAFETY FACTOR CONSTANT CONTROL - 1.88 HR 12.1 12.1 12.1 12.1 12.1 12 B. CALCULATION VARIABLES HDPT 5.1 5.4 6.0 6.6 7.3 INCKEMENTAL HEIGHT of ROCKERY - 1.0 FT VOLR 18 28 24 28 33 37 MAXIMUM FAILURE PLANE ANGLE Is CALCULATED for EACH INCREMENT of HEIGHT of ROCKERY BPRSH 3885 469 2539 3567 3984 4164 BPRST 6559 3712 191 -1122 -1720 -2025 NOTE: 25 DEGREES IS THE RECOMMENDED ANGLE OF TILT E -6D Q•ITY AND SHAPE OF ROCKS • NO GOOD! NO E -6E GOOD! GOOD! E -6F E -6G To prevent deterioration from weathering, only top quality rocks should be used. The rocks should be hard, sound, and durable, and should be free from seams, cracks, and other defects tending to destroy resistance to weathering. The rocks should have a density of at least 165 pcf. PLACEMENT OF ROCKS Rocks should have fairly flat tops and bottoms to allow for adequate contact to resist overturning, and to allow for a relatively tight wall. Rocks should be placed so that the vertical seam between 2 adjacent rocks is not above or below the vertical seam for the upper and lower layers. In other words, as much as possible, each rock should overlap at least two different rocks below. Rock shapes should be chosen and placed so that no more than 20% of the wall face is voids. A lower percentage of solid rock reduces the required weight of rock needed to resist overturning and sliding. FILTER SYSTEM A properly constructed filter system behind the retaining wall is imperative to prevent the loss of structual fill behind the rockery resulting from seepage erosion from infiltrated .rainfall or runoff. As shown in Figure 9 the first layer of the filter system behind the rockery should be composed of crushed rock or other granular material that is well graded from the approximate size of the void spaces of the rockery to a coarse sand. Any further filter requirements will depend on the type of structural fill, and should be determined by HEMPHILL. ROCKERY DESIGN OPTIONS The design of a rockery is based on numerous variables, such as the lateral pressures induced by the structural fill and surcharge loads behind the rockery, the soils resisting sliding in front of the rockery. the allowable percentage of void spaces, the density of the rock, and the friction factors for both rock and soil. Those values have already been established for design purposes. 13 HEMPHILL FIGURE 10c REQUIRED WALL THICKNESS for VARYING ANGLES of TILT (assuming constant location for top of wall) SLOPE of WALL DEGREES 8 5 18 15 29 25 39 35 48 45 WALL HEIGHT OV•rr SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID OVTN SLID 18.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 9.1 1.3 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 8.1 1.5 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 7.8 1.3 2.6 1.5 2.8 1.5 1.6 1.5 1.5 1.5 1.5 1.5 *1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 6.8 1.5 3.5 1.5 2.7 1.5 2.1 1.5 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 5.8 1.o 4.4 1.6 3.4 1.5 2.6 1.5 2.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 4.8 2.2 5.3 1.9 4.1 1.6 3.1 1.5 2.4 1.5 1.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 3.8 2.b 6.2 2.3 4.7 1.9 3.6 1.6 2.n 1.5 2.1 1.5 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 2.8 3.0 7.1 2.6 5.4 2.3 4.2 1.9 3.2 1.5 2.4 1.5 1.8 1.5 1.5 1.5 1.5 1.5 11.3 1.5 1.5 1.8 3.4 7.9 3.8 6.1 2.6 4.7 2.2 3.6 1.7 2.7 1.5 2.8 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 3.8 8.8 3.4 6.8 2.9 5.2 2.5 4.8 1.9 3.8 1.5 2.2 1.5 1.6 1.5 1.5 1.5 1.5 1.5 1.5 -1.8 4.2 9.7 3.8 7.4 3.3 5.7 2.8 4.4 2.2 3.4 1.6 2.5 1.5 1.7 1.5 1.5 1.5 1.5 1.5 1.5 -2.8 4.7 18.6 4.1 8.1 3.3 5.7 2.b 4.4 2.2 3.4 1.6 2.5 1.5 1.7 1.5 1.5 1.5 1.5 1.5 1.5 -3.8 5.1 11.5 4.1 8.1 3.3 5.7 2.8 4.4 2.2 3.4 1.6 2.5 1.5 1.7 1.5 1.5 1.5 1.5 1.5 1.5 DEP 3.0 2.8 1.9 1.0 1.8 1.8 1.8 1.8 1.8 1.8 Uri. 3.8 1.3 -.1 -.1 .- .1 .1 -.1 HR 13.0 12.0 11.2 11.4 11.7 12.1 12.7 13.4 14.4 15.6 HDPT 10.0 7.6 6.1 5.8 5.7 6.9 6.6 7.7 9.2 11.8 VOLR 84 58 48 34 28 24 21 28 22 23 BPRSB 4243 3989 3711 3620 3318 2539 618 26 1334 2688 BPRST -2382 -2867 -1781 -1584 -948 191 2650 3513 2145 676 NOTE: 25 DEGREES IS THE RECOMMENDED ANGLE OF TILT 0 r values that have an fect on the required th ckness of the rockery arWthe angle of slope of the rockery. and the factor of safety. The-safety factor is an indication of the amount of over - design to prevent a failure. Generally. the more that is known about the materials and the better their placement is controlled, the lower the safety factor. HEMPHILL has determined that if a high level of inspection is conducted to control the placement of the structural fill and the rockery, then a safety factor of 1.8 could be employed. If minimal inspec- tion is conducted, then a safety factor of 2.5 should be employed. HEMPHILL recommends a safety factor of 2 be employed, and that some inspection of the rockeries be conducted. Once the degree of inspection to be conducted has been determined by the owner based on the relative costs, then the thickness requirements for the rockery at each depth is shown in Figures 10 a, b, and c for any slope of wall chosen by the owner.. Each design of wall has the same safety factors against overturning and sliding. E -7 DRAINAGE E -7A SITE DRAINAGE HEMPHILL recommends that an interceptor drain be placed near the west property line on the top of the site to intercept any water seeping onto the site from adjacent properties. The excavating process for the site might expose the surface that supports the groundwater and other drainage methods might be desireable. If any interceptor ditch is placed, the size of pipe should be determined by the quantity of water either observed or anticipated. It is important that the drainage ditch be backfilled with a proper gradation of soils that will permit the expected quantity of water to flow to the drainage pipe, but will prevent the natural soils from seeping into the drainage system. The filter requirements should be determined by HEMPHILL after the soils have been exposed. 14 HEMPHILL • FIGURE 11 PROTECTION OF FLOOR SLAB FROM CAPILLARY WATER CONCRETE FLOOR SLAB PLASTIC CAPILLARY GRAVEL FILTER-____ SAND SILT or CLAY ▪ • A. • • •t • • �: .:0 �! rift ;�i iiiii *`i i i ...04.04 0. :6•••••: j:1 ••∎ �•�ii E -7B •INAGE for FOUNDATION WALIL Any drainage requirements for foundation walls should be determined after the soils have been exposed during the excavating. The required height of drainage material and the composition of the material, should be determined by HEMPHILL after the soil and water conditions have been exposed. E -7C DRAINAGE for PAVING Any drainage soils placed beneath the paving should be properly filtered to prevent the existing fine grain soils from seeping into the drainage system. Any coarse soils placed beneath paving as a subgrade should be underlain by, a proper filter soil to prevent the coarse soils from punching into the existing fine grain soils. E -8 FLOOR SLABS Floor slabs can!be placed directly on any granular material, provided that the percentage of fines is low. Silty soils are capable of raising water from the groundwater table by capillary action. As shown in Figure 11, any floor slabs placed directly on silt soils where dampness could be undesireable, should be underlain by a 4 inch thick capillary break composed of gravel approximately 1/4 inch in size. The gravel should be underlain by a 2 inch layer of fine to coarse sand to prevent the gravel from punching into the finer underlying soils. The gravel should then be overlain by a plastic material to prevent the wet concrete from seeping into the gravel and clogging the pore spaces. The plastic material will also act as a vapor barrier against the forming of condensation on the underside of the concrete due to differential temperatures. E -9 PAVING For minor parking lots and access roads in the Seattle area, the usually accepted asphalt surface, base course, and subbase have limitations that are generally tolerated based on economic requirements. 15 HEMPHILL A 'per vent' asphalt surface would require design and constrilkion procedures similar the requirements for highway paving. Those procedures Muire that the existing site soils be investigated and tested for the soil modulous, which determines the amount of deflection that occurs for given loadings. If a structural fill is placed to achieve the required grade, then the soil modulous of that soil must be determined by either laboratory or field testing of the structural fill in its specified compacted condition. A base course and asphalt topping are then designed to distribute the anticipated concentrated wheel loads to the underlying soils in a manner to limit the amount of deflection to the specified amount and to prevent shear failures within the underlying soils. A critical factor to be considered in the design of the base course is the depth of freezing to be anticipated. Generally the cost of the engineering, the testing, and the materials required for a permanent asphalt surface is considered to be excessive. Owners and architects usually consider that repair and replacement is more feasible than the costs for the overdesign required to cover all possible modes of failure. The generally accepted practice is to place a standard thickness of asphalt and base course over the underlying soils that are compacted to 90 or 95% of the Modified Proctor maximum density. Such asphalt surfaces sometimes crack and rut because of shear failures in the subgrade soils. after they have softened from freezing and thawing conditions, or from unusually heavy concentrated loads. The failures will occur because the asphalt and base course cannot dissipate the heavy loads to the allowable strength of the underlying soils. THE OWNER SHOULD BE MADE AWARE OF THE LIMITATIONS OF THE ASPHALT PARKING SURFACE, AND SHOULD LIMIT THE ALLOWABLE VEHICLE LOADS. AND SHOULD LOWER THE ALLOWABLE LOADS DURING PERIODS OF THAWING. If drainage is not installed, or if water is to be acceptable in the upper load supporting soils, then free draining soils must be placed as structural fill. If the soils are too fine grained, then water trapped in the pore spaces cannot escape as the soils are compressed under a wheel load, and the load will be temporarily supported by the pore water. Since the water has no strength, a displacement failure will occur where the load punches into the soil. and adjacent soils heave around the load. 16 HEMPHILL • • - E -9A •L -DEPTH ASPHALT PAVING • Because a large portion of the site is covered with silty soils, HEMPHILL recommends that a full depth asphalt pavement be placed directly on any areas with less than 2 feet of structural fill over the existing site soils. The advantages of full depth asphalt without a gravel base course are: a. Water will not collect under the pavement. b. The pavement will be strong enough to distribute traffic loads where any softening of the soils occurs from thawing conditions. c. There is no gravel to punch into the underlying fine grained, softer soils. d. The thicker asphalt can bridge larger soft spots. e. The thicker asphalt can withstand greater differential settlement. Prior to placement of any full -depth asphalt, the areas to be paved should be proof - rolled to tighten up any loose soils. E -9A1 FULL -DEPTH ASPHALT PAVING FOR TRUCK PARKING Where heavy trucks will be parked during loading and unloading procedures, the pavement should include a 1.5 inch asphalt concrete surface, and a 5.5 inch asphalt concrete base, for a total thickness of 7 inches. E -9A2 FULL -DEPTH ASPHALT PAVING FOR CAR PARKING In areas where only passenger cars will be parked, a pavement with a total thickness of 4 inches will be satisfactory, including a 1 inch asphalt concrete surface and a 3 inch asphalt concrete base. E -9B PAVING FOR PARKING AREAS WITH MORE THAN 2 FEET OF STRUCTURAL FILL If more than 2 feet of select structural fill is placed directly over the existing site soils, an alternate asphalt paving could be: (A filter soil might be required to separate the crushed rock from the structural fill) 17 HEMPHILL • ., E -9B1 PAVING for TRUCK PARA on STRUCTURAL FILL In areas where heavy trucks will be parked, a 4.5 inch thick asphalt surface should be placed over a 4 inch crushed rock base. E -9B2 PAVING FOR CAR PARKING on STRUCTURAL FILL In areas where passenger cars will be parked, a 3 inch thick asphalt surface should be placed over a minimum 3 inch thick crushed rock base. .E -9C ALTERNATE ASPHALT PAVING An alternate asphalt paving for parking areas over natural soils includes a crushed rock base overlain by a thinner asphalt surface. A filter soil might be required to separate the crushed rock from the fine - grained natural soils. E -9C1 FOR HEAVY TRUCKS In areas where heavy trucks will be parked, a 4.5 inch thick asphalt surface should be placed over a 6 inch crushed rock base. E -9C1 FOR PASSENGER CARS In areas where passenger cars will be parked, a 3 inch thick asphalt surface should be placed over a minimum 4 inch thick crushed rock base. E -9D .ROADWAY PAVING Any roadway paving placed on the original undisturbed site soils can be designed based on a CBR value of 40 or a subgrade modulous of 300 pci. Roadway paving placed on structural fill compacted to 95% of the Modified Proctor maximum densiy can be designed based on a CBR value of 30 or a subgrade modulous of 250 pci. 18 HEMPHILL E -10 •RECOMMENDED DESIGN PROCEDURES HEMPHILL should review those portions of the final plans and specifications which pertain to earthwork and foundations to determine that they . are consistent with our recommendations, that our recommendations have been correctly interpreted, and that we have not misinterpreted preliminary construction plans, or .omitted some recommendations due to design changes, or because of our incomplete knowledge of the project because of the preliminary nature of the project at the time of our involvement. E -11 RECOMMENDED CONSTRUCTION PROCEDURES 1. HEMPHILL should inspect the soils that are exposed during excavating to verify that the the allowable bearing soils have been encountered and that there are no unexpected conditions that would require changes in the foundation design. 2. HEMPHILL should inspect any footing excavations located on or adjacent to slopes to determine that the footings will be placed at the required depth into the undisturbed soils to achieve stability. 3. HEMPHILL should inspect, and if necessary conduct tests, to determine that any fill is composed of the proper soils, and that the required density has been achieved by the compaction process. 4. HEMPHILL should inspect the excavations to verify any suspected groundwater conditions, or to determine any unexpected conditions that will require design changes. 5. HEMPHILL should determine that any drain pipes are placed at the proper locations, and within the proper soils, and that any backfill has the required Permeability, and that properly designed and installed filter systems will protect against subsurface soil erosion and clogging of drainage. 19 . HEMPHILL REGISTERED ENGINEER NO. 14777 STATE of. WASHINGTON HEMPHILL