基于能量平衡的钢筋混凝土框架结构抗震塑性设计方法

在已有研究成果基础上发展了基于能量平衡的钢筋混凝土框架结构塑性设计方法。通过结构多失效模式分析，以“强柱弱梁”整体破坏机制作为塑性设计的失效模式；推导了结构能量平衡方程并给出了地震输入能和弹性振动能的计算式。为反映混凝土结构的承载力、刚度退化和捏缩效应，给出了修正的结构能量平衡方程，对结构的非弹性应变能进行修正。根据外力做功等于结构的非弹性应变能，求出考虑P-Δ效应的结构的侧向力大小，进而根据结构的耗能机制计算出梁柱构件截面的内力值。最后对1榀3跨7层钢筋混凝土框架进行塑性设计，并与对应的弹性设计结果进行对比。分析结果表明：塑性设计结构能充分形成“强柱弱梁”型屈服机制，结构的延性好，层间变形更加均匀，其抗震能力更强，验证了该方法的有效性和优越性。

Seismic plastic design of RC frame structure based on energy balance

This research focused on the development of plastic design methodology under strong earthquakes using energy balance concept for reinforced concrete frame structures. The strong-column weak-beam mechanism was selected as the basic failure mode of plastic design through the multiple failure mode analyses. From the differential equation of motion, the structural energy equilibrium equation was derived, and the elastic vibration energy and earthquake input energy were given. In order to reflect the deterioration of load-carrying capacity, stiffness degradation and pinching effects, the modified energy equilibrium equation was proposed. Based on the fact that the external work equals the internal work, the lateral forces could be obtained, taking into account the P-Δ effects. Then, the sectional internal forces of beams and columns could be calculated through the energy dissipating mechanism. A seven-story RC frame structure was designed based on the plastic design method and the performance of plastic design structure was compared with that of elastically designed structure. The results show that the plastically designed structure can fully develop the strong-column weak-beam yielding mechanism and have a better ductility performance and uniform maximum story drift along the height, indicating the effectiveness of the proposed plastic design method.