Search

An enhanced U-shaped network (EU-Net) based on deep semantic information fusion and edge information guidance is studied to improve the segmentation accuracy of road cracks under hazy conditions. The EU-Net comprises multimode feature fusion, side information fusion and edge extraction modules. The feature and side information fusion modules are applied to fuse deep semantic information with multiscale features. The edge extraction module uses the Canny edge detection algorithm to guide and constrain crack edge information from the neural network. The experimental results show that the method in this work is superior to the most widely used crack segmentation methods. Compared with that of the baseline U-Net, the mIoU of the EU-Net increases by 0.59% and 5.7% on the Crack500 and Masonry datasets, respectively. [ABSTRACT FROM AUTHOR]

Following the 2010/2011 Canterbury, New Zealand earthquake sequence, Auckland Council actively identified and assessed commercial buildings within the Auckland region to establish whether they were earthquake prone. Masonry infill buildings are one class of building type that was considered to be potentially earthquake-prone, with this building type constituting a significant proportion (9%) of all commercial buildings in the Auckland region. Despite the Auckland region being categorised as a low seismicity region in the current New Zealand seismic loadings standard, rupture of the Wairoa North fault located within the Auckland region could potentially generate significant earthquake shaking in the future. The reported study was undertaken to forecast the damage distribution for low-rise and mid-rise masonry infill buildings when subjected to ground motions from the Wairoa North fault that incorporated a combined mainshock-aftershock earthquake sequence. The results showed that mid-rise masonry infill buildings were forecast to exhibit significant damage when compared to low-rise masonry infill buildings. In addition, the seismic risk associated with mid-rise masonry infill buildings was forecast to significantly increase when aftershock earthquake scenarios were applied. It is noted that the increased seismic risk of mid-rise masonry infill buildings (when compared to their low-rise equivalent) was unsurprising because post-earthquake observation following the Canterbury earthquake sequence showed that mid-rise masonry infill buildings sustained higher levels of damage in comparison to low-rise masonry infill buildings. [ABSTRACT FROM AUTHOR]

Due to long-term exposure to outdoor environments, stone artifacts exhibit complex and varying degrees of disease that need to be conserved urgently in order to perpetuate their historical, artistic and scientific values. Owing to the varying degrees of damage inflicted upon cultural relics, discrepancies exist in intervention strategies and conservation materials employed. Hence, it is considerably crucial to conduct a scientific and precise assessment of the preservation status of cultural relics at an early stage for the advancement of cultural relic conservation efforts. In this research, three masonry components of the Hailongtun Fortress site were selected as study objects. A secondary fuzzy comprehensive evaluation system was established through selecting a total of 12 indicators from four aspects, namely, surface change, rock mass structure, physical properties and matrix weathering. The weight of each indicator was determined by using an improved AHP-EWM weight coupling model. The membership degree was calculated by selecting a modified ridge function. The asymmetric nearness method was employed in the final decision-making process so as to correct the error caused by the principle of maximum membership degree. The research shows that the results of the improved evaluation method are in line with the real damage degree of each masonry component, which provides a scientific and quantitative basis for determining the priority of the conservation of masonry components in the Hailongtun Fortress Site. This method is also a reference for carrying out the disease assessment and conservation of other types of cultural relics. [ABSTRACT FROM AUTHOR]

In this paper, a computational approach based on numerical dissipation is proposed to simulate rocking blocks. A rocking block is idealized as a solid body interacting with its foundation through a contact-based formulation. An implicit time integration scheme with numerical dissipation, set to optimally treat dissipation in contact problems, is employed. The numerical dissipation is ruled by the time step and the rocking dissipative phenomenon at impacts is accurately predicted without any damping model. A broad numerical campaign is conducted to define a regression law in analytic form for the setting of the time step, depending on the block size and aspect ratio, the contact stiffness, as well as the coefficient of restitution selected. The so-obtained regression law appears accurate and an a posteriori validation with cases not in the training dataset confirms the effectiveness of the approach. Finally, the comparison with available experimental tests highlights the approach efficacy for free rocking and harmonic loading cases (in a deterministic sense), and for earthquake-like loading cases (in a statistical sense). It is found that rocking blocks with sizes of interest for structural engineering (e.g., cultural heritage structures) can be simulated with time steps within 10–3 ÷ 10–1 s, so allowing very fast computations. [ABSTRACT FROM AUTHOR]

Following the seismic events that shook Albania in November 2019, more than 14,000 buildings were impacted, resulting in 51 fatalities, over 3000 injuries, and displacing around fourteen thousand residents from their homes. The majority of these affected individuals were concentrated in highly populated Tirana and Durres. This result was expected because of the predominant building type in the region, which is characterized by unreinforced masonry structures that have not been subjected to recent assessments or rehabilitation initiatives. The study outlines observed issues and challenges, leading to an analytical investigation into the seismic capacity of various masonry building types observed during post-earthquake reconnaissance. Nineteen masonry structures, ranging from 2 to 6 stories, were selected to correspond to frequently used typified projects in construction. Based on the laboratory test results assessing the characteristics of structural wall parts, analytical models for each building were created. Nonlinear static analysis was employed to estimate the seismic displacement capacities of each building. To further explore the importance of the findings, the nonlinear behavior of a group of representative buildings was analyzed in relation to the seismic sequences that occurred during the 2019 Albania earthquakes. The outcomes of this study are believed to be generalizable to various similar buildings and applicable to a wide range of masonry structures. [ABSTRACT FROM AUTHOR]

Mortar bedding is a high cement-based material placed between concrete blocks and can improve the tensile and shear strength of the joints. Two types are recommended, full bedding, which covers the entire liquid area of the block, and face shell bedding, where the mortar is placed only on the longitudinal walls of the block, forming a lateral cord. The union of the lack of technical regulation on the choice of the laying pattern and the execution of a wall by more than one professional, in some cases, results in the appearance of a third pattern, mixed bedding, the rows mix the full bedding and the face shell bedding types. This paper aims to evaluate the influence of the mortar bedding on the mechanical behavior of the structural masonry, where walls of concrete blocks with face shell and full and mixed bedding were made, evaluating their respective failure modes. The inputs of the wall and the structures of each proposed bedding type were individually studied and subjected to the compressive strength test. Some LVDTs have been used to evaluate and compare the displacements between patterns. In addition, the failure modes in each type of mortar bedding were analyzed. The results of the compression tests of the walls showed that the type of laying significantly influences the compressive strength of the masonry, with the face shell and mixed bedding patterns showing a loss of capacity of compressive strength in relation to the full bedding of approximately 18.5% and 21.7%, respectively. In addition, it was noted that in addition to being less resistant, the mixed pattern failed at the end of the elastic zone, demonstrating a brittle behavior. Given the facts, the full and face shell bedding is indicated; the face shell bedding is used with caution, considering its reduced load capacity and failure mode, when dimensioning the masonry. [ABSTRACT FROM AUTHOR]

This special issue focuses on the seismic performance of adjacent interacting masonry structures, particularly in historical European city centers. The AIMS project provided unique data on interacting masonry structures through large-scale shake table tests on two adjacent half-scale stone masonry buildings. The experimental campaign was accomapgnied by a blind prediction study where participants modeled the aggregate's seismic response. Findings highlight challenges in accurately predicting displacement demands and failure modes, providing critical insights for improving future modeling techniques for masonry buildings. [ABSTRACT FROM AUTHOR]

Masonry aggregates have developed throughout city centres of Europe due to a centuries-long densification process that generally lacked consistent planning or engineering. Adjacent units are connected either through interlocking stones or a layer of mortar. Without interlocking stones, the connection between the units is weak, and an out of-phase response of the units can lead to separation and pounding. Modelling guidelines and code instructions are missing for modelling the interaction of such adjacent units because of scarce experimental data. Therefore, in this study an unreinforced stone masonry aggregate was tested on the bidirectional shake table with an incremental seismic protocol as a part of the SERA AIMS—Adjacent Interacting Masonry Structures project. The aggregate was constructed at half-scale with double-leaf undressed stone masonry without interlocking between the units. Floors were built with timber beams and one layer of planks, with different beam span orientation for each unit. After significant damage, one of the units was retrofitted by anchoring the timber beams to the walls to prevent out-of-plane failure and testing was continued. Significant interaction between the units was observed with specific damage mechanisms. Cracking and separation were observed at the interface in both longitudinal and transverse direction, starting at lower intensity runs and progressively increasing. Bidirectional seismic excitation affected the unit separation, with friction forces seemingly playing a role in the transverse direction. Signs of pounding at the interface were observed during higher intensity runs, together with the formation of a soft storey mechanism at the upper storey of the higher unit. The mechanism involved an out-of-plane response of the shared wall, with a horizontal crack at the height of the interaction. These findings contribute to a better understanding of the seismic behaviour of masonry aggregates. [ABSTRACT FROM AUTHOR]

Experimental tests performed on scaled masonry buildings provide key information to improve the knowledge under seismic actions. Masonry buildings behavior is strongly influenced by their physical and mechanical parameters under dynamic actions. In fact, the actual structural behavior is very complex to predict due to the significant variability of the input parameters and the strong heterogeneity of masonry. Furthermore, the behavior of masonry buildings is often influenced by the interaction with adjacent building units. In this context, the SERA AIMS project aims to improve knowledge on the interaction between adjacent buildings. In order to assess the seismic capacity of masonry structures and their damage evolution, nonlinear models often require a numerical calibration of nonlinear parameters. Simplified Finite Element (FE) models, with some very simple assumptions, can be more suitable for complex problems like as the interaction between adjacent building aggregates. The low initial knowledge level in the SERA AIMS blind competition favored simple assumptions. The availability of simple models allowed to perform consecutive time histories including the cumulative effects of previous signals. In fact, the tested prototype was subjected to many replicas. The masonry structure and the crucial interfaces between the units have been modelled by means of nonlinear elements according to the reduced knowledge level at the blind prediction stage. The main goal was to estimate the key information of a masonry building under seismic action like as: triggering and the type of damage at the most stressed areas and therefore the load threshold at which evident damage is expected. Global FE model provides information on the global behaviour (in plane behaviour), while, according to the failure models typically found in masonry buildings, kinematic analyses have been performed to assess the out of plane (local) behaviour, too. The numerical results obtained by the preliminary analysis have been compared with the experimentally detected damages. The simplified approach, based on limited information without calibration, discussed in this paper, represents a useful support tool to design dynamic tests on full-scale or scaled masonry buildings, but also to assess the vulnerability of real masonry structures. [ABSTRACT FROM AUTHOR]

Strong seismic events frequently strike Chile. The last three significant events that caused considerable damage and losses are the 2010 ( M w 8.8, Maule), 2014 ( M w 8.2, Iquique), and 2015 ( M w 8.3, Illapel) earthquakes. Therefore, reliable fragility curves are necessary to evaluate the threat of earthquakes to the built environment. This study aims to develop empirical fragility curves of Chilean houses using damage from the 2014 and 2015 earthquakes. The data from 9085 and 7431 damaged houses from the 2014 and 2015 earthquakes, respectively, was obtained by the government. The fragility curves were estimated for reinforced concrete, reinforced masonry, timber, and adobe houses. Additionally, the fragility curves were constructed using three different Peak Ground Acceleration (PGA) maps to quantify the variation of the fragility parameters based on the selected PGA map and to identify which PGA map generates the highest correlation with observed damage. Additionally, fragility curves obtained in this study are compared with curves from other studies. The median θ values of the fragility curves obtained in this study are larger than those from other reported studies. [ABSTRACT FROM AUTHOR]

The research deals with an interesting interdisciplinary case study for the knowledge and dissemination of masonry sail vaults in Malta between the 16th and the 17th centuries. In particular, it focuses on the sail vaults of the Magistral Palace, which have a distinctive structure. Based on a digital survey, the necessary data was extrapolated to critically analyse the geometry, through drawing and three-dimensional modelling. The paper, therefore, presents graphical and geometric investigations, which complement the study of the history of the Magistral Palace. Comparisons with the Maltese architectural context between the 16th and 17th centuries show the use of different solutions for the construction of sail vaults, according to different geometries. This implies knowledge of the international debate on the theory of stonecutting at the time. [ABSTRACT FROM AUTHOR]

Medieval defensive walls are a distinctive feature of Italian cultural heritage. These structures testify the origins of historical centres and, in some cases, the consequences of the events occurred over time. The typical configuration of medieval defensive walls, generally characterized by high slenderness ratios, out-of-plumb, the absence of deep and adequate foundations, made these elements particularly vulnerable toward seismic actions. This study focused on the assessment of the seismic safety of Italian medieval defensive walls toward out-of-plane failure mechanisms induced by seismic actions. To this end, a simple approach based on the use of generalized dimensionless capacity curves is presented. These curves, derived by the Authors from a calibration process involving a set of selected real cases, allows for a rapid preliminary seismic assessment of masonry walls particularly useful for getting an initial idea of the condition of the walls with respect to seismic actions also considering the presence of pre-existing out-of-plumb configurations. The proposed approach has been applied in the paper to the real case study of medieval walls of Cittadella, a town in northern Italy, considering the pre-existing out-of-plumb configuration. The obtained results have shown the vulnerability of these walls in case of occurrence of masonry disaggregation and, consequently, the importance of performing specific surveys finalized to investigate this phenomenon. The application of the proposed approach has clearly shown its feasibility and usefulness for the seismic evaluation. Moreover, the comparison with the corresponding results obtained by using the actual capacity curves, rather than the generalized ones, has underlined its good level of reliability. [ABSTRACT FROM AUTHOR]

Accurate and timely data collection of material deterioration on the surfaces of architectural heritage is crucial for effective conservation and restoration. Traditional methods rely heavily on extensive field surveys and manual feature identification, which are significantly affected by objective conditions and subjective factors. While machine vision-based methods can help address these issues, the accuracy, intelligence, and systematic nature of material deterioration assessment for large-scale masonry towers with complex geometries still require significant improvement. This research focuses on the architectural heritage of masonry towers and proposes an intelligent assessment system that integrates an improved YOLOv8-seg machine vision image segmentation model with refined 3D reconstruction technology. By optimizing the YOLOv8-seg model, the system enhances the extraction capabilities of both detailed and global features of material deterioration in masonry towers. Furthermore, by complementing it with image processing methods for the global visualization of large-scale objects, this research constructs a comprehensive intelligent assessment process that includes "deterioration feature extraction—global visualization—quantitative and qualitative comprehensive assessment." Experimental results demonstrate that the intelligent assessment system significantly improves the performance of target feature extraction for material deterioration in masonry towers compared to existing methods. The improved model shows improvements of 3.39% and 4.55% in the key performance metrics of mAP50 and mAP50-95, respectively, over the baseline model. Additionally, the efficiency of global feature extraction and visualization of material deterioration increased by 66.36%, with an average recognition accuracy of 95.78%. Consequently, this system effectively overcomes the limitations and subjective influences of field surveys, enhancing the objectivity and efficiency of identifying and analyzing material deterioration in masonry towers, and providing invaluable data support for the subsequent preservation and restoration efforts. [ABSTRACT FROM AUTHOR]

In a recent work, we evidenced some empirical discrepancies between the macroseismic intensity estimates in Italy in the last decade with respect to those made previously. A possible reason might be the progressive adoption by Italian researchers of the European Macroseismic Scale (EMS) in place of the Mercalli Cancani Sieberg (MCS) scale mostly used up to 2009. In theory, in modern settlements where reinforced concrete (RC) buildings are increasingly replacing those in masonry, EMS should overestimate MCS because the former accounts for the lower vulnerability of RC whereas the latter does not because RC buildings were not considered at all by the MCS scale since they were almost absent at the time (1912–1932) when it was compiled by Sieberg. However, such theoretical inference is contradicted by the empirical evidence that, on average, MCS intensities really estimated in Italy over the past decade slightly overestimate EMS and not vice versa as it should be. A possible explanation is that the EMS scale had not been well calibrated to reproduce the MCS, as its authors intended to do. Another possible reason for the discrepancies between the last decade and the previous ones might be that the MCS scale applied today is not the same as that defined by Sieberg at the beginning of the twentieth century. In order to better understand the possible causes of such discrepancies, we present here a formal comparison between the definitions of the different degrees of such macroseismic scales. After such analysis, we might argue that another possible reason for the observed discrepancy may come from the inaccurate assessment of building vulnerability when assessing the EMS intensity. [ABSTRACT FROM AUTHOR]

The proposed research work presents a comprehensive approach to assessing the seismic vulnerability of archaeological sites. This approach aims to be a quick and easy-to-use investigation procedure that enables accurate and large-scale evaluations. While the methods employed are well-established in the literature and have been widely applied to buildings, this study contributes by proposing a structured framework that integrates different assessment procedures at different levels of analysis, specifically tailored to archaeological sites. The analysis is divided into three stages within the conceptual framework: (i) the application of the Masonry Quality Index; (ii) seismic vulnerability assessment and prediction of expected damage; and (iii) analysis of individual walls' structural response through strength domain, capacity and fragility curves. Specifically, the study explores and adapts four Vulnerability Index methods, i.e. GNDT, Formisano, Vicente and Ferreira methods, to suit the specific characteristics of archaeological sites. To this end, a simplified procedure is proposed to estimate the conventional strength in the methods' forms. The comparison of the index-based methods is then crucial for critically evaluating the reliability of vulnerability estimations. The paper illustrates the application of this framework through a detailed case study, i.e. the archaeological site of Wupatki Pueblo in Arizona (US), demonstrating its effectiveness in evaluating the seismic risk and defining the vulnerability distribution of the site. Consequently, this approach facilitates the identification of the most sensitive areas, which necessitate further investigation, providing useful outcomes for the decision-making process concerning the conservation and protection of archaeological sites. [ABSTRACT FROM AUTHOR]

This paper presents verification of the numerical model of masonry infill walls against the experimental results. Three cases are investigated: an undamaged model, a damaged model, and a carbon fiber-reinforced polymer (CFRP) strip. ABAQUS commercial finite element model (FEM) software was used in the modeling. Nonlinear behavior as well as cracking and crushing of masonry bricks were simulated using the Concrete Damaged Plasticity (CDP) model. To solve this, a three-dimensional simplified micro-model was used. Experimental and simulation of the hysteresis curve, skeleton curve, damage patterns, maximum and minimum stresses, and plane strain distribution were compared. The changes in natural frequencies, and mode shapes before and after CFRP strengthening masonry wall are evaluated. A sensitivity analysis was done to study the effect of damage and strengthening on the nonlinear behavior of steel frames with masonry infill. This investigation demonstrated that the numerical model was able to effectively simulate and predict the strength of these models. Then a look at the effect on seismic performance is reported and commented on. [ABSTRACT FROM AUTHOR]

This paper presents the outcomes of a comprehensive experimental investigation aimed at characterizing the in-plane shear strength of Unreinforced Masonry (URM) wallettes subjected to diagonal compression. The study focuses on the strengthening of these wallettes using precast Ultra-High Performance Concrete (UHPC) diagonal strips, externally bonded onto the wall substrates through high-strength epoxy mortar. Twenty-three wallettes, each measuring 1000 mm × 1000 mm × 70 mm, were meticulously constructed and subjected to in-plane diagonal compression. Among these, eighteen wallettes underwent strengthening utilizing various configurations of UHPC, with a key emphasis on variables such as UHPC strip width and thickness, substrate nature, and corner confinement with enlarged UHPC rectangular plates. Findings from the experimental program highlighted the significant influence of UHPC retrofit parameters on the wallettes performance. Notably, corner confinement emerged as an effective strategy against premature toe crushing failure, enhancing the wallettes ability to withstand higher in-plane compressive loads. While UHPC strip width exhibited moderate impact, UHPC strip thickness emerged as a dominant factor. Increasing strip width from 100 to 250 mm yielded an approximate 8% shear strength improvement, whereas doubling strip thickness from 10 to 20 mm led to a substantial 27% enhancement. Notably, enhanced strip width demonstrated pronounced benefits in terms of ductility and energy dissipation capacity. Excessive UHPC retrofit thickness induced brittle failure despite escalating shear strength. Conversely, thinner UHPC retrofits achieved a favorable balance between strength, ductility, and energy dissipation. Wallettes retrofitted with 5 mm UHPC exhibited an impressive 2.36-fold shear strength increase compared to reference walls, while those with 10 mm and 20 mm UHPC retrofits experienced 2.14 and 2.78-fold improvements, respectively. Furthermore, the manner of UHPC application significantly influenced the strengthening system's behaviour. For identical strengthening layouts, the direct bonding of UHPC onto masonry substrates resulted in a 25% increase in shear strength compared to UHPC bonding onto plaster overlays. [ABSTRACT FROM AUTHOR]

The precise prediction of the fundamental vibrational period for reinforced concrete (RC) buildings with infilled walls is essential for structural design, especially earthquake-resistant design. Machine learning models from previous studies, while boasting commendable accuracy in predicting the fundamental period, exhibit vulnerabilities due to lengthy training times and inherent dependence on pre-trained models, especially when engaging with continually evolving data sets. This predicament emphasizes the necessity for a model that adeptly balances predictive accuracy with robust adaptability and swift data training. The latter should include consistent re-training ability as demanded by real-time, continuously updated data sets. This research implements an optimized Light Gradient Boosting Machine (LightGBM) model, highlighting its augmented predictive capabilities, realized through the astute use of Bayesian Optimization for hyperparameter tuning on the FP4026 research data set, and illuminating its adaptability and efficiency in predictive modeling. The results show that the R2 score of LightGBM model is 0.9995 and RMSE is 0.0178, while training speed is 23.2 times faster than that offered by XGBoost and 45.5 times faster than for Gradient Boosting. Furthermore, this study introduces a practical application through a streamlit-powered, web-based dashboard, enabling engineers to effortlessly utilize and augment the model, contributing data and ensuring precise fundamental period predictions, effectively bridging scholarly research and practical applications. [ABSTRACT FROM AUTHOR]

As a material masonry is anisotropic in nature as it is constituted of various components that differ each other in many ways. Though, the ideas of modeling of concrete are also valid for masonry, still there are difficulties in determining the exact behavior of masonry. The micro modeling (simplified) approach has been adopted in this study for modeling masonry samples subjected to various nature of loadings. The brick masonry units were modeled as discrete elements and linked together by interface element. The coulomb friction model was used to describe the interface element as mortar joint. Damage was assumed to be governed by the compressive strength of both the constituents i.e., mortar and brick. The mechanical properties of the masonry samples were determined by means of variety of tests and those properties then served as input parameters in the constitutive model. The results clearly indicate that numerical model predicted the behavior of the experimentally tested samples, in compression as well as tension prims for both unconfined and confined cases. The proposed model is suitable for modeling any type of brick masonry walls. [ABSTRACT FROM AUTHOR]

Up to the beginning of the twenty-first century, most of quasi-brittle structures, in particular the ones composed by concrete or masonry frames and walls, were designed and built according to codes that totally ignored fracture mechanics theory. The structural load capacity predicted by strength-based theories, such as plastic analysis and limit analysis, do not exhibit size-effect. Within the framework of fracture mechanics theory, this paper deals with the analysis of the effect of non proportional loadings on the strength reduction with the structural scaling. In particular, this study investigates the size-effect of quasi-brittle materials subjected to self-weight. Although omnipresent, gravity-load is often considered negligible in most studies in the field of fracture mechanics. This assumption is obviously not valid for large structures and in particular for geometries in which the dead load is a major driving force leading to fracture and structural failure. In this study, an analytical formulation expressing the relation between the strength-reduction and the structural scaling and accounting for self-weight, was derived for both notched and unnotched bodies. More specifically, a closed form expression for size and self-weight effects was first derived for notched specimens from equivalent linear elastic fracture mechanics. Next, equivalent linear elastic fracture mechanics theory being not applicable to unnotched bodies, a cohesive model formulation was considered. Particularly, the cohesive size effect curve and the generalized cohesive size effect curves, originally obtained via cohesive crack analysis for weightless bodies with sharp and blunt/unnotched notches, respectively, were equipped of an additional term to account for the effect of gravity. All the resulting formulas were compared with the predictions of numerical simulation resulting from the adoption of the Lattice Discrete Particle Model. The results point out that the analytical formulas match very well the results of the numerical model for both notched and unnotched samples. Furthermore, the analytical formulas predict a vertical asymptote for increasing size, in the typical double-logarithm strength versus structural size representation. The asymptote corresponds to a characteristic size at which the structure fails under its own weight. For large structural sizes approaching this characteristic size, the newly developed formulas deviate significantly from previously proposed size-effect formulas. The practical relevance of this finding was demonstrated by analyzing size and self-weight effect for several quasi-brittle materials such as concrete, wood, limestone and carbon composites. Most importantly, the proposed formulas were applied to the failure of semi-circular masonry arches under spreading supports with different slenderness ratios. Results show that analytical formulas well predict numerical simulations and, above all, that for vaulted structures it is mandatory accounting for the effect of self-weight. [ABSTRACT FROM AUTHOR]

The paper presents a novel optimization framework aimed at the minimization of seismic retrofitting-related costs for existing unreinforced masonry building structures. The framework provides topology optimization of reinforcements (reinforced plasters) to implement in masonry walls for the accomplishment of seismic safety checks under the reference seismic load combinations. Optimization is carried out by a genetic algorithm (GA) developed in MATLAB®, which controls a 3D finite element equivalent frame model of the masonry structure developed in OpenSees. The GA routine iterates the reinforcement configurations employing specific genetic operators. The feasibility of each candidate retrofitting solution is assessed by performing in-plane shear and flexural safety checks of masonry walls. The framework is finally tested with a case study masonry structure supposed to be made of average-quality or poor-quality masonry. Results will show that the proposed framework can effectively provide the minimization of seismic retrofitting costs for existing masonry structures, giving as output the optimal configuration of the reinforcements within the structural layout. [ABSTRACT FROM AUTHOR]

To overcome negative effects of traditional masonry infilling walls (MIWs) on the seismic resilience of a self-centering prestressed concrete (SCPC) frame, a novel SCPC frame with sliding infill walls (SCPC-SIW frame) is proposed. This study compares the seismic performance of the SCPC-SIW frame and the SCPC frame with MIWs (SCPC-MIW frame) through quasi-static tests, fragility analysis, and risk assessment. To begin, quasi-static tests on single-story SCPC-SIW and SCPC-MIW frame specimens are performed to compare their failure characteristics, hysteresis response, energy dissipation, and self-centering ability. The numerical simulation methods for SCPC-SIW and SCPC-MIW frame specimens are then presented and validated. Subsequently, two four-story SCPC-SIW frames and two four-story SCPC-MIW frames are designed, and their dynamic response under MCE is preliminary analyzed. Finally, the fragility analysis and risk assessment of these multi-story SCPC-SIW and SCPC-MIW frames are conducted to determine the probability of their peak inter-story drift ratio (PIDR), residual inter-story drift ratio (RIDR), and peak floor acceleration (PFA) exceeding the specified limit states under any intensity earthquake and within 50 years. The results indicate that, except for cracks caused by fatigue damage appearing on the SIW at the end of loading, the SCPC-SIW frame specimen remains undamaged, whereas the SCPC-MIW frame specimen exhibits diagonal step cracks on the MIW. The hysteresis curve of the SCPC-SIW frame specimen exhibits an ideal and repeatable flag shape, whereas the stiffness and strength of the SCPC-MIW frame specimen degrade during the test. Besides, the probability of exceeding the 4% PIDR and exceeding 0.2% and 0.5% RIDRs within 50 years for the SCPC-SIW frame is significantly lower than that for the SCPC-MIW frame. The SCPC25-MIW frame has a higher probability of exceeding the 1 g PFA within 50 years than the SCPC25-MIW frame. In other cases, the SCPC-SIW frame has a lower probability of exceeding 1 g, 2 g, and 3 g PFA within 50 years than the SCPC-MIW frame. [ABSTRACT FROM AUTHOR]

In unreinforced masonry structures, among the most dangerous events that can occur during earthquakes are the out-of-plane mechanisms. This type of response significantly changes if the wall is restrained by a horizontal element. The collapse, in this case, could take place for slipping/failure of the diaphragm connection or for overturning of the wall, following the formation of a crack at an intermediate height between the base and the top. A specific analytical model is used to capture the complex dynamic behavior of the wall, formed by two stacked rigid bodies (free to rock) with the top one connected to a flexible diaphragm. The model is calibrated using experimental data available in the literature and it is then used to carry out a dynamic parametric analysis. The variation range of relevant parameters refers to the building features surveyed in Emilia-Romagna region, Italy, and their effect on the global response of the system is investigated. Further, the influence of ground motion is considered, using different ground accelerations. The results of the analysis highlight that, for the considered area and return period, the maximum rotations of the system are significant only for large slenderness values. Further, the investigation shows that the diaphragm plays a crucial role in the dynamic response of the system. The stiffness of the diaphragm can significantly reduce the rotations and consequently the risk of overturning. Additionally, the study on the effect of the wall size pointed out how a top spring causes a reverse scale effect. [ABSTRACT FROM AUTHOR]

Architected porosity in masonry structures can be created by transforming stock materials into a lattice of interlocking units through an automated batch process. Porous masonry forms numerous enclosed cavities for thermal performance and reduces material usage while maintaining structural integrity. This work investigates the potential and limits of digital tectonics of porous masonry through a complete process of design, manufacturing, and construction. The confluence of digital fabrication with tectonic exploration opens new dimensions unattainable by traditional stereotomy. Interlocking materials inspired by Abeille vault and digital stereotomy have made rapid progress. Following the theory of poetic construction, this work proposes that masonry construction should evoke visual or haptic enhancement through the fulfillment of pragmatic functions. We formulated a design challenge for a confined dry masonry wall for the envelope of the 2226 building. It assumes batch-cutting bespoke units out of large blocks of high-strength foam. Through a process of cutting and reassembling, the stock material is topologically expanded into a porous structure. A series of prototypes were developed to explore novel articulation, structural and thermal performance, and economical manufacturing. One can perceive the logic of porous construction through visual and haptic empathy. The materialization process interacts with the design masonry units and the interlocking mechanism. For future practice in masonry, the porosity should be planned at multiple scales (molecular scale, aggerate scale, construction scale) across the life cycle of the material. [ABSTRACT FROM AUTHOR]

The primary fine aggregate in cementitious construction is often natural sand or river sand. The construction of masonry blocks, in particular, necessitates using sand as a primary raw material, including a significant proportion ranging from 70 to 90%. The demand for river sand is seeing substantial growth. However, the availability of high-quality river sand is constrained due to regulations imposed on sand extraction from river beds. The adverse environmental repercussions have arisen due to the over-mining of river sand in response to the growing demand. The researchers were motivated by the ongoing challenges to seek a viable and environmentally friendly substitute for river sand. In contrast, Construction and Demolition (C&D) waste is a major environmental issue due to its high volume, potential for hazardous materials, and potential for release of pollutants into the environment. The current study examined the viability of using three specific forms of C&D waste derived from masonry structures as substitutes for river sand in cement mortar production. Cement mortar was made and tested, each with varying C&D waste composition levels of 25, 50, and 75% as sand replacement. The examination included the assessment of physical, mechanical, and durability characteristics. The results suggest that the cement mortar with C&D had better dry and wet compressive strength and equivalent flexural and impact strength to the control mortar. The cement mortar containing C&D waste, excluding concrete block waste, absorbs more water than the control mortar. Only cement mortar with fired clay brick waste shows a minor reduction in strength to acid and alkaline chemicals, comparable to the control mortar. Findings show that C&D waste improves cement mortar strength. However, cement mortar durability remains a concern. [ABSTRACT FROM AUTHOR]

To predict the response of masonry buildings to various types of loads, engineers use finite element models, specifically solid-element and macro-element models. For predicting masonry responses to seismic events in particular, equivalent frame models—a subcategory of macro-element models—are a common choice because of their low computational cost. However, an existing bottleneck in modeling pipelines is generating the geometry of the model, which is currently a slow and laborious process that is done manually using computer-aided design tools. In this paper, we address this by automating the modelling process using recent advancements in computer vision and machine learning. We present an image-based end-to-end pipeline that automatically generates finite element meshes for solid-element and equivalent-frame models of the outer walls of free-standing historical masonry buildings. As the input, our framework requires RGB images of the buildings that are processed using structure-from-motion algorithms, which create 3D geometries, and convolutional neural networks, which segment the openings and their corners. These layers are then combined to generate level of detail models. We tested our pipeline on structures with irregular surface geometries and opening layouts. While generating the solid element mesh from the level of detail model is straightforward, generating equivalent frame models required algorithms for segmenting the façade and the meshing. Experts in the field analyzed the generated equivalent frame models and determined them to be useful for numerical modeling. These finite element geometries will be invaluable for future predictions of the seismic response of damaged and undamaged buildings. The codes and dataset are publicly available for future studies and benchmarking (https://github.com/eesd-epfl/FEM%5fbuildings and https://doi.org/10.5281/zenodo.8094306). [ABSTRACT FROM AUTHOR]

Model updating procedures based on experimental data are commonly used in case of historic buildings to identify numerical models that are subsequently employed to assess their structural behaviour. The reliability of these models is closely related to their ability to account for all the uncertainties that are involved in the knowledge process. In this regard, to handle these uncertainties and quantify their propagation, Bayesian inference is frequently employed being able to deal with the effects of parameter uncertainty, observation errors and model inadequacy. The computation of the posterior distribution through Bayesian inference needs–however–the evaluation of the likelihood function, which requires solving complex multi-dimensional integration problems. To bridge this shortcoming, the paper compares two Bayesian inference approaches to show how different approximations affect the results of simulated inference: a discrete approach for the likelihood computation in the Bayesian Model Updating (BMU) and a Monte Carlo likelihood-free method known as Approximate Bayesian Computation (ABC) are reported. As reference, the typology of historic masonry towers was considered by using their natural frequencies as experimental data for model updating. The two procedures provide very similar results supporting the validity of both methods despite ABC turns out to be a more flexible approach. [ABSTRACT FROM AUTHOR]

Adding a reinforced stucco layer to the masonry infill walls is a preferred method for strengthening RC frame system structures with an easy-to-apply method that does not require a long time, is economical, and does not require detailed and extensive workmanship. However, no research has been discovered as a result of the extensive literature review that investigates the effects of masonry-infilled RC frames strengthened with a reinforced stucco layer on the seismic performance of openings that must be due to architectural requirements such as doors, windows, installations, and similar ventilation systems. As a result, an experimental study was planned to investigate the effects of the dimensions and location of the opening in the masonry infill walls on the performance of the strengthening method with the reinforced stucco layer. The applied strengthening method increased the ultimate load capacity, initial stiffness, and energy dissipation capacity values of reinforced concrete frames with masonry infill walls by 83%, 226%, and 62%, respectively, but resulted in a 38% decrease in displacement-ductility ratios. The study found that the openings in the masonry infill walls harm the performance of the strengthening technique by adding a rebar-reinforced stucco layer and decreasing the success level. When the opening size increased, and the opening was located at the corner of the masonry wall, the performance of the applied strengthening technique was negatively affected and decreased. Furthermore, nonlinear numerical analyses of the experiments conducted as part of the study were performed using ABAQUS finite element software. The numerical analysis results were compared to the experimental results. It has been determined whether numerical analysis models are compatible with experimental results. [ABSTRACT FROM AUTHOR]

Seismic risk estimation for urban building clusters is essential when developing regional seismic resilience models. A masonry structure is a type of building with a large stock, broad applicability, and simplified construction technology. The traditional seismic intensity measures and fuzzy quantification of structural vulnerability levels result in low accuracy in estimating and predicting seismic damage to masonry structure clusters. This paper proposes a method for evaluating bivariate seismic intensity measure. Nonlinear dynamic and spectral analyses were conducted on real acceleration records monitored by ten stations during the Wenchuan earthquake in Sichuan, China, on May 12, 2008. The outdated seismic vulnerability level of masonry structures is updated, and an optimized structural seismic risk model based on the seismic damage database of 2407 masonry structures in Dujiangyan city under the influence of the Wenchuan earthquake is established. An innovative seismic risk membership index algorithm was developed, and a vulnerability curve was generated for masonry structures considering multiple risk membership indices. An improved seismic risk index calculation function is proposed using the proposed updated vulnerability level, and the seismic risk index curve and stripe model of typical urban masonry building clusters are established. According to the field investigation of the actual structures in Dujiangyan city affected by the Wenchuan earthquake, the typical failure features and disaster mechanism of masonry structures are reported and analysed, and measures and methods to improve and enhance the seismic capacity of such buildings are proposed. The developed seismic risk model for urban masonry structures can contribute positively to the development of relatively accurate seismic resilience models for urban buildings and can improve the accuracy of seismic risk estimation for masonry structures. [ABSTRACT FROM AUTHOR]

This study provides a discussion using a database of historic masonry bell towers struck by past Italian earthquakes, which is the result of an extensive literature review on post-earthquake reconnaissance reports and scientific publications. The observed damage is analysed to give an insight into the seismic behaviour and vulnerability of this peculiar building typology. To this end, a macro-scale approach is adopted, two distinct damage mechanisms are identified and evaluated, and a damage index for each tower is computed. This enables to develop the damage probability matrices, providing the frequency of damage occurrence. Moreover, vulnerability and fragility curves are derived to help the prediction of future possible damage scenarios. The developed vulnerability and fragility curves are compared with the mean damage observed in the samples included in the database. This comparison allowed to check the robustness of rapid procedures today available in the field of seismic risk assessment for the specific case of historic masonry towers. [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]

The paper reports on four cyclic tests of brick masonry spandrels in reference state and strengthened state. The tests were carried out on full-scale, H-shaped masonry panels to investigate the coupling role of the spandrel in connecting two piers in a historical masonry wall subjected to in-plane lateral actions. Two 250-mm-thick solid-brick masonry samples were tested—one single-leaf, the other two-leaves masonry. Both samples were tested before and after strengthening by applying a Composite Reinforced Mortar (CRM) coating on one surface. The CRM coating consisted of a lime mortar coating (nominal thickness = 30 mm), reinforced with mesh made of Glass Fibre-Reinforced Polymer (GFRP) that was anchored to the wall by GFRP transverse connectors. For the double-leaf masonry, there were additional transverse connectors made of steel bars in concrete cores (artificial diatones) to prevent masonry leaves separation and to improve the bonding of the CRM coating to the masonry. The test responses are compared in terms of crack pattern, failure mode, resistance, displacement and energy dissipation capacity. The tests showed the effectiveness of the proposed CRM system, which increased the spandrel resistance by 33% and 125% in the single—and double-leaf masonry, respectively, with the ultimate drift being 3.2% (one order of magnitude greater than for the unstrengthened reference samples). Data on energy dissipation and the equivalent viscous damping are also collected and compared. Importantly, the presence of the reinforcing mesh and the composite action of the coating and the wall changed the damage evolution and response mechanism, which resulted in a much better seismic response. [ABSTRACT FROM AUTHOR]

Based on experiments and micro-modelling analyses, the interaction between the RC frame and the infill wall with/without openings under lateral loads was investigated. According to the load transmission mechanism and the stress states around the openings, a macro-model with multiple blocks around the opening was proposed. In a comparison with the experimental data, the proposed macro-model was proven to adequately simulate the different failure modes and hysteretic behaviours of masonry infilled RC frames with openings. By using the opening rate and opening position as variables, 52 macro-modelling analyses of masonry infilled RC frames with different window and door openings were carried out. The results showed that the presence of masonry infill walls greatly increased the initial stiffness and ultimate load bearing capacities of single-story, single-bay RC frame structures. A larger opening rate resulted in lower initial stiffness and ultimate load-carrying capacity values, which decreased more as the opening locations deviated further from the centre to the sides. [ABSTRACT FROM AUTHOR]

Fabric-reinforced cementitious matrix (FRCM) materials are increasingly common for strengthening existing masonry structures. The constitutive behaviour of these materials is complex to model due to the inner complex mechanisms that develop in composite mechanics, such as stress transfer between matrix and fabric, mortar cracking, friction at the matrix-to-fabric interface, and bonding with the substrate. This paper aims to address these phenomena by presenting a numerical approach able to predict the bond behaviour of FRCM-to-masonry systems through the use of simple truss elements and nonlinear springs to simulate the fabric-to-matrix and composite-to-substrate interactions. The model was implemented in an open-source environment and allowed direct sensitivity analysis to assess the role of the constitutive variables. The comparisons between the results of the numerical approach and experimental responses show that the proposed methodology is an effective and easy tool to predict the mechanical behaviour of FRCM composites, with a reduced computational effort. [ABSTRACT FROM AUTHOR]

The preservation and the safety of historic centers is certainly related to a large-scale assessment of the seismic vulnerability of their buildings. In this regard, fragility curves represent one of the most effective and widely used tools. Different methods, based on empirical, analytical and hybrid approaches, can be employed for deriving the fragility curves. Regarding the analytical-based fragility curves, their reliability is strongly influenced by the knowledge of the typological and structural features of the buildings, including constructive details, as well as by the evaluation of the seismic input, as evidenced in recent studies. This paper proposes an approach for evaluating the fragility curves of URM buildings towards OOP failure modes. The focus on OOP failure modes relies on the fact that in the past and more recent seismic events, most ordinary UnReinforced Masonry (URM) buildings in historic centres have shown to be particularly vulnerable to Out-Of-Plane (OOP) failure modes. The proposed approach combines the knowledge process concerning the typological and structural features of the buildings, with the analytical derivation of the fragility curves throughout an integrated multistep approach. In addition, the study also investigates the influence of the seismic input. The approach is discussed in detail in the first part of the paper and, in the second part of the paper, it is applied to the building stock of an Italian historic centre. [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]

The behaviour of masonry infilled RC frames, with and without openings, subjected to both in-plane (IP) and out-of-plane (OoP) shear loading, indicates the most unfavourable shear (seismic) design condition. A series of calibrated computational micromodels of previously tested 1/2.5 scaled single-bay and single-story RC frames with masonry infill walls, were employed to investigate the effect of openings of various type, size and position, on structure's shear resistance under different IP and OoP load combinations. The load combination was characterised by an angle α of the IP (or OoP) resultant force, ranging from 0° to 90°. Considered were walls with centrically or eccentrically positioned door or window opening, of an opening to wall area ratio Ao/Ai = 0.1–0.3, walls without openings, and frame without wall i.e. bare frame. A total of 252 models were considered. The obtained behaviour revealed the specific load resisting mechanisms and accompanying failure modes. The IP–OoP shear resistance interaction curves and surfaces were constructed with regard to load direction α and opening to wall area ratio Ao/Ai. Considering these criteria, the IP–OoP shear resistance estimation functions were derived in order to improve the existing shear (seismic) design methodologies of masonry infilled RC frames. [ABSTRACT FROM AUTHOR]

This article presents a sophisticated approach to updating the finite element model of two historical arch masonry bridges located in the challenging terrain of Kalka Shimla mountain railway, using vibration testing results. To estimate the dynamic characteristics of the bridges, ambient vibration testing was carried out. Next, initial finite element models of the bridges were developed based on geometrical survey data. Sensitivity analysis was used to determine which parameters needed to be modified for the bridges. The response surface method and global optimization techniques were employed to identify the optimal values of structural parameters that would result in a satisfactory agreement between the numerical and measured natural frequencies of the heritage bridges. Ultimately, the methodology provided a surrogate mathematical model to represent the relationship between structural parameters and dynamic response, and could predict the damage status of the historical bridges. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study carried out to assess the probable seismic loss, in terms of damage to residential buildings, in the case of the west segment of the North Tehran Fault (NTF) seismic scenario in Karaj, Iran. Accordingly, it is crucial to first properly estimate the ground motion intensities. However, most of empirical ground motion prediction equations are poorly constrained at short ranges, and the data may only partially account for the rupture process. Hence, the stochastic finite-fault method with dynamic corner frequency was applied. This is an appropriate tool for addressing source, path, and near-source effects. It is noted that this method is dependent on many parameters which should be properly tuned. Thus, a set of sensitivity analyzes for the hypocenter locations and the quality factors were performed. The results from the simulations were used to develop a curve for estimating the ground motion values. Then, a high-quality building exposure model composed of 26 building classes based on the most recent census data was compiled. Finally, by applying appropriate fragility curves, damages to buildings from potential earthquakes were assessed. The outcomes showed that the mean damage ratio for the whole of the city is about 18.2% ± 5.3. In addition, a disaggregation analysis is done to identify the most vulnerable building types. The results showed that adobe and low-quality masonry buildings contribute the most to loss. The findings from this study can be used to provide risk reduction plans in Karaj. [ABSTRACT FROM AUTHOR]

The construction industry currently aims to reduce its environmental impact while adopting to sustainable practices. One solution is using reusable building components. Osteomorphic blocks, a topologically interlocking system, offer advantages like eliminating mortar and increasing the flexibility of design arrangements, making them a promising solution. This paper presents an approach that integrates design and performance analysis to develop a sustainable masonry system using osteomorphic blocks. Finite element analysis is employed to optimize block's shapes and efficiency. The study emphasizes distinct characteristics of osteomorphic systems, demonstrating their potential to create adaptable and durable masonry structures. This study promotes osteomorphic blocks as mortarless masonry system for waste reduction and circular economies. Through this research, designers and architects can create osteomorphic block masonry systems that are both aesthetically pleasing and well-performing. [ABSTRACT FROM AUTHOR]

This paper presents an algorithm to solve a non-linear rectangular cross-section analysis by means of closed form equations. The equations are provided in a dimensionless form in order to provide generalizable results. The algorithm is based on the direct integration of the non-linear constitutive behaviour of the materials into the stress-block constitutive behaviour. The algorithm is based on masonry rectangular cross-sections characterized by an external axial load similar to Reinforced-Concrete cross-sections. The failure of the strengthening system and the masonry are analysed in the proposed algorithm, in an unconventional manner, analysing the behaviour even after the attainment of the ultimate strains, accounting for progressive damage. The algorithm allows to prevent the cross-section fiber analysis and the consequential iterative procedure to retrieve the neutral axis depth. Furthermore, the direct integration allows to evaluate the exact solution of the problem without numerical approximations. The results are discussed by means of several parametric analyses in terms of P–M domains and bending moment–curvature diagrams in dimensionless form. The proposed approach aims to simplify the cross-section analysis process in complex algorithms as in the risk analysis based on a large scale approach, where a large number of structures and structural members are analysed in the vulnerability process. [ABSTRACT FROM AUTHOR]

This paper proposes an effective approach to realise circular construction with concrete, and shows Unreinforced Masonry as a foundational building block for it. The paper outlines the importance of circularity in building structures. It specifically focuses on the impact of circular construction with concrete on improving the sustainability of the built environment in a rapidly urbanising world economy. Subsequently, the relevance of principles of structural design and construction of unreinforced masonry to achieve circularity is articulated. Furthermore, the paper presents and summarises recent developments in the field of Unreinforced Concrete Masonry (URCM) including digital design tools to synthesise structurally efficient shapes, and low-waste digital fabrication techniques using lower-embodied-emission materials to realise the designed shapes. The paper exemplifies these using two physically realised, full-scale URCM footbridge prototypes and a commercially available, mass-customisable building floor element, called the Rippmann Floor System (RFS). The paper also outlines the benefits of mainstream, industrial-scale adoption of the design and construction technologies for URCM, including accelerating the pathway to decarbonise the concrete industry. In summary, the paper argues that URCM provides a solution to significantly mitigate the carbon emissions associated with concrete and reduce the use of virgin resources whilst retaining its benefits such as widespread and cheap availability, endurance, fire safety, low maintenance requirements and recyclability. [ABSTRACT FROM AUTHOR]

The effect of a supports settlement in a symmetric masonry arch is studied by modeling the arch as a system of rigid plastic blocks with frictional sliding. It is shown that in a collapse state due to a horizontal settlement the thrust attains its minimum statically admissible value, so extending to the case of frictional sliding a well-known result of standard limit analysis, which considers collapse states only due to the opening of joints. The case of both vertical and horizontal settlements is also analyzed. It is demonstrated that the collapse thrust in case of horizontal settlement is a lower bound for the collapse thrust in case of generic settlement. Extensive numerical analyses illustrate the above results. [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]

This study presents a comprehensive investigation of the in-plane response of unreinforced masonry shear walls with regular openings, under the action of monotonic lateral displacement. Walls are considered with several pre-compression loads as well as different window and door openings configurations. To this end, a group of masonry shear walls built with clay bricks and hydraulic lime-sand mortar was selected featuring regular opening layouts. The micro-modeling approach was utilized by considering complex constitutive laws for materials' nonlinear behavior for capturing damages in elements. Results from the nonlinear analysis of the walls were obtained, including the lateral load capacity of shear walls at different performance points, their lateral displacement, stiffness, ductility capacity, normalized absorbed energy, and the overstrength, force reduction, and response modification factors. Moreover, a full discussion is presented regarding the estimating equations from the ASCE 41–17 code on the maximum shear capacity of the walls including their accuracy to predict the shear capacity of URM walls with openings. It is observed that opening reduces the shear strength of the unreinforced masonry shear wall between 5 and 60% as well as a reduction of 10–85% in its effective stiffness, depending on the intensity of the pre-compression load. Moreover, the code's estimation equations for shear strength of unreinforced masonry shear walls lead to an underestimation. For walls with two or more openings of window or door, the average strength from the upper and lower bound of the code-based strength seems appropriate, considering an intense pre-compression load on the wall. [ABSTRACT FROM AUTHOR]

The structural behavior prediction of the multistory reinforced concrete (RC) buildings with masonry infill walls (MIWs) during earthquakes is challenging. This paper presents a nonlinear macromodeling strategy seeking a simple, reliable, and low-cost computational analysis of the multistory RC buildings that comprise MIWs, and that use frames or shear walls (SWs) for resisting the lateral load. The strategy employed four plastic hinge (PH) models for tracking the deformations (flexural, shear, and torsion) of the frame elements and joints, a multilinear plastic link for modeling the MIW, and a nonlinear multilayer shell element for modeling the SW. A flexural PH model characterized by discretization into fibers, a recommended position, and an iterative estimating for the PH length using a distinct formula for each loading level was proposed. This strategy was validated through eleven macromodels investigating four bare frames, four MIWs frames, and a SW where the average ultimate lateral load error was 9.2%, 3.6%, and 0.4%, respectively. Finally, the structural behavior of real ten-story buildings with/without MIWs was investigated. The results showed that the MIWs increased the shear capacity and the lateral stiffness with an average of 44.3% and 118.6%, respectively. Also, both the frames buildings with MIWs and the bare SWs buildings showed approximately equal lateral load capacities. Local damages in the RC vertical elements and yielding of the MIWs were recorded simultaneously. However, the MIWs yielding (and also failure) occurred earlier for the frames buildings compared with the SWs buildings in which the stress was relaxed in their MIWs. [ABSTRACT FROM AUTHOR]

The present work is focused on studying the behavior of unreinforced brick masonry (URBM) structure under the seismic loading. A single story unreinforced brick masonry structure was made on a shake table with a scale of 1:4. Based on the experimental findings, the failure of the URBM structure happened at frequency of 62.5 cycle per second (cps) which means the resonant frequency of the structure was 62.5 cps. Besides, the highest acceleration and displacement occurred at frequency 62.5 cps leading to confirming the resonance at the same frequency. The failure pattern of URBM structure is like a stair step that means in-plane failure has developed in the mortar. In addition, the numerical analysis of the same building was performed using the SAP2000 finite element software. A time history analysis was conducted using elastic properties of the brick masonry building. The numerical and experimental results of peak acceleration and displacement were obtained at the roof level of the structure with respect to the varying base excitation. Consequently, the numerical results corresponded well with the experimental outcomes. [ABSTRACT FROM AUTHOR]

This study discusses the effects of local sites and hazard amplification on the seismic vulnerability assessment of existing masonry buildings. In this context, a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Galata, located in Istanbul, to determine the seismic risk priority of the built heritage. Damage scenarios were generated for all soil classes, different moment magnitudes, and source-to-site distances to obtain more accurate results for the seismic vulnerability assessment of the studied building stock. Consequently, damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerability owing to amplification effects. In this study, by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment, the importance of site effects on the vulnerability and risk assessment of built heritage was underlined. The proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerability assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results. [ABSTRACT FROM AUTHOR]

Barcelona is in an area of low- to medium-seismicity and its earthquake vulnerability and risk has been assessed in different studies over the last 20 years. Most of these works have developed vulnerability models for the representative building classes of the city, trying to capture their main characteristics, and have been mostly represented through fragility curves. However, due to the lack of data for historical earthquake losses in the city, it has not been possible to validate, nor calibrate, any of these vulnerability models. In the absence of earthquake loss data, the objective of this paper is to compare the earthquake risk results of Barcelona, using common hazard and exposure datasets and different sets of vulnerability functions from previous studies to see how they rank compared with other locations with similar studies but more complete historical loss data. The results show large differences between the analysed vulnerability datasets, with some results that in our view tend to overestimate earthquake risk in Barcelona, and also allow identifying critical aspects that require future research. [ABSTRACT FROM AUTHOR]

The present paper adopts a sophisticated numerical modeling technique using a plasticity-based simplified micro-model method and the extended finite element method for simulating the nonlinear behaviour of unreinforced masonry (URM) walls with different types of sizes and positions of openings. The validity of this model has been proven by comparing the results subjected to a similar loading obtained by the experimental approach. Thereafter, the validated computational model is used to study the behaviour of the 3D URM wall model with different opening percentages. The effect of the position of the openings is also studied. Further, the load–displacement curves are drawn to provide a clear idea about the load-carrying capacity of the same URM walls. The hysteretic behaviour obtained in each model under cyclic loading gives an idea about the energy dissipation capacity of each of the models studied. The same walls are analyzed by strengthening the walls with two cost-effective materials, wire mesh and polypropylene bands. Since the study on lateral behaviour of masonry walls, particularly regarding the effect of area and the position of the opening, is very rarely available, the present detailed study is believed to be helpful in reducing the seismic vulnerability of actual masonry structures, which always have openings with different sizes and positions. [ABSTRACT FROM AUTHOR]