HomeMy WebLinkAboutTIC 2020-09-21 Item 2C - Discussion - 42nd Avenue South Bridge In-Depth Inspection Results
INFORMATIONAL MEMORANDUM
TO: Transportation and Infrastructure Committee
FROM: Hari Ponnekanti, Interim Public Works Director
BY: Adam Cox, Transportation Project Manager
CC: Mayor Allan Ekberg
DATE: September 18, 2020
SUBJECT: 42nd Avenue South Bridge In-Depth Inspection
Project No. 91810404
Bridge Results
ISSUE
Provide results from the in-depth inspection of the 42nd Avenue South Bridge. The Committee
received a status report in August 2020 on the bridge closure that was necessary for the inspection
to be safely completed and the feedback the City received during and after the closure.
BACKGROUND
Currently, the 42nd Ave S Bridge has a sufficiency rating of 7.56 out of 100, per King County Road
Division’s inspection. Sufficiency ratings are calculated by a formula implemented by the Federal
Highway Administration to inventory the nation’s infrastructure, and to determine allocation of
federal funds for bridge replacement. Some of the considerations in establishing a bridge’s rating
include:
• Structural Adequacy
• Serviceability and Functional Obsolescence
• Special Reductions
In December 2019, the full Council supported staff’s recommendation to perform additional analysis
beyond the routine scope of inspection that King County normally performs on the City’s bridges.
The City contracted with TranTech Engineering for a more in-depth structural inspection in the
amount of $39,884.00. This in-depth inspection provides a better understanding of how the bridge
steel is performing internally. During the inspection, the 42nd Ave S Bridge was closed to all
vehicular traffic to allow the inspectors to safely maneuver on the bridge. The inspection was
delayed due to the Seattle Department of Transportation (SDOT) restricting the use of the Under-
Bridge Inspection Truck (UBIT) due to the West Seattle Bridge closure and COVID-19 measures.
The UBIT inspection was conducted on July 22 and 23, 2020, allowing inspectors access to the
steel members under the 42nd Ave S Bridge. The inspectors then used a boom lift on July 24 to
access the connection points at the top of the bridge.
ANALYSIS
The 42nd Ave S Bridge has areas of section loss and corrosion (i.e. an element has lost area from
its original design/constructed area, affecting its engineering properties) that had been painted over
in the last painting of the bridge. This analysis shows that the corrosion is particularly true along the
lower chord and gusset plates. In some areas, the corrosion is becoming active again with minimal
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42nd Ave South Bridge In-depth Inspection
September 18, 2020
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Ave Inspection Results_2020-09-21.docx
section loss at the panel points. Most diagonal members that are in compression have rust along
seams where two of the steel beams have been secured together with rivets. The corrosion along
the seam is causing the rivet heads to deflect along the diagonal members. Additionally, there is
seam rust along most vertical steel members and along sway bracing with areas of rust with
minimal section loss. Several sway bracing members have high load impact damage due to
oversized trucks striking the overhead members, which have caused upward deflection in flange
angles. The observed section loss and deflection in the steel members are within design standards
given the age of the bridge but should continue to be monitored to observe if the corrosion or
section loss is expanding or becoming an issue.
According to the attached TranTech report, the results of in-depth inspection and the subsequent
analysis showcase that the deficiencies observed/measured do not require further weight
restrictions for the 42nd Ave S Bridge. It is of the opinion of the Professional Engineer who
performed the analysis, that if the truck traffic continues to abide by the posted weight, speed, and
occupancy restrictions, the deterioration of the bridge will be minimal. However, in the event of a
catastrophic event (e.g., earthquake, flood, or major impact damage), the bridge is highly
susceptible to damage that could require a full shutdown and further analysis.
The results from the inspection and analysis also confirm that the 42nd Ave S Bridge is approaching
the end of its service life. Without replacement or major maintenance repairs, it will require more
and more restrictions for its continued safe use in the coming years. Maintenance projects have
been studied from the past and it has been determined that the cost of repairing the bridge would
exceed the replacement cost and a full replacement of the bridge would still need to occur.
NEXT STEPS
The 42nd Ave S Bridge will continue to receive interim inspections to monitor its concrete piers and
will continue to receive annual inspections and biennial fracture critical inspections performed by
King County. Public Works staff will continue with the bridge replacement design and explore
multiple funding sources to replace the structure. Following receipt of the in-depth inspection, staff
continues to believe that this is an important project to pursue diligently.
As early as 2016, the City recognized the issues with this important bridge, the magnitude of
required rehabilitation, and the scope of a potential replacement project. Projects of this scale
historically take years and sometimes decades to develop and fund. As such, the City has been
correctly prudent to start the work on the 42nd Ave S Bridge before the end of the bridge’s designed
service life.
Attachments: Bridge Memo Report
Bridge Inspection Pictures
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TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
42nd AVE S BRIDGE INSPECTION EXECUTIVE SUMMARY
Date: September 9, 2020
To: City of Tukwila
From: Kash Nikzad, PhD, P.E.
Re: 42nd Ave S Bridge Inspection Executive Summary
TranTech Engineering (TranTech) and Fickett Structural Solutions (Fickett) teamed up to provide an in-
depth fracture critical inspection of the 42nd Avenue South Bridge under City of Tukwila (Tukwila)
Contract Number 20-030. The field inspection was performed by Fickett on July 22-24, 2020. The
inspection details are presented in Appendix A and have been used to form an opinion of the ability of
the existing truss to continue to safely serve with continued proper management and monitoring.
Background
The 42nd Avenue South Bridge is a 3-span 280-foot-long bridge built in 1949. The bridge is composed
of a 220-foot-long fracture critical steel thru-truss main span with 30-foot-long concrete T-beam
approach spans at each end. A critical feature of the bridge is it’s extreme 38° skew, a design aspect that
has contributed to its current condition rating. The existing bridge has a sufficiency rating of 7.53 and is
both Structurally Deficient and Functionally Obsolete.
The Sufficiency rating (SR) is a method of evaluating highway bridge data by calculating four separate
factors to obtain a numeric value which is indicative of bridge sufficiency to remain in service. The
result of this method is a percentage in which 100 percent would represent an entirely sufficient bridge
and zero percent would represent an entirely insufficient or deficient bridge. The four factors are:
1. Structural Adequacy and Safety
2. Serviceability and Functional Obsolescence
3. Essentiality for Public Use
4. Other Special Reductions for bridges where the first three factors sum to less than a score of 50.
The SR is not a direct indication of the service life remaining but is an evaluation of the condition of the
bridge, how it fits the route it serves, and what kind of demand route puts on the bridge. Historically, the
SR has been used as a funding eligibility measurement and ranking tool. In addition, structural
deficiency has been given priority over functionality and risk-based deficiencies in funding decisions.
As long as the bridge is managed properly, it can be safely used. This management of the structure
usually means a reduction in service to the travelling public. As a result, the 42nd Avenue Truss has been
load-restricted to limit additional damage from the high volume of trucks crossing the bridge each day.
The current SR is a combination of its functional problems, how important it is to the traveling public,
and its deteriorating condition.
Analysis shows that the 42nd Avenue Truss is at risk during a seismic event, but in order to seek funding
from the Local Agency Bridge Program, Tukwila must show condition issues. This has been done
through analysis and inspection. While the bridge’s condition does not indicate imminent collapse, it
does point to the risk of collapse during a major seismic event and/or the continued accumulation of
fatigue stresses in the fracture critical bridge which at some point may result in a fracture collapse. A
fracture critical bridge is constructed of steel and has only two major load carrying components. In the
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TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
case of the 42nd Ave S Bridge, these primary load carrying components are the two longitudinal steel
trusses.
In-depth Inspection
To further ensure the safety of the load-posted 42nd Ave S Bridge, Tukwila requested that TranTech
provide an in-depth inspection to ensure its continued safe use. The attached inspection report tabulates
and locates the condition of each main span truss element. Below is a summary of the in-depth
inspection results provided by the bridge inspectors from Fickett Structural Solutions:
The structure has areas of painted over section loss in localized areas along the lower chord and gusset
plates. In some areas, the corrosion is becoming active again with minimal section loss at panel points.
There are large amounts of debris and guano in most lower panel points and some upper panel points.
Most diagonal compression members have pack rust along seams between rivet heads causing up to
1/8” deflection along the member. There is seam rust along most vertical members and along sway
bracing with areas of pack rust up to 1/4” and 1/16” section loss. Several sway bracing members have
high load impact damage which have caused upward deflection in flange angles. The paint system has
widespread areas of peeling paint with surface corrosion present.
Concluding Remarks
Based on this in-depth inspection, it is TranTech’s opinion that the bridge can safely continue to serve at
a restricted level barring a large-scale seismic event. This continued use must be monitored by more
frequent inspections and adjusted as necessary while the process of funding and designing the
replacement bridge continues.
These results also confirm that the bridge is approaching the end of its service life. Without replacement
or major maintenance repairs, it will require more and more restrictions for its continued safe use in the
coming years. Maintenance projects have been investigated in the past and it has been determined that
the cost of repairing the bridge would not be justified as compared to the replacement cost. Especially
the cost to strengthen an old fracture critical bridge to allow unrestricted legal loads.
TranTech concurs with Tukwila’s timely decision to begin the development of a replacement project. As
early as 2016, the City recognized the issues with this important bridge, the magnitude of required
rehabilitation, and the scope of a potential replacement project. Projects of this scale historically takes
years and sometimes decades to fund /develop and was correctly started well before the end of the
bridge’s designed service life.
Should you have any questions, please call me at 425.453.5545 or email me at
knikzad@trantecheng.com
Best regards,
Kash Nikzad, PhD, PE
Project Manager
TranTech Engineering, LLC
Attachments: Appendix A – In-depth Inspection Tabulated Results
Appendix B - Select Inspection Photos
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APPENDIX A |In-depth Inspection Tabulated Results
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Bridge # 0810970042nd Ave South Bridge, Span 2Owner: City of TukwilaSUMMARY:Bridge #08109700 is 3 span bridge built in 1949 carrying 42nd Ave South. The main span is a 220 ft. steel riveted through truss built with a 38oskew over the Duwamish River. There is one 32 ft. concrete T-girder approach span on each end. An in-depth inspection of the main span was completed by Fickett Structural Solutions on behalf of TranTech Engineering and the City of Tukwila to determine the extent of section loss throughout the structure. A 62-ft UBIT was used to inspect the lower chords, lower panel points, floor beams, and lower lateral system. A 45-ft. man-lift was used to inspect the upper chords, upper panel points, sway bracing, and upper lateral system. DATE:July 22, 2020-July 24, 2020Agency: Fickett Structural SolutionsLead Inspector Signature:Co-Inspector Signature:Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 1 of 1114
Inspection SummaryCondition Notes:The structure has areas of painted over section loss in localized areas along the lower chord and gusset plates. In some areas, the corrosion is becoming active again with minimal section loss at panel points. There are large amounts of debris and guano in most lower panel points and some upper panel points. Most diagonal compression members have pack rust along seams between rivet heads causing up to 1/8” deflection along the member. There is seam rust along most vertical members and along sway bracing with areas of pack rust up to 1/4” and minimal section loss. Several sway bracing members have high load impact damage which have caused upward deflection in flange angles. The paint system has widespread areas of peeling paint with surface corrosion present. Legend:IB - Inboard side of member OB = Outboard side of member General Notes:Note 1: Pack rust with section loss in gusset plates along seam with member.Note 2: Section loss in gusset plate.Note 3: Section loss in member flangesNote 4: Section loss in member websNote 5: Pack rust between cover platesNote 6: Section loss in tie platesNote 7: Pack rust with section loss in bottom flange along transverse seam with wind plate.Note 8: Section loss to rivet headsNote 9: Surface corrosionNote 10: Debris accumulationNote 11: Pack rust along seam stressing exterior rivet line.Note 12: Peeling paint, exposed steel with surface corrosion.Note 13: Pack rust along top and bottom edges of interior web plate, near full member length w/ 1/4” distortion along the edge bulging out up to1/2” between rivets Note 14: Pack rust between vertical flanges with distortion in wind bracing.Note 15: Seam rust along gusset plate and lower chord outboard web vertical seam.Note 16: Seam rust along top chord cover plates.Note 17: Seam rust along sway brace angle connection to truss. Note 18: Spots of peeling paint with surface corrosion present on exposed steel. No measurable section loss or pack rust.Note 19: Pockets of pack rust along seams between diagonal channels and web plates. North and South webs are deflecting from painted over pack rust. No strained rivets. Note 20: Pack rust along bottom seam of handrail plate and between member angles, IB face of member.Note 21: Some corrosion along member seams.Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 2 of 1115
Span 2 Layout and NomenclaturePrinted: 8/17/202042nd Ave Truss 2020 In-DepthPage 3 of 1116
Bridge: TUKxNx14 42nd Avenue South BridgeStructure ID: 08109700Date Inspected:West TrussEast TrussL0-L1 Bottom ChordL1: Note 1, 1/8" pack rust, no section loss, between wind plate and bottom flange of chord. Note 14.L1: Note 1, 1/8" pack rust along OB vertical seam with gusset plate, no section loss. Note 1, 1/4" pack rust along OB horizontal seam between gusset plate and web and between wind plate and bottom flange of chord, no section loss. Surface corrosion forming along top flange of chord below seam with wind plate, no section loss. L1-L2 Bottom ChordL1: Note 1, 1/8" pack rust, no section loss, between wind plate and bottom. Note 14.L2: Note 14.L2: Note 10.L2-L3 Bottom ChordL2: Note 10. Paint along top flanges of chord and wind plate is bubbling and peeling. Note 14.Along member: Note 13.L3: Note 1, 1/4" pack rust, active, no section loss, between top size of wind plate and bottom flange of lower chord, along full length of OB gusset plate. Note 3, 1/32" OB and IB. Note 14, along bracing.L2: Note 10. L3: Note 4, 1/16" section loss along bottom edge of web plate. Note 13. Note 14.L3-L4 Bottom ChordL3: Note 1, 1/4" pack rust, active, no section loss, between top size of wind plate and bottom flange of lower chord, along full length of OB gusset plate. Note 3, 1/32" OB.Along member: Note 13.L4: Note 10. Note 14, up to 1/2" pack rust.Along member: Note 13. L4: Note 10. Note 14, along wind plate.L4-L5 Bottom ChordL4: Note 1, 1/4" pack rust, no section loss between wind plate and bottom flange. Note 10. Note 14, up to 1/2" pack rust. Short fillet welds between OB gusset plate and member.Along member: Note 13.L5: Note 10. Note 14, up to 1/2" pack rust.L4: Note 10. Note 14, along wind plate.Along member: Note 13.L5: Note 14, along wind plate.L5-L6 Bottom ChordL5: Note 10. Note 14 up to 1/2" pack rust.Along member: Note 13.L6: Note 4, 1/16" section loss to top of wind plate along end 1", IB and OB. Note 10. Note 14, up to 1/2" pack rust along end 4 ft.L5: Note 14, along wind plate.L6: Note 9. Note 10. Note 14, along wind plate.L6-L7 Bottom ChordL6: Note 10. Note 14, up to 1/2" pack rust along end 4 ft.Along member: Note 13, web bracing.L7: Note 1, 1/8" pack rust, no section loss, along horizontal seam between wind plate and OB bottom flange. Note 9, no section loss, along top side of top flange, 3" OB, 6" IB. Note 14, up to 1/2" pack rust along end 4 ft. L6: Note 4, 1/16" section loss to thickness along bottom edge of interior web plates, IB and OB, no section loss. Note 7, no pack rust, 1/16" loss of bottom flange along seam with IB gusset plate. Note 8, 10% section loss, 6 rivets, along bottom flange. Note 9. Note 10. Note 14, along wind plate. No paint on member from last tie plate to end of member.Along member: Note 13, web bracing.L7-L8Bottom ChordL7: Note 1, 1/8" pack rust, no section loss, along horizontal seam between wind plate and OB bottom flange. Note 14, up to 1/2" pack rust, along end 4 ft. Along member: Pack rust along top and bottom edges of interior web plate, near full member length, with 1/4" distortion along edge, bulging out up to 1/2" between rivets. Note 12.Along member: Note 13, web bracing.L8: Note 10. Note 15. Note 14, along wind plate. Note 15.Member7/22/2020-7/24/2020Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 4 of 1117
West TrussEast TrussMemberL8-L9 Bottom ChordL8: Note 8, 10% head loss, 8 rivets, along bottom flange. Note 10. Note 14, 1/2" pack rust along vertical flanges of sway bracing. Note 12.L9: Note 1, 3/8" pack rust, no section loss between wind plate and bottom flange. Note 3, 1/32" pitting type corrosion. Note 9. Note 12.L8: Note 4, 1/16" section loss to thickness along bottom edge of web plate. Note 8, 10% section loss, 8 rivets along bottom flange. Note 10. Note 14, along wind plate.L9: Note 9, along top tie plate surface, no section loss. Note 10. Note 14, along wind plate.L9-L10 Bottom ChordL9: Note 1, 3/8" pack rust, no section loss between wind plate and bottom flange. Note 3, 1/32" pitting type corrosion. Note 12.L9: Note 10. Note 14, along wind plate.U1-U2Upper chord U1: Note 16, 1/8", no section loss. Note 17, along seams with angle connections.U1: Note 16, 1/4", no section loss.U2-U3Upper chord U2: Note 10. Note 16, 1/8", no section loss.Along member: Note 5, 1/8", 3 ft. long.U3: Note 16, 1/8" between bottom wind plate and bottom cover plate.U3-U4Upper chordU3: Note 5, 20 ft. long, 1/4" along bottom flange, 1/16" top flange. Note 12.U4: Note 16, 1/8" top, no section loss, 1/4" bottom, no section loss.Along member: Note 5, along bottom flange, 1/8", 10 ft. longU4-U5Upper chordU4: Note 16, 1/8" top, no section loss, 1/4" bottom, no section loss.U5: Note 12.U4: Note 10. Along member: Note 5, along bottom flange, 1/8", 10 ft. longU5-U6Upper chordU5: Note 12.U6: Note 10. Note 12. Note 16.U6: Note 12. Note 16, 1/8" along top wind plate and top cover plate.U6-U7Upper chord U6: Note 12. Note 16.U6: Note 12. Note 16, 1/8" along top wind plate and top cover plate.U7: Note 12, along top and bottom wind plates.U7-U8Upper chord Along member: Note 5, 1/8" along center 10 ft.U8: Note 12, along top wind plate and top cover plate.U8-U9Upper chord U9: Note 16, 1/16".U9: Note 12, along top wind plate and top cover plate.L0-U1Diagonal No defects observed.Along member: Note 18.L1-U1Vertical Note 20, 1/4" pack rust, with up to 1/32" section loss in each member angle, for 4". Along member: Note 18.L2-U1Diagonal No defects observed.Along member: Note 10, with moss growth along member. Note 18.U1: Note 16.L2-U2Vertical Note 20, 1/4" pack rust, no section loss, for 1".Along member: Note 10, with moss growth along member. Note 18. At 4.5 ft. from deck level, 3 areas of scattered pitting corrosion up to 2" long, along seam between member web plate and IB south angle with up to 5/32" painted over section loss. Paint is starting to peel from active corrosion in areas. L2-U3Diagonal No defects observed.Along member: Note 10, with moss growth along member. Note 18. Note 19, up to 1/16" active pack rust along seams and 1/8" deflection of members. Peeling paint along top web.U3: Note 1, no pack rust, with 1/32" section loss in member web. Tack welds along end of member and IB side web plates along rivet line.L3-U3Vertical No defects observed.Along member: Note 18. L4-U3Diagonal No defects observed.L4: Pitting corrosion with lass than 1/32" section loss for 4 in. along vertical gusset plate seam. Corrosion has been painted over, but is active again with peeling paint. L4-U4Vertical L4: Note 1, seam rust only.L4: Up to 1/32" pitting corrosion, painted over but becoming active, along angle leg at IB gusset plate vertical seam for 6". L4-U5DiagonalAlong member: Note 18, along top member web. Note 19, starting at 6 ft. above deck level. U5: Tack welds along top and IB web, no cracking observed.Along member: Note 19, up to 1/16" active pack rust along seams and 1/8" deflection of members. Peeling paint along top web.U5: Note 1, 1/4" pack rust, 2" long, no section loss. Short tack welds along top and IB web, no cracking observed. Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 5 of 1118
West TrussEast TrussMemberL5-U5Vertical No defects observed.Along member: Active pitting corrosion, along OB face of IB angle, no section loss. Less than 1/32" section loss along 2" seam with original railing. Railing is bolted, not welded.U5: Vertical tack welds along member and gusset plate. No cracking observed.L6-U5DiagonalAlong member: Note 19, up to 1/8" deflection. Note 20, 1/16" pack rust, no section loss, for 4".L6: Note 21.Along member: Note 19, up to 1/16" active pack rust along seams and 1/8" deflection of members. L6-U6Vertical L6: Note 21.L6: Note 1, 1/32" pack rust along top seam with OB gusset plate for 4", no section loss. Pitting corrosion, painted over but becoming active, along vertical seam with IB gusset plate. Paint is cracked, bulging, and peeling. Tack welds along vertical seams between member and gusset plate.L6-U7Diagonal L6: Note 21.L6: Note 1, 1/32" pack rust along OB top seam for 4", no section loss. 1 rivet with surface corrosion. U7: Note 12, especially on tie plates.L7-U7Vertical No defects observed.Along member: Note 18.L8-U7DiagonalAlong member: Note 19, 1/8" deflection on bottom web plate.L8: Seam rust along member near panel point.At L8: Heavy moss growth.Along member: Note 19, up to 1/16" active pack rust along seams and less than 1/8" deflection of members. Peeling paint along top web.L8-U8VerticalAlong member: Note 20, corrosion just beginning, no section loss . L8: Seam rust along member near panel point.L8: Heavy moss growth.L8-U9Diagonal L8: Seam rust along member near panel point. L8: Heavy moss growth.U9: Note 17, up to 1/16".L9-U9VerticalAlong member: Note 20, 1/32" section loss for 1". Scattered seam rust between angles, no section loss, full length.U9: Tack welds present between gusset plate and member.Along member: Note 18.L10-U9Diagonal No defects observed.Along member: 1/32" pitting corrosion with up to 1/32" section loss in bottom plate near IB face at original rail bracket seam. At original rail, along topside of bottom plate and OB face of OB angle seam, peeling paint with surface corrosion and no section loss, 6" long. Bracket is bolted to member.L0Gusset Plate Minor rust bleeding on OB gusset around bearing pin. No section loss. No defects observed.L1Gusset PlateNo defects observed.L2Gusset PlateNote 1, 1/8" pack rust, no section loss, along OB gusset plate and vertical member seam. Note 1, 1/4" pack rust, no section loss, along IB gusset plate edge seams with vertical members. Note 9, peeling paint, no section loss in OB gusset along member seams.No defects observed.L3Gusset PlateNo defects observed.L4Gusset PlateNote 1, 1/8" pack rust, 1/32" loss in OB gusset plate, 1/8" pack rust, no section loss in IB gusset plate. Note 9 OB.4" active corrosion along top seam of gusset plate, OB face, no section loss. Peeling paint.L5Gusset PlateNote 1, 1/4" pack rust between gusset plate and lower chord web and gusset plate and bottom flange, OB and IB. Note 8, heavy surface corrosion with pitting, 1 rivet. Note 15, OB and IB. Note 1, 1/4" pack rust between OB gusset plate and web, no section loss. L6Gusset Plate No defects observed.Note 1, 1/32"pack rust, active, for 4" along top seams of OB gusset plate, no section loss. L7Gusset Plate Note 1, 1/8" pack rust, no section loss, along vertical seams with bottom chord, OB. Note 1, 1/8" pack rust, no section loss, along OB gusset plate top seam with U7-L7. Note 1, 1/8" pack rust, no section loss, along bottom edge of OB gusset plate.L8Gusset Plate No defects observed.No defects observed.Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 6 of 1119
West TrussEast TrussMemberL9Gusset PlateNote 1, up to 1/8" pack rust, no section loss along OB gusset plate edge seams. Note 1, OB gusset plate no pack rust with up to 1/32" section loss along horizontal seam with bottom chord top flange.No defects observed.L10Gusset Plate No defects observed.No defects observed.U1Gusset Plate No defects observed.No defects observed.U2Gusset Plate No defects observed.No defects observed.U3Gusset Plate No defects observed.No defects observed.U4Gusset Plate No defects observed.No defects observed.U5Gusset Plate No defects observed.No defects observed.U6Gusset Plate No defects observed.No defects observed.U7Gusset Plate No defects observed.No defects observed.U8Gusset Plate No defects observed.No defects observed.U9Gusset PlateNote 1, 1/16" pack rust, no section loss between OB gusset plate and L8-U9. Note 1, 3/8" pack rust, no section loss between OB gusset plate and bottom chord web.Note 1, 1/8" between gusset plate and L8-U9.U10Gusset Plate No defects observed.No defects observed.L0W-L0E Floor beam No defects observed.No defects observed.L0W-L1E Floor beam No defects observed.No defects observed.L1W-L2E Floor beam No defects observed.Corrosion along edge of top flange. Full thickness of flange edge affected, no lifting of deck or adjacent deck area distress observed. Monitor for pack rust formation and lifting of deck.L2W-L3E Floor beam No defects observed.No defects observed.L3W-L4E Floor beam No defects observed.No defects observed.L4W-L5E Floor beam No defects observed.No defects observed.L5W-L6E Floor beam No defects observed.No defects observed.L6W-L7E Floor beam No defects observed.No defects observed.L7W-L8E Floor beam No defects observed.Lite surface corrosion along edge of top flange embed between stringer #1 and stringer #2. Stringer #2, south face of floor beam looking west. Typical sharp 90o cope. No cracking observed.L8W-L9E Floor beam No defects observed.No defects observed.L9W-L10E Floor beam No defects observed.No defects observed.L10W-L10E Floor beam No defects observed.No defects observed.South Portal (U1W-U1E)Sway BracingAlong member: Note 1, with up to 1/8" pack rust, active along gusset seams. Up to 1/32" pitting type corrosion active along angle seams and gussets. Note 22, up to 1/4" pack rust, scattered. Along member: Note 1, with up to 1/32" pitting type corrosion, active along gusset seams. South inboard face gusset plate has up to 1/16" pitting corrosion along gusset and horizontal sway brace angle seam. Note 22, up to 1/4" pack rust, scattered. Just east of centerline along lower portal angle, 1 high impact load hit: 7" long impact bowed 1/2" north. Paint is still in tact and no cracks observed. 2 ft. east of lower gusset plate 1 high impact load hit along lower portal angle: 21" long impact bowed 1" north with paint missing along impact area, heavy surface corrosion with no measurable section loss. Inboard face of portal angle is cracked at leg bend, approximately 50% depth, 6" long. No active crack growth observed. U1E: Lower portal connection angle web exhibits corrosion along northern seam, full length, with up to 1/8" pack rust and 1/32" of section loss in pockets near gusset plates and brackets. Paint is bubbling and cracked, scattered along length due to active corrosion underneath.U1W-U2E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. High impact load hit, no cracked or peeling paint.U2W-U3E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. High impact load hit, no cracked or peeling paint. Note 23, up to 1/8" pack rust at all connections. U3E: Note 17, connection to truss. Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 7 of 1120
West TrussEast TrussMemberU3W-U4E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U4W-U5E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U5W-U6E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U6W-U7E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U7W-U8E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U8W-U9E Sway BracingAlong member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. U8W: Note 17, 1/8". Along member: Note 22, up to 1/4" pack rust, scattered. Note 23, up to 1/8" pack rust at all connections. North Portal (U9W-U9E)Sway BracingAlong member: Note 22, up to 1/4" pack rust, full length. U9W: Note 1, up to 1/16" pack rust, no section loss, at all connections.Along member: Note 22, up to 1/4" pack rust, full length.U9E: Note 1, up to 1/16" pack rust, no section loss, at all connections.L0 Movable BearingBearing in expanded position with weather: 61oF and overcast. Rocker is tilted south approx. 7o. Rust bleeding on both inboard and outboard plates indicating possible pin corrosion. No signs of pin movement.Bearing in expanded position with weather: 61oF and overcast. Rocker is tilted south approx. 7o. Rust bleeding on inboard plate indicating possible pin corrosion. No signs of pin movement.L10 Fixed Bearing No defects observed.No defects observed.Lateral systemsGeneral CommentsLead Inspector:Co-Inspector:Alyssa Escobedo, P.E. G2001*Note: Sway bracing nomenclature does not match "Nomenclature FC Plan" Document in WSBIS. See page 2 in this document titled "Nomenclature" for nomenclature used in this in-depth report.Andy Packard, P.E. G0507Top chord lateral bracing horizontal struts and diagonal members have seam rust scattered between bottom flange angle and web plate with cracked and peeling paint, full length. Members have similar seam between top flange angle and web, full length. No section observed in members.Printed: 8/17/202042nd Ave Truss 2020 In-DepthPage 8 of 1121
Photo Number Location Photo Description
Inspector
Initials
3518 L9W
1/32" section loss in OB gusset plate along horizontal seam with top flange of bottom chord, looking
south.ALP
3519 L9W
3/8" pack rust, no section loss between OB gusset plate and bottom chord web seam and between wind
plate and bottom chord bottom flange. ALP
3520 L10E-L9W, L9W General floor beam photo, near panel point. ALP
3521 L9W "Note 12"ALP
3522 L9W General gusset plate photo, looking north.ALP
3523 L8W 10% head loss, 8 rivets along bottom flange of lower chord.ALP
3524 L8W General gusset plate photo, looking south.ALP
3525 L8W 1/2" pack rust between vertical flanges of sway bracing at L8W.ALP
3526 L9E-L8W, L8W South face of floor beam, looking north near panel point. ALP
3530 L8W General gusset plate photo, looking down. Note seam rust along vertical members.ALP
3533 L8E-L7W, L7W North face of floor beam, looking south near panel point. ALP
3534 L7W
1/8" pack rust, no section loss, along horizontal seam between wind plate and bottom chord bottom
flange OB. ALP
3535 L7E-L6W, L6W North face of floor beam, looking south near panel point. ALP
3536 L6W General gusset plate photo, looking north.ALP
3538 L6E-L5W, L5W General floor beam photo, near panel point. ALP
3539 L5W "Note 15"ALP
3540 L6E 1/16" section loss along bottom flange transverse seam with wind plate, looking south.ALP
3541 L6E-L5W, L6E North face of floor beam, looking south near panel point. ALP
3542 L6E General gusset plate, looking south.ALP
3545 L7E General gusset plate photo, looking south.ALP
3546 L8E-L7W, L8E General floor beam photo near panel point.ALP
3547 L8E-L7W, L8E Lite surface corrosion along edge of top flange embed between stringer #1 and stringer #2.ALP
3548 L8E General gusset plate photo, looking south.ALP
3549 L9E-L8W, L9E General floor beam photo, near panel point. ALP
3550 L9E General gusset plate photo, looking south.ALP
3566 L4W Typical of short fillet welds between OB gusset plate and lower chord member.ALP
3567 L5E-L4W, L4W South face of floor beam, looking north near panel point. ALP
3568 L4W General gusset plate photo, looking north.ALP
3571 L3W General gusset plate photo, looking north.ALP
3572 L4E-L3W, L3W North face of floor beam, looking south near panel point. ALP
3573 L4E-L3W, L3W South face of floor beam, looking east near stringer #3. ALP
3578
FB L3E-L2W,
L2W South face of floor beam, looking north near panel point. ALP
3579
FB L2E-L1W,
L1W South face of floor beam, looking north near panel point. ALP
3580 L1W General gusset plate photo, looking north.ALP
3581 L1W General wind plate photo, looking south.ALP
3584 FB L2E-L1W, L2E South face of floor beam near panel point , looking north. ALP
3585 L2E General gusset plate photo, looking south. ALP
3586 L2E General gusset plate, looking south.ALP
3586 FB L3E-L2W, L3E South face of floor beam, looking north near panel point. ALP
3587 L3E General gusset plate, interior, looking north.ALP
3588 L3E General gusset plate photo, looking south.ALP
3589 L4E-L3W, L4E South face of floor beam, looking north near panel point. ALP
3590 L4E General gusset plate photo, looking south.ALP
3591 L4E Typical of debris accumulation and nesting pigeons.ALP
3599 L5E General gusset plate, looking south.ALP
3600 L5E-L4W, L5E North face of floor beam, looking south near panel point. ALP
3605 L6E-L5W, L6E South face of floor beam, looking north near panel point. ALP
3659 U1W General gusset plate photo, looking south.ALP
3662 U2E Top of upper chord, looking south.ALP
3663 U2E General gusset plate, looking south.ALP
3667 U3E 1/32" section loss in gusset plate along seam with L2E-U3E.ALP
3670 U1E-U3E High load impact hit between sway bracing members U1-U3.ALP
3671 U1E General gusset plate, looking south.ALP
3674 U4E Top of upper chord, looking south.ALP
3675 U4E General gusset plate photo, looking south.ALP
3678 U5E General gusset plate photo 3678, looking north.ALP
3681 U4W Top of upper chord, looking north.ALP
3682 U4W General gusset plate photo, looking north.ALP
3685 U3W Top of upper chord, looking south.ALP
3689 U5W Top of upper chord, looking south.ALP
3690 U5W General gusset plate photo, looking south.ALP
3691 U6W General gusset plate photo, looking north.ALP
3692 U6W Top of upper chord, looking north.ALP
Photo Log
Printed: 9 42nd Ave Truss 2020 In-Depth Page 9 of 1122
Photo Number Location Photo Description
Inspector
Initials
3693 U7E General gusset plate photo, looking north.ALP
3694 U7E Top of upper chord, looking north.ALP
3695 U6E Top of upper chord, looking south.ALP
3698 U7W General gusset plate photo, looking south. ALP
3699 U7W Top of upper chord, looking south.ALP
3700 U7W General gusset plate photo, OB, looking south.ALP
3704 U8W Top of upper chord, looking north.ALP
3706 U9E General gusset plate photo, looking north.ALP
3708 U8E General gusset plate photo, looking south.ALP
3709 U8E Top of upper chord, looking south.ALP
3717 U9W Top of upper chord and portal connections, looking north.ALP
3718 U9W General gusset plate photo, looking north.ALP
3722
North Portal U9E-
U9W North portal looking south.ALP
3727
L10E-L10W,
L10W Leaking joint looking from below.ALP
3730 L10W General gusset plate photo, OB, looking south.ALP
3731
L10E-L10W,
L10W South face of floor beam, looking north near panel point. ALP
3750 U9E Top of upper chord, looking north.ALP
3752 Bearing L0W Degree of tilt toward south.ALP
3757 Bearing L0E Degree of tilt toward south.ALP
3759 Bearing L0E Underside of deck, looking north.ALP
3707 U9E General picture of gusset plate exterior face at end portal.ALP
3527-3529 L8W
Pack rust along top edges of interior web plate, near full member length, with 1/4" distortion along
edge, bulging out up to 1/2" between rivets.ALP
3532-3533 L8W
Pack rust along bottom edges of interior web plate, near full member length, with 1/4" distortion along
edge, bulging out up to 1/2" between rivets.ALP
3543-3544 L7E-L6W, L7E North face of floor beam, looking south near panel point. ALP
3551-3552 L8E-L7W, L8E Stringer #2, south face of floor beam looking west. Typical sharp 90
o cope. No cracking observed.ALP
3553-3565
Diag. U7W-L8W,
U7W "Note 13" between top and bottom flange of cover plates, full length. ALP
3564-3577 L3W General gusset plate photo, looking north.ALP
3569-3570 L4W
General gusset plate photo IB, looking south. Note: 1/8" pack rust between gusset plate and member
seams.ALP
3582-3583 FB L2E-L1W, L2E
South face of floor beam, looking north near panel point. Corrosion along edge of top flange. Monitor
for pack rust formation and lifting of deck.ALP
3592-3596 L1E
General gusset plate, looking north. (Up to 1/4" pack rust with no section lack along seam with
member.)ALP
3597-3598 FB L1E-L0W, L1E South face of floor beam near panel point, looking north.ALP
3655-3658 U1W Top of upper chord and portal connections, looking south.ALP
3664-3665 L2E-U3E
Rippling from pack rust along L2-U3 East compression member. Tack welds between top of member at
U3 and IB side web plates of chord along rivet line.ALP
3668-3669 U3E Top of upper chord, looking north.ALP
3672-3673 U1E Top of upper chord, looking south. "Note 16"ALP
3676-3677 U5E Top of upper chord, looking north ALP
3679-3680 U5E Vertical tack welds between member and gusset plate, looking south.ALP
3684-3685 Typical pack rust between cover plate and member.ALP
3686-3688 U3W General gusset plate photo, looking north.ALP
3696-3697 U6E General gusset plate, looking south.ALP
3702-3703
Sway Brace U9E-
U8W, U8W "Note 17" with 1/8" seam rust, looking north.ALP
3710-3717 Sway Braces
General photos of sway bracing conditions includes: U8E-U9W looking northeast, U8E-U7W looking
south, and U9E-U9W (north portal) looking northeast. ALP
3719-3721
North Portal U9E-
U9W North portal looking north. ALP
3728-3729 Bearing L10W General bearing photos.ALP
3760-3765 Span 1 General photos of underside framing, Span 1, looking south.ALP
South Approach 1 -
South Approach 6 Span 2 General Span 2 deck and structure photo, looking north.ADE
L0E 1-L0E 4 L0E General panel point internal, looking down.ADE
L1E 1-L1E 2 L1E General panel point internal, looking down.ADE
L1E 3 L1E General member elevation photo at deck level, looking north.ADE
L1E 4 L1E General member elevation photo at deck level, looking south.ADE
L2E 1-L2E 2 L2E General member elevation photo at deck level, looking north.ADE
L2E 3 L2E General panel point elevation photo at deck level, looking northeast.ADE
L2E 4-L2E 5 L2E General panel point internal, looking down.ADE
L3E 1-L3E 2 L3E General member elevation photo at deck level, looking north. ADE
L3E 3 L3E General member elevation photo at deck level, looking south.ADE
L3E 4-L3E 5 L3E General panel point internal, looking down.ADE
Printed: 10 42nd Ave Truss 2020 In-Depth Page 10 of 1123
Photo Number Location Photo Description
Inspector
Initials
L4E 1-L4E 7 L4E-U5E
Pockets of pack rust along seams between diagonal channels and web plates. North and South webs are
deflecting from painted over pack rust. No strained rivets. ADE
L4E 8-L4E 9 L4E-U5E General member internal photo.ADE
L4E 10-L4E 13 L4E General panel point internal, looking down.ADE
L4E 14-L4E 16 L4E General panel point external at deck level, looking down.ADE
L5E 1 L5E-U5E General member elevation photo at deck level, looking west.ADE
L5E 2 L5E-U5E General member elevation photo at deck level, looking south.ADE
L5E 3-L5E4 L5E-U5E General member elevation photo at deck level, looking north.ADE
L5E 5-L5E 7 L5E General panel point internal, looking down.ADE
L6E 1 L6E General panel point elevation photo at deck level, looking southwest.ADE
L6E 2-L6E 5 L6E General panel point internal, looking down.ADE
L6E 6- L6E 9 L6E-U5E
Pockets of pack rust along seams between diagonal channels and web plates. South web is deflecting
from painted over pack rust. No strained rivets. ADE
L1W 1-L1W4 L1W-U1W
1/4" pack rust along bottom seam of handrail plate and between member angles and IB face of member
with up to 1/32" section loss in each member angle, for 4". ADE
L1W 5 L1W-U1W General member elevation photo, looking south.ADE
L1W 6 L1W General panel point internal, looking down.ADE
L2W 1-L2W 2 L2W-U2W
1/4" pack rust along bottom seam of handrail plate and between member angles and IB face of member
with no section loss, for 1". ADE
L2W 3-L2W 4 L2W General panel point internal, L2W southside, looking down.ADE
L2W 5 L2W General panel point internal, L2W northside, looking down.ADE
L3W 1-L3W 2 L3W General panel point internal, L3W southside, looking down.ADE
L3W 3-L3W 4 L3W General panel point internal, L3W northside, looking down.ADE
L3W 5 L3W-U3W General member elevation photo at deck level, looking west.ADE
L3W 6 L3W-U3W General member elevation photo at deck level, looking northwest.ADE
L4W 1 L4W-U4W General member elevation photo at deck level, looking west.ADE
L4W 2 L4W General panel point elevation photo at deck level, looking west.ADE
L4W 3-5 L4W-U5W
Pockets of pack rust along seams between diagonal channels and web plates. North and South webs are
deflecting from painted over pack rust. No strained rivets. ADE
L4W 6 L4W General panel point internal, L4W northside, looking down.ADE
L4W 7 L4W General panel point internal, L4W southside, looking down.ADE
L8E 1, L8E 5 L8E-U7E
General member elevation photo at deck level, looking east. Note: pockets of pack rust along seams
between diagonal channels and web plates with up to 1/16" active pack rust along seams and less than
1/8" deflection of members.ADE
L8E 2 L8E General panel point elevation photo at deck level, looking northwest.ADE
L8E 3 L8E General panel point elevation photo at deck level, looking southwest.ADE
L8E 4 L8E General panel point internal, looking down.ADE
L10E 1 L10E-U9E General member elevation photo at deck level, looking northwest.ADE
L10E 2 L10E-U9E General member elevation photo at deck level, looking southwest.ADE
L10E 3 L10E-U9E
At original rail, along topside of bottom plate and OB face of OB angle seam, peeling paint with surface
corrosion and no section loss, 6" long. Note: Bracket is bolted to member.ADE
L10E 4 L10E General panel point internal, looking down.ADE
L8W 1 L8W General panel point elevation photo, looking west.ADE
L8W 2 L8W-U8W
Pack rust just beginning along bottom seam of handrail plate and between member angles and IB face of
member, no section loss.ADE
L8W3 - L8W6 L8W-U7W
Pockets of pack rust along seams between diagonal channels and web plates. South web is deflecting
1/8" from painted over pack rust. No strained rivets. ADE
L6W 1 L6W General panel point elevation photo at deck level, looking west.ADE
L6W 2-L6W 7 L6W-U5W
Pockets of pack rust along seams between diagonal channels and web plates. South web is deflecting
1/8". No strained rivets. ADE
L5W 1- L5W 2 L5W-U5W General member elevation at deck level, looking west.ADE
L5W 3-L5W 4 L5W General panel point internal, L5W southside, looking down.ADE
P3 Joint 1-P3 Joint 3, P3
Joint 5 Joint at P3 General joint condition photos.ADE
P3 Joint 4 Joint at P3 D spalling near centerline of joint.ADE
Deck 1 Span 2 Typical deck cracking and abrasion across deck.ADE
Deck 2 Span 2 General deck photo, looking south.ADE
P2 Joint 1-4 Joint at P2 General joint condition photos.ADE
B L0W 1 Bearing L0W General bearing photos, looking east. Note: Rocker is tilted southward approx. 7o ADE
B L0E 1, B L0E 4 Bearing L0E General bearing photos, looking northwest. Note Rocker is tilted southward approx. 7o ADE
B L0E 2-B L0E 3 Bearing L0E General bearing photos, looking northeast.ADE
SP 1-SP 3, SP 6-SP 7, SP
11 UW1-U1E Active pack rust along gusset and angle seams.ADE
SP 4-SP 5 UW1-U1E
21" long impact bowed 1" north with paint missing along impact area, heavy surface corrosion with no
measurable section loss. ADE
SP 8 - SP 10 UW1-U1E
21" long impact bowed 1" north with paint missing along impact area, heavy surface corrosion with no
measurable section loss. Inboard face of portal angle is cracked at leg bend, approximately 50% depth,
6" long. ADE
Printed: 11 42nd Ave Truss 2020 In-Depth Page 11 of 1124
APPENDIX B |Select Inspection Photos
25
TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
Inspection Photo 1 – Deck View Looking South
Inspection Photo 2 – Elevation View Looking North
Bridge Inspection Pictures
26
TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
Inspection Photo 3 – Lower Connections with Horizontal Gussets Retain Moisture and Guano
Inspection Photo 4 – Frozen Truss Bearings Induce Additional Stresses on the Trusses
27
TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
Inspection Photo 5 – Pack Rust is Distorting some Connections
Inspection Photo 6 – Rust and Guano at Truss Bottom Chord
28
TranTech Engineering, LLC
365 – 118th Ave SE, Suite 100, Bellevue, WA 98005
425-453-5545. Fax: 425-453-6779
Inspection Photo 7 – Rust at Top Flange of Fracture Critical Floor Beams
Inspection Photo 8 – Moisture from Deck Penetrating and Corroding Top Flange of Stringers
29