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The estimation of lateral strength in reinforced concrete (RC) columns subjected to cyclic loads is crucial in structural design. The failure of RC columns under lateral forces can lead to catastrophic structural collapses. This fact emphasizes the need for accurate assessments of their dynamic behavior. This paper proposes a data-driven model for estimating the lateral strength of RC columns. A historical dataset comprising 12 predictor variables and 247 samples has been compiled to train and validate of the proposed approach. The extreme gradient boosting machine (XGBoost) is employed to establish a predictive relationship between the lateral strength of RC columns and their influencing factors. Since model selection is critical for constructing a reliable prediction mode, this study relies on utilizing metaheuristic approaches, including Genetic Algorithm, Particle Swarm Optimization, Artificial Bee Colony, and Ant Colony Optimization, to optimize the performance of the XGBoost model. Experimental results show that the integration of Ant Colony Optimization and XGBoost can help attain outstanding prediction accuracy with a correlation of determination (R2) of 0.95. Additionally, an asymmetric squared error loss function is utilized to reduce overestimations by 12 %. The newly developed method can be utilized in practical applications where reliable predictions of the lateral strength of RC columns under cyclic loads are required.

Compressed earth block (CEB) is a sustainable and cost-effective option for eco-friendly constructions. The blocks are produced without burning fossil fuels and have low embodied energy. The abundance of its constituents, including clay and sand, is another merit. However, the susceptibility of CEB constructions against seismic forces is still considered a prominent hindrance to their widespread acceptance. The study aims to improve the in-plane seismic performance of CEB walls by using common reeds as a natural reinforcing material. For this purpose, seven wall panels with dimensions of 1000×900×120 mm3 were constructed. Seismic loading was simulated using an incrementally increasing lateral cyclic displacement combined with a constant vertical stress of 0.3 MPa. The results are discussed in terms of the hysteresis load-displacement responses, displacement ductility, energy dissipation, and stiffness degradation. Based on laboratory experiments, the strength and lateral displacement of the reinforced specimen with four vertical reeds were increased by 44 % and 76 %, respectively, compared to the non-reinforced ones. Ultimately, Seismic assessments and damage indexes of the tested walls indicated that the in-plane seismic performance of CEB walls could be significantly improved by using vertical sand-coated reeds.

An experimental and numerical research, aimed at evaluating the in-plane seismic performance of an innovative external steel modular system for the strengthening of load-bearing masonry walls, is currently underway at the EUCENTRE Foundation in Pavia. This paper presents, in particular, the results of the experimental part of this research campaign. Solid clay brick and hollow clay "doppio UNI" masonry typologies, representing common solutions in Italian existing buildings, were considered. After the mechanical characterization of the masonry and of the components of the reinforcement system, cyclic in-plane pseudo-static tests on full-scale specimens were performed in order to investigate the influence of the proposed system on the in-plane response of the walls, compared to the unreinforced conditions. The main seismic parameters of the masonry walls (i.e. elastic stiffness, lateral resistance, displacement capacity and energy dissipation) were assessed depending on the achieved damage mechanism. The proposed reinforcement system provided very promising results, improving the in-plane seismic performance of masonry walls at serviceability and especially at ultimate conditions, with a significant increase of deformation capacity above all in the case of shear mechanisms. [ABSTRACT FROM AUTHOR]

Awaludin et al. created an anti-earthquake temporary shelter called RISBARI (Rumah Instan Baja Ringan/Light Steel Instant House), featuring an X-shaped strap-braced wall system using cold-formed steel as its primary structure. A similar temporary shelter (hunian sementara/huntara) was developed by Biru Bumi Hijau using Z-shaped wall bracing. While experimental research on the lateral strength of cold-formed steel wall panels with X-brace bracing, such as in RISBARI, has been conducted extensively, there has been limited in-depth study on Biru Bumi Hijau's huntara. Hence, this research aimed to identify the load capacity, stiffness, and ductility of both bracing configurations on lateral strength using cold-formed steel wall panels. This study used an experimental method through the monotonic static load in the laboratory. The test results were analyzed with One-way ANOVA. The load capacity, stiffness, and ductility of the X-brace panel increased by 201%, 4452%, and 105%, respectively. In contrast, the load capacity, stiffness, and ductility of the Z-brace panel increased by 201%, 4253%, and 156%. The bracing capacity on both was not directly proportional since both test objects had different configuration structures, although they had equalized length and width.

Scoured pile-group foundations in bridges are likely to undergo inelastic deformation during earthquakes, which can be utilized to dissipate seismic energy and withstand seismic loads by the post-yield hardening strength of the foundation. However, limit states and associated ductility indices and post-yield strength indices are yet to be well documented. This study develops a surrogate model, namely, the classification–regression combination model (CRCM), for the efficient, interpretable, and high-confidence quantification of displacement ductility factor (μΔER) and associated strength hardening factor (RFER) of scoured bridge pile-group foundations at the easy-to-repair limit state, where the damage of piles is limited to the aboveground region (thereby being relatively easy to repair). To this end, a proper pushover method from those with different load patterns is first identified for efficient nonlinear analyses of scoured bridge pile groups. A large number of bridge samples are then analyzed to prepare a comprehensive database for the development of CRCM, which first classifies the failure process of scoured bridge pile-group foundations and then regresses μΔER and RFER with variables characterizing the soil–bridge systems. It is found that the pushover method with a two-node load pattern (i.e., load at the superstructure and pile-cap centroids) can very well capture μΔER and RFER and the failure process of bridge pile groups. The data-driven CRCM can efficiently provide reasonable predictions of μΔER and RFER with errors mostly within 20%; it is specifically compared with a regression-only model to demonstrate the necessity of incorporating a classifier in advance of the regression model. [ABSTRACT FROM AUTHOR]

In high-rise building structures, the designers tend to utilize tube systems, or their combination with other structural frame systems, as an efficient lateral resisting structural system. The drawbacks of tube systems include the effect of shear lag and the architectural problems arising from the closely spaced columns. These drawbacks can be remedied by using exterior braces (concentric bracing system), which provide high shear stiffness in combination with the tubes. Since in high-rise building structures control of bending drift is so difficult and complicated, utlizing the exterior braces is regarded as a practical method due to its high shear and bending stiffenesss. In so doing, in this paper, an innovative concept was investigated in which steel plate shear walls are utilized at the two extreme bays of a frame, and giant exterior braces are used between the shear walls. These two walls act as strong moment arms against the overturning moment and, because of their high stiffness, absorb most of the produced shear; consequently, the shear lag effect diminishes. The obtained results indicate that in the proposed system, the lateral displacement is diminished by around 2.13 times; consequently, the axial forces and bending moments in columns are reduced considerably by about 30 % and 50 %, respectively, demonstrating this system's high effectiveness.

A simple and accurate analytical model for defining the lateral strength of the multi-span RC frame with masonry infill has been developed in this study. This model is developed due to the limitation of the current analytical model which only can be applied to the single-span RC frame. Meanwhile, the structure in the building also is in a multi-span frame and masonry infill greatly impacts the portal structure. In the existing building, this analytical method is needed to calculate the lateral strength of the RC frame. Besides, the analytical method was developed based on the lateral strength analysis method of a single-span RC frame in which the modeling of a multi-span RC frame with masonry infill along with uniform span spacing was applied. Furthermore, an equivalent diagonal strut with the same thickness and material as the masonry panels was used instead of masonry infill in the frame structure. The external column has diagonal compressive forces on the top or bottom of the column. On the other hand, diagonal compressive forces work at the top and the bottom of the column in the internal column. The lateral strength of the infill was determined based on the frame infill contact length. Furthermore, in order to obtain the lateral strength of the structure, the experimental study of a multi-span RC frame with masonry infill under cyclic load was also tested. Applying the analytical model has shown promising results even after being compared with the results of the experimental work.

This paper studies the lateral strength of traditional (unstabilized) adobe walls subjected to lateral loading, either in-plane or out-of-plane, using the finite element method. The focus of the numerical parametric study is on adobe walls that have a moist region in their lower part immediately above the footing. The variables of the parametric study are the length, height, and water content of the moist region. The lateral strength of adobe walls can be affected by the moist region depending on its size and water content. Generally, the threshold of gravimetric water content of the moist region associated with a considerable decrease in lateral strength is 12% for I-shaped walls under in-plane lateral loading and 10% for cantilever walls under out-of-plane lateral loading. A short moist region that is at most one-third or one-fourth of the wall length for out-of-plane or in-plane loading, respectively, does not compromise significantly the wall lateral strength even at relatively high water content. Even though the results depend on the model geometry and characteristics, this information can be useful to those working in adobe repair and preservation because approaching or exceeding these limiting water contents might indicate an immediate need for shoring the walls. [ABSTRACT FROM AUTHOR]

Although steel plate shear walls have been used to resist lateral loads in recent decades, its complex behavior has brought about difficulties in employing this system. In this study, the lateral behavior of unstiffened steel plate shear walls is investigated via nonlinear static analysis (i.e., pushover analysis). Three different special steel moment frames having 1, 5, and 10 stories are designed based on the codes criteria. Then, the finite element models incorporating both the plastic behavior of steel material and large displacement of the steel plate due to buckling are developed as exact models. In addition, simplified equivalent strip models are created as a more practical code-based approach to modeling for comparison against the exact method. The effects of different parameters including applying gravitational loads, the lateral loads distribution pattern, modeling technique, and rectangular opening in shear wall panel are evaluated. Results of the analyses show that in monotonic loading, results of the strip model are consistent with those of the more rigorous finite element model; of note, results of the former were achieved faster than the latter. Also, it is observed that use of the design method promoted by the design code results in the formation of plastic hinges first on the columns rather than walls. When the wall contains rectangular openings, it is shown that they must be accompanied with perimeter stiffeners on the edges of the opening. Otherwise, a large stress concentration would occur at the corners of the opening. Even with the peripheral stiffeners, the presence of an opening reduces the lateral stiffness and strength of the wall system more or less linearly with regard to variation in the opening size. Eventually, semi-analytical relations are proposed to estimate the lateral stiffness and strength reduction due to the presence of an opening.

Numerous studies on masonry infill panels have greatly contributed to the research of strength, stiffness and energy dissipation capacity of various buildings. If the effects of masonry panels are disregarded, structural damage will occur under any significant ground motion, and even lead to collapse of the entire structure. The mode of failure is strongly dependent on the masonry and RC frame interaction. This work proposes an evaluation method for determining the participation ratio of masonry infill panels on RC frames under lateral loads.

Previous studies and observations of the earthquake have shown that frame filled with concrete 3d panel wall, can have adverse effects on the seismic behavior of structures. On the other hand, yielding dampers that used with steel braces, have a high capacity to absorb and depreciating energy from the earthquake. In this paper, targets are reducing damage to the infills and moment frame in during of the earthquake, reduce the horizontal and vertical irregularities in structure. To rech these targets, Three experimentally models with half scale were constructed and tested on the shaking table under 7 scale accelerated. Also, for investigate the Effective of parameters in the seismic behavior of moment frames, using Abaqus software, finite element analysis was performed after verification of model behavior with experimentally results. Experimentally results showed that use the yielding connection between wall and frame, reduces the lateral displacement and plastic strain in the structure. Numerical analyzes showed that by adding the yielding connection to the frame and infill wall, The frame has linear behavior In high intensity earthquake, and not be created plastic hinges in the members of the frame. The input energy is amortized only in the connections. So the number and geometric specification of these connections can affect the lateral hardness and lateral strength of the structure.

This study investigates the in‐plane lateral stiffness and ductility of composite PVC encased concrete walls subject to the lateral loads using pushover tests to determine lateral strength and ductility characteristics of composite PVC encased walls filled with plain concrete, macro‐synthetic fiber reinforced concrete (RC), and steel RC. Eighteen concrete wall specimens were cast and subjected to pushover test to determine the load‐deflection curves. Based on the capacity curves resulting from the pushover tests, the yield and maximum displacements and subsequently structural ductility and performance factors according to Australian Standard for seismic design of buildings have been determined. The determined parameters as well as the initial and effective lateral stiffness values measured from the load‐deflection curves for all three cases were compared and the final findings have been discussed. Based on the outcomes of this study, it has become apparent that the tested composite PVC encased macro‐synthetic fiber RC walls can exhibit superior performance in terms of ductility when compared to the unreinforced concrete specimens. In addition, the results indicated that the initial in‐plane lateral stiffness values of the tested composite PVC encased macro‐synthetic fiber RC walls increased by 25% compared to the tested walls filled with plain concrete. In order to enable structural designers to design composite PVC encased concrete walls, ductility factors for this type of walls have been extracted from the test results for the three mentioned cases and proposed for practical applications. It has been concluded that all the PVC encased concrete walls evaluated in this study can be categorized as fully ductile structures. [ABSTRACT FROM AUTHOR]

Code requirements are usually fulfilled during the design of a building. On the other hand, reinforced concrete (RC) frames (particularly in the developing regions of the world) are deficient (in many cases) due to unregulated construction. Majority of such deficient structures lack shear reinforcement in beam-column joints. Collapse of these deficient buildings (as a result of limited ductility) triggered many socio-economic and human losses which is evident from recent earthquake disasters. This paper presents an experimental study which was conducted on a 1:4 reduced scale three-storey RC special moment resisting frame (SMRF) lacking shear reinforcement in the beam-column joints. The lack of confinement bars causes shear hinging of joints that reduces the displacement ductility of the frame. Shake-table tests were conducted on test model that was subjected to acceleration time history of 1994 Northridge earthquake, having a peak ground acceleration of 0.57 g. The acceleration was linearly scaled to multiple levels and to sinusoidal base excitations of various frequencies and displacements. Moderate to severe damage at each storey level was observed in the joint panels due to the lack of lateral reinforcing ties in the joints. The data obtained from shake table tests were processed and analysed to develop a lateral force-deformation capacity curve, which was bi-linearized as an elasto-plastic curve to compute various response parameters of frame. The ductility factor (Rm) of the tested model was found to be equal to 1.95, which is thirty-five percent less than the code recommended value of Rm for RC SMRF structures. [ABSTRACT FROM AUTHOR]

This study focuses on a study of cold‐formed steel wall framing installed with hold‐down anchors and subjected to lateral loads. The steel framing wall specimens were assembled with sheathing on one or both sides. Two different thicknesses of calcium silicate board were used as the sheathing material. The wall specimens were tested under both monotonic and cyclic loads. All wall specimens were fixed at both ends with hold‐down anchors. In addition to structural strength, the energy absorption, ductility ratio, overstrength factor and response modification factor were studied for all wall specimens. Previous studies in which the specimens were tested without a hold‐down anchor are discussed for comparison. The test results show that the ultimate strengths are similar for the specimens with the same configuration tested under either monotonic or cyclic loads. The wall specimen installed with hold‐down anchors has a higher ultimate strength but lower ductility ratio compared with the same configuration's wall specimen without hold‐down anchor. The response modification factor given in the AISI standard was found to be conservative for the wall framing with sheathing of calcium silicate board tested in the present study. [ABSTRACT FROM AUTHOR]

This article discusses the results of an experimental program to retrofit unreinforced masonry walls by means of diagonal and vertical steel strips. The technique has several advantages such as simplicity to apply, relatively low costs, and insignificant disruption of service functions during the repair. The tests were conducted on three specimens: two with both diagonal and vertical steel strips and one with only diagonal steel strips, and all attached to one face of the walls. The tests showed that the steel strips improved lateral strength, increased non-linear displacement capacity, and changed the nature of the failure modes. [ABSTRACT FROM AUTHOR]

Rice husks as common agricultural remnants with low density and good thermal conductivity properties have been used in infill walls in the northern area of China. Accordingly, many tests and numerical simulations were conducted to address a difficult issue, the inaccurate estimation on the lateral load-bearing capacity of different types of husk mortar energy-saving (HMES) wallboards. The difficulty has not been overcome so far, implying that the novel methods are anticipated to achieve the accurate estimation. This paper tests the full-scale HMES wallboards with different openings and obtains the strains at the points distributed on the wallboard sides. The experimental strains are modeled as the approximate strain energy values to produce the characteristic parameter of the HMES wallboard's stressing state. Furthermore, the inherent working state characteristic points of HMES wallboards are revealed from the evolution of the characteristic parameter called as the normalized approximate strain energy sum, leading to the redefinition of the failure loads for the HMES wallboards. Finally, it investigates the stressing state mode evolution of the HMES wallboard around the failure loads. The achieved results provide the reference to the accurate estimation of the bearing capacity of the HMES wallboards. [ABSTRACT FROM AUTHOR]

In order to conserve or reuse historic buildings in Taiwan which are located in an earthquake-prone area, it is critical to ensure their seismic capacity. The historical Japanese-style wooden houses are those of concern in this study. Three historical offices of this kind which were damaged in the 2010 Kaohsiung earthquake were selected. First, ambient vibration measurements were taken to investigate their natural frequency and vibration mode. Performance-based assessment for wooden buildings in Japan was adopted and modified to evaluate the seismic capacity of the offices. By comparing the evaluation results and the damage observed in the earthquake, applicability of the method was verified. Accordingly, a seismic evaluation method for the Japanese-style wooden buildings in Taiwan was established. In addition, the relationship between measured natural frequency and calculated base shear coefficient was investigated and compared to the empirical formula for wooden houses in Japan.

• Seismic performance of full-scale squat RC wall specimens with openings was investigated. • First story backside exterior walls of row houses in Taiwan were designed and tested. • Effects of location and size of the window opening were studied. • Detailed and simplified models for the lateral strength of the wall specimens are proposed. Five full-scale reinforced concrete wall specimens with openings typical of the first story backside exterior walls of row houses in Taiwan were tested using lateral cyclic loading to study their seismic behavior. The effects of location and size of the window opening were studied. Test results showed that the wall with the window opening on the side of the wall web showed a higher average lateral strength than that with the opening placed around the center of the wall web. The increase of the opening length reduced more the lateral strength than the increase of the opening height. A critical wall segment tended to show a lower lateral strength when the edge of the segment is bordered by a door than by a boundary column. To estimate the lateral strength of the wall specimens, a detailed and three simplified models are proposed. Comparison with the test results shows that ignoring variation in the axial force among the wall segments and columns does not change the average prediction but increases the scatter of prediction. Simply summing the lateral strengths of all the wall segments and columns together further increases the scatter and greatly reduces the degree of conservatism. Summing the lateral strengths of all the web segments requires the least computational effort but greatly increases the degree of conservatism. [ABSTRACT FROM AUTHOR]

The purpose of this study is to find the effect of shape configuration of carbon fibre reinforced polymer (CFRP) strips on the lateral capacity of shear walls. For this purpose, a model of shear wall strengthened with different layout configurations of CFRP was investigated by pushover analysis. All carbon fibres placed symmetrically on reinforced concrete (RC) walls, and any sliding effect of fibres on concrete was neglected. Also, the effect of change in the aspect ratio of the RC wall on CFRP strengthening pattern was studied. Throughout the study, the results of all CFRP configurations and the increase in lateral strength were compared. With an increase in the number of fibre layers on all specimens strengthened with CFRP, change in lateral strength and in the shear wall damage occurred. By all specimens' comparison, the best fibre configuration in each h/L ratio was determined. Abbreviations: CDP: Concrete Damage Plasticity; CFRP: Carbon Fiber Reinforced Polymer; FRP: Fiber Reinforced Polymer; h/L: Height/Length; RC: Reinforced Concrete; 2D: Two Dimensional; 3D: Three Dimensional [ABSTRACT FROM AUTHOR]

• Experiments were conducted for lightly reinforced concrete columns with short lap splices. • Cyclic behaviour of these columns subjected to unidirectional and bidirectional loadings was investigated. • The measured values of modelling parameters deviated from the ASCE 41-17 values. Reinforced concrete (RC) buildings constructed prior to the 1970s could be vulnerable to earthquakes due to inadequate reinforcement details such as widely spaced transverse reinforcement and short lap splices. Most of these buildings were designed without considering seismic loads. The objective of this study was to investigate the cyclic behaviour of the lightly reinforced concrete columns with short lap splices in older RC buildings under unidirectional and bidirectional loadings. Experimental tests were conducted using four full-scale specimens. The estimates of modelling parameters and lateral strength obtained from the measured cyclic curves of the specimens were compared with the values calculated according to ASCE 41-17. Cyclic behaviour of lightly-reinforced columns with short lap splices was significantly affected by loading types and the levels of axial load. The modelling parameters and lateral strength were also affected by the levels of axial load and by loading types (unidirectional and bidirectional) deviating from the constant values specified in ASCE 41-17 for these parameters. [ABSTRACT FROM AUTHOR]

This paper discusses the experimental results for defining the seismic performance of the brick masonry infilled reinforced concrete (RC) frame with a central opening under lateral static reversed cyclic loading. The influence of the presence of the rebar reinforcements on the opening interface to the masonry is compared to the opening without rebar reinforcement. In this study, six of 1/4 scale-down of single-story singlebay RC frame specimens have been constructed and tested. These specimens included one bare RC frame, one unreinforced brick masonry infilled RC frame, two unreinforced brick masonry infilled RC frames with a central opening and two brick masonry infilled RC frames with a central opening embedded with 2Ø6 horizontal steel reinforcements above and below of the opening. The ratios of opening size to the panel area of the infilled specimens were 25% and 40%. The experimental results confirm that the existence of the opening reduces the stiffness, the lateral strength and energy dissipation of the RC infilled frame system. However, the infilled frames with 25% and 40% opening ratios show better performance compare to bare frame specimen. Although the strengthening by using embedded rebars does not significantly increase the performance of the RC frame system, the brick infill with horizontal reinforcements installed above and below the opening was verified to resist large deformation of masonry infill in out of plane direction. [ABSTRACT FROM AUTHOR]

Highlights • A dataset collecting the results of 188 in-plane cyclic tests on URM piers has been developed. • Different masonry typologies constituted by bricks and blocks are included. • A preliminary investigation on the in-plane lateral strength and displacement capacity has been performed. • Some inconsistencies between code criteria and experimental evidence have been pointed out. • The dataset provides a tool available for future studies on the in-plane response of URM piers. Abstract In this paper, a dataset collecting the results of in-plane cyclic tests on unreinforced masonry piers, carried out within different research projects, is presented. The dataset includes brick and block walls with different materials, bed-and head-joint typologies, dimensions, boundary conditions and vertical applied loads. The development of such dataset aims at providing a tool for the improvement of the understanding and the evaluation of the main parameters that may influence and govern the lateral response of the URM piers under seismic excitation. A preliminary investigation on the in-plane lateral strength and displacement capacity, being two of the most significant parameters used in seismic analyses for the design and assessment of masonry buildings, has been proposed. The dataset, that already groups several specimens, is freely shared and might be continuously updated. This source of information of consistent and reliable test results represents a necessary step into the process of definition of shared rules within the scientific and technical community, in particular for the improvement of codified criteria, analytical and numerical models and testing procedures. [ABSTRACT FROM AUTHOR]

This article proposes a numerical modeling approach to account for the weakening effect of moisture on the in-plane (lateral) resistance of adobe masonry walls. The approach uses a variable that links the water content of the soil to its strength properties, with varying locations of a moist region in the wall (i.e., length across the wall). A nonlinear, isotropic finite element model was used to study adobe walls at the macro scale. The adequacy of the proposed approach was examined numerically through finite element (FE) analysis for I-shaped adobe walls with varying length and water content of a moist region along the base. The analysis showed that the lateral strength of adobe walls, defined as the maximum force required to cause a given displacement, may drop considerably (up to about 40% for the cases considered) depending on the length, location, and water content of the moist (weakened) region of the wall. [ABSTRACT FROM PUBLISHER]

Using X-braced frames in steel structures is a current procedure to achieve good strength against lateral loads. Study on mid-connections of X-braces and their effects on frame behavior is a subject whose importance has been more or less disregarded by researchers. Experimentally inspecting models involves considerable expense and time; however, computer models can be more suitable substitutes. In this research, a numerical model of X-braced frame has been analyzed using finite element software. The results of pushover analysis of this frame are compared with those of the experimental test. With the help of computer model, the effects of different mid-connection details on ductility and lateral strength of the frame are inspected. Also performances of bolted and welded connections are compared. Taking into account ductility and strength, this study suggests details of a decent pattern for the mid-connection. [ABSTRACT FROM AUTHOR]

This paper presents the results of several experimental campaigns recently carried out by the authors and devoted to the investigation of the mechanical performance of wall panels strengthened by applying repointing mortar and high strength stainless steel or composite cords. The reinforcement system, known as Reticulatus, allows the reinforcement of regular and irregular-shape masonry walls, when the fair-faced aspect must be kept. In the perspective of using this reinforcement method, this article summarizes the research that has been done so far, presenting new original test results and discussing the design procedures. Twenty-two square wall panels were loaded in their plane by means of a single point load acting through the panel's diagonal. Experimental results are presented for four types of cord reinforcement using matched samples, reinforced and not. Increases in shear strength from 15 to 170 % were achieved for the strengthened panels. Each wall panel was loaded well into the lateral post-elastic regime and then unloaded. Experimental results were in good agreement with predictions from simple models which assume the wall panels to behave like a plate, neglecting the contribution of the repointing mortar, and accounting for the non-linear behavior of the masonry. [ABSTRACT FROM AUTHOR]

In this paper, residual displacement ratios, C r , of highly damped single degree of freedom (SDOF) systems are studied by considering soft soil effects. For this purpose, a large number of ground motions recorded on soft soil deposits are used in the analysis. In order to calculate the residual displacement ratios, linear and nonlinear time history analysis are conducted for 79 SDOF systems with lateral strengths of R = 2, 3, 4, 5, 6, damping ratios of ξ = 0.05, 0.1, 0.2, 0.3, and post-yield stiffness ratios of α = 0, 0.03, 0.1 subjected to 426 pairs of earthquake ground motions recorded on soft soil. Therefore, a large number of data is obtained for C r by using the results of time history analysis. After investigating the impact of lateral strengths, damping ratios, and post yield stiffness ratios on residual displacement ratios, a simplified new equation is proposed with nonlinear regression analysis. The results show that higher damping ratios cause the residual displacement ratios to reduce. Furthermore, comparison of C r for soft soil and stiff soil conditions indicates the soil condition influence on C r. • Development of a new predictive equation for residual displacement ratios. [ABSTRACT FROM AUTHOR]

This study presents an experimental study on responses of eight constrained masonry walls with tie columns and ring beams, subjected to in-plane cyclic loading before and after being retrofitted with basalt-fiber-reinforced polymer (BFRP). Among these eight walls, two without any strengthening measures served as reference specimens; two were directly strengthened with horizontal and diagonal BFRP strips after they were constructed; and the rest were tested to defined damage levels and then repaired for retesting. The opening in the wall, the layer of the BFRP strip, and the vertical compression level were considered in the test design. Experimental results showed different failure modes of the specimens. Details of testing results were discussed regarding strength and drift, hysteretic characteristics, stiffness degradation, energy dissipation, and BFRP strip strains. A performance comparison analysis was also conducted between the constrained masonry walls and the unreinforced ones. Finally, a calculation method was proposed to estimate the ultimate lateral strength of BFRP retrofitted masonry walls. [ABSTRACT FROM AUTHOR]

• Three transfer learning strategies are investigated to address the data scarcity problem. • Three knowledge transferring scenarios, across section type, shear reinforcement, and concrete compressive strength, are considered. • The knowledge transfer techniques outperform existing approaches when there is insufficient training data. • Knowledge transfer approaches allow an efficient machine learning model without excessive efforts to augment data. Transfer learning aims to extract knowledge from one or more source tasks and apply the knowledge to a different task for more accurate predictions. The main purposes of this study are to investigate different knowledge transfer techniques, apply them to accurately predict the lateral strength of reinforced concrete columns with only a small amount of training data, and compare the transferability of each method. According to the various source and target domains, three different experiments are designed to directly compare the performance across section type, shear reinforcement area, and concrete compressive strength. In all cases in this study, knowledge transfer techniques show better prediction performance than the models trained without any knowledge transfer techniques. Therefore, we can conclude that transferring pre-trained knowledge from the source domain enables a model to better explain the response variable in the target domain. The performance improvement is particularly emphasized when the available data for the target domain is small. Thus, transfer learning can be one way to address the data scarcity problem in structural engineering. Furthermore, transferring the pre-trained knowledge is more associated with the underlying physical relationship between the source and the target domains and less associated with the discrepancy between the source and the target domain distributions. [ABSTRACT FROM AUTHOR]

• Reeds are used to improve the in-plane capacity of adobe walls. • The surface of reeds is sand-coated to improve its bond behavior. • The in-plane behavior of adobe walls is significantly improved after reinforcing. • The combined vertical and horizontal reeds were the most effective scheme. This study aims to develop a novel internal reinforcing method using sand-coated reeds to enhance the in-plane cyclic lateral behavior of adobe walls. The experimental program involves five adobe wall panels tested under a constant pre-compression stress of 0.3 MPa combined with incrementally increasing lateral loading reversals. The results are compared in terms of failure mode, hysteretic curve, ductility, stiffness degradation, dissipated energy, viscous damping ratio, and residual deformation. It is found that the in-plane seismic behavior of adobe walls can be significantly improved by using sand-coated reeds as a sustainable natural reinforcement with the combined vertical and horizontal scheme surpassed the others. [ABSTRACT FROM AUTHOR]

An innovative occupant friendly retrofitting technique has been developed for reinforced concrete (RC) building structures with hollow brick infill walls used as partition walls which constitute the major portion of the existing building stock in Turkey. The idea is to convert the existing hollow brick infill wall into a load carrying system acting as a cast-in-place RC wall by reinforcing it with relatively thin concrete plates bonded to the mortar coated infill wall by use of tile adhesive and fixed by Φ6 (6 mm diameter) bolts. Test parameters were the shape and thickness of the plates, presence of reinforcement in plates, number and arrangement of Φ6 bolts. It was observed that lateral strength, stiffness, energy dissipation capacity, and ductility of the strengthened infill walls were improved and behaviour was enhanced by the proposed technique. Plates with two different basic shapes were used to strengthen the test specimens. [ABSTRACT FROM AUTHOR]

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In this study, inelastic displacement ratios and ductility demands are investigated for SDOF systems with period range of 0.1-3.0 s. with elastoplastic behavior considering soil structure interaction. Earthquake motions recorded on different site conditions such as rock, stiff soil, soft soil and very soft soil are used in analyses. Soil structure interacting systems are modeled with effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. Results are compared with those calculated for fixed-base case. A new equation is proposed for inelastic displacement ratio of interacting system (C͂R) as a function of structural period of interacting system (T͂), strength reduction factor (R) and period lengthening ratio (T͂/T). The proposed equation for C͂R which takes the soil-structure interaction into account should be useful in estimating the inelastic deformation of existing structures with known lateral strength. [ABSTRACT FROM AUTHOR]

The article presents a study on nonlinear finite element with regards to energy dissipator wall with shear connectors and the impact of elasto-plastic behavior of shear connectors. It discusses how the study was conducted which involved a comparison of the structural wall with an ordinary solid wall and steel plate modelling. It concludes that shear connections must maintain their energy dissipation and load carrying capacities for best performance.

• The effects of corrugation direction and type on the seismic behavior of corrugated DSCW are analyzed. • The seismic behavior of corrugated DSCW with different connector types is compared. • The corrugated DSCWs with flexural failure achieve a drift ratio exceeding 2%. • The axial compression ratio limitation of corrugated DSCW is considered. • Equations for calculating the flexural strength of corrugated DSCW are provided. This paper presents the seismic behavior of corrugated double-skin composite wall (DSCW) with concrete-filled steel tube boundary elements. Fifteen 1/3-scale DSCW specimens, varying in shear span ratio, axial compression ratio, corrugation direction and shape, connector type and steel faceplate profile, were tested under cyclic loading. All specimens except W15 failed in flexural failure. The cyclic response of vertical corrugated DSCW was much better than that of horizontal corrugated DSCW. Compared to flat DSCW, corrugated DSCW, even with a 20% reduction in the concrete cross-sectional area, had considerably higher peak load, ductility ratio and energy dissipation. The setting of connectors slowed down the damage rate of the corrugated DSCW in the failure stage, and also significantly improved the peak load and ductility of the corrugated DSCW with λ = 1.5. Increasing the shear span ratio significantly reduced the peak load and initial stiffness of the DSCW, but did not affect the ductility and energy dissipation. The corrugated DSCW, failed in flexural-dominated mode, had excellent collapse resistance, achieving a drift ratio exceeding 2% and a ductility ratio greater than 3.3, and it was recommended to take n = 0.3 as the limit value of axial compression ratio of corrugated DSCW. Moreover, the average ratio of P t / P c was 1.082 with a mean absolute error of 0.068 and a root mean square error of 0.084, indicating that the calculated value of proposed formulas for calculating the lateral strength of vertical corrugated DSCW can reflect the measured data well. [ABSTRACT FROM AUTHOR]

Test data for interior flat-plate slab-column connections subjected to concentric gravity load and combined gravity and lateral loads were collected. The connection strength was evaluated using AC1 Code design equations. From test data, equations for connection gravity load capacity as a function of concrete strength, slab reinforcement ratio and yield strength, and the ratio of column size to slab effective depth were developed. A model for strength of connections subjected to lateral load using a beam analogy concept that includes resistance from flexure, shear, and torsion at the critical section is proposed. [ABSTRACT FROM AUTHOR]