Abstract
abstract: This study has as its main purpose the structural optimization of plane frames in concrete, having as the objective function the minimum total weight of the structure. For this purpose, external actions, considered within the optimization process, are intended to represent accurately all effects observed in a real situation. In such manner, loads are dependent on the cross-section obtained in each optimization step, as well as the static and dynamic effects of the wind are considered for a more realistic representation. The optimization method adopted is the Teaching-Learning Based Optimization (TLBO). Thus, all proper design constraints were considered in accordance with Brazilian standards for concrete structures. From the results obtained in both situations (static and dynamic effects), it is possible to notice the difference regarding external actions, in which higher loads were obtained in higher floors, using the simplified dynamic model proposed in standards. Regarding the analysis of the structure optimization, the weight was higher when the applied forces were the result of the dynamic wind model, in which the larger cross-sections were found at the bottom of the structure. Even though this may be a well-known issue, the present work shows a quantitative study in which both effects are discussed in detail, as well as it features a methodology, based on a novel optimization method and with a straightforward implementation, that could be adapted for the analysis of more complex structures.
Highlights
High building construction trend is increasing over recent years, due to factors such as urban sprawl and high land costs, stimulating the construction of cost-effective structures and bracing systems, as these buildings are mainly affected by lateral loads induced by wind effects [1]
The efficiency of the Teaching-Learning Based Optimization (TLBO) method for the optimization of frames, in which the results found in this study were lower when compared to those presented in the literature
The main objectives of this paper were to analyze the influence of wind action on a building, considering both the static and simplified dynamic model loads of NBR 6123:1988 [12], as well as to perform the optimization of the structural weight of a building through a 2D model
Summary
High building construction trend is increasing over recent years, due to factors such as urban sprawl and high land costs, stimulating the construction of cost-effective structures and bracing systems, as these buildings are mainly affected by lateral loads induced by wind effects [1]. Tall and slender structures have, in general, low frequencies and small rates of damping and under the action of dynamic environmental forces, such as those generated by the wind, can present great amplitude of oscillation, causing problems related to the comfort of users, use in service and even safety and service life of the structure [2]. External actions can cause vibrations in the structures and affect the users’ comfort, in which the slender buildings are more susceptible to these effects. Structural designs consider the wind effect wind as static loads, calculated from the average speed, without considering the components of the fluctuation part that can induce vibrations in the structural system. Most practical optimization procedures for concrete structures are based on iterative procedures, which may guarantee structural safety, but may not result in optimal structures [7]
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