ADMINISTRATIVE REPORT

Date: September 30, 1999
Author/Local: M. Robertson 7321
RTS No. 00986

CC File No. 5752-1

Council: October 19, 1999

TO:	Vancouver City Council
FROM:	General Manager of Engineering Services
SUBJECT:	Design Concepts for the Replacement of the Nanaimo Street Bridge and the Lakewood Drive Bridge Over the Grandview Cut

RECOMMENDATION

A. THAT the conceptual designs for the new Nanaimo Street and Lakewood Drive Bridges over the Grandview Cut, as described in this report, be approved and that the detailed design and construction proceed on this basis, all at the cost of the Rapid Transit Project 2000.

B. THAT the City enter into an Agreement which is acceptable to the General Manager of Engineering Services and the Director of Legal Services for each bridge, with the Burlington Northern and Santa Fe Railway Company (BNSF) for the construction of the bridges over their railway, and that the Director of Legal Services execute the Agreement on behalf of the City.

COUNCIL POLICY

Prior to the detailed design and tender preparation for the construction of a roadway bridge, Council is normally asked to approve the design concept.

PURPOSE

This report seeks Council approval of the design concepts for the new Nanaimo Street Bridge and the Lakewood Drive Bridge over the Grandview Cut.

BACKGROUND

The Provincial Government intends to expand the SkyTrain system and the proposed alignment utilizes the Grandview Cut. The bridges over the Grandview Cut at Nanaimo Street and at Lakewood Drive are of timber construction and were built in the early 1950's. Both bridges need to be replaced as they are in conflict with the SkyTrain alignment. The bridges are to be replaced at the cost of the Provincial Government as part of the SkyTrain expansion project.

Prior to the SkyTrain project each bridge was estimated to have a remaining useful life of approximately 25 years.

The Rapid Transit Project 2000 Ltd. (RTPO) was created by the Province to coordinate the SkyTrain extension. The City has been working with the RTPO on the design of the new bridges. The City’s Rapid Transit Office has been the liaison with RTPO on behalf of the City for the SkyTrain extension and bridge replacements. The RTPO have engaged the firm of Cochrane Engineering Ltd. to design the new bridges. The first phase of the Consultant’s work consisted of a recommendation on the design concepts of the two bridges in conjunction with the proposed SkyTrain extension.

DESIGN CONCEPT

The Consultant investigated several alternative concepts for the bridges, consisting of concrete I-girders or concrete trapezoidal box girders in single, 2-span and 3-span configurations. It was determined that the most economical and optimum bridges will be asymmetric 2-span arrangements utilizing concrete I-girders supporting the decks. These concrete I-girders are the most common type of superstructure used in British Columbia and are the same configuration as used on the Broadway and Victoria Drive Bridges. This bridge configuration is also recommended because it is well suited to support the utilities and associated maintenance crawlways, is economical to maintain, and is aesthetically pleasing.

The existing Nanaimo Street Bridge has 2 lanes northbound and 3 lanes southbound plus a southbound left turn bay, and narrow sidewalks on each side. The new Nanaimo Street Bridge will be 24.8 metres wide which will provide for 2 lanes in each direction plus a southbound left turn lane, and an approximately 3.0 metre clear-width sidewalk on each side. There will be an asphalt overlay on the roadway as a wearing surface and a waterproof membrane for corrosion protection. The sidewalks will have a decorative surface treatment, railings and lighting.

The existing Lakewood Drive Bridge has a lane in each direction and a narrow sidewalk on each side. The new Lakewood Drive Bridge will be 14.2 metres wide providing 2 lanes of 3.7 metre width and approximately 3.0 metre clear-width sidewalks on each side. The new bridge will continue to be used for local traffic but is also designed with a greater emphasis on pedestrians and cyclists as it is both a greenway and bikeway link over the Grandview Cut. Accordingly, a stamped asphalt pattern is planned for the bridge deck, as well as decorative sidewalk treatment and railings and decorative lighting similar to the Nanaimo Street Bridge. In addition, the design contemplates a small plaza at the north end of the bridge, connected to a pocket park which would be incorporated into the greenway along Grandview Highway North.

These elements are shown in concept on Appendix A (3 pages).

CONSTRUCTION AND SCHEDULE

Due to the significant impact on cost and schedule for staged construction as well as the time line associated with the SkyTrain construction, the bridges will be reconstructed under complete closure as has been done with all the other bridges previously reconstructed over the Grandview Cut.

The replacement of the bridges will coincide with the construction of the SkyTrain extension. The current schedule for the work has the reconstruction of the bridges commencing in late January 2000. As a result of this coordinated construction, the Lakewood Drive Bridge is tentatively scheduled to be closed from February to October 2000 while the Nanaimo Street Bridge is expected to be closed from February to mid July 2000.

The bridge contractor and the Provincial RTPO will be required to prepare and implement a traffic management plan for pedestrians, cyclists, transit and vehicles in accordance with parameters already given to them by the City. The traffic plan will have to be approved by Engineering Services. It is anticipated that vehicle traffic be detoured away from the bridge site by installing advanced warning signs at key locations in the City to encourage motorists to use alternate north/south routes. Public notification, through newspaper ads, new releases and flyers will be coordinated in advance so that the public, commuters, the trucking association and the local area residents will be informed of the bridge closures and the traffic diversion plan. We will advise Council on the details of the traffic diversion plan in advance of the start of construction.

The duration of the closure of the Nanaimo Street Bridge will be kept to a minimum by doing as much preliminary work as possible while the bridge is still open to all traffic. In addition, because of the large volume of traffic being rerouted, the detour details will be closely monitored for the first few weeks in the event that modifications are needed. For example, reserve Police officers may be needed for traffic control during peak hours, in order to keep vehicles and transit from being unnecessarily delayed.

Neighbourhood schools have been contacted regarding the bridge closures and they have said there should be little impact on their students. This will be monitored, and if required, it has been agreed that shuttling of students around the bridge sites will occur.

TRANSLINK IMPACTS

TransLink have been advised of the bridge closures for reconstruction and they have said that they can accommodate the closure by using existing trolley bus routes, and using diesel bus shuttle routings. All bus rerouting shall be subject to approval by the City. Some temporary bus stops will be required to accommodate the bus rerouting.

CROSSING AGREEMENT

In the past, an application to the National Transportation Agency (NTA) was required for an order authorizing the construction of a new bridge. The NTA has been replaced by the Canadian Transportation Agency (CTA) and the requirements have changed. An agreement between the City and the railway for the construction and maintenance of the bridges and for their attached utilities is now all that is required. While the detailed design of the bridges is in progress, an agreement satisfactory to the General Manager of Engineering Services and the Director of Legal Services will need to be executed.

COSTS AND FUNDING

Reconstruction costs for the Lakewood and Nanaimo Bridges will be borne by the Rapid Transit Project 2000 as part of the SkyTrain extension project. No City funding will be required.

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(c) 1998 City of Vancouver