Spatial Analysis on Bridges with Big Boundary Beam Structure Based on Correction Virtual Longitudinal Beam Method

By setting virtual longitudinal beam at big boundary beam,design formula has been derived with consideration on lateral load distribution factors of excess bending stiffness and torsional stiffness of big boundary beam and the correctness of the formula has been verified by using the calculated value examples. And based on the formula,matlab program has been made and the influence It0 of the ratio of torsional stiffness I of inner beam and excess bending stiffness of big boundary beam on lateral load distribution factors has been analyzed. The result shows that,while the torsional stiffness of boundary beam increases a little,its influence on lateral load distribution factors is so little that it may be ignored; while the torsional stiffness of boundary beam increases greatly,generally equals to 10% to 10 times of torsional stiffness of inner beam,its influence on lateral load distribution factors is big; while the torsional stiffness of boundary beam increases by more than 10 times of torsional stiffness of inner beam its influence on lateral load distribution factors is tend to be stable which means the lateral load distribution factors of the whole bridge is tend to be stable.