现浇混凝土空心双向板实用计算方法

基于弹性理论,假定单宽空心板带与实心板带中点挠度比值等于整体空心板与整体实心板中点挠度比值,单宽空心板带与实心板带中点弯距比值等于整体空心板与整体实心板中点弯距比值。推导出单向布管的空心双向板的内力修正系数。在此基础上给出了基于实心双向板常规计算图表的现浇混凝土空心双向板的挠度和弯距计算公式。ANSYS通用有限元程序对算例的计算结果表明,挠度和中点弯距值的计算误差均小于10%;空心双向板的双向受力特性十分明显;平行于管轴方向的截面惯性矩大于垂直于管轴方向的截面惯性矩,其差值小于7%。此外,本文还对空心板布管方向和钢筋布置提出了建议。

Practical calculation method for cast-in-place two-way hollow concrete slab

According to the elasticity theories.Assumption is made that the midpoint deflection ratio of hollow strip with unit width and solid strip are equivalent to the midpoint deflection ratio of whole hollow slab and solid slab,and the midpoint moment ratio of unit width hollow strip and solid strip are equivalent to the midpoint moment ratio of whole hollow slab and solid slab.The internal force modification factor of the hollow two-way slab with one-way laid tube is deduced.On this basis,the cast-in-situ two-way hollow concrete slab deflection and moment formulas are given.The computation results of cast-in-situ two-way hollow concrete slab by given formula is compared with analysis using ANSYS general finite element program.It showed that given formula had errors less than 10%;the characteristics are very obvious that the hollow two-way slab bears force in two-way;the section moment of inertia in the direction of parallel tube axis is bigger than the direction of perpendicular tube axis,but difference in the two-directions is less than 7%.In addition,suggestions are made about how to lay the tube and the steel bar in the hollow slab.