HomeMy WebLinkAboutTrans 2013-11-26 Item 2C - Discussion - Beacon Avenue South Bridge Load Limit SignsTO:
City of Tukwila
Jim Haggerton, Mayor
INFORMATIONAL MEMORANDUM
Mayor Haggerton
Transportation Committee
FROM: Bob Giberson, Public Works Director'
By: Grant Griffin, Senior Program Manager
DATE: November 22, 2013
SUBJECT: 2013 Annual Bridge Inspections and Repairs
Project No. 91310402
Bridge Load Rating Review and Update
Posting Load Limits on Beacon Ave S Bridge
ISSUE
Load Posting the Beacon Ave S Bridge in accordance with the National Bridge Inspection
Standards (NBIS), 23 CFR 650C.
BACKGROUND
Review of the official bridge files for City of Tukwila owned bridges in the summer of 2013
revealed several deficiencies with respect to bridge Toad ratings. As a result, a contract with
Sargent Engineers was executed for a Load Rating Review and Update on July 31, 2013 as
part of the 2013 Annual Bridge Inspections and Repairs Program.
DISCUSSION
Sargent Engineers provided an analysis of several existing bridge load ratings and updated
these documents using current load rating standards. The result of applying these current
standards resulted in a calculated capacity reduction and the need to post load limiting
warning signs on the Beacon Ave S Bridge. The load limit posting for the Beacon Ave S
Bridge will state "One Truck At A Time On Bridge ". It would be uncommon for more than one
truck to be on the bridge at one time as Beacon Ave S is a residential street. This change will
cause the least service impact for bridge users.
FISCAL IMPACT
The new signs for the Beacon Ave S Bridge should cost less than $500.
RECOMMENDATION
Information only.
Attachments: Load Rating Summary Sheet
Sign Choice Email from Sargent Engineers
WSDOT Standard Sign
W:iP W Eng1PROJECTS'A- RW & RS Projects \Bridge Inspection Programs \Bridge Inspections 2013 (91310402y Sargent Load Rating,Info Memo Beacon Ave Posting.docs
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Bridge Name:
Bridge Number: Tuk 11 - 08001800
Span Types:
Bridge Length: 182
Design Load:
Rated By:
Checked By: JSS
Date:
Bridge Rating Summary
Boeing Access Road Bridge (Airport Way)
4 Span RC Girder
H 20
MJS
Sept. 2013
Inspection Report Date
4118/2013
Substructure Condition
6
Rating Method
LFR
Deck Condition
6
Overlay Thickness
3"
Superstructure Condition
6
Truck
Type 3
Type 3S2
Type 3-3
NRL
OL-1
OL-2
RF (INV)
1.08
1.11
1.16
0.00
0.62
0.51
RF (OPR)
1.81
1.85
1.94
0.00
1.03
0.85
Controlling Point
Shear in girder
Shear in girder
Shear in girder
Shear in girder
Shear in girder
Shear in girder
NBI Rating RF Tons Controlling Point
Inventory (HS-20) 0.79 29 Shear in girder
Operating (HS-20) 1.33 48 Shear in girder
Remarks:
This updates the previous rating. Ratings were not performed on NRL vehicles.
8
Trucks
NRL
Single-Unit 4
Single-Unit 5
Single-Unit 6
Single-Unit 7
Bridge Rating Summary
(Single-unit Trucks)
RF (INV) RF (OPR) Controlling Point
0.00 0 If the NRL is less than 1 for operating, the below
trucks shall be evaiu ted
0.00 0.00 Shear in girder
0.00 0.00 Shear in girder
0.00 0.00 Shear in girder
0.00 0.00 Shear in girder
WSBIS Coding Recommendations:
Design Load (WB75-50) 4
Operating Rating:
Type (WB75-51)
Tons (WB75-52)
Inventory Rating:
Type (WB75-54)
Tons (WB75-55)
F
48
F
29
Operating Level (WB76-60) 5
Recommended Posting:
There is no recommended posting at this time.
9
Grant Griffin
From: Monte Smith <montes @sargentengineers.com>
Sent: Tuesday, November 05, 2013 11:14 AM
To: Grant Griffin
Subject: Beacon Avenue Bridge
All elements of the bridge have rating factors above one except for the girders. If we restrict the bridge to one
lane then the number of wheel lines going to one girder is 1.60. The bridge was rated with two lanes with 2.59
wheel lines going to the girders. So if we restrict the bridge to one lane the ratings increase by 2.59/1.60 =
1.62. This will raise all of the ratings to above legal loads.
Monte Smith
Sargent Engineers, Inc.
320 Ronlee Lane NW
Olympia, WA 98501
(360) 867 -9284
Fax (360) 867 -9318
ww sargente i_0i
1
10
R12 -1101
11/97
C
4,
G
B
ONE TRUCKI
AT ATIMEI
ON BODGE
A
DIMENSIONS (MILLIMETERS)
A
B
C
D
E
F
G
900
900
16
22
125C
78
56
DIMENSIONS (INCHES)
A
B
CD
E
F
G
36
36
5/8
7/8
5C
3 1/8
2 1/4
COLORS
LEGEND - BLACK (NON -REFL)
BACKGROUND - WHITE (REFL)
E
F
E
F
E
11