集中荷载下预应力FRP布钢与混凝土组合梁变形计算

针对在外荷载作用下,组合梁中的钢梁与混凝土交接面必然产生相对滑移,同时,预应力FRP布的内力逐渐增加,导致组合梁发生内力重分布,影响组合梁的承载力与变形的情况,用弹性理论,建立同时考虑交接面相对滑移和预应力FRP布内力增量影响的组合梁变形微分方程,给出对称集中荷载作用下的组合梁变形计算公式.计算结果证明,交接面相对滑移增加了组合梁的变形,FRP布内力增量对组合梁变形影响相对较小,给出了预应力FRP布钢与混凝土组合梁变形的简化计算公式.

Deformation Calculation of Steel-Concrete Composite Girders with Prestressed FRP Sheets Under Symmetrical Point Load

The interface slip will occur unavoidably in the steel-concrete composite girder with prestressed FRP sheets if the girder is under the external load,and the internal force of prestressed FRP sheets will gradually increase with the external load to redistribute the internal force of the girder so as to affect the bearing capacity and deformation of the girder.The differential equations of deformation are therefore derived on the basis of the theory of elasticity,considering the effect of the relative interface slip internal force increment of FRP sheets.And the calculation formulas of deformation are given for the composite girder under symmetrical point load.The calculated results show that the deformation of composite girder increases gradually with the interface slip,but the effect of internal force increment of the prestressed FRP sheets on the composite girder deformation is so small that can be ignored,thus giving the reduced calculation formulas of deformation for the steel-concrete composite girder with prestressed FRP sheets.