| Reinforced concrete frame-shear wall structure is widely used in high-rise buildings in China,but the optimal design of wall layout is still completed by continuous trial calculation under the guidance of basic concepts.The design method of manually adjusting trial calculation is not only inefficient,but also the result of optimization is often not ideal.It is of great practical value and theoretical significance to develop an efficient automatic optimization algorithm.In this paper,according to the characteristics and complexity of the optimal layout of the frame-shear wall structure,based on the parameterized modeling of the frame-shear wall structure,the particle swarm optimization algorithm is improved,and the optimization program of the wall layout based on the improved particle swarm optimization algorithm is developed.Combined with the engineering example,the parameterized optimization analysis is carried out,and the influence of the building parameters on the layout of the shear wall is quantitatively studied The main research results are as follows:1.In the frame-shear wall structure,the same wall length will form different lateral stiffness due to different layout.Therefore,the optimization of wall layout has the characteristics of high nonlinear degree and high computational complexity.According to the theory of computational complexity,the problem of high computational complexity is difficult to be solved by simple deterministic algorithm.In this paper,the heuristic optimization algorithm based on improved particle swarm optimization algorithm has achieved good optimization effect.2.The layout of shear wall is composed of position,direction and length.The traditional method of direct coding in sequence leads to a long code,which seriously affects the efficiency of heuristic algorithm.The position coordinates of shear wall are taken as the first level code,and the length of wall limb in each direction at each position is arranged in order to get the secondary floating point number code.Then,the invalid code of the position that cannot be arranged is removed by index vector,which is a simplified two-level code for heuristic algorithm.The two-level coding method not only solves the problem of mixed information of wall layout,but also is simple and efficient,which greatly reduces the calculation amount of optimization algorithm.3.When particle swarm optimization(PSO)is used to solve the problem of falling into local optimal solution due to too fast convergence in the early stage and low efficiency in the later stage,the inertia weight factor and learning factor of global dynamic adjustment are proposed,and the adaptive mutation strategy is adopted to solve the problem The improved algorithm has high optimization efficiency and good optimization effect.4.The objective functions of structural shape optimization mainly include the minimum material consumption and the minimum strain energy.Three objective functions of single objective optimization,external archive strategy multi-objective optimization with minimum strain energy in two directions and multi-objective optimization with fixed weight sum method are used to program and compare the results.The results show that taking the concrete content of concrete wall as the optimization objective will lead to the unreasonable results of the wall in a wide range of tension,and it is more reasonable to take the wall concrete dosage after the wall bottom tensile stress weighted correction as the optimization objective;the results of the two kinds of multi-objective optimization are basically consistent with the single objective optimization results,and the results of the external archive strategy multi-objective optimization are slightly better than the single objective optimization However,the calculation efficiency is obviously lower than that of single objective optimization.It is suggested that the wall concrete dosage after the wall bottom tensile stress weighted correction is used as the optimization objective.5.Taking practical projects in different design stages as examples,the design conditions such as storey height,wall thickness and structure height are analyzed,and the variation rules of two indexes,namely,the area distribution rate of bottom shear wall and the concrete consumption of shear wall per unit area are studied.The main conclusions are as follows:(1)Although it is convenient to extract the index,it is difficult to find out the law of the change of the index with a single parameter because of the coupling between the index and multiple parameters such as building height,floor number and building area.The concrete dosage index of shear wall per unit area can more directly reflect the material utilization efficiency of shear wall when the parameters such as floor height and building height change,and the regularity is stronger,which is more convenient for the index control in the actual project.(2)When the building height is constant,the concrete consumption per unit area of shear wall increases linearly with the increase of floor height,but the increase is small,which is about 1/10 of the increase of floor height.The concrete consumption of shear wall per unit area increases in parabola with the increase of building height.When the height increases from 60 m to 180 m,the concrete consumption of shear wall per unit area increases by 6 times.(3)The thickness of the shear wall should be gradually reduced along the height.Too high or too low position of the variable thickness will lead to the increase of the concrete consumption of the shear wall.For the example of 150 m in this paper,the location of the first variable thickness should be 1/6 of the building height,the location of the second variable thickness should be 1/3 of the building height,and the location of the third variable thickness should be 0.6 times of the whole building height.(4)The material utilization efficiency of the outer wall of the core tube is 1.6 times that of the inner wall,and the shear wall is preferentially arranged along the periphery of the core tube. |
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