Moment-Rotation Relationships for Unified Autostress Design of Continuous-SpanBridge Beams and Girders

摘要

The report summarizes the development and trial application of simplified moment-rotation relationships for inelastic design of continuous-span beam and girder bridges. The research described within involves the execution of a reasonably comprehensive set of finite element parametric studies to fill in knowledge gaps in the available experimental data pertaining to the hogging moment-plastic rotation behavior of steel and composite steel-concrete bridge girders. Based on these studies, relationships have been developed for the moment-plastic rotation behavior at the pier sections in these types of bridges. The moment-rotation model is validated against available experimental data, several focused new experimental tests, and current American specification strength formulas. This study concludes with a detailed trial inelastic design of a three-span continuous plate-girder bridge using suggested new inelastic design procedures. The characteristics of the calculations and the resulting proportions are compared to those of an elastic design of the same bridge by current AASHTO LRFD procedures. The elastic design is a modified version of a three-span continuous plate-girder bridge example recently published by the American Iron and Steel Institute for a Highway Structure Design Handbook.