Study of jointless bridge behavior and development of design procedures.

摘要

Jointless bridge literature is reviewed and the analytical information on jointless bridge behavior is synthesized in this research. The behavior of jointless bridges is found to depend on superstructure to substructure stiffness ratio, including span length and abutment heights, load types and their combinations, time dependent creep and shrinkage effects, hinge locations, foundation types, soil properties, boundary conditions, approach slab type, approach slab length, and approach slab connection details. The analytical data are generated by conducting a parametric study of hypothetical and real bridges. The data are synthesized to develop a better understanding of jointless bridge behavior. In order to compare jointless bridges with jointed bridges, analytical data are also generated for jointed bridges. The results of the parametric study serve as a guide to select superstructure and substructure sizes and also to provide a tool for structural optimization. A simple method is also developed for analysis of single span and two-span jointless bridges, which is referred to as the WVU simplified beam analysis. In order to develop proper explanation for the jointless bridge behavior based on fundamental engineering principles and at the same time satisfy the field data, an insight into the performance of jointless bridges is provided in terms of primary loads, e.g., dead load and live load, and secondary loads, e.g., temperature, creep, shrinkage, and settlement. The discussion includes the effect of primary and secondary loadings, effects of secondary loadings with respect to primary loadings, and effect of different systems (boundary conditions) on the stresses at various locations. Furthermore, different models are used to analyze approach slabs based on typical field conditions. The induced stresses obtained from different models are evaluated at various locations. Based on the present study, preliminary design steps and recommendations are developed for jointless bridges. Furthermore, the present research has resulted in the state-of-the-art analysis and design of McKinleyville bridge, Brooke County, WV. The innovation of the bridge system is a three-span, continuous jointless bridge with concrete deck reinforced with Fiber Reinforced Plastic (FRP) rebars. McKinleyville bridge is going to be one of its first kind in the U.S. The construction of the bridge is in progress and the bridge is tentatively scheduled to be opened for traffic in August 1996.