Research On Optimal Design Of Semi-rigid Connected Steel Frame With Infilled Shear Wall Structure

The connection of steel structure is considered to be a semi-rigid connection between fully rigid and pinned connection.Even though semi-rigid connection has many advantages in fabrication cost and on-site installation,the semi-rigidity of the connection will increase the lateral displacement of the structure and lead to large cross-section of frame beams and columns,so the application of semi-rigid steel frames in high-rise buildings is limited.In the traditional steel frame concrete shear wall structure,the concrete shear wall not only carries the horizontal force effect,but also needs to share a certain vertical load,and the thickness of the bottom shear wall is normally larger,resulting in the advantage of semi-rigid steel frame is limited,and the cost of this structure is relatively high,and the arrangement of shear wall is inflexible.Semi-rigid steel frame with infill shear wall structure system not only can make full use of the respective characteristics of semi-rigid connected steel frame and shear wall,but also has the advantages of flexible shear wall arrangement and effective reduction of wall thickness.However,this structural system still needs to solve two important problems in its application:1)how to use one or a small number of structural calculation models to consider many different forms of shear walls at the same time;2)how to arrange shear walls in semi-rigid steel frames in a reasonable and effective way so that the structure can reach the optimum in terms of cost and mechanical performance.To address the above issues,this study focuses on the following aspects:(1)By analyzing the characteristics of Dolphin Echo Algorithm(DEA)and Genetic Algorithm(GA),two algorithms were combined and a hybrid Dolphin Echo-Genetic Algorithm(DEGA)was proposed.The algorithm not only has the good convergence performance and convergence speed of the DEA,but also performs an efficient global search ability of the GA.Besides,the DEGA effectively improves the disadvantage of the DEA,which is easy to fall into the local optimal solution,and the "premature" problem from the GA.The example shows that the algorithm outperforms the other two algorithms in terms of convergence speed and optimization results.(2)This study analyzed and summarized the force mechanism of different types of shear walls,and proposed two structural calculation models that can take different types of shear walls into account.The calculation models were divided into two types based on the mechanism,concrete type shear wall and steel plate type shear wall.The shear wall was equated with oneway support according to the principle of equal lateral displacement under the same horizontal force,and the direction of the support varied according to the mechanism of the shear wall.The models consider different types and forms of shear walls comprehensively.Parameterization of shear walls using elastic lateral stiffness characterization,combined with semi-rigid steel frames,structural calculation of semi-rigid steel frame with infill shear walls was achieved.By comparing the structural lateral stiffnesses obtained from different experimental studies,the proposed calculation models were verified in terms of the effectiveness and accuracy.(3)For the shortcomings of the traditional design,the inverse design concept of infill concrete shear wall was proposed.The shear wall was characterized by using the lateral stiffness,and the specific thickness of different types of shear walls was calculated according to the structural demand for lateral stiffness.The optimal design of semi-rigid steel frame with infill shear walls under conventional shear wall arrangement scheme and the structural topology optimization were achieved.The calculation results show that this structural system effectively combines the benefits of semi-rigid steel frame and infill shear wall.Besides,the inverse design concept accomplishes the structural optimization in a more effective way and provides a comprehensive understanding for structural designers.(4)This study analyzed the mechanical characteristics and proposed a modified formula for the elastic lateral stiffness of non-stiffened steel plate shear walls,taking into account the effect of additional action of non-stiffened steel plate shear walls on horizontal boundary element and vertical boundary element.Combined with this formula,the optimized design study of the semi-rigid steel frame with non-stiffened steel plate shear wall was carried out.A two-stage design method was used to optimize the topology of this structural system.The calculation example shows that the method effectively obtains optimized design results that reflect the force characteristics of the structure accurately.(5)To address the shortcomings of the single-objective topology optimization results,a hybrid algorithm based on Pareto ranking was proposed,and combined with this algorithm,multi-objective optimization of semi-rigid steel frame with infill shear wall structures was performed.The numerical example shows that the multi-objective-based topology optimization is necessary for this type of structural system.The proposed method not only makes the distribution of shear walls more reasonable,but also improves the structural designers’ overall understanding of the results.Finally,a decision analysis of the Pareto optimal solution set was carried out to provide an effective decision-making method for project participants.