5. Athabasca River Bridge (Steinhauer) Replacement, Alberta Transportation, Fort McMurray, AB

Fort McMurray has got a new, five-lane bridge for northbound traffic crossing the Athabasca River, with extra lanes to be added to the two existing bridges that will handle southbound traffic only. As part of Highway 63 Upgrade project, the functional planning study had concluded that the existing Steinhauer Bridge needs to be widened to 3 lanes with wider shoulders, and shall be supported on the existing piers; the number of lanes crossing the river will be boost from 4 to 10. Description of the Project: The existing Steinhauer Bridge is 7 spans (61, 76, 61, 76, 76, 61 m) Figure (1). It was built in 1974, and carried two (2) lanes, with an overall width of 9.6 m. It consisted of four (6) steel plate girders composite with a cast-in-place concrete deck. In 2000, the steel girders were postensioned to carry an extreme overload vehicle. To meet the current highway geometric standards and the required design speed, the wider CD lanes and shoulders entail widening of the present roadway onto the existing pedestrian walkway deck resulting in the requirements of removing the existing pedestrian walkway bridge. The existing bridge elevation shall be changed to accommodate the new roadway profile and due to the increase of design speed in Highway 63, the existing curve on the east approach needs to be extended onto the bridge. As a result, the existing bridge need to be jacked as well as The new spiral curve requires the first east span girders to be re-constructed in order to accommodate both the spiral curve and the super-elevation on the bridge deck Role in the Project: In the first design stage: prepared feasibility study and proposed several options for modifying the bridge to be 3 lanes with wide shoulders by adding 3 new girder lines (5 lanes with wide shoulders and extended substructure in the early proposals), the modification options entailed several reports, drawings and cost estimates submitted to the client. Performed thorough analysis and estimates for the options, and made comparison to develop advantages and disadvantages regarding the traffic safety, structural efficiency, aesthetics as well as the cost estimates. Comparison between full deck removal and partial deck removal. Propose alternatives for connecting the existing structure with the new widened one. Jacking the existing bridge to accommodate the new roadway profile, and compare them with an overall new superstructure. Communicated with different contractors to discuss the constructability and pricing for various options, and advised with an engineering decision of having the old existing Steinhauer bridge replaced by new 6 girder lines bridge as a cost-effective solution and the right way to go. In the detailed design stage: Proposed a detailed removal/erection of Steinhauer Bridge, and reviewed the structural capacity of the existing post-tensioned bridge, and the ability to carry two heavy lifting cranes at the time with truck carrying segments. Detailed analysis and evaluation was carried out regarding the general stability and structural strength. As well as for localized stress effects and local buckling of all bridge components and during all construction phases which included: phase I: removing the pedestrian bridge off the existing roadway bridge, phase II: erect 3 new girder lines over new widened substructure caps, phase III dismantle and remove the existing roadway bridge off the 3 new girder lines, and phase IV: erect another 3 girder lines over the extended new substructure caps. Performed a very detailed analysis and design for the new superstructure while the existing substructure was tested and evaluated for the new loading received from the new superstructure. Complete tender documents was submitted in November 2010