In this study, the seismic performance of the reduced beam section (RBS) steel moment-resisting frame (SMRF) equipped with composite steel plate shear wall (CSPSW) and high-performance fiber-reinforced cementitious composites (HPFRCC) is investigated using Abaqus software. The finite element model of HPFRCC-CSPSW was validated using experimental results. Then, the seismic performance of the six-story SMRF with common SPSW, as well as HPFRCC composite CSPSW systems under near-field (NF) and far-field (FF) earthquakes, was investigated and the results (bearing capacity, stress, deformation, and energy absorption) were compared. For this purpose, 5 NF and 5 FF seismic records were used. The results showed that the energy absorption and shear capacity of HPFRCC-CSPSW increased significantly but the maximum stress value decreased compared to common SPSW. The seismic performance of the investigated systems largely depends on the type of earthquake. However, in both SPSW and HPFRCC-CSPSW systems, the maximum displacement and the base shear under the NF earthquakes were higher than those of FF earthquakes. Besides, for all NF and FF earthquakes, maximum displacement in the SPSW system occurred in lower stories, but in the frame with CSPSW, the major displacement occurred in the upper stories. The highest increase in shear capacity and energy absorption of the system in FF earthquakes was for the Tabas accelerometer (75 and 128%, respectively) and the Imperial Vali earthquake (94 and 101%, respectively). Also, the maximum displacement in SPSW and HPFRCC-CSPSW systems occurred in Northridge (14.6 cm) and Tabas (16.2 cm) NF earthquakes, respectively; the Chichi earthquake also had the greatest damage to the structure under FF earthquakes.

The steel shear wall, as a system to resist the lateral loads, buckles when it is vulnerable to the lateral loads applied to the frame before it reaches its ultimate strength. This phenomenon is due to the small thickness of shear wall relative to the adjacent beam and column. Hence, the idea of reinforcing shear wall to control the sheet buckling seems to be quite applicable. In this research, cross sheet have been used to increase loading capacity of reinforced sheets, which are attached to the both sides of the steel shear wall. In this regard, at first the steel shear wall was modeled according to Qomy experimental model. After verification of the developed model conducted by comparing with the results from laboratory test, parametric study was carried out on the thickness and width of the reinforcing sheet. The obtained results of the analysis showed that by increasing the sheeting thickness to 1.5 times, shear strength is enhanced by 7%. Increasing the sheeting width by 1.5 times shear stiffness and shear strength are decreased by 42% and 32% respectively and decreasing of this parameter by 50% leads to decrease of shear strength by 8%. According to the obtained results for the verification model, numerical and experimental results are in good agreement.

Based on the several advantages of steel shear walls as lateral resistant system (stiffness, strength, ductility and energy absorption), the cyclic and nonlinear analysis of steel shear walls strengthened with vertical and horizontal stiffeners and boundary columns filled with concrete was investigated in this paper and displacement controlled analysis at ABAQUS F.E. based on ATC24 protocol for different models were conducted. The numerical model was calibrated with experimental results and then four new steel shear wall models with vertical and horizontal stiffeners and steel column filled with concrete were considered and analysed. The hysteresis curves results conducted in this paper indicated that the steel shear wall with stiffeners and boundary column filled with concrete strength was higher than post-buckling strength, and the steel plate post-buckling strength was fully gained due to increasing rigidity of boundary columns. The absorption energy of strengthened specimen filled with concrete in push-over analysis was 11% higher than non-strengthened specimen without concrete, and also the total energy absorption at cyclic loading of strengthened specimen was 415% (5.15 time) comparing to non- strengthened specimen indicating that this combined stiffeners and concrete filled column was effective. The behaviour ratio of strengthened specimen was 21% more than that of non-strengthened specimen.

Despite many advantages of steel plate shear wall (SPSW) system, such as lightness, high stiffness, ductility, and fast implementation, this system is not as pervasive as other lateral load resisting systems such as bracing or reinforced concrete shear walls. To solve this problem, numerical parametric studies of system with consideration of seismic uncertainties which needs accurate non-linear models including behavioral deterioration of system is necessary. So, in this paper, besides studying existing macroscopic modeling of steel plate shear walls, a new model is introduced which is modified version of Strip model’s application with focusing on stress-strain curve proposed by one of researchers. After suggesting essential adjustments in this model and showing their necessities with emphasizing on experimental and finite element results, correctness of new model by doing several finite element analysis in different models with various plate thickness and length to height ratio is verified and proper values for parameters is proposed.

M.Gholhaki1*,Gh.Pachideh2, O. Rezayfar3, S.Ghazvini41- Associate Prof., Structure Eng. Dept., Faculty of Civil Eng., Semnan University2- Phd Candidate, Structure Eng. Dept., Faculty of Civil Eng., Semnan University3- Assistant Prof., Structure Eng. Dept., Faculty of Civil Eng., Semnan University4- Msc, Structure Eng. Dept., Faculty of Civil Eng., Semnan UniversityToday, with the increasing spread of high constructions, as a development symbol, the need for selecting robust and suitable system for bearing optimally loads from earthquakes and wind and with high energy absorption power, has been significantly considered. Steel plate shear walls have been used over four decades as an efficient lateral resistance system. This paper analyzed the over strength factor, Ductility Factor and behavior factor of these system. For this, 7, 15 and 30 floors frames possessing one or two steel plate shear wall spans, have been analyzed in non-linear static, linear dynamic or increasingly dynamic analysis (IDA). For considering inherent uncertainty of earthquake, it was used of increasingly dynamic analysis and 7 records of the strongest earthquakes have been ever occurred were selected. The results showed that the behavior factor of this system in limit form for high construction is 8 and for short and middle construction is about 9.

One of the seismic load resistant systems is the slit steel shear wall system. Using inclined slits in the plate, the performance of the strips is flexural-axial and they act as a passive damper by forming plastic deformations. In this model, by changing the length of these axial members, the yield displacement and other seismic parameters of the shear wall can be changed. The purpose of this study is to numerically evaluate the slit steel shear wall with oblique slots and with different slit composition and end stiffener. For this purpose, after modeling validation, a parametric study was performed on the steel wall with different placement of different slits and end stiffeners. The reversed cyclic behavior was compared with a non-slot sample. Comparison of the results shows that despite the reduction of initial strength and stiffness in the slit model, this wall has a better cyclic behavior and dissipated energy. The results show less resistance drop and better performance in drifts above 2%. The results also show that only by changing the location of the slots, the final strength and initial stiffness will be changed up to 19 and 25%, respectively. Using end stiffeners with higher inertia moment is one of the most effective methods to increase energy dissipation; The use of Box100 cross section as a stiffener, increases the energy dissipation up to 2 times compared to the normal sample. Overall, the performance of the steel shear wall with the proposed groove shape is excellent.

Steel shear wall is one of the most suitable common systems for the strength and stability of the structure against lateral loads. In this system, vertical boundary elements around the shear wall, in addition to being part of the lateral load-bearing system, are responsible for bearing the weight of the structure during and after the earthquake, and therefore in designing this system, the border elements are tried to be remained in the elastic state after complete yield of the web plate. Also, to provide uniform stress along the length and height of the wall, vertical and horizontal boundary elements must have high flexural stiffness. Code provisions in this case sometimes lead to the selection of non-economic sections in the beams and columns attached to the wall. In this study, in order to reduce the demand for vertical boundary elements attached to the wall and to make the design economical, vertical and inclined stiffeners are predicted inside the wall. These stiffeners direct the plastic deformations mainly into the wall and away from the columns. To evaluate and compare the behavior of the proposed model, 30 finite element models were studied under lateral monotonic and cyclic loading. The results show that the addition of stiffeners, in addition to increasing the stiffness and lateral resistance of the system, increases the ductility of the lateral bearing system and reduces the required flexural stiffness of horizontal boundary elements.

Sequential earthquakes have severe destruction on structures, including the accumulative structural and non-structural damage, compared to single earthquakes and due to the lack of sufficient opportunity to repair of the structure, the possibility of structural damage increases. In this research, the effect of seismic sequence on the relatively new system of reinforced concrete frames equipped with steel plate shear walls has been investigated. Based on this, four system of 4, 8,12and 24 stories, which represent short, intermediate, tall, are modeled in finite element software and subject to four sets of single and sequential earthquake and with a variety of application methods. Sequential earthquakes, including real, repetitive and randomized methods, are subjected to nonlinear dynamic dynamic analysis under four sets of single and sequential acceleration. The seismic scenarios used include sequential recorded critical earthquakes. The analysis showed that the predominant period of the aftershock significantly influences the post-mainshock response. Real seismic sequence increases the tatio of peak interstory drift by an average of 2 times the similar demand in a single earthquake and increases the ratio of maximum ductility demand by 1.52 times in the structure.In artificial sequence, the ratio of peak maximum interstory drift demand increase is in 100%, 150% and 200% aftershocks, In the iteration method, it is equal to 1.2, 2.0 and 2.6 times the single earthquake. Aftershocks may change the direction and magnitude of residual displacement in real and artificial seismic sequences. Continuation of the equation to calculate the demand for seismic sequence ductility was extracted.

Recently, researchers have introduced CLT (Cross Laminated Timber), a kind of engineered wood product that is one of the most suitable construction materials for green building development for the future cities. In the design steel-timber hybrid structure presented in this study, steel is used for the intermediate moment resisting frame of the building and CLT are used as floor panels and shear walls. Therefore, the lateral load-resisting system of the hybrid structure in this study is the dual system of steel intermediate moment resisting frame and CLT shear wall. In order to investigate the structural performance of the above-mentioned system, a sample 6 stories building are considered to be constructed using two types of structural systems were designed using ETABS software; 1- a steel intermediate moment resisting frame with composite concrete-steel floor, and, 2- dual steel intermediate moment resisting frame plus CLT shear walls with timber-steel floor using CLT horizontal panels. Then, FEM model of each of structural frame two types was analyzed using pushover method by ABAQUS software. The behavior of the two type 6-story frame systems were compared. By comparing the weight of Structure with the two types of lateral load-resisting system, it was concluded that the total weight of the building reduced by %22.01 in the structure with a dual system of steel intermediate moment resisting frame and CLT shear wall and composite timber-steel floors, compared to the structure with the steel intermediate moment resisting frame system and composite concrete-steel floors. Comparison of the results concludes that the application of possible substitution of CLT panels instead of steel and concrete common materials of structural members results in light weight structure with acceptable seismic behavior. Furthermore, development of hybrid timber-steel construction can provide buildings with less greenhouse, environmental, and noise pollution for producing materials and building structure, lower energy consumption, less weight, good seismic behavior, fast construction speed, and renewable resource capability.