The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismi...The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismic response of building structures is examined. Three multi-story RC buildings, representing a very common structural typology in Italy, are used as case studies for the evaluation. They are, respectively, a rectangular plan shape, an L plan shape and a rectangular plan shape with courtyard buildings. Nonlinear static and dynamic analyses are performed by considering different seismic levels, characterized by peak ground acceleration on stiff soil equal to 0.35 g, 0.25 g and 0.15 g. Nonlinear dynamic analyses are carried out by considering twelve different earthquake directions, and rotating the direction of both the orthogonal components by 30° for each analysis(from 0° to 330°). The survey is carried out on the L plan shape structure. The results show that the angle of the seismic input motion signifi cantly infl uences the response of RC structures; the critical seismic angle, i.e., the incidence angle that produces the maximum demand, provides an increase of up to 37% in terms of both roof displacements and plastic hinge rotations.展开更多
城市作战的重要性日益凸显,城市作战路径规划也受到了更多的关注。如何在城市复杂的环境和众多危险区中寻找安全迅速的路径是非常重要的。为保障作战安全,提出了一种基于选拔科特鸟和路径缩减的不规则危险区路径规划算法。首先,结合城...城市作战的重要性日益凸显,城市作战路径规划也受到了更多的关注。如何在城市复杂的环境和众多危险区中寻找安全迅速的路径是非常重要的。为保障作战安全,提出了一种基于选拔科特鸟和路径缩减的不规则危险区路径规划算法。首先,结合城市危险区特征和受限情况以构建更符合真实战场的不规则危险区数学模型。其次,建立路径空间缩减模型对路径威胁度进行评估和量化,以剔除掉高威胁路径来降低作战风险。最后,基于选拔策略的科特鸟优化算法(COOT Bird Optimization Algorithm based on Selection Strategy,SS-COOT)结合优质个体以提高算法的寻优效率。经实验验证,该算法在结合不规则危险区的城市路径规划问题上具有搜索速度快、寻优效果好的特点。展开更多
One of the major challenges of constructing any high rise building for civil engineers is to make it earthquake resistant. This resistance largely depends on the building’s shape and structural system. A comparative ...One of the major challenges of constructing any high rise building for civil engineers is to make it earthquake resistant. This resistance largely depends on the building’s shape and structural system. A comparative study has been done in this paper about the seismic behavior and response of buildings having a regular plan and plan irregularity (re-entrant corners). The 5 building models considered in this study are 15 stories each, the same area and identical weight. Among the 5 building models, 2 are with a regular plan (square, rectangle) and the other 3 building models are with plan irregularity (re-entrant corners). All of them are modeled using ETABS 2015 program for Dhaka, Bangladesh (seismic zone 2). Static loads, wind loads and seismic loads are considered for each model and dynamic response under Bangladesh National Building Code (BNBC) 2006 response spectrum has been meticulously analyzed. A comparison for story displacement, base shear, story drift and time period has been established and explored for dynamic response spectrum among the models. The results show that buildings with irregularity have a greater value of time period, drift and displacement and hereby are more susceptible to damage during an earthquake or disaster.展开更多
基金partially funded by Italian Department of Civil Protection in the frame of the National ReLUIS Project 2005-2008 line 2-Theme 2
文摘The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismic response of building structures is examined. Three multi-story RC buildings, representing a very common structural typology in Italy, are used as case studies for the evaluation. They are, respectively, a rectangular plan shape, an L plan shape and a rectangular plan shape with courtyard buildings. Nonlinear static and dynamic analyses are performed by considering different seismic levels, characterized by peak ground acceleration on stiff soil equal to 0.35 g, 0.25 g and 0.15 g. Nonlinear dynamic analyses are carried out by considering twelve different earthquake directions, and rotating the direction of both the orthogonal components by 30° for each analysis(from 0° to 330°). The survey is carried out on the L plan shape structure. The results show that the angle of the seismic input motion signifi cantly infl uences the response of RC structures; the critical seismic angle, i.e., the incidence angle that produces the maximum demand, provides an increase of up to 37% in terms of both roof displacements and plastic hinge rotations.
文摘城市作战的重要性日益凸显,城市作战路径规划也受到了更多的关注。如何在城市复杂的环境和众多危险区中寻找安全迅速的路径是非常重要的。为保障作战安全,提出了一种基于选拔科特鸟和路径缩减的不规则危险区路径规划算法。首先,结合城市危险区特征和受限情况以构建更符合真实战场的不规则危险区数学模型。其次,建立路径空间缩减模型对路径威胁度进行评估和量化,以剔除掉高威胁路径来降低作战风险。最后,基于选拔策略的科特鸟优化算法(COOT Bird Optimization Algorithm based on Selection Strategy,SS-COOT)结合优质个体以提高算法的寻优效率。经实验验证,该算法在结合不规则危险区的城市路径规划问题上具有搜索速度快、寻优效果好的特点。
文摘One of the major challenges of constructing any high rise building for civil engineers is to make it earthquake resistant. This resistance largely depends on the building’s shape and structural system. A comparative study has been done in this paper about the seismic behavior and response of buildings having a regular plan and plan irregularity (re-entrant corners). The 5 building models considered in this study are 15 stories each, the same area and identical weight. Among the 5 building models, 2 are with a regular plan (square, rectangle) and the other 3 building models are with plan irregularity (re-entrant corners). All of them are modeled using ETABS 2015 program for Dhaka, Bangladesh (seismic zone 2). Static loads, wind loads and seismic loads are considered for each model and dynamic response under Bangladesh National Building Code (BNBC) 2006 response spectrum has been meticulously analyzed. A comparison for story displacement, base shear, story drift and time period has been established and explored for dynamic response spectrum among the models. The results show that buildings with irregularity have a greater value of time period, drift and displacement and hereby are more susceptible to damage during an earthquake or disaster.
