为了确定弹塑性单自由度(single degree of freedom,SDOF)体系地震输入能,分析了中美场地土剪切波速转换关系,将从美国PEER地震记录数据库选取的220条强震记录按中国场地土类型进行分类,基于能量平衡原理,采用归一化方法,建议了一种基...为了确定弹塑性单自由度(single degree of freedom,SDOF)体系地震输入能,分析了中美场地土剪切波速转换关系,将从美国PEER地震记录数据库选取的220条强震记录按中国场地土类型进行分类,基于能量平衡原理,采用归一化方法,建议了一种基于复合强度指标的弹性SDOF体系三段式等效速度谱.分析了5类场地土条件下SDOF体系系统参数对地震输入等效速度谱的影响.研究结果表明:刚度折减系数对等效速度谱无明显影响;延性系数和阻尼比增大均对等效速度谱峰值和下降段衰减速度有削弱作用.综合考虑各类影响因素,通过参数多次拟合,得出弹性SDOF体系归一化等效速度谱峰值段及下降段修正系数,提出了一种适用于我国场地土类型、可直接供设计使用的弹塑性SDOF体系归一化等效速度谱确定方法,并验证了其有效性.展开更多
In this paper,a modified single-degree-of-freedom(SDOF)model of reinforced concrete(RC)beams under close-in explosion is proposed by developing the specific impulse equivalent method and flexural resistance calculatio...In this paper,a modified single-degree-of-freedom(SDOF)model of reinforced concrete(RC)beams under close-in explosion is proposed by developing the specific impulse equivalent method and flexural resistance calculation method.The equivalent uniform specific impulse was obtained based on the local conservation of momentum and global conservation of kinetic energy.Additionally,the influence of load uniformity,boundary condition and complex material behaviors(e.g.strain rate effect,hardening/softening and hoop-confined effect)was considered in the resistance calculation process by establishing a novel relationship between external force,bending moment,curvature and deflection successively.The accuracy of the proposed model was verified by carrying out field explosion tests on four RC beams with the scaled distances of 0.5 m/kg~(1/3)and 0.75 m/kg~(1/3).The test data in other literatures were also used for validation.As a result,the equivalent load implies that the blast load near the mid-span of beams would contribute more to the maximum displacement,which was also observed in the tests.Moreover,both the resistance model and test results declare that when the blast load becomes more concentrated,the ultimate resistance would become lower,and the compressive concrete would be more prone to softening and crushing.Finally,based on the modified SDOF model,the calculated maximum displacements agreed well with the test data in this paper and other literatures.This work fully proves the rationality of the modified SDOF method,which will contribute to a more accurate damage assessment of RC structures under close-in explosion.展开更多
爆炸作用下地面建筑目标的破坏分析对制定实战打击策略和工程防护具有重要的实践指导意义。采用LS-DYNA有限元分析软件对已有含填充墙钢筋混凝土(reinforced concrete,RC)框架结构的近区爆炸试验进行复现,充分验证了所采用的精细化数值...爆炸作用下地面建筑目标的破坏分析对制定实战打击策略和工程防护具有重要的实践指导意义。采用LS-DYNA有限元分析软件对已有含填充墙钢筋混凝土(reinforced concrete,RC)框架结构的近区爆炸试验进行复现,充分验证了所采用的精细化数值仿真方法的适用性。结合建筑结构混合单元建模方法,对典型三层含填充墙RC框架结构在典型战斗部(100 kg和200 kg TNT当量)爆炸作用下的动态响应开展了仿真分析,考察了爆炸波在结构内部的传播和结构损伤特性。基于等效单自由度(single-degree-of-freedom,SDOF)方法预测了爆炸荷载作用下框架结构梁、柱、板和填充墙等构件的损伤等级,建立了内爆炸作用下建筑目标的破坏简化分析方法,并通过与精细化数值仿真结果对比检验其适用性。结果表明,在100 kg和200 kg TNT爆炸工况下,精细化数值仿真分析中建筑物整体功能性和结构性毁伤等级均为中度和轻度,等效SDOF简化分析得到的相应毁伤等级与数值仿真结果一致。此外,从各构件的毁伤等级可以看出,相比于板、梁和柱等承重构件,砌体填充墙更易发生破坏,从而导致爆炸波在层内水平方向房间的毁伤破坏范围更大。展开更多
建立具有设计意义的地震动总输入能量谱是实现结构能量设计的基础。根据中长周期段修正的加速度反应谱及地震动有效持时,提出了一种生成地震动输入能量谱的方法。统计270组人工波的时程分析结果,得到了以等效速度表征的四段式弹性单自由...建立具有设计意义的地震动总输入能量谱是实现结构能量设计的基础。根据中长周期段修正的加速度反应谱及地震动有效持时,提出了一种生成地震动输入能量谱的方法。统计270组人工波的时程分析结果,得到了以等效速度表征的四段式弹性单自由度(single degree of freedom,SDOF)体系总输入能量谱,并给出了不同场地类型、抗震设防烈度等设计条件下归一化等效速度谱的参数取值。在考虑延性系数及刚度折减系数的影响后,提出了弹塑性SDOF体系修正输入能量谱的等效速度谱,估算了引起结构损伤的滞回耗能占总能量的比值。该能量谱可为基于能量的结构设计及研究提供参考。展开更多
文摘为了确定弹塑性单自由度(single degree of freedom,SDOF)体系地震输入能,分析了中美场地土剪切波速转换关系,将从美国PEER地震记录数据库选取的220条强震记录按中国场地土类型进行分类,基于能量平衡原理,采用归一化方法,建议了一种基于复合强度指标的弹性SDOF体系三段式等效速度谱.分析了5类场地土条件下SDOF体系系统参数对地震输入等效速度谱的影响.研究结果表明:刚度折减系数对等效速度谱无明显影响;延性系数和阻尼比增大均对等效速度谱峰值和下降段衰减速度有削弱作用.综合考虑各类影响因素,通过参数多次拟合,得出弹性SDOF体系归一化等效速度谱峰值段及下降段修正系数,提出了一种适用于我国场地土类型、可直接供设计使用的弹塑性SDOF体系归一化等效速度谱确定方法,并验证了其有效性.
基金National Natural Science Foundation of China(Grant No.12102337)to provide fund for conducting experiments。
文摘In this paper,a modified single-degree-of-freedom(SDOF)model of reinforced concrete(RC)beams under close-in explosion is proposed by developing the specific impulse equivalent method and flexural resistance calculation method.The equivalent uniform specific impulse was obtained based on the local conservation of momentum and global conservation of kinetic energy.Additionally,the influence of load uniformity,boundary condition and complex material behaviors(e.g.strain rate effect,hardening/softening and hoop-confined effect)was considered in the resistance calculation process by establishing a novel relationship between external force,bending moment,curvature and deflection successively.The accuracy of the proposed model was verified by carrying out field explosion tests on four RC beams with the scaled distances of 0.5 m/kg~(1/3)and 0.75 m/kg~(1/3).The test data in other literatures were also used for validation.As a result,the equivalent load implies that the blast load near the mid-span of beams would contribute more to the maximum displacement,which was also observed in the tests.Moreover,both the resistance model and test results declare that when the blast load becomes more concentrated,the ultimate resistance would become lower,and the compressive concrete would be more prone to softening and crushing.Finally,based on the modified SDOF model,the calculated maximum displacements agreed well with the test data in this paper and other literatures.This work fully proves the rationality of the modified SDOF method,which will contribute to a more accurate damage assessment of RC structures under close-in explosion.
文摘爆炸作用下地面建筑目标的破坏分析对制定实战打击策略和工程防护具有重要的实践指导意义。采用LS-DYNA有限元分析软件对已有含填充墙钢筋混凝土(reinforced concrete,RC)框架结构的近区爆炸试验进行复现,充分验证了所采用的精细化数值仿真方法的适用性。结合建筑结构混合单元建模方法,对典型三层含填充墙RC框架结构在典型战斗部(100 kg和200 kg TNT当量)爆炸作用下的动态响应开展了仿真分析,考察了爆炸波在结构内部的传播和结构损伤特性。基于等效单自由度(single-degree-of-freedom,SDOF)方法预测了爆炸荷载作用下框架结构梁、柱、板和填充墙等构件的损伤等级,建立了内爆炸作用下建筑目标的破坏简化分析方法,并通过与精细化数值仿真结果对比检验其适用性。结果表明,在100 kg和200 kg TNT爆炸工况下,精细化数值仿真分析中建筑物整体功能性和结构性毁伤等级均为中度和轻度,等效SDOF简化分析得到的相应毁伤等级与数值仿真结果一致。此外,从各构件的毁伤等级可以看出,相比于板、梁和柱等承重构件,砌体填充墙更易发生破坏,从而导致爆炸波在层内水平方向房间的毁伤破坏范围更大。
文摘建立具有设计意义的地震动总输入能量谱是实现结构能量设计的基础。根据中长周期段修正的加速度反应谱及地震动有效持时,提出了一种生成地震动输入能量谱的方法。统计270组人工波的时程分析结果,得到了以等效速度表征的四段式弹性单自由度(single degree of freedom,SDOF)体系总输入能量谱,并给出了不同场地类型、抗震设防烈度等设计条件下归一化等效速度谱的参数取值。在考虑延性系数及刚度折减系数的影响后,提出了弹塑性SDOF体系修正输入能量谱的等效速度谱,估算了引起结构损伤的滞回耗能占总能量的比值。该能量谱可为基于能量的结构设计及研究提供参考。
