Concrete Structural Walls Research Articles

Incorporation of machine learning into multiple stripe seismic fragility analysis of reinforced concrete wall structures

This study proposes a novel procedure that incorporates machine learning (ML) into the multiple stripe analysis (MSA) approach to efficiently produce seismic fragility curves for reinforced concrete (R/C) shear walls in building frame systems. The proposed procedure aims to mitigate computational challenges associated with the original MSA approach. In this context, ML models were developed for predicting the failure probability of R/C walls subjected to ground motions based on a specified threshold of maximum interstory drift ratio (MIDR). Specifically, the result of each numerical analysis, taken as the output variable of the ML models, was classified as either “B” (Below) or “E” (Exceeding) to indicate whether the MIDR of R/C walls was below or exceeding the specified threshold. This binary categorization was then used to calculate the failure probability points, which are necessary to derive fragility curves per the MSA approach. Data for training and testing the ML models were generated from nonlinear time history analyses of 46 distinct R/C walls subjected to 1000 ground motions. The R/C walls varied in height from four to 40 stories, and the ground motions included far-field, near-field pulse, and near-field no-pulse types. Four well-established ML methods, including random forest (RF), extreme gradient boosting, light gradient boosting machine, and categorical boosting, were considered. The performances of the ML models were compared using a confusion matrix. Based on this comparison, the RF model was selected and incorporated into the proposed procedure. Subsequently, the proposed approach was demonstrated to create the seismic fragility function of a new R/C wall structure. This study highlights the potential of ML applications in optimization problems within the earthquake engineering domain.

Performance of channel shear connectors in steel frame with reinforced concrete infill walls

To examine the mechanical properties of channel shear connectors employed in steel frame with reinforced concrete infill wall (SRCW) structures, the improved push-out tests were performed on three specimens of channel shear connectors subjected to the monotonic and cyclic loading. This study investigated the influences of loading protocol and concrete strength on the mechanical behavior of channel shear connectors. After the refined finite element (EF) models of channel shear connectors were validated based on the push-out tests, a systematical parametric analysis was conducted to evaluate the effects of RC infill wall thickness, concrete strength, and channel dimensions on its shear strength of the channel shear connectors. In addition, this study also compared the accuracy of the CSA S16, AISC 360 and GB50017 design code in predicting the shear capacity of channel shear connectors in SRCW structures. The experimental results and parametric studies indicated that the current design equations inaccurately evaluate the shear capacity of channel shear connectors used in SRCW structures. Consequently, an alternative equation was developed to estimate the shear-resistant capacity of channel shear connectors in SRCW structures, which provided the desirable calculation precision for engineering design.

Development of data-driven models to predict seismic drift response of RC wall structures: An application of deep neural networks

This research aimed to develop data-driven models using deep neural networks (DNNs) that can rapidly predict the seismic drift responses of reinforced concrete (RC) wall structures in building frame systems, aiming to overcome the challenges of costly seismic performance evaluation of building structures. A total of 46 RC wall structures ranging from four to 40 stories were analyzed and subjected to 1,000 ground motions including far-field, near-field-pulse, and near-field-no-pulse types. Two input sets were investigated initially. The first input set comprises peak ground acceleration (PGA), spectral accelerations at 1 s–6 s with 1-s intervals, and the first five natural periods of the wall structure. The second input set contains PGA and spectral accelerations at the first five natural periods of the wall structure. The DNN model developed based on the first input set demonstrated superior accuracy achieving an R2 value of 0.880, and slightly outperformed other reputable machine learning models. To enhance the applicability of the developed model, the ground motion type was incorporated as an additional variable to the first input set, which led to an R2 value of 0.869. Ultimately, two DNN models, one based on the first input set and the other considering the ground motion type, were proposed in this study. Finally, the two models were applied to quickly predict seismic drift responses of a new 24-story RC wall structure, and the predicted results were then utilized to efficiently construct the fragility function. The findings highlight the potential of DNNs as an efficient solution to address complex and costly challenges in the earthquake engineering domain.

Seismic behavior of lightweight steel frame with thin-walled steel skeleton-lightweight concrete wall

In this study, an innovative prefabricated lightweight steel frame with thin-walled steel skeleton-lightweight concrete composite wall structure (LSF-TSLC) is proposed. The proposed LSF-TSLC has the lightweight steel frame (LSF) as the vertical load-bearing system, whereas the thin-walled steel skeleton-lightweight concrete composite wall (TSLC) acts as the main component for horizontal earthquake resistance. A full-scale LSF specimen and three full-scale LSF-TSLC specimens were prepared considering the variables of wall installation method (embedded, external) and thin-walled steel skeleton distribution (frame type, truss type). The corresponding seismic behavior was experimentally investigated by evaluating the hysteretic characteristics, failure mode, ultimate bearing capacity, deformation performance, stiffness degradation, energy dissipation, and strain characteristics. The results showed that the plastic hinges appeared at the beam ends and column bases of LSF. Due to the shear failure, the embedded and external TSLC exhibited grid cracks and diagonal cracks, respectively. The LSF and TSLC had a good coordinating deformation capacity, while the LSF-TSLC structure had two seismic fortification lines. Compared with LSF, the ultimate bearing capacity and stiffness of LSF-TSLC were increased by 2.1 times and 5.1 times, respectively. The deformation capacity and energy dissipation of LSF-TSLC were significantly improved compared to LSF. The self-tapping nail joint of the embedded wall and the high-strength bolt joint of the external wall had reliable connectivity performance. The numerical simulation of LSF were conducted to verify the plastic analysis model for LSF. And the ultimate bearing capacity calculation method for the LSF-TSLC structure was proposed based on the Strut-and-Tie model.

Structural performance analysis of a new bolt–steel plate connection precast concrete sandwich wall structure

This study proposed a new low-rise bolt–steel plate connection precast concrete sandwich wall structure (PCSWS). Shake table testing was conducted on an experimental model of the bolt–steel plate connection PCSWS with two stories. The experimental phenomenon, failure pattern, displacement response, dynamic characteristics, and global hysteresis were analyzed in detail. The test results revealed that the proposed structure demonstrated excellent seismic performance without any structural cracks when subjected to an excitation intensity level of IX for Model-1. The seismic damage was moderate with no significant structural cracks after an excitation intensity level of IX for Model-2. Cracks in Model-2 occurred in the sequence of the places at the bottoms of the columns, the door corners, window opening corners, and the filled surfaces in the bolt–steel plate connection joint zone on the first floor. The observed damage states were primarily light and moderate, indicating the structure’s ability to withstand seismic events.

Steel truss reinforced concrete composite walls: Numerical investigation and design consideration

Conventional design practices for reinforced concrete (RC) structural walls in the lower stories of super high-rise buildings involve employing large thickness and dense reinforcement to ensure satisfactory seismic performance. This is necessary to withstand the considerable gravity and seismic forces caused by the superstructure. However, this approach brings a design challenge in engineering practice because excessively thick RC walls not only occupy useable space but also magnify earthquake forces due to the increased self-weight. For this reason, steel truss RC (STRC) composite walls have been developed to address the above-mentioned shortcomings of conventional designs. This paper elucidates the working mechanism of STRC walls under cyclic loading, indicating that these two diagonal embedded steel elements mainly exhibit truss behavior. The working mechanism is further verified through computational models developed in OpenSees with high accuracy and efficiency. Moreover, the design provisions in the current specification are evaluated in terms of the flexural strength and shear strength of STRC walls. Results show that the flexural strength of the design equations for STRC walls in the current specification is underestimated because the contribution of steel trusses is not considered. The findings of this study offer valuable insights into the engineering application of STRC walls.

On estimating the drift capacity of reinforced concrete walls with lap splices at their bases

AbstractFailures in reinforced concrete (RC) structural walls have been reported to occur at longitudinal lap splices in earthquakes as far back as 1964 (Kunze et al. in JP 62:635–650, 1965) and as recently as 2023 (Pujol et al. in ES 63:777, 2024). Design codes such as ACI318-19 (2019) and JSCE Standard Specification for Concrete Structures (2007) have been adjusted accordingly and have banned the placement of lap splices near sections where longitudinal reinforcement is expected to yield in reinforced concrete structural walls. But minimizing lap splice vulnerabilities in new construction does not address existing buildings that may be vulnerable to earthquakes because of lap splices placed at or near critical sections. A simple, rapid assessment technique should be adopted to address the large number of existing buildings with potentially vulnerable RC walls. To investigate the deformation capacity of structural walls with lap splices near sections where longitudinal reinforcement yields, a two-part experimental program is ongoing: four large-scale walls with non-staggered lap splices were tested at Purdue University (Pollalis Drift capacity of reinforced concrete walls with lap splices, Purdue University: West Lafayette, 2021) and two large-scale walls with staggered lap splices have been tested at the University of Canterbury (Kerby et al. Experimental study of staggered lap splices in RC structural walls, 2023). Results from these six tests are added to a dataset of 15 previous tests of walls with non-staggered lap splices compiled by Almeida et al. (JSE 143:853, 2017). A method to estimate drift capacity of walls with lap splices is proposed based on estimates of lap splice strength, steel stress–strain relationships, and moment-area theorems. Two sets of assumptions can be used to produce estimates of drift capacity. The first set of assumptions applies when detailed information of reinforcement stress–strain relationships is available, and the second set of assumptions applies when reinforcement stress–strain relationships must be assumed. Both sets of assumptions produce reasonable estimates of the drift capacity of walls with lap splices, and the second set of assumptions can be used for rapid assessment given minimal information about the detailing and material properties of a wall.

Efficient beam-based model for reinforced concrete walls considering shear-flexure interaction

This paper presents an efficient beam-based modelling scheme for the seismic analysis of reinforced concrete structural walls. The model combines a force-based beam element with a fibre section for flexural response and a zero-length element for shear response. The fibre-based element simulates the nonlinear flexural behaviour through uniaxial material laws that account for concrete cracking, concrete crushing, and yielding and rupture of reinforcing bars. The zero-length element represents the shear behaviour with a trilinear lateral force-displacement curve representing, in a phenomenological way, nonlinear deformations caused by diagonal cracking. The reduction of shear resistance caused by inelastic flexural deformations is accounted for in the model to reproduce failures due to shear-flexure interaction. The model has been validated using data from 52 tests on wall specimens exhibiting flexure, shear and mixed shear-flexure modes from experimental campaigns reported in the literature, showing good accuracy in predicting the effective stiffness, maximum strength and displacement capacities obtained in the tests. Model results for ultimate displacement capacity correlate better with experimental results than simplified code-oriented expressions in performance-based evaluation standards and recommendations. Considering its balanced accuracy and computational efficiency, it is concluded that the proposed modelling scheme can effectively be used for performance-based seismic design and assessment of RC wall buildings.

Seismic behavior of modular buildings with reinforced concrete (RC) structural walls as seismic force resisting system

Modular construction is becoming more popular worldwide due to its reduced construction time, lower construction waste, decreased on-site labor requirements, among other benefits. However, the unique structural characteristics of modular buildings, such as discrete floor diaphragms, limited connections between modules, may result in different behavior during earthquakes compared to conventional buildings. However, the seismic response of modular buildings is not well understood, and the force demand in seismic collectors (i.e., connections between modules and seismic force resisting elements) is not quantified. To address this problem, a 9-story prototype building with reinforced concrete (RC) walls was used to investigate the structural properties and responses of modular buildings. Firstly, a nonlinear numerical model was created to accurately model the RC walls, modular frames, inter-module connections, seismic collectors, and other key structural elements. Elastic modal analysis and nonlinear response history analyses were conducted to assess the building's behavior under seismic loads. Subsequently, a simplified numerical model was developed to investigate the effect of three key parameters: the stiffness of seismic collectors, RC wall strength, and earthquake intensity. It was found that modular buildings with RC walls in the center are torsional flexible. Reducing the seismic collector's rigidity can lead to greater force response in the collector. The maximum forces experienced by seismic collectors at the first floor are sensitive to earthquake intensity but not significantly affected by the RC wall strength. Both an increase in the of RC wall strength and earthquake intensity can lead to an increase in the maximum forces experienced by seismic collectors. The method in ASCE 7–16 substantially underestimated the maximum acceleration coefficients at stories below 80 % of the structural height.

Optimal seismic design for self-centering concrete wall structures equipped with U-shaped flexural plate dissipaters

In self-centering wall (SCW) structural system, additional energy dissipation devices are crucial members that are expected to provide both partial lateral force resistance and energy dissipation capacity aiming at mitigating structural response. This research aims to develop a seismic design framework based on particle swarm optimization algorithm for SCW structures equipped with U-Shaped Flexural Plates (UFPs), which can be used to seek out the optimal configuration of UFPs of each floor to reduce seismic response, while maintaining a constant total lateral force resistance provided by all UFPs. For validation, a 10-story SCW structure is chosen as the design case. Specifically, two configurations are considered: a 10-story SCW structure equipped with identical UFPs following conventional design (SCF10-Original) and one equipped with UFPs from optimized configuration (SCF10-Optimized). Their drift and acceleration response are calculated and compared under different seismic intensities through nonlinear time history analysis (NATH). The results demonstrate that the optimized configuration of UFPs can significantly mitigate the drift response in SCW structure. For instance, the maximum inter-story drift ratios of SCF10-Optimized are 0.2 % smaller than those of SCF10-Original under maximum considered earthquake, while the maximum residual inter-story drift ratios of SCF10-Optimized are only half those of SCF10-Original under Extremely Rare Earthquake. Furthermore, the optimized UFPs can effectively reduce the maximum floor acceleration response under various seismic intensities. Therefore, the optimized configuration of UFPs is more effective in reducing both structural and non-structural damage for SCW structural systems compared to conventional configuration. It is also found that greater energy dissipation levels in SCW structure equipped with UFPs may not always result in smaller seismic response, while the configuration of UFPs may play a major influencing factor due to different inter-story lateral force resistance and inter-story energy dissipation demands of SCW structure.

Effect of Wall Size on the Rotation Capacity of Reinforced Concrete Structural Walls

Effect of Wall Size on the Rotation Capacity of Reinforced Concrete Structural Walls

Parametric detailing of structural walls in reinforced concrete using revit software

The use of BIM has become increasingly important in the development of civil construction and architectural projects. The methodology integrates various design stages and allows for compatibility between different software. The parameterization process in Revit, a software used for architectural design, was researched to assist professionals in creating projects using reinforced concrete structural walls. These walls are flat elements with welded screens as reinforcements to resist structural stresses. The objective of the research was to model and parameterize a wall with an opening and a monolithic model. Firstly, data about the norms and characteristics of structural walls used in Brazil was collected, and technical drawings were produced using AutoCAD. This was done to recognize the parameters that would be used in Revit while modeling. Finally, the parameterization process was initiated using Revit functionalities to model the concrete wall and insert the necessary reinforcement using the "rebar" tool that the software offers. Technical drawings such as plans and cuts were produced from these models, which showed the sections of concrete and steel elements. Automated quantitative data was also obtained.

Uma contribuição para o estudo de concreto geopolimérico leve com argila expandida: avaliação de seu desempenho térmico

Purpose: The objective of this work was to evaluate the thermal insulation performance of lightweight geopolymer concretes with expanded clay, considering their implications for energy consumption and construction efficiency. Theoretical framework: The urgent need for sustainable construction practices amid global concerns about climate change and environmental degradation has been increasingly discussed. With the cement industry being a major contributor to CO2 emissions, alternative materials like geopolymers offer a promising solution, once the consumption of concrete tends to grow bigger. The production of geopolymer concrete, known for its strength and low environmental impact, involves combining a precursor rich in aluminosilicates with an alkaline activator, usually sodium hydroxide and sodium silicate. Notably, geopolymer cement can cut up to 64% of greenhouse gas emissions. Expanded clay, as a lightweight aggregate, garners attention for its porous structure and ability to provide thermal and acoustic insulation to concrete. Its application in constructing vertical enclosures, such as concrete walls, enhances thermoacoustic comfort and aids in assembly and transportation on construction sites. Effective thermal insulation, achieved through materials with low thermal conductivity, plays a pivotal role in creating thermally suitable environments, impacting user satisfaction, productivity, and energy conservation. Method and materials: The materials used for concrete production, including metakaolin, sodium hydroxide, sodium silicate, expanded clay, crushed stone, and sand, were initially characterized. Subsequently, the dosage calculation for the production of test specimens was performed, involving mini concrete slabs with dimensions of 20x40x12 cm, compacted on a vibrating table. The concretes were produced with volume substitutions of crushed stone by expanded clay at 0% (GP) 30% (GP30%) and 70% (GP70%). For the thermal insulation test, the slabs were exposed to a heat source, and temperatures on the exposed and opposite faces were measured over 12 hours, at 30-minute intervals. After obtaining the experimental data, logarithmic equations with three parameters were fitted to achieve the stabilization temperature of the surfaces. Results and conclusion: Despite the expectation of stabilization in temperature after exposure to a heat source, it was not observed for the faces of the tested panels. A mathematical curve was derived through a curve-fitting process using logarithmic equations with three parameters. All curve fittings yielded R² values equal to or higher than 0.95, indicating satisfactory representativity and suggesting viability in analyzing panel thermal insulation through the adjusted equations. Considering the adjusted data, thermal insulation values for GP, GP30%, and GP70% were 31.82 °C, 35.30 °C, and 40.24 °C, respectively. Expanded clay's effect on increasing thermal insulation was evident, aligning with references indicating its insulating characteristics. Moreover, the substitution of crushed stone with expanded clay led to a noticeable reduction in specific mass, highlighting the lightweight nature of the compositions. Both 30% and 70% mixes fall under the lightweight category. Research implications: To produce a more environmentally friendly concrete using geopolymer cement, combined with expanded clay, aiming for a weight reduction in precast concrete wall structures and an improvement in the thermal insulation of these systems. Originality/value: To assess the feasibility of using lightweight geopolymer concretes with locally sourced materials through tests conducted in Brazilian studies, aiming to contribute to the existing gap in knowledge regarding the behavior of this alternative binder.

Heat loss characteristics of typology-based apartment building external walls for a digital twin-based renovation strategy tool

Information about existing building structures is necessary for creating a renovation strategy. Older buildings are often built using typical building envelope structures. However, this information is presented in the building register at a general level, specifying the material type but not its characteristics. For a cross-regional reconstruction strategy, it is necessary to link the scarce information in the building register with the heat loss characteristics of the building envelope structures. In the current study, we classified external wall solutions according to building typologies and linked this with building register information. The typology database includes log, timber frame, brick, concrete, and aerated lightweight concrete external wall structures. Comparing the typology-based values and the actual situation showed that the wall structures’ expected and actual heat loss characteristics agreed. However, there were also significant deviations, primarily because the data from the building register did not allow for precise classification. Nevertheless, data showed that building typology-based heat loss properties are necessary for developing a district-based renovation strategy.

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.

Experimental Study on Structural Performance of Cast-in-Place Frame Printed Concrete Wall

A growing number of nations and regions have printed concrete structures thanks to the application of 3D printing technology in the field of civil engineering. However, the houses built with printed concrete are mostly printed concrete wall structures with composite load-bearing walls and cast-in-place frames. This structure solely takes into account the performance of the structure under vertical loads, which does not address its ability to withstand horizontal loads. In this paper, wall specimens were designed and tested under horizontal reciprocal loads in order to investigate the structural performance of this cast-in-place border-frame printed concrete wall structure under horizontal loads. Four factors are examined in order to determine how well the cast-in-place frame printed concrete wall structure performs when subjected to horizontal loads: column longitudinal reinforcement strain, hysteresis curve, skeleton curve, and energy dissipation capacity. According to the test results, the addition of the wall increased the bearing capacity and accumulated energy dissipation of the specimen, but the increase in stiffness also caused the structural ductility to decrease. As a result, cracks were more likely to generate at the wall–column joints, so the stiffness matching between the printed concrete wall and the cast-in-place side frame needed to be further coordinated to obtain a higher ductility. It turns out that the wall sections have little impact on the seismic performance of the members.

Parameter optimization for pivot hysteresis model for reinforced concrete walls with different failure modes

AbstractReinforced concrete structural walls are major vertical lateral load‐resisting members in reinforced concrete structures located in seismic regions. It is important to understand and evaluate the hysteresis behavior of these members for an efficient earthquake‐resistant design. Among the various models available for estimating this hysteretic behavior, the Pivot hysteresis model, which models hysteretic behavior through parameters α and β, respectively, representing the unloading stiffness and pinching behavior, has been effective and efficient for use with columns. In this paper, an effort is made to extend the application of the Pivot hysteresis model to reinforced concrete walls. Key variabratiosuch as axial load ratio, wall height‐to‐length ratio, web reinforcement indices, boundary element reinforcement indices, and length‐to‐effective thickness ratio were considered to derive expressions for α and β suitable for walls. Equations for α and β were calibrated through the hysteretic test data of 108 wall specimens subjected to cyclic loading and exhibiting different failure modes. The calibration is based on the optimization of energy dissipation for specimens from the collated database—a numerically complex task achieved through a superior optimization technique known as Simulated Annealing. The proposed formulations showed reasonably good accuracy in predicting complex hysteretic responses when verified against an extensive database of wall test specimens with flexural and shear modes of failure.

Toward coupled fire‐structure simulations for forecasting smoke leakage in case of concrete structures under fire

AbstractComputational modeling of the fire‐structure interaction demands the coupling between several models typically implemented in independent simulation software describing distinct physical processes. For instance, in the event of a fire breakout or building on fire, the fire not only increases the temperature of the immediate area but also initiates structural damage, leading to the spalling of the concrete along with the propagation of the smoke, heat, and radiation originating from the fire. As a result of the progressive structural damage caused by the fire such as macro cracks or breakthroughs in the wall, smoke and other hazardous gases begin to disperse and spread into previously unaffected zones. Thus, it represents a coupled multi‐physics problem, which is not well addressed in the scientific community, yet. Therefore, the investigation of such fire‐structure interactions requires a comprehensive computational modeling and simulation framework that couples the consequences of various phenomena with minimal invasive solver modifications. In this work, the structural model treats concrete as a multi‐phase porous material exposed to high temperatures resulting from the fire. For this purpose, the structural solver is at the moment manually coupled with a computational fluid dynamics (CFD) solver to setup a computational framework for such fire‐structure simulations. Herein, the combustion process of the fire and the smoke propagation is carried out using the open‐source software denoted as Fire Dynamics Simulator (FDS) and the thermo–hydro–mechanical fracture is computed using a FEniCS‐based solver. The finite‐difference method based FDS solves the filtered Navier–Stokes equations using the large‐eddy simulation technique to describe the turbulent flow and heat transfer including radiation and combustion inside the fluid domain. The concrete damage such as cracks, holes, or spalling is computed using a phase‐field method in a separate solver based on the thermal boundary conditions from the fire simulation. Subsequently, both solvers are coupled using the open‐source coupling framework preCICE. Based on the rate at which the crack or spalling is developing, the computational domain of the fluid solver has to be adapted taking the generated holes in the wall structure into account for the ongoing CFD simulation. It allows for the leakage of smoke gases through the concrete wall structure and thus the spreading of the fire scenario. The proposed model is illustrated by an exemplary case that forecasts the leakage of smoke and hazardous gases from the successive damage caused by the thermal spalling induced on a concrete wall structure.

A Study on Seismic Effect on High Rise Building with & Without Shear Wall

In this paper we compare & analyze on high rise building, in this we included the reactions of seismic & effect of wind. In past years many research done on Analysis of building with and without shear walls. All the same we work for little Analysis of high rise building (G+10) with & without shear walls. The current work consist the correlation between framed & framed with shear wall building in presence wind force, earthquake force, etc For seismic design of buildings, reinforcement concrete structural walls or shear walls are higher earthquake resisting members which abstain from lateral load resistance.

Post-Earthquake Strengthening of RC Coupling Beams with GFRP Wrapping: Experimental Investigation.

This research aims to address a post-earthquake urgent strengthening measure to enhance the residual seismic capacity of earthquake-damaged reinforced concrete wall structures with coupling beams. The study consists of a series of tests on half-scale prototype coupling beams with various detailing options, including confined with reduced confinement, partially confined, and unconfined bundles, under cyclic loading conditions. The methodology employed involved subjecting the specimens to displacement-controlled reversal tests, and carefully monitoring their response using strain gauges and potentiometers. The main results obtained reveal that GFRP wrapping significantly enhances the seismic performance of earthquake-damaged coupling beams, even in cases where specimens experienced strength loss and main reinforcement rupture. The strengthened beams exhibit commendable ductility, maintaining high levels of deformation capacity, and satisfying the requirements of relevant seismic design codes. The significance of the study lies in providing valuable insights into the behavior and performance of damaged coupling beams and assessing the effectiveness of GFRP wrapping as a rapid and practical post-earthquake strengthening technique. The findings can be particularly useful for developing urgent post-earthquake strengthening strategies for high-rise buildings with structural walls. The method may be particularly useful for mitigating potential further damage in aftershocks and eventual collapse. In conclusion, this study represents a significant advancement in understanding the post-earthquake behaviors of coupling beams and provides valuable guidance for practitioners in making informed decisions regarding post-earthquake strengthening projects. The findings contribute to the overall safety and resilience of structures in earthquake-prone regions.