توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱INTERNAL STEEL BRACING OF RC FRAMES
نویسنده(ها):
اطلاعات انتشار: سومین کنفرانس بین المللی بتن و توسعه، سال
تعداد صفحات: ۱۸
Steel bracing systems can be used effectively for seismic retrofitting of existing RC buildings as well as for seismic design of new buildings. Although adaptation of bracing to upgrade the lateral load capacity of existing RC frames has been the subject of a number of successful studies, guidelines for its use in newly constructed RC frames need to be further developed. This paper reports on some
recent experimental and numerical work conducted by the author and his colleagues on internal bracing of RC frames using direct connections between the bracing system and the frame. The effects of X–bracing and knee bracing on enhancing the seismic capacity of the frames are investigated experimentally through pushover tests as well as cyclic tests. A compression release device has also been introduced and tested to enhance the seismic performance of the bracing system by avoiding the buckling of the compression member. An important consideration in the design of steel–braced RC frames is the level of interaction between the strength capacities of the RC frame and the bracing system. In this paper, results of experimental and numerical investigations aimed at evaluating the level of capacity interaction between the two systems are also discussed. It is found that the capacity interaction is due primarily to connections verstrength. Based on the numerical results the connection overstrength has been quantified and guidelines for the seismic design of the internally braced RC frames with direct connections are provided.<\div>

۲Size and topology optimization of trusses using hybrid genetic–particle swarm algorithms
نویسنده(ها): ، ،
اطلاعات انتشار: نهمین کنگره بین المللی مهندسی عمران، سال
تعداد صفحات: ۸
Optimal design of truss structures is an active branch of research in optimization. Three main classes of truss optimization include size, geometry and topology. Extensive research in a range of different types of optimizing methods have been done. Nowadays many of optimization algorithms are inspired by natural phenomena such as genetic algorithm, particle swarm and ants colonies. These, so–called metaheuristic algorithms, produce random initial solutions and improve their efficiency during the process of optimizing, and search for global optimum. In order to overcome the disadvantages of genetic algorithm (high computational cost of the slow convergence rate in solving engineering optimization problems) and particle swarm algorithm (falling into local optimum and premature convergence), these two algorithms are combined to reach better solutions and increased stability. In hybrid algorithms, the main advantages of using the particle swarm optimization include directing the agents toward the global best (obtained by the swarm) and the local best (obtained by the agent itself) so that the genetic algorithm is improved in performance. In this paper, size and topology of trusses are optimized using hybrid genetic–particle swarm (HGAPSO) algorithms. To optimize truss weight, complex design variables, cross section of members and node connectivity, are selected as discrete design variables, so that desired constraints such as stress and displacement restrictions and buckling of members are satisfied. Finally, some design examples are tested using the new method compared to other heuristic algorithms to demonstrate the effectiveness of the present work<\div>
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