Seismic Performance Of Walls Research Articles

An Analytical Study of the Out-of-plane Seismic Performance of Masonry Walls Reinforced with High-Performance Fiber-Reinforced Cementitious Composites

Frequent earthquake occurrences in various regions of Korea have highlighted the urgent need that exists for the seismic retrofitting of unreinforced masonry buildings, which are particularly vulnerable to lateral forces. In this study, the out-of-plane seismic performance of masonry walls reinforced with high-performance fiber-reinforced cementitious composites (HPFRCCs) was evaluated using finite element analysis. ABAQUS was used to establish the analysis model, and the reliability of the model was validated by comparing the model results with shaking table test results. A parametric study of the reinforced masonry walls was thereafter conducted using the parameters of the reinforced sides of the walls (unilateral and bilateral) and thicknesses (10 and 20 mm). The analysis of the acceleration and displacement of the masonry walls revealed the beneficial effects of HPFRCCs on the out-of-plane seismic performance of the walls. The seismic performance of the walls was significantly enhanced when the HPFRCCs were applied to both sides of the walls.

CALCULATION METHOD OF LATERAL STIFFNESS OF PVC CAVITY PARTITION WALL WITH DIFFERENT CONNECTION FORMS

To explore the difference in seismic performance of walls with different connections, this paper designs a pseudo-static test of three groups of steel frames infilled with walls and a group of empty steel frame as a control. The test phenomena and the datum are used to evaluate the performance of structures. The results show that: (I) the initial stiffness and the peak load of the cast-in-place wall are large. The main failure modes are cracking at the joint between the wall and the frame, crushing at the corner, and internal splitting as well as curving outwards under large displacement. (II) The wall with L-shaped connectors dissipates energy by bolt slip and the yield deformation of connectors, which has the lowest contribution to the frame in stiffness and strength. The main failure is the cracking of cement mortar at the joint. (III) The connection mode of U-shaped and L-shaped connectors is relatively safe and reliable, which could make the steel frame and wall panel work better together under the action of earthquake. It could be recommended to use according to the bearing capacity requirements; Walls connected by reinforcement are not recommended because of brittleness failure, poor ductility, ordinary bearing capacity and energy dissipation capacity. Based on the principle of equivalent tension and compression bar, a simplified formula for calculating the lateral stiffness of polyvinyl chloride (PVC) cavity wall panel embedded in fabricated steel frame is proposed, and the accuracy of the calculation results is verified.

Experimental study on seismic performance of recycled aggregate concrete shear wall with high-strength steel bars

In order to investigate the seismic behavior of recycled aggregate concrete (RAC) shear wall using high-strength steel bars (HSS), five concrete walls with an aspect ratio of 2.2 were tested under the horizontal cyclic load. The influence of various parameters which include replacement percentage of recycled coarse aggregate (RCA), concrete strength, and the grade of longitudinal bars at boundary elements on the seismic performance of shear walls were analyzed. The failure mode, hysteresis behavior, skeleton curve, stiffness and energy consumption of RAC shear walls were analyzed. The results showed that as the replacement rate of RCA increased, the seismic performance of the wall hardly changed. The use of higher concrete strength could significantly improve the bearing capacity, initial stiffness and energy dissipation of the shear walls, while the ductility was similar. Almost all seismic indexes of the shear wall reinforced with HRB400 bars decreased. Reasonable matching of HSS and RAC could help the shear wall to achieve better seismic performance. The flexural strength and secondary stiffness of the RAC wall with ultra-high-strength steel bars (UHSS) were significantly improved and the concrete damage was reduced. In addition, the restoring force model based on experimental data was established and the hysteretic behavior of RAC shear walls was well predicted.

Experimental and numerical study of the seismic behavior of cold-formed steel walls with diagonal braces

In this paper, the seismic performance of cold-formed thin-walled steel walls with diagonal braces is studied by means of experiments and finite element analysis. In total, horizontal hysteretic loading tests were carried out on six full-scale cold-formed thin-walled steel walls. The influence of diagonal bracing, the screw spacing, wall panels and vertical loads on the seismic performance of the walls was investigated from the aspects of hysteretic curves, skeleton curves, the lateral stiffness degradation and the energy dissipation capacity. It was found that diagonal bracing could significantly improve the load-bearing capacity, stiffness, and energy dissipation capacity of the walls. However, the lateral resistance increased slightly because of premature buckling of the transverse braces at the connection between the diagonal and transverse braces. In addition, finite element models of the wall specimens were established by ABAQUS software and validated against the experimental data. A preliminary parametric study was also conducted to further examine the influence of essential parameters on the behavior of cold-formed steel walls with diagonal braces.

Study of the Seismic Performance of Composite Shear Walls with Embedded Steel Truss For Use in High-rise Buildings

Abstract The composite wall with encased steel braces (ESB wall) is a novel type of steel–concrete composite wall that consists of a steel braced frame embedded in reinforced concrete. This arrangement is supposed to enhance the seismic performance of the wall, as the steel columns encased in the boundary elements can increase the flexural strength of the wall and the steel braces encased in the web can increase the shear strength. ESB walls have seen use in super tall building structures constructed in regions of high seismicity. The ESB walls are commonly used on stories where the shear force demand is very high. Currently, no design guidelines exist for the design of ESB Walls in the Eurocode. More research is required before a distinct set of guidelines can be prescribed for the design of ESB Walls. The present research will investigate behavior of composite walls with encased steel braces (ESB walls). Time history analysis will be performed to examine the shear strength and stiffness of the ESB walls. In this study, two frames with three floors and five floors will be modeled in ABAQUS software. Then the X- shaped braces and inverted V brace is added to frames. Later, reinforced concrete shear wall will be added to braced frames, so the steel braces encased in the reinforced concrete shear wall. Time history analysis, on the braced frames will be done Compare and note with each other. The results of the study are in good agreement with those of previous studies. However, none of these studies examined the effect of using V- and X-shaped struts and shear walls simultaneously, nor did they examine which struts reinforce the structures more strongly against earthquake vibrations. This has led the study to examine the effect of these reinforcements under various earthquakes. In future studies, reinforced concrete structures can also be used in addition to steel structures, and the results can be compared. In addition, these braces can also be used in other parts of the building. To meet this objective, one can use the very important data provided in this thesis, and ultimately better and more accurate results can be extracted using this approach. The main aim of this thesis is to study the effect of increasing the number of floors on how to extend the stress on the building structure. To this end, the number of floors increased from three to five. Therefore, it can be concluded that an increase in the number of floors also more than 5 storey causes stress values, but these modes are quite consistent with the three- and five-storey buildings.

Influence of shear span ratio on the seismic performance of L-shaped RC walls

Owing to their capability of meeting both structural and architectural demands, L-shaped reinforced-concrete (RC) walls are widely employed in low-rise and high-rise buildings. In spite of their popularity, the experimental data on the seismic performance of these walls is relatively sparse, especially with respect to their behaviour under lateral loads that are not parallel to the wall segments. In order to obtain improved understanding of such walls, quasi-static cyclic tests on six slender L-shaped RC walls were conducted under displacement control in Nanyang Technological University (Singapore). Through comparison with four squat L-shaped RC walls described in the literature, the influence of shear span ratio was highlighted in terms of cracking patterns, failure mechanisms, hysteretic responses, deformation components and strain profiles. Moreover, shear lag effect and effective stiffness were analysed using non-linear section analyses and methods available in the literature. The results showed the shear span ratio had a significant impact on the seismic performance of L-shaped RC walls, and should be addressed discretely in the design.

Seismic behavior and shear strength of new-type fired perforated brick walls with high void ratio

A new type of fired perforated brick with void ratio of more than 30% has been developed to improve the applicability of brick masonry structures. When the new perforated bricks are used for load-bearing walls, it will be a question whether the seismic performance of walls could satisfy the requirements under not obviously increasing the cost. This article presents an experimental study to investigate the seismic behavior and shear capacity of new-type perforated brick walls with high void ratio. For this purpose, six cross walls and three longitudinal walls with constructional columns under low reversed cyclic loading were tested, and the failure patterns, hysteretic characteristics, skeleton curves, energy dissipation capacity, ductility and reinforcement strain were observed. The test results indicate that (1) most new-type perforated brick wall specimens display shear failure, and hysteretic curves of cross walls are plump while there is some pinch phenomenon for longitudinal walls; (2) the specimens have considerable deformation and energy dissipation capacity, with displacement ductility factors of over 2.0; (3) the bearing capacity of walls increases but the ductility decreases with an increase of vertical compressive stress, and the bearing capacity and deformation all increase while considering the effect of horizontal reinforcement; and (4) the central brick wall and construction columns could resist shear force together before the peak load, while the shear force would be mainly born by construction columns at the later loading stage. Based on the test results, the constraint coefficient in current Chinese code was modified, and the calculation formula of shear capacity for cross walls was proposed. Comparison of calculated results with test data shows that the method will provide a way to predict the shear capacity of new-type fired perforated brick walls.

Seismic Performance Assessment of Slender T-Shaped Reinforced Concrete Walls

T-shaped slender reinforced concrete (RC) structural walls are commonly used in medium-rise and high-rise buildings as part of lateral force resisting system. Compared to its popularity, experimental results on seismic performance of these walls are relatively sparse, especially for data regarding these walls in the non-principal bending directions. This article aims at providing additional experimental evidence on seismic performance of T-shaped RC structural walls. Experimental results of six T-shaped RC walls were presented. These walls resemble the structural walls found in existing buildings in Singapore and possess slightly inferior details compared to the requirements of modern design codes. The test variables were the loading direction and the axial load ratio. The experimental results were discussed in terms of the failure mechanisms, cracking patterns, hysteretic responses, curvature distributions, displacement components, and strain profiles. In addition, the experimental results were compared with methods commonly adopted in current design practice including the nonlinear section analyses, shear strength models and effective width of the tension flange. The experimental data illustrate that the shear lag effect not only was not accurately accounted for by the effective width method but also significantly affected the strength and stiffness of the tested specimens.

Test on Embedded Perforated Steel Plate Shear Wall with Concrete Filled Steel Tube Columns

In view of the proposal of embedded steel plate concrete shear wall with concrete filled steel tube columns which contains a new kind shear connector of tie-bars through the circular holes linking concrete layers on both sides of the plate. In order to prove the seismic performance of walls with circular holes on the plate, three steel plate shear wall specimens, including the plate without holes bolted with columns, welded with columns, and the perforated plate welded with columns, were tested under cyclic loading. According to the results, the load-bearing capacity, ductility, energy dissipation, hysteretic behavior and failure phenomena were analyzed. It is showed that the load-bearing capacity of the three specimens were quite close. However, the wall with perforated steel plate has better ductility, energy dissipation and hysteretic behavior. So, it is an effective way to improve the seismic performance of walls by means of embedded perforated steel plate instead of ordinary ones.