预应力在钢-混凝土组合梁剪力键中的传递

针对混凝土翼板设置后张预应力的连续组合梁,建立预应力从梁端混凝土向组合梁全截面传递的力学模型,根据连接件剪切滑移本构关系及预应力束对称截面处的界面滑移为零的边界条件,解得混凝土翼板轴力、钢梁轴力及界面剪力的分布函数,求得组合梁考虑连接件柔性的混凝土有效预压应力。结果表明,影响组合截面内力分布的主要因素是剪力连接件的滑移刚度、预应力束长度及混凝土板与钢梁的轴向刚度比;预应力束越长,界面剪力分布越平缓,界面滑移愈小。

Transferring of Prestressing Forces in Shear Connector of Steel-Concrete Composite Beam

For the continuous steel-concrete composite beam whose flange is in proportion with prestressing tendons,a mechanical model for the transferring of prestressing forces from the concrete slab to the whole section was presented.Based on the constitutive relation of interface slipping and the boundary condition that no slippage was considered at the symmetry section of prestressing tendons,distribution functions of axial in the concrete flange and steel girder,and shear force in the interface were obtained.Effective prestressing force in composite beams considering flexibility of shear connectors would be found accordingly.It is concluded that factors such as slipping stiffness of connection components,length of prestressing tendons,and axial stiffness ratio of concrete flab and steel girder will affect the interforce distribution in composite beams greatly,and with the lengthening of prestressing tendons,interface shear force becomes even and slippage is reduced.