Joint Rehab 2012-256 - Responsive - 10

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Report

City of Vancouver

Burrard Street BridgeExpansion Joint Rehabilitation

March 2012





REPORT

Table of Contents

SECTION PAGE NO

Table of Contents i

1 Introduction 1

2 Existing Expansion Joints 1

3 Joint Types Considered 3

5 Recommendations 8

s.13(1); s.15(1)(l); s.17(1)(c), (d), & (f); s.18(a); and s.19(1)(b)

s.13(1); s.15(1)(l); s.17(1)(c), (d), & (f); s.18(a); and s.19(1)(b)



REPORT

1 Introduction

Associated Engineering (AE) has been retained by the City of Vancouver to complete the retrof

and rehabilitation design for the Burrard Street Bridge. As part of that assignment we have

reviewed design alternatives for the rehabilitation of the existing expansion joints. The

following report summarizes the alternatives considered and our recommendations.

2 Existing Expansion Joints

Existing expansion joints are located at the abutments, Bents 4, 7, 10, 13, 16, 19, 24, Pier 2 and

Pier 5, and at each side of Piers 1, 3, 4, and 6. Each joint extends the full width of the bridge

superstructure.

The record drawings indicate that all expansion joints were originally designed as sliding-plate

joints. However, all of the expansion joints currently on the bridge are either compression seal or

strip seal type joints. No record drawings were found for the last expansion joint upgrade. Most

expansion joints appear to be uncovered compression-seal joints, except the expansion joints at

Piers 1, 2, 5, and 6 which have incorporated compression seals into the original sliding-plate joints.

There are also four strip seals at Piers 2 and 5; and on the through-truss side of Piers 3 and 4.



City of Vancouver

From our site inspection, the majority of the compression seals are locally deformed, depressed, or

damaged; all are leaking. Figure 2-1 above shows some of our inspection photos of existing deck

joints over truss spans.

Debris and water are accumulating at expansion joints where the joint seal is depressed or split. A

of the expansion joints have reached the end of their service life and need to be replaced. Details

of the current condition of all expansion joints can be found in detail in our inspection report titled

Burrard Street Bridge Condition Assessment Report , dated February 2012. Table 2-1 summarizesthe current configuration of the expansion joints.

Table 2-1

Current Expansion Joint Configuration

Location Width (mm)Functioning

(Y/N)Comments

SA 22 at W. curb N 61 mm at west sidewalk

B4 53 N

B7 50 N 52 at west sidewalk





ReportBurrard Street Bridge

Expansion Joint Rehabilitation

3 Joint Types Considered

Expansion joints shall be designed to accommodate the structure movement due to temperature

change, as well as to allow the movement induced by the live loads. The most commonly used

expansion joints include compression seal and strip seal types. Figure 3-1 shows the expansion

joint detail for different type of joints from Watson Bowman ACME, which are representatives of

typical joint types by other suppliers as well.

Compression Seal

Accomondate smaller

movement (up to 76 mm)

[Is this true? Most have

very small movement

capacity]

Ease of installation

Performs well when

properly installed



City of Vancouver

OthersMulti-Gland Modular Joint

Finger Joint

Figure 3-1

Watson Bowman ACME Expansion Joint Details

When replacing deck joint consideration shall be given to the different requirements of cyclists,

pedestrians, wheelchairs, motorcyclists, and other vehicular traffic. We recommend that any joint

design include a cover plate over the deck joints in sidewalks to provide smooth riding for

pedestrian and wheelchair users. The cover plate design for active users in walkway areas will

also need to accommodate wheel loading from maintenance vehicles. We do not recommend the

use of cover plates in the vehicle lanes.





Currently. there are a total of 19 expansion joints on the Burrard Street Bridge. We analyzed the

temperature movements based on the existing expansion joint layout and the live load rotations

using the structural model. We conclude that it is possible to eliminate most of the intermediate

deck joints to accommodate the thermal movement without taking into account of seismic

restrainers.

However the approach spans of the bridge have been fitted with diagonal seismic braces which

effectively prevent the intermediate expansion joints from straining transversely as well aslongitudinally. There are two concerns raised if new link slab are installed:

.1 Thermal Movement: The longitudinal thermal movement will accumulate after the deck

slabs are linked.

.2 Live Load Rotation: With link slabs installed, girders on both sides shall be able to

accommodate the rotations from live load. The current lateral seismic restrainers of

diagonal braces will restrain the girder from live load rotations. Live load demands will

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the live load rotations will not compromise that performance of the braces. Therefore, we

do not recommend link slabs at these locations.

It appears possible to replace two joints with concrete link slabs between deck truss spans, which

ld ff i l li i h i l f d k ff f i i d d di h



City of Vancouver

s.13(1); s.15(1)(l); s.17(1)(c), (d), & (f); s.18(a); and s.19(1)(b)





s.13(1); s.15(1)(l); s.17(1)(c), (d), & (f); s.18(a); and s.19(1)(b)



City of Vancouver

5 Recommendations

We recommend that the City upgrade the deck joints described in Option 1 ± expansion joint

replacement; this option has the lowest capital cost. Option 2 is similar to Option 1, except that two

deck joints will be replaced by link slabs. Although there is a minor benefit in maintaining two fewer

GHFNMRLQWVDGRSWLQJWZROLQNVODEVZLOODOWHUWKHEULGJH¶VVHLVPLFUHVSRQVH At this stage we have

not established whether there are any seismic benefits to Option 2. These two options have higher

life-cycle costs associated with ongoing maintenance and rehabilitation than Option 3.

Option 3 adds high risk to the integrity of the existing seismic components, and requires in-depth

investigation and evaluation of the seismic components. It is possible that this option will either

require significant modifications to the seismic restrainers, or may otherwise prove to be

impractical. Accordingly, we do not recommend adopting Option 3.

If you have any questions with this report, please call either David Harvey or me.

Prepared by: Reviewed by:

s. ; s. ; s. c , , ; s. a ; an s.



; ; , , ; ;

s.13(1); s.15(1)(l); s.17(1)(c), (d), & (f); s.18(a); and s.19(1)(b)



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Joint Rehab 2012-256 - Responsive - 10