钢-混凝土组合框架梁变形计算的有效翼缘宽度

Effective flange width for calculation of the deformation of steel-concrete composite frame beams

由于剪滞效应的存在,组合框架梁的混凝土翼板不能完全参与共同工作,按照完全组合的换算截面法计算组合梁的变形将得到不安全的计算结果。首先根据弹性理论推导传统的完全组合梁以及剪滞组合梁理论模型的基本方程,并采用有限元软件Msc.Marc对理论模型进行验证,理论结果与有限元计算结果吻合良好,说明理论模型的准确性及合理性。然后基于两个理论模型,提出一种物理意义更为明确的有效翼缘宽度系数的定义,直接用于组合梁的变形计算。研究楼板的宽跨比、楼板宽厚比、板梁高度比以及组合梁高宽比这4个无量纲参数对有效翼缘宽度系数的影响。研究发现,影响有效翼缘宽度系数的关键参数为楼板的宽跨比。在此基础上,提出有效翼缘宽度的计算公式,为组合梁的研究及设计人员提供参考。

The concrete flange of composite frame beams may not be fully involved to work together with the steel beam because of the shear-lag effect. The traditional methods with complete interaction for calculating the deflection of composite frame beams would be unsafe. This paper presents the derivation of the basic equation of theoretical models of fully composite beam and shear-lag composite beam. The theoretical models were verified by a finite element model established in Msc. Marc. The theoretical results are in good agreement with the finite element results. Based on the theoretical models, a new definition of effective flange width with clear physical meaning for calculating the deformation of composite beams was proposed. Parametric analyses were carried out to study the impact of some dimensionless parameters on the effective width factor. These dimensionless parameters include width-span ratio of slab, widththickness ratio of slab, height ratio of concrete slab, height-width ratio of the composite beam. It parameter influencing the effective width factor is the width-span ratio of slab. Equations for calc width factor were proposed for steel-concrete composite frame beams. was found that the key ulating effective flange