Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provi...Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provided by rectangular hoops that did not meet current ACI specifications for ductile frames. For comparison purposes, the columns in three of these frames were jacketed by carbon-fiber-reinforced-polymer （CFRP） sheets to avoid possible shear failure. A nonlinear pushover analysis, in which the force-deformation relationships of individual elements were developed based on ACI 318, FEMA 356, and Chen＇s model, was carried out for these frames and compared to test results. Both the failure mechanisms and impact of infills on the behaviors of these frames were examined in the study. Conclusions from the present analysis provide structural engineers with valuable information for evaluation and design of infilled concrete frame building structures.展开更多
Strong near-fault ground motion, usually caused by the fault-rupture and characterized by a pulse-like velocity- wave form, often causes dramatic instantaneous seismic energy （Jadhav and Jangid 2006）. Some reinforce...Strong near-fault ground motion, usually caused by the fault-rupture and characterized by a pulse-like velocity- wave form, often causes dramatic instantaneous seismic energy （Jadhav and Jangid 2006）. Some reinforced concrete （RC） bridge columns, even those built according to ductile design principles, were damaged in the 1999 Chi-Chi earthquake. Thus, it is very important to evaluate the seismic response of a RC bridge column to improve its seismic design and prevent future damage. Nonlinear time history analysis using step-by-step integration is capable of tracing the dynamic response of a structure during the entire vibration period and is able to accommodate the pulsing wave form. However, the accuracy of the numerical results is very sensitive to the modeling of the nonlinear load-deformation relationship of the structural member. FEMA 273 and ATC-40 provide the modeling parameters for structural nonlinear analyses of RC beams and RC columns. They use three parameters to define the plastic rotation angles and a residual strength ratio to describe the nonlinear load- deformation relationship of an RC member. Structural nonlinear analyses are performed based on these parameters. This method provides a convenient way to obtain the nonlinear seismic responses of RC structures. However, the accuracy of the numerical solutions might be further improved. For this purpose, results from a previous study on modeling of the static pushover analyses for RC bridge columns （Sung et al. 2005） is adopted for the nonlinear time history analysis presented herein to evaluate the structural responses excited by a near-fault ground motion. To ensure the reliability of this approach, the numerical results were compared to experimental results. The results confirm that the proposed approach is valid.展开更多
该本主要目的是运用向量式有限元(VFIFE,V-5)方法,提出以VFIFE刚架元所建立车辆模型称为车辆刚架元模型(Vehicle Model Using Frame Element,简称VMUFE)来模拟车辆运动。VFIFE方法不但可仿真轨道与桥梁非线性变形,亦可分析车辆变形体的...该本主要目的是运用向量式有限元(VFIFE,V-5)方法,提出以VFIFE刚架元所建立车辆模型称为车辆刚架元模型(Vehicle Model Using Frame Element,简称VMUFE)来模拟车辆运动。VFIFE方法不但可仿真轨道与桥梁非线性变形,亦可分析车辆变形体的运动与振动,且可简化模拟刚体车辆运动。此外,VFIFE方法不需要调整任何计算参数以及不需要反复迭代运算过程。为证明研究方法确实能模拟车辆与轨道分离后运动行为,以两题数值算例来证明分析精确性,以及模拟车辆脱轨运动的行为。展开更多
基金Science Council of Chinese Taipei Under Grant No. SC-92-2625-Z-027-003
文摘Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provided by rectangular hoops that did not meet current ACI specifications for ductile frames. For comparison purposes, the columns in three of these frames were jacketed by carbon-fiber-reinforced-polymer （CFRP） sheets to avoid possible shear failure. A nonlinear pushover analysis, in which the force-deformation relationships of individual elements were developed based on ACI 318, FEMA 356, and Chen＇s model, was carried out for these frames and compared to test results. Both the failure mechanisms and impact of infills on the behaviors of these frames were examined in the study. Conclusions from the present analysis provide structural engineers with valuable information for evaluation and design of infilled concrete frame building structures.
基金Science Council, Chinese Taipei 106, Under Grant No. NSC-95-2625-Z-027-004
文摘Strong near-fault ground motion, usually caused by the fault-rupture and characterized by a pulse-like velocity- wave form, often causes dramatic instantaneous seismic energy （Jadhav and Jangid 2006）. Some reinforced concrete （RC） bridge columns, even those built according to ductile design principles, were damaged in the 1999 Chi-Chi earthquake. Thus, it is very important to evaluate the seismic response of a RC bridge column to improve its seismic design and prevent future damage. Nonlinear time history analysis using step-by-step integration is capable of tracing the dynamic response of a structure during the entire vibration period and is able to accommodate the pulsing wave form. However, the accuracy of the numerical results is very sensitive to the modeling of the nonlinear load-deformation relationship of the structural member. FEMA 273 and ATC-40 provide the modeling parameters for structural nonlinear analyses of RC beams and RC columns. They use three parameters to define the plastic rotation angles and a residual strength ratio to describe the nonlinear load- deformation relationship of an RC member. Structural nonlinear analyses are performed based on these parameters. This method provides a convenient way to obtain the nonlinear seismic responses of RC structures. However, the accuracy of the numerical solutions might be further improved. For this purpose, results from a previous study on modeling of the static pushover analyses for RC bridge columns （Sung et al. 2005） is adopted for the nonlinear time history analysis presented herein to evaluate the structural responses excited by a near-fault ground motion. To ensure the reliability of this approach, the numerical results were compared to experimental results. The results confirm that the proposed approach is valid.
文摘该本主要目的是运用向量式有限元(VFIFE,V-5)方法,提出以VFIFE刚架元所建立车辆模型称为车辆刚架元模型(Vehicle Model Using Frame Element,简称VMUFE)来模拟车辆运动。VFIFE方法不但可仿真轨道与桥梁非线性变形,亦可分析车辆变形体的运动与振动,且可简化模拟刚体车辆运动。此外,VFIFE方法不需要调整任何计算参数以及不需要反复迭代运算过程。为证明研究方法确实能模拟车辆与轨道分离后运动行为,以两题数值算例来证明分析精确性,以及模拟车辆脱轨运动的行为。
