Optimized Prestressed Continuous Composite Girder Bridges with Corrugated Steel Webs

This paper proposes different optimization schemes for enhancing the performance of conventional continuous composite girder bridges with corrugated steel webs. In particular, for the positive moment region, the substitution of a ribbed steel plate for the reinforced concrete bottom flange is proposed for optimizing such bridges. Three-dimensional finite-element analysis was used to preliminarily validate this optimization scheme based on the background project, Dongbaohe Xinan Grand Bridge. An experimental study revealed that the optimization scheme can afford advantages, such as reduced self-weight, avoidance of cracking in the bottom flange, and convenient construction. If the steel plate with proper thickness is used, higher flexural stiffness and load capacity can be achieved as additional advantages due to the enhanced steel ratio of the cross section. For the negative moment region of the bridge, the optimization scheme was implemented in two parts identified as Optimization Schemes I and II. In Scheme I, corrugated steel plate-concrete composite webs were used, whereas a steel-concrete composite bottom flange was further adopted in Scheme II. Compared to the conventional scheme, both Optimization Schemes I and II significantly reduced the shear stress in the corrugated steel web and at the steel-concrete interface due to the lined concrete in the web. Thus, it can be deduced that the applied load corresponding to the yield of the corrugated steel web will be enhanced; namely, the shear capacity will be enhanced. Because shear connection failure was prevented in both optimization schemes, there were remarkable improvements of the load capacity and ductility of the girder. The confining effect of the lined concrete decreased the prestress lead-in ratio, but not significantly. In addition, Optimization Scheme II afforded much greater construction convenience compared to both Optimization Scheme I and the conventional scheme. (C) 2016 American Society of Civil Engineers.