Search

This article presents a detailed analysis of a numerical model for studying the failure of masonry structures that have been retrofitted with timber solutions. The model accurately reproduces the failure mechanisms of masonry and evaluates the effectiveness of timber-based retrofitting. The study validates the model through comparisons with experimental and numerical results and assesses its efficacy through nonlinear static analysis. The article also discusses the use of a timber frame system as a retrofitting strategy for masonry walls, highlighting its significant enhancement of the wall's load-bearing capacity against lateral forces. However, the post-peak behavior of the retrofitted cases reveals potential weaknesses in the timber frame system, which can lead to sudden drops in resistance. The article concludes by emphasizing the importance of preventing simultaneous failure of multiple bracing elements in the retrofitting system and the need for further research to improve its design and mitigate brittle behavior. [Extracted from the article]

Featured Application: The system under study will provide a modification of the classic use of exoskeletons installed outside buildings on their facades. The lightweight intervention technique will act as an integrated retrofit system of existing RC and masonry buildings by improving both the seismic performance and the energy efficiency with a negligible increase in the mass, a satisfactory augmentation of the stiffness and a reasonable reduction in the thermal dispersion through the structure envelope. The awareness of the vulnerability of existing structures under both seismic and energy perspectives highlights the need for integrated retrofit solutions that combine structural and thermal enhancements. From this perspective, this study explored the efficacy of the Resisto 5.9 Tube system, which is a seismic retrofit solution for masonry and reinforced concrete (RC) structures that also improves the energy performance by integrating a thermal coat integrated within its basic steel framework. This research involved application to a RC building of a design procedure specifically developed for this system that was aimed at facilitating its adoption by designers involved in seismic retrofitting analysis. After designing the system components, nonlinear static analyses were performed using finite element software to compare the building's seismic performance before and after the application of the Resisto 5.9 Tube. The results demonstrate a significant increase in the seismic safety coefficient ζE from 0.26 to 0.42, which proved the potential of this intervention to enhance the seismic safety of existing RC buildings. [ABSTRACT FROM AUTHOR]

The seismic resilience of structures and infrastructures is affected by damage accumulation phenomena, mainly related to the type of hysteresis. Specifically, pinching drives the cyclic response of several building materials, such as reinforced concrete and masonry. Structural systems affected by pinching phenomena are prone to exhibit a dramatic increment of their displacement response after multiple cycles (e.g. repeated earthquakes). The authors estimate a reinforced concrete pier's response using truncated incremental dynamic analysis by concatenating three earthquake scenarios. The authors adopted a Bouc–Wen class hysteresis model to simulate the reinforced concrete pier's cyclic response, matching its experimental cyclic response. The current analysis proved that ductility and resistance primarily drive the seismic response after a single earthquake. However, the performance after multiple earthquakes strongly depends on the pinching, degradation and drift accumulation, which are generally neglected in standard design practices. [ABSTRACT FROM AUTHOR]

In recent years various studies have explored the seismic behavior of controlled rocking masonry walls (CRMWs) that utilize both gravity loading for self-centering and additional energy dissipation (ED) devices to regulate the response (ED-CRMWs). However, these studies had limitations because ED devices were installed on or within the masonry wall, making repairs difficult or impossible after ED yielding or fracturing. This study presents the testing of two half-scale CRMWs that were constructed with supplemental flexural yielding Energy dissipation devices Accessible in a Steel base (EASt-CRMWs). The proposed EASt-CRMWs simplify the installation of the energy dissipation devices and overall wall construction, while also allowing for easy replacement following damage. The walls were subjected to quasi-static, cyclic loading up to drifts of 2.35%, after which the ED devices were replaced, and the same wall was tested again. Wall 2 was built with a steel plate at the rocking point between the steel base and the foundation interface. All five tests demonstrated a favorable self-centering response, with no significant damage to the walls. The ED devices were easily replaced between tests, and the damage was confined to them. Wall 2 had better performance because of the steel plates, which reduced damage to the mortar at the steel base-foundation interface, resulting in slightly decreased lateral load capacity at lower drift ratios upon retesting for Wall 1. Moreover, residual drifts were below 0.05% for all wall tests. Finally, a numerical model and a damage index proposed previously were validated based on the experimental work presented in this study as well as additional configurations of EASt-CRMWs presented in a previous recent study. The results demonstrate that the model can capture the overall response of the walls, and the damage index can accurately predict the location, type, and severity of the damage. [ABSTRACT FROM AUTHOR]

The structural behavior of fully grouted reinforced concrete masonry (RM) walls subjected to either pure in-plane (IP) or pure out-of-plane (OOP) loading has been thoroughly examined in the literature. However, in certain circumstances (e.g., seismic loading), RM walls could be subjected to combined IP and OOP loads. This study conducts a comprehensive numerical investigation into the structural behaviors of RM walls under combined IP and OOP loading, focusing on the influence of geometric parameters (aspect ratio and height-to-thickness ratio) and precompression load. To capture the possible failure modes of RM walls under bidirectional loading scenarios, a simplified micromodeling approach is employed in this study. The numerical simulations were performed in the general-purpose finite element software package ABAQUS. The simulation results indicated that the presence of OOP loads can induce substantial IP capacity reductions, especially for flexural-governed walls characterized by a larger aspect ratio and a low level of precompression load. For flexural-governed walls, IP and OOP capacity interactions were found to be less sensitive to geometrical parameters and precompression load than shear-governed walls. The most interaction was observed for highly slender walls without precompression loads, indicating a reduction in IP capacity by 45% when OOP loading is at 80% of its corresponding capacity. A further comparison between the RM walls and their counterparts, unreinforced masonry (URM) walls, suggested that the IP capacity reduction of RM walls could be 11.6% less than that in URM walls, indicating the positive effects of reinforcements in mitigating the IP–OOP interaction effects. [ABSTRACT FROM AUTHOR]

An experimental study was carried out to contribute to the rather limited data on the out-of-plane (OOP) behavior of masonry infills in reinforced concrete (RC) frames strengthened with the wall post and the textile-reinforced mortar (TRM). For this purpose, one unreinforced specimen served as the control, one specimen was reinforced with the wall post, and two specimens were reinforced with the TRM. They were fabricated and subjected to cyclic OOP loading until a drift ratio of 6%. Load and displacement values were recorded, and the research team discussed the failure mechanisms of the specimens. Results showed that the application of the wall post had the highest efficiency as it increased the load by about 3 times, while this value for TRM-strengthened walls was only 1.5. Strengthening modified the cracking, shifting it towards the middle parts of the wall, changing it from a brittle to a failure mode. Comparison of the envelope curves of specimens revealed significant improvements. The ultimate displacement and energy absorption capacity for the specimen reinforced with the post wall increased by 30% and 300% respectively. Similarly, for TRMstrengthened specimens, these values were 48% and 100%. [ABSTRACT FROM AUTHOR]

In this study, a masonry panel under a high compressive stress to strength ratio is considered. The panel is modeled as a composite structure by considering a repeated unit cell of mortar and brick. Load redistributions due to creep in mortar and brick as composite materials are accounted for. A step-by-step in-time analysis is performed to calculate the load redistribution in the composite masonry. Time-dependent system reliability analysis of the masonry panel is performed by defining the component and system limit state functions at each time step. While the reliability index of ductile materials depends on the load level in each part of masonry, the reliability index of brittle materials depends only on the overall load. By proposing the reliability index of quasi-brittle materials being between these two reliability index bounds, the reliability index of quasi-brittle materials depends on both the load level in each part and the overall load. Using the proposed reliability index of quasi-brittle materials, partial safety factors for masonry panel design considering creep and damage are calibrated based on the Hasofer and Lind method. A design example using the proposed partial safety factor is presented. [ABSTRACT FROM AUTHOR]

This paper investigated the lateral resistant behavior of grid-reinforced steel corrugated shear walls (GR-SCSWs), which are applied to shear walls with large width-to-height ratio. By revealing the resistant mechanism, the stiffness requirement of the subgrid, the wall–frame interaction, and the overall lateral resistance were studied. First, compared with ordinary steel corrugated shear walls, the lateral resistant behavior of GR-SCSWs and the bending moment of the boundary column were analyzed. Second, the threshold stiffness ratio was defined for the subgrid, and design suggestions were proposed to ensure that the infill panel has high and stable in-plane lateral resistance. Finally, the yielding development and shear force distribution in GR-SCSWs were explored, and an improved plate–frame interaction (PFI) model and formulas predicting the lateral resistance curve of GR-SCSWs were established by numerical analysis and theoretical derivations. It was found that, due to the full out-of-plane restraining effect of the subgrid, the GR-SCSW with optimized subpanels can achieve an in-plane shear yielding mechanism. GR-SCSWs can resist lateral loading with an appropriate yield sequence from the infill panel to the subgrid and then to the boundary frame. The modified PFI model proposed fully considered the interaction between the infill grid-reinforced panel and the boundary frame, while the theoretical formulas agreed with the FEA results and can be used to predict the lateral resistant curve and shear force distribution of GR-SCSWs. [ABSTRACT FROM AUTHOR]

Recent research has underscored the effectiveness of engineered cementitious composites (ECC) in retrofitting unreinforced masonry (URM) structures. The retrofitting method of embedding ECC in the bed mortar joints is suitable for strengthening historic masonry buildings because the ECC can be concealed within the mortar joints. This study introduces an experimental campaign aimed at understanding the effects of this strengthening method on the in-plane seismic performance of URM walls. Four half-scale masonry walls, one of them unreinforced and the remaining three reinforced with ECC, were built and tested under in-plane cyclic loads. From the test results, it was found that the proposed retrofitting method can mitigate brittle diagonal shear damage and improve the integrity of the masonry walls. Furthermore, the results demonstrated that ECC reinforcement effectively increased the seismic behavior of URM walls in terms of shear bearing capacity, ductile behavior, stiffness degradation, and energy dissipation capacity. The ductility coefficient is defined as the ratio of ultimate displacement to yield displacement. The maximum lateral load and ductility coefficient of the reinforced masonry walls increased by a maximum of 26.08 and 25.77%, respectively, in comparison with the URM wall. Additionally, the lateral bearing capacity of both unreinforced and reinforced specimens was assessed using theoretical models. The results showed that the theoretical model could be used to predict the maximum lateral loads of the specimens, with the error of the calculated and tested maximum lateral loads being within 5%. The hysteresis curves of ECC-reinforced walls were predicted using an idealized trilinear model and a modified Clough model, and the applicability of the hysteresis model was assessed by comparing the force demand history and energy dissipation history of the computed and experimental hysteresis curves. [ABSTRACT FROM AUTHOR]

Several studies have been carried out to assess the building's seismic vulnerability, to mitigate the seismic risk in urban areas, which is one of the most devastating natural hazards causing considerable economic and human losses. These studies must be incorporated to improve the planning of urban areas to have resistant and resilient cities in case of disasters. The seismic feedback has shown that the build-back-better concept has a direct impact on the city's economic growth. In this paper, the existing buildings' resilience is assessed, in order to highlight the capacity of these last to keep the functionality when an earthquake occurs. This building's resilience has been determined for three types of structures: masonry, reinforced concrete and steel, according to the reconstruction time, the reconstruction cost and the damage state. This last has been assessed from empirical fragility curves developed using the log normal distribution for five structures typologies (Unreinforced masonry; reinforced masonry; RC frame; RC shear walls/Mixed RC frame-RC shear walls and steel structures). A seismic resilience scenario was performed using a geographic information system (GIS) and applied for the Blida city (Algeria) classified as a high seismic zone according to Algerian seismic regulations. According to the results found, the old districts of the Blida city, built mainly during the so-called pre-code period, will not be resilient in case of disaster. The other districts built later in the low-code and high-code periods will have, respectively, medium and good functionality. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth analysis of the Kopčić House, a significant example of modernist architecture in Sarajevo, Bosnia and Herzegovina, focusing on its structural-specific features and seismic performance. The Kopčić House embodies a confined masonry structure with innovative construction features, combining load-bearing masonry walls with reinforced concrete elements. This architectural approach was pioneering for its time, combining traditional construction methods with innovative materials and techniques. Detailed analysis using numerical modeling techniques, specifically 3D modeling with the 3Muri software (Vers.14.2.0.4), was conducted to assess the seismic resilience of the structure. The analysis considered different load distributions and eccentricities to comprehensively evaluate the building's response to lateral forces. The findings of this research reveal the structural capacity and potential vulnerabilities of the Kopčić House when subjected to seismic events. While the building demonstrates inherent strength due to its confined masonry design, areas requiring structural strengthening were identified through numerical simulations. This study contributes to the broader understanding of confined masonry construction within the context of modernist architecture. By integrating historical research with advanced structural analysis, this work aims to bridge the gap between architectural heritage and contemporary engineering practices. [ABSTRACT FROM AUTHOR]

Deep faults significantly impact the structural stabilities and deformation behaviors of their overburden rocks, which are key factors in underground engineering and geological hazard research. Considering the problem of deep-fault-overburdened breaking during mining of super-thick coal seams and taking the Yaoqiao Coal Mine as the research object, the mining fracture evolution characteristics and overburden displacement law of the non-structured and fault-bearing overburden corresponding to fully mechanized caving mining are compared and analyzed using numerical simulations and physical similarity simulations. The results of this study show the following: 1) The fracture height of the overlying rock presents a specific change law with advancement of the working face; the initial rapid increase to a maximum height of 74 m is achieved when the working face advances to 90 m; with the development of the plastic zone indicating past yield, the fracture height decreases to 54 m and becomes stable, and the final caving angle of the fracture stabilizes at 70°. 2) In coal mining under normal fault conditions, when the working face advances from the upper to lower walls, the roof forms a masonry beam structure that slows down fault activation and crack development. When moving away from the fault, the overburden movements and water-conducting cracks are fewer, and the crack height is lower than that without faults. When approaching the fault, the influence of the faults in the fracture zone increases, and the height of fracture development reaches the maximum value after crossing the fault, highlighting the significant influence of the fault on fracture development. 3) Through a similarity simulation test, it is shown that the overburden caving zone is further compacted by the overburden rock and that the roof collapses in a large range, resulting in rapid upward development of the overburden rock cracks and separation of the central overburden rock cracks that are gradually compacted and closed. These findings are expected to have important theoretical and practical significance for deep underground engineering design, geological disaster prevention, and fault activity monitoring. [ABSTRACT FROM AUTHOR]

The research proposes a method to reinforce and rehabilitate steel structures using the masonry veneer technique with welded wire steel mesh. The reinforcement involves anchoring a welded wire mesh coated with mortar on both sides of the wall. The mesh is connected to the frame system and the upper and lower slabs, enabling a complete transmission of forces. Cyclic lateral load tests were conducted on four different prototypes. The first test was conducted in the linear range on an unfilled frame; the second test involved a frame with an unreinforced infill panel, conducted until moderate damage to the panel was generated. The third test, a system consisting of a steel frame with a reinforced infill panel, without prior damage, was subjected to full damage. Finally, in the fourth test, a system comprising a frame with an infill panel, initially with moderate damage but reinforced using the veneer technique, was subjected to full damage. Hysteresis curves were generated, and maximum resistance, maximum drifts, dissipated energy, and stiffness were determined. Finally, a comparison of the test results revealed that the proposed reinforcement increased the strength by up to three times and the stiffness by up to eight times compared to the original. [ABSTRACT FROM AUTHOR]

Due to rapid growth in tourism and other economic activities, several small cities and towns in the Indian Himalayan region are facing problems of unplanned construction and extended use of deteriorating old structures. Despite being in the most active zone of seismic activity, significant nonengineered construction is practiced in this region. Hence, it becomes essential to examine the existing engineered and nonengineered building typologies and assess their vulnerabilities against earthquake shaking. This study presents typical engineered and nonengineered construction practices observed through a survey of 1,009 buildings located within Mandi, a small town in the lap of the great Himalayas in the Indian state of Himachal Pradesh. An attempt is made to identify the typical building typologies, visible structural irregular features and their seismic vulnerability. A few building typologies predominantly prevail in the northern zone of the Indian Himalayan region are identified. Rapid visual screening (RVS) of the surveyed buildings is performed using different existing guidelines. It is observed that a substantial number of buildings with hybrid typology (stone masonry mixed with brick masonry or reinforced concrete) prevail in the study area. It is also observed that the seismic vulnerability, as per the adopted RVS guidelines, of the majority of the buildings is high, indicating urgent demand to safeguard the vulnerable built environment and develop the framework for a seismic resilient society. It is further concluded that use of region-specific vulnerability attributes can improve the segregation of buildings based on expected damage. The seismic assessment of large existing building stock through rapid visual screening (RVS) is important for preliminary evaluation. This study presents crucial insights into seismic vulnerability assessment and earthquake-resistant construction practices in the Indian Himalayan region. It identifies new building typologies, prevalent poor construction practices, and critical vulnerable attributes in the case study region. These findings hold significant practical implications for various stakeholders, including engineers, researchers, policymakers, and practitioners. By understanding the ground conditions of construction practices, building typologies, and vulnerability attributes, stakeholders can develop robust RVS methodologies which accurately assess their seismic vulnerability for planning effective seismic risk mitigation strategies and promote earthquake-resistant construction practices. Identifying new building typologies will encourage future research to quantify vulnerability through numerical studies, experimental investigation, and field data. [ABSTRACT FROM AUTHOR]

Predicting the seismic response of masonry-infilled (MI) RC frames holds immense importance due to the significant influence of masonry on the structural performance. Despite numerous studies delving into the seismic behavior of these frames, their complex interaction of masonry infills and RC frame presents ongoing challenges for researchers, designers, and standards committees. Although numerous studies have been conducted to investigate the seismic behavior of masonry-infilled reinforced concrete frames, its complex behavior poses a challenge to researchers, designers, and the specification-making committees. In recent years, several national codes have been revised to include the estimation of the stiffness of reinforced and nonreinforced masonry walls and have provided guidelines for the modeling and analysis of structures considering MI. This article aims to provide a comprehensive review of how infilled masonry walls impact the seismic performance of RC frames, drawing comparisons with codal provisions. The focus lies on scrutinizing experimental, numerical, and analytical studies that explore in-plane and out-of-plane behaviors. Factors like masonry strength, stiffness, area of openings, stiffness degradation, energy dissipation capacity, and damage patterns are thoroughly examined. Key findings with critical implications are highlighted, shedding light on potential future research directions in this crucial field. [ABSTRACT FROM AUTHOR]

The objectives of this study were to investigate the out-of-plane behavior of unreinforced masonry (URM) infill walls and to identify the effectiveness of tie systems that were proposed to enhance the infill stability under both in- and out-of-plane effects. This study examined three types of tie systems: a full-length tie system (prototype), a staggered tie system and a half-length tie system. For this purpose, four 1/4-scale, single-story, one-bay masonry infilled reinforced concrete (RC) frame specimens with and without the proposed tie systems were sequentially tested under in-plane static cyclic loading and out-of-plane dynamic excitation. In the experimental study, two series of shaking table tests were conducted to investigate the out-of-plane behavior of the infill walls. The first series compared the fundamental out-of-plane performance of three proposed tie systems, and the second series verified the effectiveness of the full-length tie system to prevent infill out-of-plane failure under an excitation simulating the severe floor response in medium-rise buildings. The test results indicated the following: (1) the presence of the tie systems caused minor differences in the in-plane capacity and ductility of each specimen, (2) the effectiveness of the full-length and staggered tie systems was superior to that of the half-length tie system, and (3) the full-length tie system not only prevented the infill out-of-plane failure but also significantly reduced the infill damage under realistic excitation conditions. The above research outcomes provide a useful contribution of the infill to upgrade the seismic resistance of buildings. [ABSTRACT FROM AUTHOR]

Historical masonry structures are the most important features that distinguish our cultural heritage, from here comes the importance of protection this type of masonry structures from collapse under earthquakes effect or other dynamic loading such as blast loading. Therefore, Seismic Base Isolation is used to reduce earthquakes damages and protect structures from collapse. This paper aims to study the Effect of Seismic Base Isolation, using High Damping Rubber Bearing (HDRB) on Existing Masonry Structures subjected to dynamic loads such as earthquakes, through utilizing numerical modeling of masonry structures. This paper includes definition of seismic base isolation mechanical characteristics, and definition of numerical modeling approaches for structural masonry analysis. The studied masonry structure is the old AWQAF Directorate Building in Aleppo, which is islamic government building affiliated to the Syrian Ministry of AWQAF; In order to perform the numerical modeling, equivalent masonry properties used for this structure were also determined. This structure was analyzed applying nonlinear dynamic analysis-time history method, and reanalyzing it by using seismic base isolation, type HDRB applying the same method. The results of the two analyses were discussed and compared, and the conclusions of this paper showed reduction in shear force when using seismic base isolation, and reduction in stresses that appear in structure because the stresses are located in the level of base isolation system. [ABSTRACT FROM AUTHOR]

This study assessed the seismic damage to historical masonry towers using a three-dimensional finite element (FE) numerical model. The FE model was validated by comparing the dynamic characteristics and seismic analysis results with experimental data obtained using shaking table tests conducted on a 1/8 scaled tower model. Based on this analysis, a numerical analysis model of the damaged ancient brick masonry tower was established by introducing factors such as initial cracks and inclination, and the damage FE model was validated using experimental data provided by the shaking table tests. Subsequently, the damage index of the wall components were obtained using the modified Park–Ang damage model; these were used to obtain the damage indices of the historical tower floors, which were further used to obtain the overall damage indices of the historical tower. Furthermore, the performance levels of historical towers were proposed, and the damage indices at different performance levels were quantified using various parameters. Finally, the damage to the historical tower model in the shaking table test was analyzed based on the various quantitative results. [ABSTRACT FROM AUTHOR]

Culverts are essential under earth embankments to allow watercourses, such as streams and nallas, to pass through without obstructing the natural flow. They help manage floodwaters on both sides of the embankment, reducing water levels and mitigating flood risks. Culverts come in various shapes, including arch, slab, and box configurations, and can be constructed from materials such as masonry or reinforced concrete. Culverts, embedded within earth embankments, are subjected to traffic loads similar to those on the road and must be designed to accommodate these loads. This paper focuses on the structural design and parametric analysis of RCC box culverts, both with and without cushion. Design parameters such as size, invert level, and layout are determined based on hydraulic considerations and site conditions, with the cushion depending on the road profile at the culvert location. The study examines various load cases (e.g., empty box, full box, surcharge loads) and factors such as effective width, braking force, load dispersion through fill, impact factor, and earth pressure coefficient as per IRC codes. It provides a comprehensive discussion on code provisions, design considerations, and justifications for the structural design of RCC box culverts, ensuring they can withstand maximum bending moments and shear forces. [ABSTRACT FROM AUTHOR]

Summary: Reinforced concrete (RC) shear wall buildings with unreinforced masonry (URM) infilled moment frames are common in India and neighboring countries. This study assesses the influence of the URM infills on their seismic performance. Fully infilled, open first‐storied, and bare frame versions of a 25‐story shear wall building are considered. Multiple stripe analysis is conducted at five return periods to estimate their performance. Fragility functions for the collapse prevention limit state, which is based on seven engineering demand parameter exceedance thresholds, are generated and compared. The presence of infills (full or partial) is observed to have an overall positive effect on the performance of the RC frame‐shear wall buildings. The performance of the open first‐story building was comparable to that of the fully infilled building. The ratio of story shear carried by the moment frames and shear walls is studied at all return periods to understand the variation in frame shear wall interaction with increased damage for each building. In the case of buildings with infills, the frames carry a higher proportion of story shear at lower return periods. For all three buildings, the fraction of story shear carried by moment frames increases along the height of the building. [ABSTRACT FROM AUTHOR]

Post-seismic assessments have indicated that the responses of masonry walls to seismic forces may be classified into two key categories: in-plane global mechanisms and out-of-plane cyclical actions occurring orthogonally to the wall. The initial phase of this investigation scrutinized the widely accepted shear strength models for in-plane shear resistance, Vn, of reinforced masonry (RM) walls. Subsequently, using a dataset comprising 78 samples of fully grouted hollow concrete block (HCB) RM walls, a detailed examination of the sensitivity of experimental shear strength, V exp , to geometric, mechanical, and reinforcement characteristics of the wall was undertaken. The study's second phase entailed a parametric evaluation using finite element analysis to appraise the sensitivity of lateral drift to wall geometry and bed-joint reinforcement attributes. The third phase of the research introduced an informational model for estimating the lateral drift of partially grouted RM walls, incorporating BJ and vertical reinforcement. The model was established utilizing data from 44 full-scale in-plane cyclic tests on clay brick walls and 32 tests on HCB walls. The investigation further presented a multi-objective optimization methodology to ascertain the optimal vertical and BJR ratios, ρv and ρBJ. A graphical user interface and an accompanying empirical equation were also devised to simplify the analysis and design process for reinforced masonry walls, obviating the need for lengthy analyses. Increasing the BJR size from 6 to 8 mm resulted in a 30% increase in V n for specimens with six BJR rows, while increasing the number of BJR rows from six to ten led to 16% rise in V n , as demonstrated by numerical modeling validated against experimental tests.The findings of the study highlight a notable dependence of the lateral drift capacity of reinforced masonry walls on wall geometry and ρBJ ratio. These revelations provide invaluable insights for designing earthquake-resistant masonry edifices and formulating rehabilitation strategies for existing masonry structures deficient in seismic resilience. [ABSTRACT FROM AUTHOR]

An orthotropic homogenized model is used to investigate the in-plane elastic behavior of coated masonry walls. The homogenization process mainly consists of modeling the elementary cell of a three-layer medium by using suitable designed assemblies of in-parallel springs. On the basis of the latter, the stresses distributed between masonry and reinforcement coatings are analytically assessed after the determination of the average stress acting on the homogeneous medium. The precision of the theoretical outcomes is evaluated through comparisons with finite element (FE) models. Static and dynamic numerical analyses are carried out on both non-homogeneous and homogeneous FE models of sample systems. The homogeneous model is observed to adequately capture both the local and global behavior of reinforced masonry walls. Parametric analyses are also performed to investigate the effectiveness of reinforcement on the overall behavior of the system. [ABSTRACT FROM AUTHOR]

Assessing the seismic vulnerability of existing buildings is an essential task for the management of earthquake disasters. For this purpose, the seismic behaviour of buildings is usually determined under the assumption of isolated conditions, although aggregate structures are one of the most common typologies found in urban centres. This study aims to investigate the nonlinear static behaviour of aggregate dwellings consisting of grouted reinforced concrete block configurations commonly observed in San José, Costa Rica. This research investigates the use of several strategies to model connections between adjacent buildings which are typically found in modern building practises in this country. The methodology used here to analyse the seismic behaviour of isolated and row-aggregated dwellings reveals significant differences in their response under seismic loads, especially when acting perpendicular to the aggregate. The study reveals that the type of interaction considered between adjacent buildings has a very important impact on the seismic capacity and failure mechanisms of the aggregated structures. This procedure can also be applied to the vulnerability assessment and retrofit of existing aggregates. [ABSTRACT FROM AUTHOR]

In recent years, Fabric-Reinforced Cementitious Mortar (FRCM) has gained widespread application for strengthening reinforced concrete and masonry structures. This research investigated the influence of microfibre parameters on the tensile characteristics of FRCM, focusing on the fibre type, length, and volume fraction. Three distinct types of microfibres were scrutinized: amorphous metallic (AM) fibres, polyvinyl alcohol (PVA) fibres, and nylon fibres. FRCM coupons were designed and fabricated based on the AC434 standard. A tensile experimental program, following RILEM TC232-TDT, revealed the pronounced advantage of employing AM fibres in the pre-cracking stage by significantly improving the crack stress up to 226% and pre-cracking stiffness of FRCM. Conversely, synthetic fibres such as nylon and PVA were beneficial in the post-cracking stage by enhancing cracked stiffness, peak stress, and tensile toughness. Additionally, it was found that using fibres with shorter lengths improved the tensile behavior of FRCM composites in the post-cracking stage due to better random distribution in the cement-based matrix. Finally, an artificial neural network (ANN) model was proposed to predict the tensile parameters of the FRCM composites incorporating microfibres. [ABSTRACT FROM AUTHOR]

Following recent earthquakes, precast buildings exhibited a strong seismic vulnerability related to the presence of closure external panels. The aim of this work is to simulate the seismic response of existing single-storey precast buildings in the case of explicit modelling of external panels. The considered case studies are precast buildings representative of the Italian building stock in the 1970s and 1990s, characterised by two different cladding systems, namely, masonry infills and reinforced concrete precast panels, respectively. The explicit modelling of infills and panels, typically introduced solely as participating masses, provided insights into their actual contribution on the global structural behavior. [ABSTRACT FROM AUTHOR]

Moisture in historic built heritage is one of the main degenerative agents, because it supports or manifests itself through multiple pathologies. Current knowledge allows for the diagnosis and assessment of the problem, but there are deficiencies in the evaluation of corrective systems due to the time it takes for moisture to become significant. In response, this study proposes an experimental methodology that aims to reproduce the accelerated aging of real scale specimens under laboratory conditions. Thereby improving the understanding of the impact of moisture related deterioration on masonry structures. To achive this, eight masonry walls were constructed and subjected to eight cycles of sulfate crystallization. They were saturated with different sulfate concentrations (5% or 10%) and exposed to different drying conditions (outdoor or solar dehydrator) in order to identify the factors favoring sulfate crystallization and the resulting deterioration. The progress of the experiments was monitored using a hygrometer, a thermographic camera and photogrammetry. The results indicate that it is possible to induce efflorescence in real scale specimens. Temperature and moisture monitoring helped identify the solar dehydrator as a more effective drying treatment. While digital photogrammetry was considered inefficient for quantifying volumetric damage, since this technique can present errors greater than 2%, a value exceeding the observed wear. Reason why the weight of material detached at the end of the experiment was recorded and a positive correlation between the increase in sulfate concentration and the use of the dehydrator was observed. Finally, pertinent considerations are made to improve the experimental conditions. [ABSTRACT FROM AUTHOR]

Seismic loads pose a great risk to existing masonry buildings. Modern seismic control methods that are being increasingly used today, rather than various traditional strengthening methods, appear in the retrofit of existing masonry structures. The use of seismic control in existing masonry buildings increases the functionality of the building and obviates the need for additional structural requirements. Particularly, seismic control methods are superior because they contain the least possible interventions to architectural details. On the other hand, these methods are a unique option in sensitive structures such as historical masonry structures. In this research, base isolation systems, energy-damping systems, and hybrid systems as well as architectural application details of seismic control methods in masonry structures are discussed in the context of architectural details. [ABSTRACT FROM AUTHOR]

Seismic performance of full-scale precast concrete shear walls with grouting sleeve/grouting-anchor hybrid connection was tested under low cyclic loading and compared with the cast-in-place shear wall. The tested parameters include the longitudinal steel reinforcement connection mode and the number of the connection row. The results show that all precast walls have a flexural failure under low cyclic loading, with the yielded longitudinal steel reinforcement and crushed concrete at the bottom of the walls. The ultimate interlayer displacement angle of each wall is in the range of 1/59 ~ 1/50, which meets the requirement of the elastic-plastic interlayer displacement angle limit. The hysteretic curves of the four shear walls are similar. The positive and negative average bearing capacity of precast walls PW1, PW2 and PW3 are 1.07, 1.02 and 1.2 times higher than that of the cast-in-place wall SW1, respectively; their ductility coefficients are 0.77, 0.74 and 0.96 times that of SW1, respectively, and their cumulative energy dissipation rate are 0.89, 0.64 and 0.87 times that of SW1, respectively. Besides, the four walls have a similar stiffness degradation trend. The shear deformations of PW2 and PW3 are significantly smaller than those of SW1 and PW1. The seismic performance of PW2 (double-row hybrid connection) is close to that of PW1 (grouting sleeve connection) but is poorer than PW3 (single-row hybrid connection). [ABSTRACT FROM AUTHOR]

Based on the seismic design codes to prevent soft-story failure, columns of a soft story must be designed for amplified loads due to the discontinuity of braces or shear walls in that story. Because of the masonry infill walls discontinuity, Soft story failure has been reported in the recent earthquakes. Most national seismic design codes don't consider the effect of masonry infill walls for the design of the soft story. This paper aims to investigate the soft story failure and then present a simple formula for the design of soft-story in moment resisting frame structures. In this paper, the different arrangements of masonry infill walls are considered. Structural modeling was carried out based on reliable parameters and some national or international seismic design codes. By using nonlinear static analysis, a simple methodology is proposed and the main result is a simple formula that can be used for the engineering design of concrete moment resistant frames. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The north of the state of Baja California (BC) is located in one of the regions of Mexico with a high seismic risk. The predominant infrastructure in the city of Tijuana consists of reinforced masonry housing structures, making it crucial to understand the dynamic behavior of this type of structure. Using the "Vulnerability Modeller'sToolKit" (VMTK), fragility functions were obtained for low, medium, and high levels of seismic design. It was found that the probability of achieving or surpassing the different damage states (light, moderate, extensive, and complete) is high in low-height housing (1–3 floors) for an expected value of 0.50 g of PGA and in medium-height housing (4–7 floors) for an expected value of 0.5 g of SA (T = 0.5 s).Vulnerability functions were derived, and it was determined that, for a low seismic design level, low-height and medium-height structures, respectively presented loss probability rates of 30% and 44% for an expected value of 0.50 g of PGA and SA (T = 0.5 s). These fragility and vulnerability functions can be used to estimate damage and losses in future risk scenarios, thereby reducing uncertainty in the risk analysis calculations for the city of Tijuana. [ABSTRACT FROM AUTHOR]

This paper presents results from numerical investigation into the seismic retrofit of masonry infilled reinforced concrete (RC) frame structures with soft ground story using inverted-Y steel bracing system. The dynamic response of the retrofitted four-story RC frame with an open ground story is evaluated and compared with the response of the original frame. Comparisons are carried out with the variation of the mechanical characteristics of infills in order to investigate the way in which the soft story mechanism occurs. Results from nonlinear dynamic analyses indicate that this type of bracing can effectively eliminate the formation of a soft-story collapse mechanism. [ABSTRACT FROM AUTHOR]

Background: Recent studies on masonry infills have shown that damages can be more serious when frame and infill are coupled. Although the discussion on out‐of‐plane (OOP) stability and strength of isolated infills is still open, the development of solutions able to assure the decoupling of infill panels respect to structural frame seems to be the most promising in terms of damage prevention of the building. Aim: A system for decoupling the RC frame and the aerated autoclaved concrete (AAC) masonry infill reinforced with textile reinforced mortar (TRM) is presented. The goal is to analyze the potential of this system to face the OOP actions caused by a seismic event. Method: In this system, the frame is free to deform in its plane, without interaction with the AAC infill, which is supported by retaining brackets at the top. These brackets allow relative in‐plane displacements between the RC frame and the masonry infill and avoid OOP overturning of the infill. Results: The paper shows the design of the system and provides an overview of the seismic capacities validated by testing on the system components. Based on the analysis and comparison of the test results, the performance and effectiveness of the proposed system are presented. [ABSTRACT FROM AUTHOR]

Copyright of CE/Papers is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of CE/Papers is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of CE/Papers is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bolted precast concrete shear wall structures have the potential to be disassembled and exhibit superior seismic performance. In this study, a new type of fully bolted concrete shear wall was proposed, and its seismic behaviour was examined through cyclic loading tests. The influence of the connecting method, axial compression ratio, and interface roughness on the seismic behaviour of this fully bolted concrete shear wall was analysed, and the design method was proposed. The results showed that at the axial compression ratio of 0.05, the proposed new type of fully bolted concrete shear wall structure behaved favourable seismic performance and the energy dissipation capacity was improved about 26%. Moreover, the proposed formulas used for the calculation of the bearing capacity of this connection provide a basis for the application of the fully bolted concrete shear walls. [ABSTRACT FROM AUTHOR]

This paper presents the findings of the numerical studies performed on a two-tiered reinforced fly ash wall. Fly ash was used as backfill material and jute geotextile was used as reinforcement as well as facing material. Wrap-around facing was used in which the jute geotextile was folded at the face. Three-dimensional models of fly ash walls showing offsets at varying distances between the two tiers and the length of reinforcement were prepared. The horizontal displacement on the wall face, tensile forces on reinforcement, and settlement behavior of the backfill wall were analyzed. Further, the wall model was scaled 10 times to generate large-scale fly ash models to understand the behavior of a life-size reinforced fly ash tiered wall. The displacement in the horizontal direction at the face of the wall reduced with the increase in length of the reinforcement and the distance between the tiers. The influence of the offset distance between the tiers on the tensile forces acting on the reinforcement was also investigated. The critical distance between the offsets was identified as 0.6 times the lower tier height. The tiered wall in the present study showed significant reduction in mobilized tensile force in the reinforcements especially at the lower tier as compared with a single (without tier) reinforced fly ash wall of the same height. The maximum tensile force for a single wall was observed to be 1.25 times and 5.35 times the two-tiered wall with D/L = 0.6 for upper and lower tiers, respectively, where D = distance of the offsets between the two tiers and L = height of lower tier. The safety factors were determined by using strength reduction factors. The factor of safety increased with an increase in the offset distance. Similar trends were observed for large-scale models. Jute geotextile reinforced fly ash models were analyzed using finite-element analysis. The results are relevant for the construction of fly ash wall reinforced with jute geotextile. The distance between the offsets was varied and a critical distance between the offsets was identified as 0.6L. The practical implication of the study is a reduced offset distance. The previous studies have identified a larger value of such distance. The current ratio for offset distance should be considered while designing the reinforced fly ash wall in tiered configuration. A change in position as well as value of tensile force acting on reinforcement was observed with the change in the distance between the offsets, thereby changing the location of failure plane. This should be taken in to account while designing the reinforcement for the wall. [ABSTRACT FROM AUTHOR]

The study proposed a seismic vulnerability methodology applied to the historical centre of Castelpoto, located in the province of Benevento (Southern Italy). The seismic vulnerability of the examined aggregates was examined using an index‐based procedure specifically developed for structural masonry compounds. The structural details and specific characteristics of building aggregates are crucial in determining the seismic vulnerability of buildings in urban environments. Parameters such as the plan configuration, size, and layout of buildings, including the thickness, height of the masonry walls and the connections among different components of the construction, were appropriately considered, since all might have an impact on their seismic performance. Furthermore, the type of masonry, the strength and composition of the mortar, as well as the quality of constructions, can also contribute to the global seismic performance of buildings. These structural parameters, collected in the used form, were correlated to the Masonry Quality Index (MQI) to provide an exhaustive assessment of the capacity (in‐plane and out‐of‐plane mechanisms) of the bearing elements towards seismic loads. Secondly, the susceptibility to damage of the existing building stock was evaluated by applying a parametric simulation of damage scenarios adopting an appropriate Intensity Prediction Equation (IPE). To this purpose, fault models were acquired from the Database of Individual Seismogenic Sources (DISS) and the considered IPE was validated according to the Italian Macroseismic Database (DBMI). Thus, the proposed research aims to highlight how an accurate assessment of masonry strength is crucial during the inspection phase to optimise the prediction of the expected damage scenario allowing for effective risk mitigation in urbanised contexts. [ABSTRACT FROM AUTHOR]

An experimental investigation was conducted that consisted of 12 pairs of reinforced masonry specimens in which the two specimens were constructed with their longitudinal axes oriented parallel and perpendicular to the laboratory floor, respectively. This work was conducted to reassess the need for the χ-factor accounting for the direction of compressive stresses in masonry members in relation to the direction used to establish their masonry assemblage strength included in CSA S304-14—Design of Masonry Structures. Parameters investigated included block size and reinforcement ratio. Test results suggest that the χ-factor can be eliminated from future editions of CSA S304 but should be considered with caution: a review of the literature and the current tests show that, in some cases, voids may develop between the exterior webs of adjacent blocks and so may be the source of the reduction in the magnitude of the equivalent rectangular compressive stress block. [ABSTRACT FROM AUTHOR]