摘要
合理估算大变形条件下梁板构件的极限抗力,对工程设计计算具有重要意义。传统的RC(reinforced concrete)板极限抗力一般由小变形条件下的受压薄膜效应得到,然而RC板构件的灾变断裂大部分出现在大挠度阶段,因此考虑压-拉薄膜效应的极限抗力分析尤为重要。该文将RC板从加载到断裂全过程分为板端受压上升段、混凝土开裂下降段和钢筋拉伸上升段,根据正截面抗弯的钢筋混凝土弹塑性模型得到基于受压薄膜效应的荷载-挠度全曲线。利用经典的挠曲线微分方程并引入抗弯刚度软化系数对挠度进行修正,结合能量原理推导出大变形条件下基于受拉薄膜效应的RC板极限抗力,进一步得到考虑压-拉薄膜效应的荷载-挠度全曲线。计算结果表明,考虑压-拉薄膜效应的RC板极限抗力分析方法可以更合理地预测荷载-挠度全过程,计算结果与相关试验吻合良好,为合理评估RC板的极限承载力提供参考。
It is important to estimate the carrying-capacities of beams and slab members under large deformation condition in the engineering design. The carrying-capacities of reinforced concrete （RC） slabs are conventionally obtained by the compressive-membrane effect under small deformation condition. However, it is extremely important to estimate the carrying-capacities of RC slabs by taking the compressive-tensile membrane effect into account due to most of catastrophic fractures of the members occur in the large deflection stage. The whole process from loading to fracture of RC slabs is divided into the compression of the slab end, the descending branch of concrete cracking and the ascending branch of reinforcement yielding. The load-deflection curve with membrane effect is obtained according to the elastic-perfectly plastic model of reinforced concrete member under bending moment. The carrying-capacities of RC slabs based on the tensile-membrane effect under large deformation condition are derived and the full load-deflection curves by taking the compressive-tensile membrane effect into account are further obtained by using the classical deflection differential equation and the energy principle, in which the softening coefficient of flexural rigidity is used to correct the deflection. The results show that the full load-deflection relationships of RC slab can be predicted reasonably based on the carrying-capacity assessment including the compressive-tensile membrane effect. It is indicated that the analytical results are in good agreement with the test data and can be employed to predict the carrying-capacities of RC slabs.
作者
成松松
陈万祥
郭志昆
张岩岩
CHENG Song-song;CHEN Wan-xiang;GUO Zhi-kun;ZHANG Yan-yan(State Key Laboratory of Disaster Prevention ＆ Mitigation of Explosion ＆ Impact,PLA Army Engineering University,Nanjing 210007,China;East China Sea Engineering Design Institute,Shanghai 200083,China;School of Civil Engineering,Sun Yat-Sen University,Guangzhou 510275,China)
出处
《工程力学》
EI
CSCD
北大核心
2018年第12期81-88,共8页
Engineering Mechanics
基金
国家自然科学基金项目(51578541
51378498)
关键词
钢筋混凝土板
压-拉薄膜效应
屈服线理论
挠度修正
极限抗力
reinforced concrete slab
compressive-tensile membrane effects
yield line theory
deflection correction
carrying-capacity
