Frame-shear Wall Structure Research Articles

Elasto-Plastic Seismic Shear Distributions of Frame-Wall Structures

ABSTRACT In this study, theoretical and numerical methods were used to research seismic shear distributions of frame-shear wall structures under elasto-plastic conditions. The shear distributions of frame-shear walls were analyzed based on a simplified elasto-plastic analysis model of flexural shear. Based on a preliminary project, three groups of 2D models with different stiffness eigenvalues were designed and used to compare the shear distributions of whole structures and frames. The characteristics of the shear distributions of structures and frames and the development of plastic hinges were analyzed, and the rationality of shear adjustment based on Chinese standards was discussed from the perspectives of structural design, seismic performance and collapse resistance. The results revealed obvious differences between shear distributions of structures caused by strong vs. frequent earthquakes. For strong earthquakes, the shear distributions tended to be evenly distributed with respect to height, while the shear force of the bottom story was significantly larger than that of the upper stories. This was mainly caused by the redistribution of plastic internal forces due to the development of plastic hinges. The shear adjustment of the frame usually affected the reinforcement in the beams rather than in the columns, which contradicted the design concept of strong columns – weak beams. Additionally, shear adjustment had little effect on the seismic performance and collapse resistance of structures. This paper suggests that by ensuring the ability of strong columns, weak beams and plastic hinges to rotate, shear force adjustment can be prevented.

Pseudo-Dynamic Tests on Frame–Shear Wall Structure with Precast Concrete Diaphragm

In order to study how to improve the spatial action of precast monolithic composite floor slabs, and examine replacing the cast-in-place surface layer for reducing the weight of structure, we used pseudo-dynamic tests on one-quarter scale models of two-span and three-story frame structures. The lateral load tests compared the stresses and displacements with a cast-in-place floor frame–shear wall structure (SJ1) and a precast monolithic floor frame–shear wall structure with X horizontal braces at the bottom of the floor (SJ2). The results show the X horizontal braces can improve the spatial action. Structural integrity (SJ2) as well as the effective transmission of the horizontal force can be ensured by additional X bracing at the bottom of the rigidity of the floor without a cast-in-place concrete topping. The results show that X horizontal braces more effectively transfer horizontal stress, which provides a beneficial reference for similar research.

A Three-Dimensional Seismic Damage Assessment Method for RC Structures Based on Multi-Mode Damage Model

To rationally evaluate the seismic damage of RC structures comprehensively and multi-dimensionally, a damage index calculation method is proposed. This is a macroscopic global seismic damage model that considers torsional damage, damage in two perpendicular horizontal directions, as well as the overall damage, based on the modal characteristics of the three-dimensional structure and the multi-mode damage model. Formulas are derived, and the steps for damage evaluation are summarized. To better illustrate the results of the proposed method, an example of an asymmetric 6-story frame-shear wall structure is built using the OpenSees program. Thirteen ground motions are selected for incremental dynamic analysis. The structure’s damage indexes are evaluated according to the proposed method and compared with the corresponding structural responses, He et al.’s index, and the Final Softening index. The results demonstrate that the proposed method can fully reflect the macroscopic damage state of the structure from different perspectives. Additionally, the results show that, despite the ground motion only acting in the y-direction, the structure exhibits responses and damage in both the x-direction and the torsional direction. The overall damage to the structure is primarily controlled by the torsional damage, attributed to the asymmetric arrangement of shear walls. The torsional effect is the key factor leading to the failure of asymmetric structures during earthquakes. Therefore, ensuring the torsional strength of the structure is crucial during the structural design process.

Study on the Influence and Optimization Design of Viscous Damper Parameters on the Damping Efficiency of Frame Shear Wall Structure

This study investigates the influence of viscous damper parameters on the damping efficiency of frame shear wall structures. Taking a specific frame shear wall structure as the background, a three-dimensional finite element model is established using a nonlinear dynamic time–history analysis method. The damping ratio, reduction in vertex displacement, reduction in base shear, and inter-story drift utilization rate are selected as the damping performance indicators. Firstly, a sensitivity analysis is conducted to study the influence of different viscous damper parameters on these indicators. Then, the relationship models between the viscous damper parameters and the indicators are fitted using the response surface method, and the fitting effect is evaluated through an F-test and determination coefficient R2. Finally, an objective function based on key damping performance indicators is established to solve for the optimal parameters. The results show that the traditional sensitivity analysis method is unable to comprehensively consider the combined effects of different damping efficiency indicators. The response surface method has high fitting accuracy and good predictability and can serve as an optimization model. Considering the stiffness of supporting components matched with the viscous damper parameters, the feasibility of the optimal damping parameters is demonstrated from an engineering application perspective. A simple and easy-to-operate damping design flowchart is proposed, providing important guidance and reference for designers in frame shear wall structure damping design in the future.

Pertinent Emplacement of Shear Walls to Diminish the Torsional Effects in Asymmetric-RC Framed Buildings

In seismic conditions, asymmetric structures typically experience lateral deflection. The magnitude of this deflection is dependent on various factors, including the configuration of the structural system, the mass of the structure, and the mechanical properties of the materials used. One critical factor that can reduce a structure's seismic resistance is torsion irregularity. To combat this, shear walls can be installed in the pertinent location to provide stability and stiffness to the structure. This study explores the seismic analysis of a G+10 storey asymmetric RC frame-shear wall structure using the response spectrum method as per ASCE7-16. The study encompasses six models with varying shear wall placements, with the initial model lacking a shear wall. The results are compared, and recommendations are made to avoid torsional irregularity destruction under seismic loads. Based on the analysis, Model-2 (shear wall in the periphery) shows the worst condition from the 1st storey through the 11th storey, possibly due to maximum eccentricity in upper storeys. In contrast, Model-5 (shear wall in core and corners) shows the best performance among all models, likely due to increased stiffness in the corners and core of the structure. Overall, this study contributes to the advancement of structural engineering practices by enhancing the understanding of complex interplay between torsional irregularity, shear wall placement, and structural asymmetry.

Analysis of 2D heat transfer of shear wall thermal bridges influencing on the exterior wall

ABSTRACT Frame-shear wall structures are widely used in high-rise buildings, and their thermal bridges account for a large portion of the entire exterior wall area. The purpose of this study was to investigate heat transfer of shear wall thermal bridge (SWTB) that influences the exterior wall of a building. A typical 3D COMSOL model of the SWTB junction was built, and indices were used to quantify its thermal characteristics of the SWTB junction. The results showed that the peak values and peak width of the heat flux at the interface of the exterior wall and thermal bridge increased with an increase in the thermal resistance of the SWTB. When the thermal resistance of the SWTB (R tb ) is greater than or equal to the thermal resistance of the exterior wall (R w ), the influencing area A i n f no longer increases. In addition, the maximum error of replacing K 2D with K 1D discussed in this paper was 3.56%, which can be neglected in engineering applications in hot summer and cold winter climate zones. Finally, strategies to reduce the heat loss of the SWTB were proposed. The results of this study provide valuable data for engineers to evaluate the thermal characteristics of SWTB in building designs.

Shaking table test and numerical simulation of a precast frame-shear wall structure with innovative untopped precast concrete floors

An innovative discretely connected precast concrete floor (DCPCF) was presented, in which the adjacent precast concrete hollow or sandwich flat slabs were connected by mechanical connectors embedded in the precast concrete slabs and beams. This paper summarized the seismic performance observed during the shaking table test of a precast frame-shear wall structure adopting DCPCF. A 1/4-scale model of a 4-storey 2-bay single-span frame-shear wall structure was designed and tested on the shaking table to evaluate the dynamic characteristics and seismic responses of building structures adopting DCPCF. In addition, a finite element model, including detailed modeling of beam-column joint and slab joint connections, was established using nonlinear dynamic modeling program. The predictions on the seismic performance using the finite element model agreed well with the test results for the designed frame-shear wall structure. The precast concrete frame-shear wall structure adopting DCPCF had satisfactory seismic performance during the test process. The in-plane deformation of DCPCF was observed under the horizontal earthquakes, and DCPCF could not satisfy the requirements of rigid diaphragm assumption in most cases under design basis seismic intensity. The seismic design method based on semi-rigid floor diaphragm had large error and safety risk in calculating the seismic shear force of building structure adopting DCPCF. Additionally, design suggestions for multi-storey and high-rise building structures using DCPCF were proposed based on the observed seismic responses.

Carbon-saving benefits of various end-of-life strategies for different types of building structures

Against the backdrop of advocating for ultra-low energy consumption buildings both domestically and internationally, much attention has been attracted to energy consumption and carbon emissions at the end-of-life (EoL) stage from the whole life cycle of buildings. Recycling of construction and demolition wastes (C&DW) is an inevitable step in achieving the goals of ultra-low energy consumption and “carbon neutrality.” In this paper, the life cycle assessment (LCA) theory was employed to study the carbon-saving benefits of four different EoL strategies (i.e., recycling, remanufacturing, reuse, and the integrated strategy) for various building structures (including frame, frame shear wall, shear wall, and light steel structures), in which the carbon-saving potential (CSP) was served as the evaluation index. The results show that compared with the traditional demolition and landfill disposal methods, the implementation of integrated management strategies for structural buildings in this study can reduce carbon emissions by 150.7–246.8 kgCO2-e/m2, with the carbon-savings of 11.9–34.8 times the carbon emissions generated by the abandoned landfill. Among the four structures, the light steel structure has the greatest CSP, reaching (73.75–77.24%), followed by the frame shear wall structure (42.67–46.93%), the frame structure (41.19–45.11%), and the shear wall structure (39.00–43.79%). When the building life span is 50 years, all CSPs of the four structural buildings significantly increased, at this point, deconstruction of the building is the most reasonable approach.

Comparison on seismic resilience of hybrid, isolation, and damping control reinforced concrete frame-shear wall buildings

To investigate the effectiveness of different vibration control methods in realizing seismic resilience of reinforced concrete (RC) frame-shear wall structures, four cases with different control methods were designed, including the damping control building using energy dissipation cladding panels (EDCPs) (RCFSW7-D), isolated building (RCFSW7-I), isolated building with enhanced stiffness of superstructure (RCFSW7.5-I), and hybrid control building using both EDCPs and isolation (RCFSW7-H). The critical seismic responses and resilient performance of four cases were analyzed based on the Chinese code. Maximum inter-story drift ratios (MIDRs) of RCFSW7-I, RCFSW7.5-I, and RCFSW7-H under maximum considered earthquake were 36%, 51%, and 72% lower than that of RCFSW7-D, respectively. Although the stiffness of superstructure of RCFSW7.5-I and RCFSW7-H were approximately identical, the MIDR of RCFSW7-H was 44% smaller than that of RCFSW7.5-I. Meanwhile, the maximum absolute floor accelerations (MAFAs) of three isolated structure under MCE were approximately 70% lower than that of RCFSW7-D. The seismic resilience level of RCFSW7-D was Level 1, which is dominated by the damage of structural components (SCs) controlled by MIDR and acceleration-sensitive non-structural components (ASNSCs) controlled by MAFA. The seismic resilience levels of RCFSW7-I and RCFSW7.5-I successfully increased to Level 2, leading by the effectively control of MAFA and damage of ASNSCs. However, the MIDR was not sufficiently controlled even the stiffness of superstructure was increased. In contrast, hybrid control building significantly reduced both the MIDR and MAFA through the currently utilization of seismic isolation and EDCPs, especially the MIDR and damage of SCs, leading to a seismic resilience level of Level 3.

Experimental study and mechanism analysis of out-of-plane seismic performance of reinforced concrete shear walls

Compared with the in-plane seismic performance, the out-of-plane seismic performance of reinforced concrete shear walls is weak and usually neglected, which leads to an inadequate study of the out-of-plane damage mechanism of shear walls and a lack of clear protective measures. In order to compare the similarities and differences in seismic performance of reinforced concrete shear walls when subjected to in-plane and out-of-plane loads in different directions and to clarify the key influencing factors, low cyclic loading tests were carried out on typical shear wall specimens in both in-plane and out-of-plane directions. The moment-curvature simulations of shear wall sections in both in-plane and out-of-plane directions are analyzed. The effects of parameters such as axial pressure ratio, wall thickness, height to width ratio and concrete grade on in-plane and out-of-plane seismic performance were analyzed at the member level in combination with finite element variable parameter analysis; at the structural system level, the time history analysis of 2 frame shear wall structures for single seismic action and main-aftershock sequence is established, and the structural damage is evaluated through the maximum story drift and rotation. The results reveal that the out-of-plane seismic performance of shear walls is significantly weaker than their in-plane seismic performance, with a difference of 1/20∼1/15 times in bearing capacity, where wall thickness and aspect ratio are the main parameters affecting in-plane and out-of-plane seismic performance; when the shear walls in the structure are subjected to seismic action in the out-of-plane direction, their out-of-plane direction will undergo large deformation and damage will occur easily, especially in the Single directional wall with less structure. The out-of-plane nonlinear analysis of the cross-section can be performed more accurately and quickly by using the new principal structure model proposed in this manuscript and some traditional principal structures. In the seismic design of shear walls, both in-plane and out-of-plane seismic performance should be ensured, and the wall thickness and height to width ratio of shear walls should be reasonably controlled.

Seismic behavior of irregular shaped beam-column connections

This paper reports test results and numerical analysis of special-shaped beam-column connections based on a frame-shear wall structure. Four connections of 1/5 scale ratio were tested under constant axial force and reversed lateral load on the top of column. The experiment investigated the effect of steel reinforced concrete (SRC) beam, in-plane and out of-plane reinforced concrete (RC) wall on the connections’ seismic behavior. The failure modes, hysteresis curves, ductility, strength degradation and energy-dissipating capacity of test specimens are reported. The results indicated that test joints were susceptible to suffer more brittle failure caused by formation of plastic hinge on column, which is considered unfavorable compared to conventional joint with regular shape in earthquake resisting. Adding in-plane shear walls to the connection switched column failure to beam failure mode, and significantly improved the connection’s strength, stiffness and ductility. Finite element models were detailed established and validated through experiment data. Influence of parameters including axial load ratio, concrete strength grade, section area and steel ratio of upper column, transverse hoops volumetric, RC wall of two orthogonal directions on connection’s seismic behavior were studied through modeling results.

Simulation calculation and analysis of building energy consumption of multi-story glued laminated timber structures

As the only renewable building material, wood has a strong carbon sequestration effect. Thus, timber structures have the natural advantages of saving energy and reducing emissions. Currently, the research objects of building energy consumption are rarely timber structures. To further control the operational energy consumption of timber structures, this paper takes six-story glued laminated timber beam-column frame and light wood-frame shear wall structures as the research objects. Building energy consumption research is conducted through testing the heat transfer coefficient of the envelope structure, air circulation ratio, and Building Information Modeling (BIM) technology on-site. The results show that the energy consumption of the building is consistent with the current energy consumption of small- and medium-sized office buildings, and the heat gain and loss of the building are mainly due to solar radiation and heat conduction of the envelope, respectively. The airtightness of the building has the greatest influence on the energy consumption of the building, and the type of building structure and window-to-wall ratio have little influence on the energy consumption of the building.

Estimation of the displacement time history of high-rise building structures using limited measurement data and structural information

A method is proposed to estimate the seismic displacement time history of a high-rise building structure. The structure is simplified to a flexural-shear mass-spring model, and the optimal parameter values of the model are determined using particle swarm optimization. Limited measured acceleration and roof residual displacement data are used to calculate the model error in the optimization process. In this method, only the number of stories and the heights of each story are needed as known structural information. The displacement time history calculated for the optimal model is treated as the estimation of the actual response of the original structure. The responses of a 13-story reinforced-concrete frame-shear wall structure obtained from numerical simulation of the ABAQUS model are used to verify the performance of the method. The results show that the average estimation error of the maximum story displacement is 5.2% and that of the maximum inter-story drift ratio is 5.3%. Having the acceleration responses of 1/3–1/4 stories is sufficient to accurately estimate the story displacement and inter-story drift ratio if the root mean square noise-to-signal ratio of the acceleration is less than 30%. The shaking table test data of a 15-story reinforced-concrete shear structure are used to verify the method’s effectiveness; the average estimation error of the maximum story displacements of the 7th, 8th, and 15th stories is found to be 4.8%.

Shaking Table Test for Seismic Response of Nuclear Power Plant on Non-Rock Site

In order to compare and analyze the seismic response characteristics of a safety-related nuclear structure on a non-rock site in the condition of raft and pile group foundations under unidirectional and multidirectional seismic motion input, a large-scale shaking table test of the soil-nuclear structure system was carried out in this paper. In the test, the soil was uniform silted clay, and the shear wave velocity was 213 m/s. Considering the similarity of the superstructure natural frenquency, the actual nuclear power structure was simplified to a three-story frame shear wall structure model. The annular laminated shear model box was used to take the boundary effect of soil into consideration; the seismic motions = were input in only one horizontal direction or three directions at the same time for the shaking table test, and the results were analyzed. The results of the test show that the acceleration response of the safety-related nuclear plant is affected by the directions of input seismic motion and the forms of the foundation. When the seismic motion is input simultaneously in three directions, the acceleration responses of the horizontal motion and vertical rocking of the safety-related plant are larger than those of the single-direction input. The acceleration response of the horizontal motion and vertical rocking of the safety-related structure with the pile group foundation is smaller than that with the raft foundation. The values of most frequency bands in the horizontal acceleration Fourier amplitude spectrum at the top of the pile-foundation structure are smaller than that at the top of the raft-foundation structure, while the displacement is basically the same as that of the raft-foundation structure. This is related to the relation between the frequency component of input seismic motion and the natural frequency of the structure system. Therefore, it is more reasonable to use three-dimensional seismic input in the seismic response analysis of nuclear power plants. The seismic performance of nuclear power plants can be enhanced by using pile group foundations.

A Stochastic Earthquake Ground Motion Database and Its Application in Seismic Analysis of an RC Frame-Shear Wall Structure

A stochastic earthquake ground motion database comprising twelve groups of simulated ground motions was introduced. Ground motions were generated using the stochastic semi-physical model of earthquake ground motions, based on a cluster analysis of 7778 recorded earthquake ground motion. All twelve groups of simulated earthquake ground motions were validated through the probability density evolution method (PDEM) by comparing their time histories and response spectra. As an application of the proposed database, an 18-story reinforced concrete (RC) frame-shear wall structure was analyzed using one group of simulated earthquake ground motions. The probability densities of the top displacement of the structure were estimated using PDEM, highlighting the significant stochasticity of the structural response. The seismic reliability of the structure was assessed by evaluating the extreme value distribution of the story drift angle. The investigations indicate that the proposed stochastic earthquake ground motion database effectively captures the inherent stochasticity of ground motions. Moreover, it contributes to enhancing the efficiency of reliability assessments for structures.

Overturning collapse responses of RC frame-shear wall structures induced by failure of vertical members

In this paper, three 1/5 scaled reinforced concrete (RC) frame-shear wall structural models with single shear wall or cross shear walls on each floor were tested to reveal the mechanism of overturning collapse induced by failure of vertical members. A three-dimensional videogrammetric measurement technique based on high-speed cameras was adopted to acquire spatial locations and status of the moving objects. Overturning collapse was obsessed in all the three structural models after partial vertical members were removed. However, although the structural model with cross shear walls overturned, it did not disintegrate, which indicated that existence of the cross shear walls improved integrity of the structure. Meanwhile, a collapse simulation system was developed based on discrete element method (DEM). Collapse processes of the three structural models, including debris stacking, were predicted and effectiveness of removing the vertical components to simulate dynamic effects in the numerical model was verified. Experimental and numerical results revealed that overturning collapse would be initiated when a sufficient number of vertical components were removed and the flexural bearing capacities of the remaining vertical load bearing members could not resist the impact load of the upper structure for an RC frame-shear wall structure. Parametric analysis indicated that the higher the failure was located, the smaller the damage of the lower remaining structure. Moreover, if the remaining vertical load bearing structural members could not support the upper structure of a high rise building due to insufficient compressive bearing capacities, progressive collapse would take place, and cross shear walls played an important role in resisting collapse for the structure.

Seismic performance assessment of precast RC shear wall structure with lead viscoelastic damper

The precast reinforced concrete (RC) shear wall structure with lead viscoelastic damper is a combination of shear wall with horizontal connectors and vertical energy-dissipating connectors. The lead viscoelastic damper (LVED) is adopted as the vertical wall-wall joint to increase the plastic deformability of shear wall and provide additional strength and energy dissipation. The pore-forming grouted lap-sliced connector is adopted as the horizontal wall-floor joint to ensure the overall seismic performance of the shear wall. Firstly, cyclic loading tests were conducted to investigate the influence of lead and viscoelastic layer thickness on the hysteretic behaviour of LVED, and the theoretical method and finite element analysis model for LVED were also proposed and validated by the test results. Additionally, the seismic behaviour of precast shear walls with and without LVEDs was studied experimentally and numerically. It was shown that better cooperative working performance was observed in the precast shear wall with LVED. Finally, the dynamic responses of precast frame-shear wall structure adopting LVED was investigated based on dynamic time-history analysis.

Seismic performance of resilient recycled aggregate piloti-type structure employing ultra-high strength bars

A resilient recycled aggregate piloti-type brick masonry structure equipped with ultra-high strength bars (UHSB) in the pilotis and shear walls was proposed. Quasi-static test and finite element analysis based OpenSees were conducted to study its seismic performance. The main parameters include different steel bar categories, reinforcement configurations, storey stiffness ratios and shear wall distributed reinforcement ratios. The results revealed that both the recycled aggregate concrete (RAC) frame-shear wall structure at the first storey and the upper recycled brick masonry structure showed satisfactory deformation performance and stable load-carrying capacity. The frame-shear wall structure at the weak first storey is prone to suffer from shear failure of the shear wall under the relatively large drift due to the larger proportion of shear deformation. The plastic damage of the pilotis and shear wall reinforced with UHSB was obviously reduced. The arrangement of diagonal UHSB in the shear wall can significantly improve the shear resistance and prevent the premature shear failure of the shear wall, and further enhance the resilience and seismic performance of the bottom-storey structure. The proposed resilient frame-shear wall structure of bottom storey presented excellent repairable performance. The innovative piloti-type brick masonry structure with resilient bottom storey can give full play to the resilience and seismic performance of its bottom-storey frame-shear wall structure even with a relatively higher storey stiffness ratio.

Seismic behavior of a precast RC frame–shear wall structure using full/half grout sleeve connections

To investigate the seismic behavior of precast RC frame–shear wall structures using full/half grout sleeve connections, two RC frame–shear wall structure specimens were constructed and tested under cyclic loadings: the first specimen was a precast RC frame–shear wall structure (Specimen PCFW), and the second specimen was a conventional RC frame–shear wall structure (Specimen RCFW) cast in situ. The seismic performance of Specimens PCFW and RCFW including the failure modes, hysteretic responses, and energy dissipation capacities was investigated. Furthermore, the mechanical behavior of Specimen PCFW was numerically simulated using the OpenSees software. The test results show that the crack distribution of Specimen PCFW is more dispersed than that of Specimen RCFW. In particular, few cracks appear in the area of full/half grout sleeves in Specimen PCFW. However, the damage to the concrete around the half grout sleeves of the side columns in the shear wall of Specimen PCFW in the 1st story was more severe than that in the corresponding region of Specimen RCFW for a less thick concrete cover. Compared to Specimen RCFW, Specimen PCFW exhibits higher lateral bearing capacity, better energy dissipation ability, and slightly lower ductility. In addition, assuming the equivalent principle of rebar area, the mechanical behavior of Specimen PCFW can be effectively simulated using the nonlinear multilayer shell element in the OpenSees software.

A Simplified Method for Evaluating the Diaphragm Flexibility for Frame-Shear Wall Structure under Earthquake Load

The rigid floor assumption is commonly used in structural design, but it is not applicable to buildings with a large plane aspect ratio. This study designed nine frame-shear wall structures with the story of 3, 6, and 12, with a plane aspect ratio of 2, 3.33, and 4. Based on the design results, the finite element models were set up by ETABS. Both the rigid diaphragm and the flexible diaphragm cases were considered in each model. The effect of elastic diaphragm deformation on structural seismic performance was investigated, including fundamental period, top displacement, inter-story drift, and base shear force. The results indicate that the diaphragm deformation on 3-story structures is more significant than that on 6-story and 12-story structures. The diaphragm in-plane deformation increases with the aspect ratio. On the basis of the analysis results, a simplified formula to calculate the internal force amplification factor and a quantitative assessment method for evaluating the diaphragm flexibility were proposed, which can provide a reference for engineering design.