Two types of alterative section preflex simple beams, alterative web plate highness and alterative steel flange thickness, are discussed on how to get the value of calculating moment of inerti.

Based on the calculation resuhs,it is found that con- tinuous composite beams are remarkably superior in economic performance to simply supported composite beams.

A method for calculating ultimate flexural strength of preflex composite beam with the elasto-plastic effect of steel;

Research on elastic-plastic ultimate capacity of preflex beam bridges;

This paper introduced the fundamental of preflexed beam; Aggregated the research development of preflexed beam at home and abroad in the past years; Discussed the material modeling and selected the stress-strain relationship of steel and concrete which is suitable for the nonlinear analysis of preflex beam; In.

Analytical theory and test study of longterm properties for the preflexed beam;

Based on the construction peculiarity of preflexed beam bridges,an analytical method is proposed for predicting properties of bridges structures.