西安建筑科技大学学报(自然科学版)

钢筋混凝土框架结构作为一种通用结构形式,已经广泛应用于国内外的土木建筑行业,随着框架结构的应用和发展,对其所开展的研究工作也非常深入和全面.然而,目前对于框架结构地震倒塌及其倒塌后对周边造成影响范围的研究依然是难点之一,且对该方面的研究还非常少.针对Abaqus软件本身材料模型在倒塌阶段适用性差的问题,本文基于Vumat子程序开发了与应变率相关的混凝土、钢筋材料大应变本构关系模型,并通过与实验数据的对比验证了所开发材料模型的准确性.利用开发的本构关系模型,建立了四层钢筋混凝土框架结构,基于单元删除法模拟了框架结构在地震动作用下的倒塌全过程,对结构的倒塌机理及其倒塌后的影响范围进行了分析.结果表明:底层轴压比较大的框架柱会率先破坏,水平地震动的破坏作用主要体现在柱脚部位而竖向地震动则主要体现在框架柱的中上部位; 竖向地震动对结构倒塌时的侧移及梁、板、柱的破坏状态及废墟分布有很大影响; 不同地震作用下,框架结构的倒塌影响范围高度比一般在0.5以内.

As a general structural form, reinforced concrete frame structure has been widely used in civil construction industry at home and abroad.With the application and development of frame structure, the research work carried out on it is also very in-depth and comprehensive.However, at present, it is still difficult to study the seismic collapse of RC frame structureand its impact on the surrounding area,and the research on this aspect is still very few.To solve the problem of poor applicability of Abaqus material model in collapse stage, a large strain constitutive relationship model of concrete and steel material related to strain rate were developed based on Vumat subroutine, and the accuracy of the developed constitutive modelswere verified by comparing with experimental data.Based on the developed constitutive model, a four-story RC frame structure was established, and the whole process of seismic collapse of the structure under the action of ground motion time history was simulated by element deletion method.The collapse mechanism of the structure and the influence range after collapse were analyzed.The results show that the column with large axial pressure at the bottom will be destroyed first, and the damage of horizontal ground motion is mainly concentrated at the column foot, while the impact of vertical ground motion is mainly concentrated on middle and upper part of the column.Both the failure states of beams, slabs, columnsand the influence range are greatly impacted by vertical ground motion.Under different earthquakes, most of the collapse influence range height ratios of RC frame structure are less than 0.5.

引言
1 钢筋混凝土材料本构关系模型
2 RC框架结构地震倒塌机理分析
3 结论

图1 钢筋材料本构关系模型开发流程<br/>Fig.1 Constitutive relation model flow chart of steel

图1 钢筋材料本构关系模型开发流程
Fig.1 Constitutive relation model flow chart of steel

图2 混凝土本构模型建立流程图<br/>Fig.2 Constitutive relation modelflow chart of concrete

图2 混凝土本构模型建立流程图
Fig.2 Constitutive relation modelflow chart of concrete

图3 RC框架结构基底剪力-顶层位移曲线对比图<br/>Fig.3 Comparison of base shear -top displacement curve of RC frame structure

图3 RC框架结构基底剪力-顶层位移曲线对比图
Fig.3 Comparison of base shear -top displacement curve of RC frame structure

图4 RC框架结构模型<br/>Fig.4 Schematic diagram of RC frame structure model

图4 RC框架结构模型
Fig.4 Schematic diagram of RC frame structure model

图5 梁柱截面配筋图<br/>Fig.5 Section reinforcement diagram of beam and column

图5 梁柱截面配筋图
Fig.5 Section reinforcement diagram of beam and column

表1 改进Johnson-Cook钢筋本构模型参数<br/>Tab.1 ImprovedJohnson-Cook steel constitutive model parameters

表1 改进Johnson-Cook钢筋本构模型参数
Tab.1 ImprovedJohnson-Cook steel constitutive model parameters

表2 修正HJC混凝土本构模型参数<br/>Tab.2 Modified HJC concrete constitutive model parameters

表2 修正HJC混凝土本构模型参数
Tab.2 Modified HJC concrete constitutive model parameters

表3 所选地震动加速度峰值与主频<br/>Tab.3 Peak acceleration and dominant frequency of the selected ground motions

表3 所选地震动加速度峰值与主频
Tab.3 Peak acceleration and dominant frequency of the selected ground motions

图6 卧龙地震波作用下框架结构不同时间的破坏状况(PGA=1.0 g)<br/>Fig.6 Failure states of frame structures at discrete times under Wolong seismic wave(PGA=1.0 g)

图6 卧龙地震波作用下框架结构不同时间的破坏状况(PGA=1.0 g)
Fig.6 Failure states of frame structures at discrete times under Wolong seismic wave(PGA=1.0 g)

图7 卧龙地震波作用下框架结构局部破坏特征(PGA=1.0 g,t=8.1 s)<br/>Fig.7 Local failure characteristics of frame structure under Wolong seismic wave(PGA=1.0g,t=8.1

图7 卧龙地震波作用下框架结构局部破坏特征(PGA=1.0 g,t=8.1 s)
Fig.7 Local failure characteristics of frame structure under Wolong seismic wave(PGA=1.0g,t=8.1

图8 房屋倒塌后影响范围示意图<br/>Fig.8 Diagram of influence scope of the collapsed house

图8 房屋倒塌后影响范围示意图
Fig.8 Diagram of influence scope of the collapsed house

表4 不同地震下影响范围高度比<br/>Tab.4 Height ratio of influence range under ground motions

表4 不同地震下影响范围高度比
Tab.4 Height ratio of influence range under ground motions

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备注

引言

1 钢筋混凝土材料本构关系模型

2 RC框架结构地震倒塌机理分析

3 结论

期刊信息