预弯复合梁刚度和强度的试验研究

Test Study on Stiffness and Strength of Pre-deflected Composite Beam

本文根据跨度为12m的预弯复合梁足尺试验结果,观察梁在重复荷载作用下裂缝发生、发展及闭合的规律,测定梁的挠度和截面的应变与作用荷载的关系,得出了预弯复合梁开裂后刚度随作用荷载的衰减规律、截面几何形心随作用荷载的移动规律,从而得出预弯复合梁开裂后刚度及强度的实用计算式。本实用计算式与国外现行规范相比,物理概念明确,计算结果更接近梁的实际工作状态。

From the full-scale test result of a pre-deflected composite beam with the span of 12m,the features of crack occurence,development and closure of the beam under the repeated loading are observed in this paper. The relation of beam deflection and applied load and that of sectional strain and the latter are measured. And the damping pattern of stiffness of the pre—deflected composite beam under applied load after its cracking and the moving characteristics of center of sectional geometric figure under applied load are obtained. Therefore,the practical formula of stiffness and strength of cracked pre—deflected composite beam is obtained. The formula has a clear physical concept and its result has a better approach to the actual working state of the beam campared with the foreign existing ones.