剪力墙竖向不连续结构的震害与抗震设计概念

介绍在1971年美国圣费南多地震、1979年美国ElCentro地震、1995年日本阪神地震中,5个有代表性的剪力墙竖向不连续结构的震害。通过分析提出这种结构的一些抗震设计概念:部分框支剪力墙结构上部楼层的剪力墙仅部分在底部中断,转换为框架,有足够的剪力墙连续贯通落地,如设计合理,其抗震性能比较好,但如设计不当,仍难免发生严重或比较严重的震害;部分框支剪力墙结构抗震设计中需要加强的部位应包括底部及转换层以上1～2层的楼板、剪力墙和柱,结构的延性耗能机制宜呈现在加强部位以上的结构中;框架-剪力墙结构中的剪力墙一般不宜中断;框支柱设计中要注意上部刚性墙体地震倾覆力矩产生的框支柱轴向拉、压力的影响。     

Design optimization of truss structures with continuous and discrete variables by hybrid of biogeography‐based optimization and differential evolution methods

This paper presents a hybrid BBO‐DE algorithm by hybridizing biogeography‐based optimization (BBO) and differential evolution (DE) methods for optimum design of truss structures with continuous and discrete variables. In BBO‐DE, the migration operator of BBO method serves as a local exploiter mechanism during the search process. Besides, DE has a role of the global exploration by performing multiple search directions in the search space to preserve more diversity in the population. By embedding of DE algorithm in BBO method as a mutation mechanism, the balance between the exploration and exploitation abilities is further improved. The comparative results with some of the most recently developed methods demonstrate the fast convergence properties of the proposed algorithm and confirm its effectiveness to solve optimum design problems of truss structures with continuous and discrete variables.     

Seismic design and assessment of structures with viscous dampers at limit state levels: Focus on probability of damage in devices

During large earthquakes, the seismic demand of viscous dampers may exceed their capacity. In this regard, current design codes must consider extreme conditions and preserve the damper at limit state levels. Here, by adjusting the damping coefficient, a procedure is introduced to mitigate device damages during severe earthquakes. To assess the procedure, 15 special moment resisting frames with a different number of stories (two, four, and eight) were designed by three methods: The recommended novel procedure, the seismic provisions of ASCE7, and the procedure proposed by Miyamoto et al. 1 for structures, installed with supplemental damping devices. A series of incremental dynamic analyses were then performed by modeling the limit state behavior of viscous dampers. Results indicated that the novel method reduces the damage probability of dampers as well as the maximum demands on the structure at different seismic hazard levels.     

Differentiation in Vital Practice: An Analysis Using RMIT University of Technology and Design Interfaces With Architects

One of the most influential figures in architectural education and practice today, Leon van Schaik , Professor of Architecture (Chair of Innovation) at RMIT in Melbourne, has dedicated the last two decades of his career to the promotion of local and international architectural culture through design practice research and the commissioning of building. Here he describes how he has nurtured a research-oriented approach through his engagement with a network of ‘vital’ practitioners worldwide who are interested in strong ideas and pushing the questioning of the status quo.