Examining the Interaction between Shear Walls and Reinforced Concrete Frames in Tall Buildings using a two-dimensional model

To enhance the functionality of buildings under dynamic earthquake loads, seismic design of structures is required. Seismic design has grown more logical in recent decades as a result of increased understanding gained through thorough study and the development of more efficient analytical methodologies. To properly mimic the real seismic behavior of buildings, however, there are still constraints. As a result, modern practices include simplifying aspects of architectural design. As there are a practically infinite number of alternative cross-sections (e.g., T, L, or C forms) for reinforced concrete shear walls, these simplifications become even more important. The seismic response of shear walls with non-rectangular cross-sections (i.e., nonplanar walls) is a difficult issue that is now the subject of study.[1] The seismic reaction of non-planar walls has been the object of much study, leading to the development of models capable of properly simulating such response. Applying these models accurately calls for precise calibration and advanced knowledge of structural dynamics. Although some of these models have lately been included into nonlinear analysis software, their usage is confined to research and Performance Based Design since elastic analysis is so central to structural design practice. For conventional strength-based design, modeling non-planar walls using 2D finite elements is a common practice since it is thought to be precise enough to evaluate the (linearly elastic) global response. However, a high degree of uncertainty is introduced into the estimation of the real capacity and demands when dealing with complicated shear wall geometry, even when elastic behavior is considered. [2] Pushover analysis is a performance-based design method used to assess the resilience of both newly constructed and preexisting buildings to earthquakes. Pushover analysis, also known as nonlinear static analysis, provides valuable insight into how well a building can withstand earthquake forces in relation to the demands of an actual earthquake. [3] By using inelastic analysis to compute a structural system's strength and deformation capacity under design earthquakes, nonlinear static analysis may assess how well that system performs under seismic loads. Important performance characteristics such overall drift, inter-story drift, inelastic element deformations, deformations between elements, and

Nayel, waleed & vara, t. (2022) There is a pressing need to set aside agricultural land in addition to meeting the rising demand for it to house people and host businesses and factories. That's why there's a recent surge in the construction of skyscrapers. Wind and earthquakes exert lateral stresses on these high-rises. The increasing slenderness of modern high-rises increases the risk of structural instability. There is a need for new structural systems that can enhance the dynamic responsiveness of these tall, skinny structures. Shear walls are one kind of structural structure used in RC construction. Shear walls are often installed parallel to the direction of lateral load and are used to counteract lateral forces caused by wind or earthquakes. These shear walls convey the lateral stresses to the foundation because of their shearing resistance and overturning resistance. This research looks at a 30-story skyscraper with and without shear wall apertures. For a more in-depth and dynamic examination, try using the response spectrum approach. [5] Seyyed Mostafa Ayatollahi Moosavi(2022) Researchers analyzed the dynamic response of many reinforced concrete wall-frame structures, taking into account failure criteria and the buildings' particular substrate, to determine the impact of soil-structure interactions. It was determined that the most up-to-date and accurate approach for calculating tensile and compressive damage parameters in concrete necessitated using a modified version of Concrete damaged plasticity (CDP) in order to represent the material accurately. The analytical model was used to examine the seismic reactions of the three laboratory models, and a comparison of the data indicates that the suggested model is very accurate. Then, Abaqus was used to model three-, seven-, and twelve-story reinforced concrete frames with shear walls. Interactions between the land and the building were also taken into account. Numerical modeling findings demonstrate that plastic behavior of concrete and the impacts of soil and structure interaction significantly affect the seismic response of reinforced concrete wall-frames. When compared to the rigid support, these reactions were either gradual or diminishing. When earth and buildings interact, the result is a weakening of the foundation and a lengthening of the structure's lifespan. This is an increase of around 3.57% for the 3-story building, 4.4% for the 7-story building, and 10.2% for the 12-story building. When the impacts of soil and structure interaction are taken into account, a noticeable shift in the base shear may be seen. Based on these findings, a base shear account, the findings show that the relative displacement increases. [6] Muhammet Kamal, Mehmet Inel, Bayram Tanik Cayci, (2022) The purpose of this research is to examine the seismic behavior of mid-rise reinforced concrete (RC) structures on soft soil while assuming different levels of structure-soil-structure interaction (SSSI), soil-structure interaction (SSI), and fixed-base (FB). High ductility RC frame elements are designed in 3D as completely nonlinear structures for buildings with 5, 8, 10, 13, and 15 stories. There are five distinct structural cases: pounding-enabled and -disabled SSSI models, pounding-enabled and -disabled FB models, and pounding-enabled SSI models. The volume of 3D inelastic soil was directly modeled using finite elements for this research. Sixty-five model permutations representing SSSI, SSI, and FB modeling techniques were considered in the comprehensive study. As a consequence, the lateral displacement requirements of the structures and displacement profiles were analyzed and displayed a total of 1365 times using 21 distinct ground motion recordings. It is discovered that nearby structures situated on soft soils exhibit seismic behavior that deviates from the fixed-base assumption. Buildings on soft soils have a reciprocal effect on one another, therefore they should not be assessed in isolation. Even if there is no collision, structures up to 8 stories need take into account the impact of their surroundings, including the earth and the buildings themselves. In the absence of a collision, it may be appropriate to focus only on SSI for structures taller than eight stories. Regardless of the height of the structures in question, soil-structure interaction and the impacts of other buildings must be considered if there is a risk of seismic pounding due to inadequate separation between them. [7] Rohit Maheshwari (2022) It is important for high-rise buildings to be stable, low-maintenance, long-lasting, and able to fit all of the necessary features into as little space as possible. Precision is required to provide enough strength and stability against lateral loads. The optimum sizing takes into consideration the ideal stiffness co-relationships among structural sections, which is of paramount relevance for the economy. Lateral loads, axial forces, shear forces, base shear, maximum story drift, and tensile forces are only some of the stresses that may affect a building's structural structure, especially at heights. With and without shear walls, G+20 RC tie-column and tie-beam framed buildings are analyzed and compared in this research. E-Tabs, a software program, is used to do the analysis. According to Indian Coda Provisions, the applied loads and load combinations are computed and taken into account. The area around the building is classified as Seismic Zone IV. Maximum drift figures Mohd Danish (2013) When an earthquake hits, it strikes the weakest part of the whole three-dimensional structure and exerts a force that is quite different from that of gravity or wind. It's not earthquakes that kill people; it's the earthquakes' victims' own stupidity in design and shoddy building that causes so much destruction. It is often assumed that masonry infills will not take part in resisting any form of load, axial or lateral, and therefore they are employed to fill the space between the vertical and horizontal resisting sections of the building frames. As a result, designers often overlook its worth in the study. In actuality, the frame's stiffness and strength are greatly improved with the addition of infill walls and shear walls. Many multi-story structures have collapsed due to earthquakes because of the designers' inability to realize that bare frames had far less stiffness and strength than infill frames and frames with shear walls. Three different RC frame models (a bare frame, a frame with shear wall taking infill, and a bare frame with shear wall) with varying story heights (G+3, G+5, G+7, and G+9) were analyzed using finite elements. All RC frame constructions have undergone linear analysis in accordance with IS: 1893 (Part 1) - 2002 and IS: 456 - 2000. Only the in-plane stiffness of the brick wall has been taken into account, with the infill panels being modeled as equal diagonal strut members. Response Spectrum Analysis using FEM based software has been used to monitor the behavior of structures exposed to Gravity and Seismic loads, including the influence on Time Period, Mass Participation factor, and Story Drift. Once infill panels and shear walls are added to RC bare frame structures, the structures' strength and rigidity are observed to improve. [9]

A 30-story structure was used for the parametric research. The structures under consideration have a square footprint of 25 meters, with 5 bays that are each 5 meters in length. In Figure 1 you can see the building's ground layout. According to Indian Standards IS 456 [10] and IS 1893[9], the dimensions of structural elements of a typical 30-story symmetric RC frame structure were calculated for the most severe load combination. Cast in situ reinforced concrete beams measure 300 x 500 millimeters, whereas 1-15 stories use 900 x 900-millimeter columns and 16-30 stories use 600 x 600-millimeter columns. Thickness of the slab is 150 mm, the height of each story is 3.5 m, and the shear wall thickness is 250 mm. Steel Grade: fey 415 MPa, Concrete Grade: M30.

A 30-storeyed reinforced concrete building with and without shear wall in Seismic In this case, we took into account Zone-V [IS: 1893, 2002]. Special Moment Resisting Frames and RC shear walls work together to withstand the lateral pressures of the design. General data:

• Plan of the model is 30m × 18m.

• Typical floor height is 3m

• Grade of concrete = M25

• Grade of steel = Fe500

• Earthquake zone = V

• Importance Factor = 1.5

• Soil type = II(Medium)

• Response reduction factor R = 5

Computer-aided design (CAD) is a suite of software tools that helps designers construct virtual models of structures, machines, components, and other items. Both 2D and 3D modeling use comparable procedures, and both may be created using CAD. However, 3D modeling goes beyond this by providing a third dimension, along with additional data and functionality. When comparing 2D drawings with 3D models, what are the key differences? To model in 2 dimensions is to make 2D drawings, plans, and blueprints. These records may outline a site's geometry and indicate where various things are located, but they lack the third dimension of depth. These two-dimensional designs may be drawn out on paper or used in two-dimensional modeling software. Fiber-based, two-dimensional, frame-element modeling for model validation: wall interaction effect. In this model, the web wall centerline is connected to the gravity columns on each floor by a stiff link, and at both ends of the connection, a 3D joint element is inserted. To represent the slab's out-of-plane flexural stiffness, the model's 2D plane parts are given a bilinear asymmetric moment-curvature relation. The top and bottom slabs of the test construction have different reinforcing matting, which accounts for the asymmetrical relationship. High stiffness values were assigned to the 3D joint's nodes 1 and 2, restricting their five remaining degrees of freedom. Improvements in the anticipated narrative shear and moment envelopes are seen on Figure 2 for EQ1 through EQ4 using the IZ-Model. The need of considering the 3D interaction impact of all structural parts in the building in order to effectively anticipate the seismic reaction is shown by this exercise.

To examine the interaction between the shear wall and the RC frame, a 2-dimensional plane model of a 20-story structure is shown in Fig. 2. Lateral loads for a 20-story, 30-story, and 35-story structure are shown in Tables 1, 2, and 3 for the external frame with shear wall and inside frame without shear wall, respectively. Lateral force sharing/distribution is shown in Figures 3-4-5 for a 20-story, 30-story, and 35-story structure, respectively, between the outer frame with a shear wall and the internal frame without a shear wall. In the instance of a 20-story structure, it has been shown that the RC frame resists about half of the lateral loads and the shear wall resists the other half at levels 8 and 9. In the eleventh floor and above, the structural dimensions of the columns alter, which causes a shift in the load distribution patterns. Nearly half of the lateral stresses on a 30-story structure are resisted by the RC frame, while the other half are resisted by the shear wall. This is shown at levels 7 through 12, and again at levels 16 through 20. Changes in the structural size of columns beginning at the 16th floor cause shifts in the load distribution patterns seen on lower floors. There is a shift in the load distribution pattern at the 16th and 26th floors of a 35-story structure because the structural dimensions of the columns vary at those floors. Table 1: Shear wall-frame interaction for 20-storeyed building

Figure 4: Interaction between frame with shear wall and without shear wall for 30-storey building

Figure 5: Interaction between frame with shear wall and without shear wall for 35-storey building The study findings of all investigated RC frames show that the RC frame alone bears the full lateral load at the top two or three stories, whereas the shear wall's role in resisting lateral force at the top is minimal. In contrast, the RC frame resists just 25% of the lateral stress, whereas the shear wall bears 75% of it at the first three basement floors. Almost 40% of the lateral ground and second levels is shared between the shear wall and the RC frame. Nonetheless, outside frame with shear wall provides superior force resistance than interior frame without shear wall when story/height declines. At a certain intermediate height, the shear wall and frame are both supporting the same load, however at the lower height/story, the shear wall is supporting a greater percentage of the load than the RC frame. Shear walls and RC frames experience different amounts of lateral force at different heights. More than 75% of total story shear is handled by frame with shear wall at lowest three stories, and this percentage rises to 100% at lowest eight stories.

CONCLUSIONS

In this work, we use simplified equivalent 2-D modeling of respective frames to examine the shear wall-RC frame interaction for a 20, 30, and 35-story RC frame structure with a shear wall. Based on the results of the study of the 2-dimensional model of the building with RC frame and shear wall, it can be concluded that the shear wall and the RC frame work together to bear the external load at the basement and the middle levels. The study findings of all investigated RC frames show that the RC frame alone bears the full lateral load at the top two or three stories, whereas the shear wall's role in resisting lateral force at the top is minimal. In contrast, the RC frame resists just 25% of the lateral stress, whereas the shear wall bears 75% of it at the first three basement floors. Almost 40% of the lateral load at intermediate story‘s is resisted by the frame with shear wall, while the remaining 60% is resisted by the frame without shear wall. External frames with shear walls also withstand more force than interior frames without shear walls, especially when story/height diminishes. At a certain intermediate height, both the shear wall and the RC frame are bearing the same load, but at the lower height/store, the shear wall bears a greater proportion of the lateral stresses.

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Research Scholar, CT University