Effect of L-Shaped Shear Wall Layout on the Seismic Performance of Medium-Rise RC Buildings

Seismic experiment and performance analysis on embedded optimized steel plate-reinforced concrete composite shear wall under multi-dimensional loading

Effect of nano-SiO2 modification on the seismic performance of recycled aggregate concrete shear walls

To overcome the shortcomings of traditional shear walls, a new type of M‐section lightweight steel‐reinforced concrete (MLSRC) shear wall is proposed. One cast‐in‐place shear wall and three MLSRC shear walls were designed. Through quasistatic tests, the seismic performance was investigated, with the research parameters being the dowel arrangements and the connection methods between the upper and lower layers of the shear wall. The results revealed that the plastic region of the wall concentrated mainly near the horizontal joint section. From the top of the lap rebar to the top surface of the foundation, the strain in the lap rebar gradually increased, whereas the strain in the M‐section lightweight steel gradually decreased. The stiffness, ductility, and load‐bearing capacity values for the three types of MLSRC shear walls are essentially consistent. The failure modes are similar to that of the cast‐in‐place concrete shear wall. Noncontact lap splicing of the upper and lower layers of rebar can effectively transfer stress. The three rebar arrangements have similar impacts on the seismic performance of MLSRC shear walls, and the shear walls exhibit comparable seismic performance to that of cast‐in‐place concrete shear walls. Finally, finite element models of the specimens were established via finite element software, with the concrete damage, rebar stress distribution, and hysteresis curves closely matching the experimental results.

Concrete shear walls or structural walls are often used in multistory buildings to resist lateral loads such as wind, seismic and blast loads. Such walls are used when the frame system alone is insufficient or uneconomical to withstand all the lateral loads or when partition walls can be made load bearing, replacing columns and beams. The analysis and design of buildings with shear walls became simple using commercially available computer programs based on the finite element method (FEM) and subsequent implementation of stress integration techniques to arrive at generalized forces (axial, shear, and moments). On the other hand, design engineers without such facilities or those with computer facilities lacking such features use simple method of analysis and design by taking the entire dimensions of the walls. This is done by considering the shear walls as wide columns of high moment of inertia and following the same procedure as for columns. The primary purpose of this paper is believed that structural engineers working in the analysis and design of high- rise buildings will be benefited from the design shear wall by using EBCS: 2-1995 and EBCS:8-1995codes and its results. KEYWORDS-concrete shear wall, Ethiopian building code standard (EBCS), lateral loads, moment of inertia, stress integration techniques. I. INTRODUCTION Shear walls are deep relatively thin vertically reinforced concrete beams .They are commonly used in the structures to resist the effects of gravity loads and storey shears. Shear walls are vertical elements in the lateral force resisting system that transmit lateral forces from the diaphragm above to the diaphragm below or to the foundation . Shear walls may also bearing walls in the gravity load system or they may be components in dual system framed so as to resist only lateral loads. Walls may be subjected to both vertical (gravity) and horizontal (Wind or Earthquake) forces. The horizontal forces are both in plane and out of plane. When considered under their in plane loads walls are called shear walls. When considered under their out of plane loads they are called normal walls. Walls will be designed to withstand all vertical loads and horizontal forces both parallel to and normal to the flat surface with due allowance for the effect of any eccentric loading or overturning forces generated. Any wall whether or not intended as part of the lateral force resisting system is subjected to lateral forces unless it is isolated on three sides(both ends and top) in which case it is classified as non structural. Any wall that is not isolated will participate in shear resistance to horizontal forces parallel to the wall. Since it tends to deform under stress when the surrounding framework deforms. The distribution of lateral loads on shear walls varies with their height. For example under lateral wind loading this distribution may vary from nearly uniform on a wall in a tall building to a single concreted force on a wall in a low building.

Shear wall are not avoidable in construction of buildings. However, the behavior of structures with these Shear wall during earthquake needs to be studied. By taking adequate precautions, the main objective of Earthquake Engineering is to design and build a structure in such a way that the damage to the structure and its structural components during an earthquake is minimized. Constructions can suffer diverse damages when they are put under seismic excitations. Although for a same structural configuration, region& earthquake, damages in the system are neither equal nor homogenous. So, there are several factors for these like – Structural system, Earthquake characteristics, the quality of construction, soil of location and its maintenance that define the seismic behavior of the structure. Present study represents the behavior with shear wall and not with shear wall of building. In this present study ten storey building is considered. The building is modeled in ETABS-2018 with shear wall and not with shear wall considered for analysis. For analysis purpose various loads are considered like dead load, live load and earthquake load in X and Y-direction. Various loads combinations are considered according to NBC 105:2020. The main objective of this project is to find out which will have better seismic performance either building with shear wall or without shear wall. The analysis of model is done using dynamic method in ETABS software. Finally the results of seismic behavior of buildings are compared with respect to time period, base shear, storey shear, member forces, overturning moment, displacement, stiffness and drifts. Keyword: Shear wall, RC buildings, NBC, Displacements, Drift.

Irregular buildings, particularly those with L-shaped plans, are more vulnerable during seismic events due to their asymmetric geometry and torsional irregularity. This study investigates the seismic performance of L-shaped reinforced concrete (RC) structures with various shear wall configurations under lateral loading. A total of 12 L-shaped six-story building models were analyzed using ETABS software, applying both Equivalent Static Method (ESM) and Response Spectrum Analysis (RSA) as per IS 1893:2016. The effect of shear wall positioning on fundamental time period, base shear, displacement, torsional irregularity and diaphragm rotation was evaluated. Results showed that shear walls significantly enhance structural performance by reducing displacement, increasing base shear, and controlling torsional behavior when placed effectively. Improper or asymmetric wall placement, however, led to increased torsional amplification and irregular seismic responses. Among all models, those with shear walls aligned along both X and Y directions performed best in terms of seismic resistance. The study highlights the importance of optimal shear wall positioning in irregular RC buildings for enhancing seismic safety and structural efficiency.

Shear walls have high strength and stiffness, which could be used at the same time to resist large horizontal loads and weight loads, making them pretty beneficial in several structural engineering applications. The shear walls could be included with openings, such as doors and windows, for relevant functional requirements. In the current study, a building of G + 13 stories with RC shear walls with and without openings has been investigated using ETABS Software. The seismic analysis is carried out for the determination of parameters like shear forces, drift, base shear, and story displacement for numerous models. The regular and staggered openings of the shear wall have been considered variables in the models. The dynamic analysis is carried out with the help of ETABS software. It has been observed that shear walls without openings models perform better than other models, and this is in agreement with the previous studies published in this area. This investigation also shows that the seismic behaviour of the shear wall with regular openings provides a close result to the shear wall with staggered openings. At the roof, the displacement of the model with regular openings was 38.99 mm and approximately 39.163 mm for the model with staggered openings. However, the model without a shear wall experienced a displacement of about 56 mm at the roof. Generally, it can be concluded that the openings have a substantial effect on the seismic behaviour of the shear wall, and that should be taken into consideration during the construction design. However, the type of opening (regular or staggered) has a slight effect on the behaviour of shear walls.

Abstract: In structural engineering, a shear wall is a vertical element of a seismic force resisting system that is designed to resist in-plane lateral forces, typically wind and seismic loads. In many jurisdictions, the International Building Code and International Residential Code govern the design of shear walls. A shear wall resists loads parallel to the plane of the wall. Collectors also known as drag members; transfer the diaphragm shear to shear walls and other vertical elements of the seismic force resisting system. Shear walls are typically light-framed walls with shear panels, reinforced concrete walls, and reinforced masonry walls. The G+15 story structures situated in earthquake zones III, IV and V will be considered for study. All frames are designed under same gravity loading. Response spectrum method is used for seismic analysis. ETABS software is used and the results are compared. The results were obtained in the form of top story displacement, Story drift, Base shear and displacement

Planning, designing, and execution of high-raise building while taking into account the impact of lateral loads such as wind and seismic loads computation with or without shear wall technology in conventional mode is a crucial task for civil engineers. The lateral loads develop high lateral stresses and sway movement in structural members and need adequate stiffness to resist lateral forces along with sufficient strength against vertical gravity loads. In this case, civil engineers establish an effective system for construction of high raise building with the usage of shear wall system is high in-plane stiffness and torsional resistance. Present the authors are considered a G+10 storey commercial shopping mall with a central cut-out at Bhimavaram location which lies in seismic zone III as, per IS 1893(part 1): 2016. The load cases from IS 875 Part I (dead loads), Part II (imposed loads), and Part III (wind loads) are used to create the load combinations in accordance with IS 456: 2000. Two models, with and without shear wall system are taken for comparing the parameters like storey drift, storey displacement, stiffness, shear force, base shear, bending moment and center of rigidity by performing linear static seismic analysis and wind analysis for both models in ETABS software. The simulations concluded that Shear wall system is the efficient and economical way of resisting lateral loads in high rise or multistory buildings.

Reinforced Concrete (RC) shear wall buildings are the most common construction practice in moderate to high seismic zones. Shear walls provide high strength, stiffness to the building system. However, the performance of RC shear wall buildings depends on various parameters like the location of shear walls, the aspect ratio of the shear wall, and the structural wall plan density. The revised Indian standards for earthquake-resistant design of structures states that RC structural wall plan density shall be at least 2% for buildings with open storeys, and for regular buildings it can be at least 2% along each principal direction. This manuscript aims to check the efficacy of the minimum structural plan density recommended in the revised Indian standard by evaluating the impact of varying structural wall density on the seismic performance of high-rise regular RC shear wall buildings located in the high seismic zone. The seismic performance of shear wall buildings with varying structural wall density is evaluated in terms of peak displacements, peak accelerations, and maximum inter-story drift by performing the time history analysis with different ground motion records. The effect of structural wall plan density on the dynamic properties of the buildings is also studied.

Seismic performance of carbonated recycled aggregate concrete shear walls

This study is aims to investigate the performance of multi-storey high rise concrete structures by linear static methods. The code suggests a different approach of analysis for asymmetric structures. The main objective of the study is to carry out the lateral load analysis to obtain performance levels of buildings. According to the load nature and structure behaviour method of liner static method be selected from storey drift, displacement, and Base shear. The study focuses on concrete structures located in seismic Zone IV, which is characterized by rocky soil conditions, according to the earthquake load specifications outlined in IS 1893 Part 1:2016. For the linear analysis G+25, G+30 and G+35 storey configuration are employed. The E-tabs software is utilized to conduct the analysis. The study compares various structural maximum response parameters to assess the performance of the structures. These parameters include displacement in the X- and Y-directions, storey drift, and base shear. In research, total 12 models with in addition to regular moment resisting frame model, moment resisting frame with shear wall, tube in tube model, and tube in tube with shear wall are considered for evaluation. Furthermore, the paper aims to compare the results obtained from the linear static methods for all the assessed parameters.

At present days, constructing a structure with all the regular configurations is not feasible in most of the cases due to the irregular plot dimensions, aesthetic visual and functional requirements in the urban cities. The structure with more irregular configuration either horizontally or vertically are more vulnerable to earthquake & wind forces which leads to collapse of structure, property loss and casualties. When an earthquake occurs, nearly all buildings in the area are exposed to seismic forces. When a tall structure is subjected to lateral or torsional deflections under the action of seismic loads, the resulting oscillatory movement can induce a wide range of response in the building occupants. Therefore, lateral stiffness is an important consideration in the design of multi storey structures. The improvement of reinforced concrete frame structure against lateral loading can be achieved by providing shear walls and cross bracings. In this study, a G+19 storey important service and community building with re-entrant corners has been analyzed and designed with shear wall with openings and cross bracings. Significance of shear walls and bracings has been studied with the help of nine models. This analysis and design was made as per IS 1893:2016 codal provision by using ETABS 20 software. The building models are analyzed by response spectrum method using ETABS software. The main parameters compared in this study are lateral displacement, storey drift, base shear, overturning moment and storey stiffness. Shear wall without openings shows better performance when compared to all models. Compared to bare frame, displacement is reduced by 38.6%, drift reduced by 37.6%, storey shear increased by 114.8% and storey stiffness increased to 25.6x10⁶ kN/m. Performance of building with the combination of shear wall with openings and bracings is good. Compared to bare frame, displacement is reduced by 37.2%, drift reduced by 34.4%, storey shear increased by 74% and storey stiffness increased to 19.4x10⁶ kN/m. The results of model 4 and model 9 are almost equal. Combination of shear wall with openings and bracings will helps to achieve the economy and also increases the strength

At present days building a structure with all the regular configurations is not feasible in most of the cases due to the irregular plot dimensions, aesthetic visual and functional requirements in the urban cities. The structure with more irregular configuration either horizontally or vertically are more vulnerable to earthquake which leads to collapses of structure, property loss and casualties. The shear walls are commonly used as a vertical element. Shear walls may have one or more openings for functional reasons such as windows, ventilation and other types of openings in shear wall. Frequently the shear wall is provided with openings thus necessary to study effect of irregular building. The present study was carried out the opening in shear wall with different shape of RC multi-Storey building and Study different building model with Combination of Horizontal & Vertical irregularities. The models were created using the ETABS software with Full Shear walls, Shear walls with a 25% opening. The location of the Shear wall was optimal. Prepared models of G+9 story and Analyze the model by Response Spectrum Analysis and Compare the Result with different buildings layout with parameters like storey Displacement, Storey Shear, Storey Drift, Storey Stiffness, Base shear, Torsion, Time Period and Mode Shape

A RC shear wall with vertical mild steel-lead energy dissipation strips was proposed as an improvement in seismic behavior over existing shear wall designs. In order to test and ascertain the projected increase in performance, five low-rise shear wall specimens: one normal RC shear wall, one RC shear wall with slits, two shear walls with vertical X style mild steel energy dissipation strips under different design parameters, and one shear wall with vertical X style mild steel-lead energy dissipation strips were tested under cyclic loading. Based on the experiment, the damage characteristics, hysteresis characteristics, load-carrying capacity, stiffness, ductility, and energy dissipation of the specimens were comparatively analyzed. Results show that the ductility and energy dissipation of the RC low-rise shear wall with vertical X style mild steel energy dissipation strips and the one with X style mild steel-lead energy dissipation strips offer a significant improvement in seismic performance over accepted designs. In addition, the failure behavior of the low-rise shear wall tended towards bending failure rather than shear failure.