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HomeMy WebLinkAboutINS-13-076 - Margaret Ave Bridge - Short & Long Term Solutions REPORT TO: Community and Infrastructure Services Committee DATE OF MEETING: September 9, 2013 SUBMITTED BY: Barbara Robinson, Director of Engineering, 519-741-2200 x 7410 PREPARED BY: Barbara Robinson, Director of Engineering, 519-741-2200 x 7410 WARD(S) INVOLVED: 10 DATE OF REPORT: September 4, 2013 REPORT NO.: INS 13-076 SUBJECT: Margaret Avenue Bridge Short and Long Term Solutions RECOMMENDATION: That the recommendation to remove the existing Margaret Avenue Bridge in the near term and initiate an Environmental Assessment to replace it, be approved, as outlined in Infrastructure Services Department report INS-13-076; and further, That the reallocation of funds from existing federal gas tax sources for the removal of the existing Margaret Avenue Bridge ($250,000) and initiation of an Environmental Assessment and predesign to replace it ($150,000), be approved, as outlined in Community and Infrastructure Services Committee Report dated INS 13-076; and further, That staff be directed to work towards identifying funding sources for a new bridge during the 2014 budget process. EXECUTIVE SUMMARY: The Margaret Avenue Bridge has been closed since June 2013 following the receipt of a structural engineers’ report recommending it be closed immediately. A Peer Review of the initial recommendation was undertaken and it supported the original findings. A consultant was retained to evaluate short and long term alternatives and costs for this bridge, and this report was received on August 23, 2013. City staff is recommending that the existing bridge be removed in the near term and an Environmental Assessment (EA) and predesign for a new bridge be undertaken immediately. BACKGROUND: The City owns 122 bridges which are inspected (under Legislation) every two years under the direction of a Professional Engineer. These inspections can result in recommendations for routine work (such as concrete or railing repairs), or for further evaluation. 6 - 1 The biannual 2012 mandated structural inspections identified the Margaret Avenue Bridge as having an “Urgent” need for a more detailed structural evaluation. This more detailed evaluation was initiated in January 2013 with AECOM consultants. The City received the Draft Evaluation of the Margaret Avenue Bridge on June 13, 2013, which recommended that the bridge be closed immediately. The bridge was closed within the hour. Representatives from all of the railways were contacted immediately and staff has been working closely with them throughout this process. Staff has also worked closely with our colleagues from the Region of Waterloo. On June 26 staff received the Final Evaluation Report from AECOM. The report identified three possible modes of sudden failure of this bridge, including: Pullout of reinforcing bars with insufficient anchorage Concrete failure in shear mode Failure of the welds in the corbel ledge (support structure) The Margaret Avenue Bridge has similar steel design and corbel ledges as the de la Concorde Bridge in Laval Quebec, which collapsed in 2006, killing five (5) people and injuring many others. In addition, the Margaret Avenue Bridge was rehabilitated in 2003, in a similar fashion as the de la Concorde Bridge. Damage during rehabilitation was considered as a possible contributor to the failure of the de la Concorde Bridge. The use of a drop in centre span supported by cantilever was a popular way to construct bridges from the 1950’s to the 1970’s because of the simplicity in construction (centre span could be dropped in once the support structure was completed) and the elegance of the structure. Likely unknown to designers at the time, the construction posed major problems because key structural elements are hidden and un-inspectable, sometimes even with modern technology. Road salt getting into these hidden elements exacerbates the problem. Bridges normally have redundant support systems. This type of bridge design does not have this redundancy and no longer meets the Canadian Highway Bridge Design Code. Due to the significance of the recommendation, the City retained the services of a second structural engineering consultant, Morrison Hershfield, to review and confirm AECOM’s recommendations. The Peer Review Report was received in July 2013. Morrison Hershfield concurred with AECOM’s recommendations regarding the design and construction of the bridge, and the possibility of abrupt failure. It also supported the decision to shut down the bridge to traffic and pedestrians. Morrison Hershfield recommended that the City investigate short and long term alternatives for the bridge, and proposed a potential short term alternative. Morrison Hershfield were retained to undertake an evaluation of short and long term alternatives for the Margaret Avenue Bridge in July 2013 and their final report was received in August. 6 - 2 REPORT: City staff received the Work Plan Recommendation for the Margaret Avenue Bridge Rehabilitation/Remedial work plan from Morrison Hershfield Consultants on August 23, 2013. The Work Plan identifies short and long term alternatives for the bridge, including advantages, disadvantages and costs. Two alternatives are available to the City at this stage, namely: 1. Undertake an immediate short term repair of the bridge, then initiate an EA to replace the bridge. 2. Remove the existing bridge in the near term and initiate an EA to replace the bridge. Note that these alternatives are being presented to allow Council to make a decision regarding a short term, immediate repair. If it is decided to replace the bridge, staff will initiate an EA and the full range of alternatives will be considered at that time. The EA is expected to be planned as a Schedule A+ or B. There is a 100mm diameter natural gas main crossing the Margaret Avenue Bridge which is the primary feed to the Bridgeport area. It was taken out of service in June as gas needs are lower in the summer. However, this link or an alternative needs to be in place this winter to avoid natural gas outages in Bridgeport. Kitchener Utilities is working on alternatives and costs for this natural main and will fund this work out of capital reserve accounts. Fire Station No. 2 is located north of the CN tracks at Lancaster and Guelph Streets. Potential impacts on emergency service response times need to be considered. During construction of the new bridge, regardless of timing, this potential will exist. Transportation Services has advised that they prefer to maintain this crossing long term as an important roadway link. They are prepared for short term disruptions regardless of the alternative elected. Alternative 1: Undertake an Immediate Short Term Repair of the Bridge; then Initiate an EA to Replace the Bridge. Alternative 1 is a short term, emergency repair, which involves bolting structural steel plates top and bottom of the bridge, to provide additional structural elements that will pick up a portion of the loads imposed on the corbel (support structure). It may be necessary to have propping below the deck as the deck may be further weakened by the repair process. The short term repair is intended to allow the bridge to be opened fully or partially to traffic and pedestrians, although whether the bridge can be opened to all four lanes of traffic or only two has not been determined. The repair will take place in fall 2013 if approvals can be secured in a 6 - 3 timely fashion, with the bridge opening by the end of 2013. Continuous monitoring will be required with this alternative to ensure that the repair continues to perform as designed. Because the plates will affect clearance for the railways, the railways will need to be consulted to approve this approach once it is designed. The short term repair is intended to be replaced with a long term solution not more than two years from completion of the work. If the short term repair is completed in fall 2013, it will be in place in 2014 and the new bridge is proposed to be constructed in 2015. Advantages of the short term solution are that it will allow at least some traffic on the Margaret Avenue Bridge while the Region is working on Weber and potentially King Streets in 2014 (note that Weber is expected to remain open to two lanes at the CN crossing except for a few weekends). This repair, if it can be implemented this fall, will allow the natural gas main on Margaret Avenue to be put back into service. And, emergency services will have a crossing of the CN tracks for the period when it is in place (2014). Disadvantages of the short term solution are that there are still some caveats with respect to its performance. The report states that the short term solution will not address poor concrete conditions, hidden damages and deteriorated components (i.e., it will not fix or change any of the existing defects). Thus, there will still be a risk of failure, although it will be significantly reduced from existing (bridge unloaded) conditions. Morrison Hershfield states that the replacement of the bridge is crucial and should not be delayed, even if the emergency temporary repair has been completed. Another disadvantage of this solution is that the costs to implement it are not recoverable. There is currently no funding in place to replace this bridge, so the short term repair costs will further compromise our ability to implement a long term solution. This solution is likely less favoured by the operators and users of the rails below. Costs of this alternative are estimated (Class C) as $400,000 capital and $50,000 in staff costs. Alternative 2: Remove the Existing Bridge In the Near Term and Initiate an EA to Replace it. With this alternative, the bridge will be removed in the near term (as soon as arrangements have been made to relocate/find alternative support for the gas main on the bridge). An EA and predesign will be initiated immediately in 2013, design will proceed in 2014 and construction of the new bridge in 2015. It is expected that the bridge will reopen at the end of 2015. With this alternative, options for pedestrian crossing of the CN rails will be explored by staff and solutions to assist pedestrians until the end of 2015 will be developed. Advantages of this alternative are that removal of the bridge will eliminate the risks associated with failure of this bridge, and remove costs to the City and the railways associated with inspection of the existing structure. The new bridge will have a design life of 75 years. Disadvantages of this alternative are that there will be no crossing at Margaret Avenue until the Potential impacts on emergency fall of 2015, an inconvenience for vehicles and pedestrians. 6 - 4 service response times need to be considered. Alternative arrangements for the natural gas main will need to be made. This alternative is likely to be strongly favoured by the railways. Total Class C costs for this solution, including EA, predesign, design, and construction are estimated as $6,000,000. There will be costs associated with the gas main, but these will be covered through capital reserve accounts. Immediate funding needs are $250,000 for removal of the existing bridge, and $150,000 for an EA and predesign. Additional funds will need to be identified through the budget process. Preferred Solution Remove the Existing Bridge in Staff is recommending that the City proceed with Alternative 2, the Near Term and Initiate an EA to Replace it. The existing bridge can be taken down as soon as the gas main is relocated or re-supported, hopefully before the end of the year, and an EA can be initiated immediately at which time alternatives and costs can be refined. Class C estimated costs to remove the bridge are $250,000. Estimated costs for an EA and predesign are $150,000. This Alternative represents the best use of City capital dollars and the lowest risk to the City and the railways. ALIGNMENT WITH CITY OF KITCHENER STRATEGIC PLAN: The Alternative to replace the Margaret Avenue Bridge will continue to contribute to Quality of Life for residents in the City, by investing in infrastructure that will support our future growth. FINANCIAL IMPLICATIONS: The costs to remove the existing bridge and initiate an EA and predesign will be funded through several Federal Gas Tax sources: accessing reserve funds and project closeouts. Funds to replace the bridge, if that is the preferred solution, will be developed through the 2014 budget process. COMMUNITY ENGAGEMENT: This project will undergo an EA process. Strictly speaking a Schedule A will suffice, but we will consider planning it as a Schedule B in order to allow the public to participate in a public meeting. CONCLUSION: The Margaret Avenue Bridge should be removed immediately. The City should initiate an EA to replace the Bridge. ACKNOWLEDGED BY: Pauline Houston, Deputy CAO Infrastructure Services Department 6 - 5