用变形和分解原理求混凝土板的受拉薄膜效应  

CALCULATION OF TENSILE MEMBRANE EFFECTS OF CONCRETE SLABS USING DEFORMATION ADDITIVE DECOMPOSITION THEOREM

作　　者：董毓利[1] 

机构地区：[1]哈尔滨工业大学土木工程学院,哈尔滨150090

出　　处：《力学学报》2010年第6期1180-1187,共8页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(50878069);科技部支撑计划(2006BAJ13B03)资助项目~~

摘　　要：利用变形梯度直和分解,提出了基于能量原理计算钢筋混凝土板大变形时极限承载力方法,该方法考虑了薄膜效应影响并与传统塑性铰线理论相统一,既适用于矩形板和方形板,也适用于各向同性配筋和各向异性配筋的板,认为薄膜效应主要是由于塑性铰线处钢筋的伸长耗能造成的,该方法还可以解释同样挠度下方形板比矩形板早破坏和同样配筋时在矩形板短跨方向钢筋断裂的试验现象.计算结果与试验具有很好的一致性.Significant experimental and theoretical research work showed that,concrete slabs at large vertical displacements could support loads considerably greater than those calculated by the well-established yield-line approach.The mechanism for supporting the load was shown to be tensile membrane action,which could form within the slab irrespective of whether it was restrained or unrestrained horizontally at its boundaries. Most of these research works were based on work method.Combining of previous research work and segment equilibrium method,Bailey（2001） proposed a simplified design method,which took account the membrane action of composite floor slabs at large displacements.This model considered the slab with no in-plane horizontal restraint at its edges,can carry a load greater than that calculated using normal yield-line theory,is partly due to in-plane tensile stresses developing at the centre of the slab and partly due to the increase in yield moment in the outer regions of the slab,where compressive stresses occur.The enhancement included two parts,one is due to membrane action and another is due to membrane forces,of yield line load for each element.Typically the enhancements of 2 elements are not equal,and the difference was explained by the effects of vertical shear or the in-plane shear.Because Bailey＇s theoretical derivation was based on in-plane resultant moment equilibrium equations,and assumed the fracture failure model of reinforcements occurred through the depth of the slab across the short span at first,so it is not unified with the yield-line theory,and may lead to tedious calculations. Based on the additive decomposition theory of deformation gradients,this paper presents an energy-based model to determine the limit carrying capacity of concrete slab at large displacement,which considered the membrane effects and unified with the conventional plastic line theory.The model could predict the load-carrying capacity of either rectangular or square concrete slabs with both orthotropic and isotropi

关 键 词：薄膜效应 钢筋伸长 塑性铰线 混凝土板 变形和分解 

分 类 号：O344.5[理学—固体力学]