The objective of this study is to increase the insight into the mechanical behaviors of steel fiber reinforced high-performance concrete （SFHPC） after exposure to high temperatures. Three types of steel fibers were ...The objective of this study is to increase the insight into the mechanical behaviors of steel fiber reinforced high-performance concrete （SFHPC） after exposure to high temperatures. Three types of steel fibers were used and three-point bending tests on notched beams of SFHPC were carried out. The results showed that the flexural toughness and fracture energy of SFHPC increased evidently with the fiber content. The hooked steel fibers with higher strength possess higher flexural toughness and fracture energy than the marked steel fibers with lower strength. After exposure to high temperatures of 300, 600 and 900 ℃ in an electrical furnace, the compressive strength, flexural toughness and fracture energy of SFHPC decreased less than that of HPC without fibers, Both steel fiber content and type had strong influences on the flexural toughness and fracture energy. In addition, the failure patterns of SFHPC beams changed from pull-out of steel fibers at lower temperatures to tensile failure of steel fibers at 900 ℃.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
基金The National Natural Science Foundation of China (No.50278013)
文摘The objective of this study is to increase the insight into the mechanical behaviors of steel fiber reinforced high-performance concrete （SFHPC） after exposure to high temperatures. Three types of steel fibers were used and three-point bending tests on notched beams of SFHPC were carried out. The results showed that the flexural toughness and fracture energy of SFHPC increased evidently with the fiber content. The hooked steel fibers with higher strength possess higher flexural toughness and fracture energy than the marked steel fibers with lower strength. After exposure to high temperatures of 300, 600 and 900 ℃ in an electrical furnace, the compressive strength, flexural toughness and fracture energy of SFHPC decreased less than that of HPC without fibers, Both steel fiber content and type had strong influences on the flexural toughness and fracture energy. In addition, the failure patterns of SFHPC beams changed from pull-out of steel fibers at lower temperatures to tensile failure of steel fibers at 900 ℃.
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。
