Comparison Of Post-tensioned Cast In Place Concrete And Steel-concrete Composite Bent Caps

Abstract

Civil engineering projects are conditioned not only by the technology available but also by resources availability as well as budget and construction time. Special conditions applicable to particular projects can also control their development.The correct selection from the different feasible alternatives can determine the final output of a project. In that sense, the importance of bridge structures on both the overall budget and schedule of civil engineering projects makes the selection of the proper structural typology decisive for their success or failure. In some cases, special characteristics can establish the need of innovative solutions to guarantee a successful development of the project.The evolution of the urban areas and consequently the increase in their population, translates into increasing traffic volumes that, eventually, may overcome the existing transportation infrastructures capacity. The construction of new projects to increase the capacity of the transportation system in consolidated urban areas generates conflicts with existing infrastructures that may require the development of new construction processes, techniques and structural typologies to limit the impact on the traffic.The complexity of the IH-635 Managed Lanes Project located in Dallas County has posed several technical and constructive challenges, leading to the adoption of solutions different from the traditionally adopted. The particular solution given to the substructure of Bridge 4 crossing over IH-35E on the IH-635 project has been analyzed on this study. Two alternatives will be analyzed in terms of structural behavior, cost-efficiency and schedule: the original cast in place post-tensioned concrete structure and the finally built steel-concrete composite prefabricated bent cap solution.