seismic performance

More than a decade, the issue of improving the quality of building engineering knowledge infrastructure is considered as one of the most important cases. Deterioration and loss of columns and decks of bridges, beams, columns, walls of buildings are attributed to some ca More

More than a decade, the issue of improving the quality of building engineering knowledge infrastructure is considered as one of the most important cases. Deterioration and loss of columns and decks of bridges, beams, columns, walls of buildings are attributed to some cases such as the age of the structure, environmental destructive factors, weak design or implementation and also change of structures’ usage, and procedures of the old regulations or events such as earthquake. On the other hand, strengthening the location of the implementation of reinforced concrete structures is not usually taken into consideration. Therefore, strengthening the proper location of the structure and increasing the structural strength and reducing the cost of retrofitting have been of great importance to the attention of various researchers. The main purpose of this study is to investigate reinforced concrete structures in various modes of reinforcement of elements using FRP fibers. For this purpose, at first, three concrete structures with 5, 7 and 9 stories were designed according to the 2800 seismic regulations in SAP 2000 software and were subjected to static nonlinear analysis for which overlapping analysis has been carried out with a reverse triangular loading pattern. This structure is reinforced so that it can use the maximum structural capacity and also the columns enter the nonlinear stage after the beams. In the next step, we consider the structure in various ways such as strengthening the entire structure, reinforcing the frames, reinforcing the elements separately, strengthening the external frame of the structure, strengthening the internal frames (structural core), etc., so that through extracting the base cutting, floor drainage, the internal force of the elements and the amount of FRP consumed, we obtain the most optimal method for reinforcing the structure, which provides the functional level of LS safety with reinforcement by FRP. Manuscript profile

Open Access Article

9 - Evaluation of the Seismic Performance of Rocking Motions and its Effects on the Controlling Provisions of Special Steel Moment-resisting‎ Systems Dual with CBF Bracing
Ali Parvari Ehsan Azizi

In this study, 4-, 8-, and 12-Story steel special concentrically braced frame (SCBFs) structures were considered in area with high seismically hazard and soil type II according to Iranian's 2800 code provision. Structures are residential use and have regularity in plane More

In this study, 4-, 8-, and 12-Story steel special concentrically braced frame (SCBFs) structures were considered in area with high seismically hazard and soil type II according to Iranian's 2800 code provision. Structures are residential use and have regularity in plane and vertical distribution. Structures were modeled using Sap 2000 software to investigate the effect of self-centering &lrm;motion under seven near-field earthquakes. All models assumed with and without dual system controlling provisions. The results of this research indicate that without dual system provisions, considering the self-centering &lrm;motion in &lrm;4-, 8-, and 12-Story SCBFs&lrm; reduces base shear of structures in contrast with increasing deformation of top floor and column axial force. In average, the self-centering &lrm;motion&lrm; dissipate energy more than fixed base one. With controlling dual system provisions, considering the self-centering &lrm;motion in &lrm;4-, 8-, and 12-Story &lrm;SCBFs&lrm; reduces base shear of structures, whereas increases deformation of top floor &lrm;and column axial force. Moreover, in this case of study, energy dissipation are more than with controlling &lrm;one. Considering the self-centering &lrm;motion in &lrm;8-, and 12-Story &lrm;SCBFs&lrm; reduces base shear of &lrm;structures and top floor deformations, meanwhile column axial force&lrm; was increased. It can be seen that in &lrm;4-, and 12-Story &lrm;SCBFs considering code provisions had a better results, whereas in &lrm;8-Story &lrm;SCBFs &lrm;neglecting code provisions was accepted. Manuscript profile

Open Access Article

10 - Evaluating the seismic performance of steel-sma hybrid Bracing structures
mohammad hooshmand behzad rafezi jafar khalileAlafi

In this study the seismic performance of hybrid braces composed of steel and shaped- memory alloys (SMA). is investigated Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El More

In this study the seismic performance of hybrid braces composed of steel and shaped- memory alloys (SMA). is investigated Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El Centro earthquake records, with the maximum acceleration of 0.6g and 0.9g. Our results showed that the seismic performance, i.e., the amount of energy absorption and residual strain, of steel–SMA hybrid braces depends on the SMA content. The optimal value of SMA content was 20%, as, at this concentration, a hybrid brace can be designed with good seismic performance at a justifiable fabrication cost. Manuscript profile

Open Access Article

11 - Evaluation the Performance and Seismic Comparison of Steel Moment Dual Systems in Rocking Frames with CBF and EBF Bracing
Ali Parvari Arman Beglar

In recent years, considering vertical movement in structures, which is known as self-centering motion, is one of the methods used to dissipate the earthquake energy. In this study, 4-, 8-, and 12-Story steel structures with special concentrically braced frame (SCBFs) an More

In recent years, considering vertical movement in structures, which is known as self-centering motion, is one of the methods used to dissipate the earthquake energy. In this study, 4-, 8-, and 12-Story steel structures with special concentrically braced frame (SCBFs) and eccentrically braced frames &lrm;(SEBFs) &lrm;were considered in order to investigate the effect of self-centering &lrm;motion under seven near-field earthquakes using Sap 2000 software. The results of this research indicate that considering the self-centering &lrm;motion, the behavior of structures are changing in SCBFs and SEBFs. In &lrm;, 4-, 8-, and 12-Story SEBFs structures with considering the self-centering &lrm;motion, the column and bracing &lrm;forces were increased which this was different with SCBFs &lrm; structures. Considering the self-centering &lrm;motion, more plastic joints are formed in the beams. Therefore, in the self-centering &lrm;of the columns, the beams outside the bay are more affected. In general, the results indicate that the self-centering &lrm;motion is better in the SCBFs. Manuscript profile

Open Access Article

12 - The Effect of Non-parallel System Irregularity on Seismic Performance of Braced Steel Frame Buildings
Ali Seyedkazemi Elmira Abbasnezhad

10.30495/civil.2022.689389

A number of buildings have irregular non-parallel systems due to ground conditions and architectural design, which fall into the category of irregularities in the plan. However, the building codes do not specify a limit as the deviation value of the vertical lateral loa More

A number of buildings have irregular non-parallel systems due to ground conditions and architectural design, which fall into the category of irregularities in the plan. However, the building codes do not specify a limit as the deviation value of the vertical lateral load bearing components from the major orthogonal axes of the building for this type of irregularities. The building frame system with bracing, on the other hand, is one of the most common systems for low- to mid-rise structures. In this research,the effect of non-parallel system irregularity on the seismic performance of steel building frame with special convergent bracing was investigated. Steel structures with 3, 6, and 9 stories were selected in this study, and in addition to the regular structural models, irregularity of non-parallel systems with different angles to the orthogonal axes from 1 to 5 degrees (i.e., 0.5 m to 2 m deviations for span length) were considered. First, the structures were designed according to the Iranian Earthquake Design Code and the Iranian Steel Structure Design Code. In order to evaluate the effect of irregularity on the seismic performance of the studied buildings, nonlinear static and dynamic analyses of time history for selected models were performed using Perform 3D software and the seismic performance indices of the structures were examined. The results indicate that with increasing irregularity; stiffness, strength, ductility and energy dissipation capacity of the structure decreases while the relative inter-story drift increases Manuscript profile

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