在静载的长期作用下钢筋混凝土梁的挠度计算

The calculation of the deflection of the reinforced concrete beam under the long-term function of the dead loads

钢筋混凝土梁在静载的长期作用下,由于混凝土徐变和收缩的影响,刚度随时间降低,而变形则随时间增大.因此,挠度的计算是比较复杂的.瞬时曲率曲线计算挠度的方法,采用了构件尺寸的变化和荷载的持续时间,混凝土的配合比,周围环境的温度、湿度,随时间的增长混凝土弹性模量的降低,梁的无裂缝区段和有裂缝区段的有效刚度等相应的研究参数,更接近试验梁的实际受力状态.对照挠度计算和试验实测的结果证明,采用瞬时曲率曲线的挠度计算方法比较简捷,并能达到适当的精度.

The reinforced concrete beam becomes weaker and deformed because of the creep effects and shrinkage of concrete under the long-term function.The stiffness is at any time lower, but deflection of beam increases at any time, th erefore the calculation of deflection is of complicacy. The method of the calcul ation of moment-curvature curve adoptes corresponding parameter of research.Th e beam length,water-cement ratio, varying moment, concrete material behavior, elasticity modules, humidity and temperature, the effective stiffness of beam cracks area segment.They are more near to the appearance and efficiency of the b eam under physical loads. Comparison with measured deflections shows that a reas onable level of accuracy can be achieved by the proposed approach.