大体积非杆系混凝土承载板的配筋

Reinforcement of massive non-member concrete bearing plate

以实际工程为背景,采用模拟施工法和叠合梁法计算大体积非杆系混凝土承载板的应力,讨论两种方法所得结果的区别及不同弹性模量随时间变化的计算公式对计算结果的影响,再按应力图形法进行承载力配筋,并采用钢筋混凝土有限元法进行裂缝验算。计算结果表明:采用模拟施工法计算时,不同弹性模量随时间变化的计算公式对最大主拉应力与关键截面的主拉应力影响不大;虽然模拟施工法得到的拉应力最大值大于叠合梁法,但两者所得应力分布规律相同,关键截面的主拉应力和承载力所需的配筋量相近;按应力图形法所配钢筋能满足裂缝宽度的要求;大体积非杆系混凝土承载板的配筋设计可采用简单的叠合梁法计算应力分布,按应力图形法配筋,除特别重要的结构外一般可不用钢筋混凝土有限元法进行裂缝宽度计算。

The stress of massive non-member concrete bearing plate is calculated based on a practical project by means of the simulating construction method and the composite beam method. The differences between their calculated results as well as the influences of different formulae for the variation of elastic modulus with time are discussed. The reinforcement of bearing capacity is determined by use of the stress graphic method, and the crack width is verified by means of the reinforced concrete finite element method （RCFEM）. The results show that the maximum tensile principal stress and tensile force of the key cross section are not obviously affected by the formula for the variation of elastic modulus with time by applying the simulating construction method. Although the maximum tensile principal stress yielded by the simulating construction method is larger than that by the composite beam method, the distribution laws of their calculated stresses are the same, and their tensile forces and reinforcements of bearing capacity of the key cross section are very close. The reinforcement according to the stress graphic method can meet the requirements of crack width control. The distribution of stress of massive non-member concrete bearing plate can be calculated by means of the simple composite beam method, and the reinforcement can be determined by use of the stress graphic method. It is not necessary to employ RCFEM to verify the crack width for similar structures except special ones.