以5层钢框架结构为对象,对钢框架在爆炸冲击作用下的连续倒塌性能进行了研究.采用备用荷载路径法,分别对钢框架结构进行了静力非线性、动力非线性以及爆炸冲击作用下的动力非线性连续倒塌分析.分析结果表明:在常规的静力和动力非线性分...以5层钢框架结构为对象,对钢框架在爆炸冲击作用下的连续倒塌性能进行了研究.采用备用荷载路径法,分别对钢框架结构进行了静力非线性、动力非线性以及爆炸冲击作用下的动力非线性连续倒塌分析.分析结果表明:在常规的静力和动力非线性分析中,该框架具有良好的抗连续倒塌能力;在5 kg TNT的初始爆炸冲击作用下,钢框架的变形比常规分析增大15%～40%;在15 kg TNT的爆炸冲击作用下,钢框架将发生整体性倒塌.因此传统的备用荷载路径法不适用于分析爆炸引起的连续倒塌问题,爆炸冲击的作用不可忽略;楼板在爆炸作用下对结构的连续倒塌性能有着至关重要的影响.展开更多
The changing law of internal forces during the whole deformation development process was analyzed. The process was divided into five stages based on the internal force state of the beam and the assumptions of internal...The changing law of internal forces during the whole deformation development process was analyzed. The process was divided into five stages based on the internal force state of the beam and the assumptions of internal force relationship of five stages were proposed. Then, the formulas for determining the midspan deflection of the steel beam under distributed load, which was restrained both in rotational and axial directions, were obtained using restraint coefficient method and rigid-plastic mechanism, thereby the deformation development process was expressed accurately in a quantified way. Priority was given to the analysis of the process from bending to tension-bending, then the final state totally depends on tension to resist the external loads, that is the problem of catenary action of the restrained beam under distributed load. Additionally, finite element analysis was carried out with soitware ABAQUS6.7 on a restrained steel beam under distributed load with different axial and rotational restraint coefficients. The accuracy of the formulas presented was verified by the results of the behavior of the restrained beams. Finally, error analysis was conducted and some formulas were corrected according to the reasons of errors. The calculated results of corrected formulas match the FEM analysis results better, thus the accuracy of these formulas is improve .展开更多
Reinforced concrete(RC) load bearing wall is widely used in high-rise and mid-rise buildings. Due to the number of walls in plan and reduction in lateral force portion, this system is not only stronger against earthqu...Reinforced concrete(RC) load bearing wall is widely used in high-rise and mid-rise buildings. Due to the number of walls in plan and reduction in lateral force portion, this system is not only stronger against earthquakes, but also more economical. The effect of progressive collapse caused by removal of load bearing elements, in various positions in plan and stories of the RC load bearing wall system was evaluated by nonlinear dynamic and static analyses. For this purpose, three-dimensional model of 10-story structure was selected. The analysis results indicated stability, strength and stiffness of the RC load-bearing wall system against progressive collapse. It was observed that the most critical condition for removal of load bearing walls was the instantaneous removal of the surrounding walls located at the corners of the building where the sections of the load bearing elements were changed. In this case, the maximum vertical displacement was limited to 6.3 mm and the structure failed after applying the load of 10 times the axial load bored by removed elements. Comparison between the results of the nonlinear dynamic and static analyses demonstrated that the "load factor" parameter was a reasonable criterion to evaluate the progressive collapse potential of the structure.展开更多
文摘以5层钢框架结构为对象,对钢框架在爆炸冲击作用下的连续倒塌性能进行了研究.采用备用荷载路径法,分别对钢框架结构进行了静力非线性、动力非线性以及爆炸冲击作用下的动力非线性连续倒塌分析.分析结果表明:在常规的静力和动力非线性分析中,该框架具有良好的抗连续倒塌能力;在5 kg TNT的初始爆炸冲击作用下,钢框架的变形比常规分析增大15%～40%;在15 kg TNT的爆炸冲击作用下,钢框架将发生整体性倒塌.因此传统的备用荷载路径法不适用于分析爆炸引起的连续倒塌问题,爆炸冲击的作用不可忽略;楼板在爆炸作用下对结构的连续倒塌性能有着至关重要的影响.
基金Project(2006BAJ01B02)supported by the National Science and Technology Pillar Program during the Eleventh Five-Year Plan Period of China
文摘The changing law of internal forces during the whole deformation development process was analyzed. The process was divided into five stages based on the internal force state of the beam and the assumptions of internal force relationship of five stages were proposed. Then, the formulas for determining the midspan deflection of the steel beam under distributed load, which was restrained both in rotational and axial directions, were obtained using restraint coefficient method and rigid-plastic mechanism, thereby the deformation development process was expressed accurately in a quantified way. Priority was given to the analysis of the process from bending to tension-bending, then the final state totally depends on tension to resist the external loads, that is the problem of catenary action of the restrained beam under distributed load. Additionally, finite element analysis was carried out with soitware ABAQUS6.7 on a restrained steel beam under distributed load with different axial and rotational restraint coefficients. The accuracy of the formulas presented was verified by the results of the behavior of the restrained beams. Finally, error analysis was conducted and some formulas were corrected according to the reasons of errors. The calculated results of corrected formulas match the FEM analysis results better, thus the accuracy of these formulas is improve .
文摘Reinforced concrete(RC) load bearing wall is widely used in high-rise and mid-rise buildings. Due to the number of walls in plan and reduction in lateral force portion, this system is not only stronger against earthquakes, but also more economical. The effect of progressive collapse caused by removal of load bearing elements, in various positions in plan and stories of the RC load bearing wall system was evaluated by nonlinear dynamic and static analyses. For this purpose, three-dimensional model of 10-story structure was selected. The analysis results indicated stability, strength and stiffness of the RC load-bearing wall system against progressive collapse. It was observed that the most critical condition for removal of load bearing walls was the instantaneous removal of the surrounding walls located at the corners of the building where the sections of the load bearing elements were changed. In this case, the maximum vertical displacement was limited to 6.3 mm and the structure failed after applying the load of 10 times the axial load bored by removed elements. Comparison between the results of the nonlinear dynamic and static analyses demonstrated that the "load factor" parameter was a reasonable criterion to evaluate the progressive collapse potential of the structure.
