Seismic Response Reduction of Steel MRF Using SMA Equipped Innovated Low-damage Column Foundation Connection

Connections in MRFs are the most important members and seismic behaviour is affected by function of beam column connections as well as column foundation connections. If the connections are able to provide the required ductility and efficiency against the seismic excitation, the seismic capacity of the MRF performed by these connections will be affected. SMAs have recently been used as a tool to dissipate energy in structures. So far, using of them for column foundation connections has been applied much less. In this paper, SMAs have been introduced and an innovated column foundation connection equipped with SMA has been suggested. Micro and macro behaviour of the connection has been studied and it was applied in sample MRF. Seismic response of the MRF under different earthquakes by equipping the connection with steels/SMAs bars have been studied and compared. Finally, results indicated that MRF with this connection showed proper seismic performance

Finite Element Analysis of Load Bearing Capacity of a Reinforced Concrete Frame Subjected to Cyclic Loading

Many methods have been developed in order to study the impact behavior of solids and structures. Two common methods are finite element and experimental method. The nonlinear finite element method is one the most effective methods of predicting the behavior of RC beams from zero-load to failure and its fracture, yield and ultimate strengths. The advantage of this method is its ability to make this prediction for all sections of the assessed RC beam and all stages of loading. This paper compares the experimental results obtained for a RC frame with the numerical results calculated by ABAQUS software, and plots both sets of results as hysteresis–displacement diagrams. This comparison shows that the numerical FEM implemented via ABAQUS software produce valid and reliable results for load bearing capacity of RC frames subjected to cyclic loads, and therefore has significant cost and time efficiency advantages over the alternative approac

Study of the seismic performance of steel frames in the elliptic bracing

This article appraises the seismic performance of a new braced steel structural system called elliptic braced moment resisting frame (ELBRF). Apart from improving the behavior of a structure, ELBRF is found non-problematic for the bracing system in a given architectural space. In this study, a single cycle time has been used for evaluating the proposed ELBRF. Here, methods of seismic design of structures as well as effective parameters in the seismic design of steel braced including ductility factor, overstrength coefficient and behavior factors, which were obtained by using capacity curves, have been presented through an adaptive pushover analysis (APA). Result of the nonlinear analysis showed that the strength and capacity of energy dissipation in the elliptic bracing system (ELBRF) is more than the system of special moment resisting frames (SMRF), coaxial braced frame (CBF) X-Braced, Inverted-V Braced CBF. Likewise, the permitted relative displacement, where the braced frame reaches to step buckling, is more in ELBRF

Effect of the axial force and material strength on the seismic behavior of the short shear walls

With respect to the height to width ratio, the concrete shear walls are divided into two categories of cantilever and short shear walls. Cantilever shear walls with the aspect ratio greater than 2 demonstrate flexural behavior while short shear walls with the aspect ratio smaller than to 2 exhibit shear behavior. In this study the behavior of short reinforced concrete shear walls are investigated using the nonlinear finite element software ATENA 3D. The failure mode and the ultimate and residual shear resistance of the short shear walls, as well as the affecting parameters such as the magnitude of the axial force, the compression strength of concrete and yield strength of reinforcements are studied. It is resulted that the magnitude of axial forces has significance effect on the ductile behavior of short shear walls

Effect of the reinforcement patterns on the seismic performance of the short shear walls at Nuclear Power stations

As the need for seismic designing of the earthquake resistant structures increases, numerous laboratory and numerical studies are being done to estimate the nonlinear response of these structures. With respect to the height to width ratio, the concrete shear walls are divided into two categories of cantilever and short shear walls. Cantilever shear walls with the aspect ratio greater than 2 demonstrate flexural behavior while short shear walls with the aspect ratio smaller than to 2 exhibit shear behavior. In this study the behavior of short reinforced concrete shear walls are investigated using the nonlinear finite element software ATENA 3D. The failure mode and the ultimate and residual shear resistance of the short shear walls, as well as the affecting parameters such as concentration of longitudinal and transverse bars at the edges of the wall, change of the horizontal and vertical bars spacing and the use of diagonal bars are studied. It is revealed that unlike the cantilever walls, the concentration of the bars at the edges have no influence on the increasing of ductility

Assesment Behaviour of the concrete flexural frame and shear wall Partially Buried system under Blast Loadings

Nowaday, with the proliferation of terrorist attacks on buildings in the world, a close examination of the behavior of structures under blast loads is a necessity. Pressure caused by the explosion of one of the most destructive loads that the structure may experience. Since the existing structures are usually designed to the common gravity and seismic loads, it is necessary to investigate their performances under blast loadings. In this study, analytical studies have been done for 2D structural models of concrete flexural frame and shear wall Partially Buried system with different number of stories 2 and 5. structures assessed based on the UFC 3-340-02 guidelines for 1000 kg TNT blast from 20 meters, the software SAP 2000 Design and nonlinear dynamic analysis have been. In order to loading, pressure values obtained from the explosion's blast wave, shock waves and pressure from the calculated reflection and As well as air blast wave parameters, including speed wavefront, period and wavelength explosion was determined and pressure graph - time of the explosion is offered. After analysis, The plastic hinge rotation, the formability and the highest axial force, shear force and bending moment occurred members, as well as maximum displacement, velocity and acceleration absolute floor level roof for all models will be investigated

ON THE ESSENTIALITY OF FURTHER RESEARCH ON COMPUTATIONAL ISSUES OF EARTHQUAKE ENGINEERING IN DIFFERENT COUNTRIES

Abstract. Further research on different issues of earthquake engineering is a major tool i