Improved Optimization Formulations for Launching Nose of Incrementally Launched Prestressed Concrete Bridges

Abstract

The conventional design process of a launching nose of an incrementally launched bridge is based on trial-and-error methods to reduce bending moment of prestressed concrete deck at the foremost support during launch. With this method, there is no guarantee that the obtained solution is the best among all the possible solutions, since they all depend on the experience and intuition of a designer, and they are also restricted by a limited number of possible iterations. Given that launched bridges constitute an important constructive typology, all the available capacities of design innovation should be incorporated, including numerical optimization. This research work proposes an objective and rigorous formulation to optimize the launching nose of a launched bridge under real constraints that a bridge designer can encounter in practice. Comparing the results obtained by conventional process and those obtained by optimization techniques allows us to verify that some of the assumptions considered in classical design methods of a launching nose are not based on any theoretical foundation. This fact demonstrates the utility of numerical optimization to improve a design.