钢筋混凝土双向叠合板的挠度计算方法研究

Study on calculation method of deflection of reinforced concrete two-way composite slab

钢筋混凝土构件在正常使用阶段均为带裂缝工作。而由于受拉区混凝土开裂,带裂缝的钢筋混凝土构件与均质弹性构件的刚度存在明显差别,其刚度下降导致构件的实际挠度与按照均质弹性理论得到的计算值之间存在较大差异。本文基于等效拉力法,在考虑裂缝间混凝土参与受拉、受压区混凝土双向受压和叠合板二次受力影响的基础上,对裂缝截面处受拉钢筋的应力加以修正,引入裂缝间混凝土拉应力所产生的抵抗力矩M′、受压区混凝土双向受压所产生的抵抗力矩M″和受拉区裂缝间混凝土拉应力影响系数k1,推导出了考虑二次受力的钢筋混凝土双向叠合板的短期刚度计算公式,并与钢筋混凝土双向叠合板的试验数据进行了对比,本文公式的计算值与试验实测值更加吻合,误差更小。

In the normal use of the stage,reinforced concrete members work with cracks.But it’s obviously different between the stiffness of reinforced concrete members with cracks and homogeneous elastic members because of the cracking of concrete in the tension zone.What’s more,the decrease of stiffness results in a big difference between the actual deflection of concrete members and the calculated value founded on the theory of homogeneous elasticity.Besides,the paper is based on an equivalent tension method.The stress of tensile reinforcement at the crack section is corrected by considering the influence of the two-way compression of concrete in the compression zone,tension concrete between cracks and the two-stage load of the composite plate.In addition,the paper introduces resistance moment M’generated by tensile stress of concrete between cracks,resistance moment M"generated by two-way compression of concrete in the compression zone and influence coefficient k1 of tensile stress of concrete between cracks in the tension zone.At last,the short-term stiffness formula of reinforced concrete composite slab with two-stage load is deduced,and the experimental data of reinforced concrete two-way composite slab face with each other.It is noted that calculation results in this paper have smaller error and higher precision.