Bridge rehabilitation — Most bridge construction is focused on rehabilitations and replacements rather than new structure builds. GSS can be modified to apply to bridge replacement projects that require construction of new abutments. To ac- complish this, abutments are constructed in the manner described previously and anchored to the existing bridge abutments. GSS can typically keep more traffic lanes open throughout construction when compared with alternative approaches. Staging — In dense population areas, it may sometimes be beneficial to lengthen a construction schedule to allow an existing roadway to remain in use throughout the project schedule. This is possible with GSS in project scenarios with multiple road lanes in each direction, requiring two or more bridge spans to be installed. To maintain roadway function, traffic is staged to occupy half of the roadway at a time while the other half goes through the construction process as outlined previously. Once the bridge spans have been installed and the underpass constructed, traffic is then rerouted to use the underpass while the second half of the roadway undergoes GSS is a modern technology that utilizes a combination of ABC techniques and conventional bridge construction practices to limit onsite construction and reduce overall construction costs. The technology increases the feasibility for grade separa- tion construction while also improving construction conditions for road users. This technology has been designed to be highly adaptable so that it can be used in a vari- ety of construction projects. The procedure has the potential to significantly reduce project costs and shorten construction schedules. construction. Conclusion
Figure 1: Schematic details placement of steel caisson liners along each side of rail track outside the railway clearance envelope for a three-span rail crossing. Also shown is the location of the level crossing.
Figure 2: Schematic details completion of substructure elements. Caisson liners, rail track, precast elements, modular trench boxes, mechanical couplers, cast-in-place concrete, and bearings are shown.
ART IVANTCHOUK, PH.D., P.ENG., BDS , is president of ART Engineering, Inc. (www.artengineering.ca), structural consulting engineers based in Carp, Ontario.
INDOTmakes $125 million available for rail overpass projects
The Indiana Department of Transportation (INDOT) is making available at least $125 million for high-priority railroad safety projects on local roads statewide through the agency’s new Local Trax matching grant program. Local Trax provides state matching funds for Indiana cities, towns, and counties interested in pursuing high-priority railroad grade separations, crossing closures, and other safety enhancements at railroad intersections with local roads. “Much like Community Crossings, Local Trax is an innovative approach to infrastructure funding that creates a partnership between the state and communities willing to put skin in the game toward improving their local roads,” Governor Eric. J Holcomb said. “Eliminating at-grade rail crossings on local roads makes our transportation network safer, reduces congestion, and better connects our communities.” INDOT began accepting project proposals from local agencies in May. The application window will stay open until Aug. 31, with the awarding funds expected to be announced in late summer. Local Trax requires local governments to provide only 20 percent of funding for land acquisition and construction with the state providing the other 80 percent.
Figure 3: Schematic details preparation for installation of the first span. Ballast walls, bearings, and disassembled trench box piece are shown. Also shown is a complete rail bridge span ready for installation and a temporary end cap.
Figure 4: Schematic details completed rail bridge after excavation of the roadway underpass.
More information about Local Trax is available at www.in.gov/indot/2390.htm.
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