Masonry Buildings Research Articles

Exploration and Characterization of Dynamic Properties for Cultural Heritage Conservation: A Case Study for Historical Stone Masonry Buildings in Zanzibar

Ancient civilizations have imprinted their legacy on Zanzibar Stone Town through the construction of revered stone masonry buildings, which are experiencing rapid deterioration due to severe ambient environmental impacts. In response to these challenges, this study presents a comprehensive field exploration through the ambient vibration test (AVT) and numerical prediction of historical stone masonry buildings in Zanzibar Stone Town to analyze the dynamic characteristics. The ambient vibration test (AVT) reveals structural dynamic properties in terms of peak resonance frequencies (fr(avg)), mode shape, and damping ratio, in conjunction with the development of correlation with the geometric parameters of the building. The results reveal fr(avg) ranges between 2.8 and 5.3 Hz for investigated structures, non-uniform deformed mode shapes, and damping ratio ranges between 1.35% and 4.45% at various orientation axes of the understudy buildings. However, the relationship between natural frequencies indicates a higher association with the geometrical parameters of the building, yielding a correlation coefficient (R2) between 0.85 and 0.99. Moreover, the numerical prediction via eigenvalue analysis (EVA) yields a considerable association with the investigated data, quantified by root mean square error (RMSE), mean absolute error (MAE) ranged between 0.29 and 0.3, with Nash–Sutcliffe efficiency (NSE) and R2 between 0.81 and 0.99, respectively. Furthermore, conservation work guidelines were also developed to assist the structural engineer and conservationist in adopting targeted conservation strategies for the efficient preservation of the historical integrity in Stone Town.

Assessment of Retrofitting Techniques for a Four-Story Masonry Building to Resist Blast Loading

Assessment of Retrofitting Techniques for a Four-Story Masonry Building to Resist Blast Loading

Assessing fragility functions of unreinforced masonry buildings

The seismic vulnerability entrenched within the historical urban landscapes of Algeria serves as a poignant reminder of the pressing need for comprehensive risk management strategies, particularly concerning low and medium height unreinforced masonry (URM) structures. These architectural gems, rich in cultural significance, stand as tangible embodiments of Algeria's storied past. However, their susceptibility to seismic disturbances presents an immediate threat, demanding meticulous attention and innovative methodologies for effective risk assessment and mitigation. In a pioneering scholarly pursuit, this research embarks on an ambitious exploration, melding fragility functions and a sophisticated vulnerability index method to unravel the intricate tapestry of seismic risk assessment. Through the lens of fragility functions, the study delves into a nuanced analysis, probabilistically delineating the vulnerabilities entrenched within the complex framework of URM buildings. Furthermore, the meticulous derivation of vulnerability functions via the vulnerability index method enhances the granularity of risk assessment, providing a multifaceted perspective to discern vulnerabilities accurately. Central to this investigation is the Belouizdad district, a microcosm of historical significance nestled within the vibrant metropolis of Algiers. By scrutinizing seismic scenarios spanning a spectrum of intensities (ranging from VII to X), the study orchestrates a symphony of empirical data and analytical prowess, unraveling the potential seismic reverberations poised to impact the district's architectural heritage. In essence, this scholarly endeavor transcends the confines of mere academic pursuit, serving as a guiding light illuminating the path towards tailored seismic reduction policies. It stands as a clarion call to safeguard Algeria's architectural patrimony, fostering resilience amidst the tremors of uncertainty and ensuring the preservation of its cultural legacy for generations to come.

Towards a practice-oriented procedure to account for static and dynamic interaction among three adjacent shallow foundations

Many historic centers in Italy and around the world consist of ancient masonry buildings closely packed together or constructed in clusters for defensive purposes. Alternatively, the recent population growth in modern megalopolises, coupled with the increasing use of reclaimed soils to address land scarcity, has resulted in the development of highly densely urbanized areas placed on soft or very soft soils. In both scenarios, neighboring structures, despite being structurally separate, may interact with one another through the underlying soil. To gain new insights into this phenomenon, the paper presents a comprehensive numerical study. It analyzes the static and dynamic responses of three closely-spaced shallow foundations in both the time and frequency domains using a rigorous 3D continuum approach. The conducted parametric study considers the effects of foundation spacing, oscillation frequency, and soil configuration (homogeneous or layered), quantifying their impact on the soil-foundation impedance matrix. The results of the numerical study reveal distinct responses between the central and lateral foundations of a group of three shallow foundations placed on the same subsoil. A comparison is drawn between the response of the pivotal foundation within a group of three identical footings and its response when paired or isolated. As an extension of an earlier work of the authors (Zeolla et al., 2023), a simplified approach is proposed to address cross-interaction effects in design practice. This approach introduces a set of group factors to modify the impedance matrix of the primary foundation when surrounded by closely-spaced neighbors. The practical approach is applied to estimate the increase in the fundamental period of a masonry terrace house. The cross-interaction effect is deemed non-negligible and warrants consideration in such squat structures, as it can result in significant increases in spectral acceleration along the ascending branch of the design spectrum.

Issues related to typological fragility curves derivation starting from observed seismic damage

In this study typological fragility curves are proposed with a macro-seismic approach. To this scope, a stock of 56.338 residential masonry buildings struck by L’Aquila 2009 seismic sequence is analyzed, whose AeDES forms are archived within Da.D.O. platform, that is a web-gis database collecting the observed seismic damage data related to buildings surveyed after several Italian earthquakes.Moreover, issues significantly influencing the fragility curves derivation are in depth discussed. In particular, a criterion for the buildings stock completion adding undamaged and not surveyed buildings is proposed, based on the distributions known of the residential building typologies. Comparisons highlight that the database completion affects the resulting fragility curves, and in particular for low damage levels. Furthermore, it is shown how the fundamental parameters estimation, by using the Maximum Likelihood Estimation (MLE) method, is conspicuously influenced by the PGA intervals number (nint), that is an issue often ignored when fragility curves are derived. The numerical investigations show that, although a non-monotonic trend is observed, the fundamental parameters tend to converge to the asymptotic values as the nint of PGA increases, and that they are markedly dispersed when nint is low.

Seismic Vulnerability of Bijapur’s Historic Architecture

Bijapur (Karnataka, India) in recent times, has been experiencing earthquake tremors frequently. The city and its environs are home to numerous historic buildings which are considered significant in the history of architectural development in the Indian subcontinent. The primary and most visual contribution to the city’s architecture happened in the 16th – 17th century CE under the Adil Shahi Sultanate. This present study focuses on the buildings of that period only. The buildings are more than 300 years old now and have decayed substantially with time. Recent earthquakes in Bijapur pose a serious threat to these structures and this study tries to assess the seismic vulnerability of the same. From the assessment, it is inferred that the sturdy design of arcuated buildings of Bijapur, arch-frame masonry structures without infill walls, slender building elements like tall minarets, and cantilevered elements like cornices collectively make the historic buildings of Bijapur vulnerable to seismic loads. Lack of maintenance, lack of conservation and consolidation initiatives, vandalism, and unplanned development in close vicinity of these edifices also contribute to the same. The method of assessment employed in this study is based on site surveys, physical documentation, condition assessment, and conceptual and non-conceptual literature available on the subject, instead of computation-based techniques of assessment for those methods have their limitation as far as (historic) masonry buildings are concerned.

Aspects Affecting the Quality of Masonry Buildings and Innovations in Masonry

The construction industry is undergoing another revolution, including the field of masonry construction. New materials and products for masonry are constantly being developed and construction details and implementation procedures are being resolved. Digitization and the introduction of automation in the masonry process (in prefabrication halls or on-site robotic bricklaying) are also an integral part of the development of the masonry construction industry. The topic of the following paper is a summary of problematic construction details of masonry buildings, i.e., the solution of the plinth console, the solution of the building opening, the bearing of lintels on the masonry and the bearing of the ceiling structure on the masonry wall. The results of laboratory tests are presented – the load-bearing capacity of the jamb of the building opening (accessory bricks / cut bricks in the jamb) and the load-bearing capacity of the lintel placed on the accessory edge brick. Furthermore, the paper deals with the construction of masonry buildings in the 21st century, including the first results of a compressive load test on masonry walls made of precast small-format units. The conclusion of the paper points out the importance of correct design details of masonry buildings before their application (programming) in software controlling the automated masonry process.

Comparison of different frost models with hygrothermal simulations to better understand frost damage in porous building materials

Frost damage is one of the most important degradation phenomena of brick facades. Evaluating the risk of frost damage in advance is of utmost importance considering the difficulty of repairing frost damage without replacing the materials, which may not be an option for protected heritage facades. Various performance criteria and methods have been developed over the past decades to assess the risk of frost damage. However, these methods are derived from frost tests under extreme conditions, such as high saturation levels and very low freezing temperatures, and do not represent realistic conditions for mild climates. In 2019, Feng et al. tested four different bricks under milder conditions to understand the relationship of frost damage with freezing temperature and saturation degree. The research in this paper combines the results of Feng's study with hygrothermal simulations, which prove to be a valuable tool for assessing the risk of deterioration of facades of masonry buildings. In this paper, the frost decay assessment methods like the Fc-index, GC-factor and counting the critical freeze-thaw cycles are examined, discussed and finally dismissed. Finally, a more representative frost decay risk assessment method is proposed.

Empirical Fragility Analysis of Haitian Reinforced Concrete and Masonry Buildings

This study develops empirical fragility curves for concrete and masonry buildings in Haiti, utilizing data from the 2021 earthquake. A dataset of 3527 buildings from the StEER database, encompassing a diverse range of building types, is used. These buildings types include reinforced concrete structures with masonry infills, confined masonry buildings, reinforced masonry bearing walls, and unreinforced masonry bearing walls. Shakemaps from the USGS are utilized to assess the earthquake’s intensity at each building, with the peak ground acceleration (PGA) as the intensity measure. Damage is classified into five distinct states: no damage, minor, moderate, severe, and partial or total collapse. For each of these states, the corresponding probabilities of exceedance are calculated, and log-normal cumulative distribution functions were fitted to those data to produce empirical fragility curves. The results show a notable similarity in performance among the four types, each having high probability of failure even under low-intensity earthquakes. Total fragility curves (including all four building types) are developed subsequently and they are convolved to the probabilistic seismic hazard map of Haiti to assess the seismic risk. This includes estimating the annual probability of partial/total collapse and the probability of partial/total collapse in the event of 475-year and 2475-year earthquakes. The results indicate a significant risk, with up to 64% probability of collapse in certain areas for the 2475-year earthquake and a probability of collapse of 15% for a 475-year earthquake. These findings underscore the critical vulnerability of Haiti’s buildings to seismic events and the urgent need for their retrofit.

2D and 3D Modelling Strategies to Reproduce the Response of Historical Masonry Buildings Subjected to Settlements

ABSTRACT In this study, 2D and 3D modelling strategies are used to represent the behaviour of historical masonry buildings on strip foundations undergoing settlements. The application focuses on a two-story building, typical of the Dutch architectural heritage. An improved 2D modelling is presented: It includes the effect of the lateral walls to replicate the response of the detailed 3D models. The masonry strip foundation is modelled and supported by a no-tension interface, which represents the soil-foundation interaction. Two settlement configurations, hogging and sagging, are applied to the models, and their intensity is characterized using their angular distortion. The improved 2D model that includes the stiffness and weight of the lateral walls agrees in terms of displacements, stress and damage with the detailed 3D models. Conversely, the simplified 2D façade models without lateral walls exhibit different cracking, and damage from 2 to 7 times lower at an applied angular distortion of 2‰ (1/500). The improved 2D model requires less computational and modelling burden, resulting in analyses from 9 to 40 times faster than the 3D models. The results prove the importance of identifying and including the 3D effects that affect the response of structures subjected to settlements.

Valorization of Cappadocia waste earth in the production of sustainable lime-based grouts

Historical structures and natural landscapes in Turkey's Cappadocia Region, a popular tourist spot, have been designated mixed heritage sites on the World Heritage List since 1985. The region's old rock-cut and masonry constructions have been damaged for various reasons. Furthermore, the waste volcanic tuff excavated during the construction of rock-cut structures in the region totals around 10 million tons of waste material per year. It creates severe visual concerns since it cannot be used effectively in the area. Because repairing ancient buildings needs precision, the restoration method and material should be selected based on the structures' structural system and material attributes. Grouting is one of the most common ways of repairing and strengthening masonry buildings or fissured architectural pieces with adequate connected voids. This technique aims to restore damaged structures' continuity, cohesiveness, and strength while keeping their morphology and load-bearing system intact. This research explores the potential use of waste earth from rock-cut structures in the Cappadocia Region in hydraulic lime-based grouts. Thus, an injection material that can be used to repair fairy chimneys and historical rock-cut and masonry structures in this region will be produced. Various lime-based grout types containing Cappadocia waste earth (CWE) were produced in this scope. The evaluation of grout performance encompassed assessments in the fresh state (Fluidity, Penetrability, and Volume Stability) and the hardened state (Flexural and Compressive strength). Furthermore, this research delved into how Cappadocia waste earth (CWE) influences the physical and microstructural characteristics of lime-based grouts. Thanks to this study, both environmental pollution will be reduced, and sustainability will be contributed.

In-plane and out-of-plane one-way vertical bending behavior interaction analysis of unreinforced masonry walls with newly developed load capacity interaction curve

The structural behavior of unreinforced masonry (URM) walls under in-plane (IP) or out-of-plane (OOP) loading in masonry buildings has been extensively investigated in the public literature. However, studies focusing on the URM walls subjected to concurrent IP and OOP loadings are limited. Neglecting IP and OOP interaction effects may lead to unsafe design practices. As such, this study conducts a comprehensive numerical investigation into the behavior of URM walls under combined IP and OOP loading, focusing on the influences of aspect ratio (i.e., height-to-length ratio), slenderness ratio (i.e., height-to-thickness ratio), and pre-compression load levels. To capture the possible failure modes of URM walls under various loading scenarios, the simplified micro modeling approach is employed. The analysis results indicate that the presence of OOP loading leads to a substantial reduction in IP capacities. Longer walls, characterized by smaller AR, exhibit more pronounced IP and OOP interaction effects. Additionally, highly slender walls show significant additional moments due to second-order effects under OOP loading, thereby negatively affecting the IP capacity. Low-level pre-compression loads are beneficial in diminishing capacity interaction effects, while high pre-compression loads exert a negative influence. To facilitate the consideration of IP and OOP capacity interaction effects in an efficient manner, a simplified analytical model is developed through curve fitting, in which the effects of aspect ratio, slenderness ratio, and pre-compression load are incorporated.

Comparative analysis of two strengthening solutions for the structural rehabilitation of a historical masonry building

The paper presents a comparative analysis based on the Finite Element Method (FEM) for a masonry building located in Iasi, the North-Eastern side of Romania. This specific region is known to be found in a seismic area having a design peak ground acceleration of 0.25g. The building was assessed as being in the 1st seismic risk class, according to the Romanian norms, with a high probability of collapse in case of future earthquakes. Being a historical monument, the structural strengthening solutions are very limited. The study consists of modal and seismic analyses for the masonry structure. A comparison of the advantages and disadvantages of two approaches of structural rehabilitation solutions is done. The structural strengthening solution “A” consists of the addition of reinforced concrete thin wall elements, while the other - called solution “B” - consists of an interior steel profile skeleton mechanically and chemically connected to the adjacent masonry walls.

Damage assessment of unreinforced masonry buildings incorporating damage accumulation

AbstractRecent earthquakes have shown susceptibility of unreinforced masonry (URM) buildings to damage accumulation in seismic sequences or long duration ground motions. Current structural modelling approaches commonly disregard the damage accumulation in URM buildings or they are unable to accurately capture this phenomenon unless sophisticated FEM models are employed. Such models are not feasible in risk‐based applications given the required large number of dynamic analyses needed to develop robust fragility and vulnerability curves. On the other hand, the common displacement‐based engineering demand parameters (EDP), such as inter‐story drift ratio, fail to capture the impact of damage accumulation in simpler, more manageable models. An alternative is to use advanced damage indices that are capable of monitoring the monotonic accumulation of damages. This study proposes a displacement‐ and energy‐based damage index that uses, as the basis, the Park and Ang damage index, modified and calibrated through experimental data of individual URM elements. Our calibration procedure maps the physical observed damage states to the hysteretic response of the elements. Consequently, damage on the individual elements is aggregated to define a global damage state at building level. Validation is carried out based on an equivalent frame model of a building tested on a shake table. Additionally, the model is subjected to multiple ground motions of seismic sequences and to long‐duration ground motions to evaluate the performance of the proposed damage index. In comparison with displacement‐based damage measures, the proposed damage index shows a superior ability to capture cumulative damage, even when simplified models are employed.

Scalable BIM based open workflow for structural analysis of masonry building aggregates

Masonry building aggregates are complex historical structures comprising interconnected buildings. The safety of each building depends not only on its structural integrity but also on the interactions with neighbouring structures and their collective performance. The structural assessment of such complex constructions can benefit from BIM methodology. The latter eases modelling complicated solid geometries and assigning mechanical properties information essential for developing a reliable finite element model. Thus far, BIM to finite element analysis procedures applied to historic constructions have remained laborious, semi-automatic, and based on proprietary software. This paper introduces an open-source automated solid finite element analysis method using OpenBIM data (IFC). The tool implemented automatically creates tetrahedron mesh and assigns mechanical properties, self-weights, and fixities at the structure's base. The methodology is applied to an actual masonry building aggregate to validate its capability of working with complex geometries and scalability.

Fractal theory based identification model for surface crack of building structures

The existing building structures are mainly composed of concrete and masonry structures. This paper proposes a Fractal Theory-based Method (FTM) designed to efficiently detect surface cracks in both concrete and masonry building structures, addressing limitations in existing crack recognition techniques, such as weak adaptability to complex building surfaces and requiring a large amount of computational and human resource. A novel Soft Box-Counting (SBC) algorithm is proposed to calculate texture roughness information from multi-channel and multi-scale crack images, effectively mitigating the influence of non-feature information on crack identification results. The SBC algorithm is integrated into neural networks through the fractal embedding mechanism, enhancing feature analysis through visualization experiments. The resulting FTM model integrates texture roughness information from crack images and employs fractal theory to accurately classify crack regions while minimizing the similarity between crack and non-crack regions. In comparison to existing models, FTM demonstrates superior identification performance at the same computational level on benchmark datasets for surface cracks in both concrete and masonry building structures. The FTM model exhibits enhanced identification universality and higher resource utilization efficiency.

Seismic design and performance assessment of a retrofitted building with tuned viscous mass dampers (TVMD)

Vibration control technologies have been widely implemented for the seismic retrofitting of buildings in high seismic regions. Among various vibration control devices, the tuned viscous mass damper (TVMD) has proven effective in mitigating both lateral inter-story drifts and floor accelerations. This paper presents the seismic design and performance assessment of a retrofitted structure located in a highly seismic area. The existing masonry building is being retrofitted into a steel frame-jacketed masonry wall interacting structural system installed with TVMDs. A simplified iterative design process is proposed for the tuning design of TVMDs used in the retrofitted structure, which is based on the fixed-point method. The seismic responses of the buildings are calculated using non-linear dynamic analysis in OpenSees. Applying the FEMA P-58 approach, the seismic performance of the buildings as measured by the repair cost and repair time is evaluated. The findings reveal that the majority of the structural damage is focused within the masonry walls, coupling beams, and non-structural components. Use of TVMDs results in reduced maximum inter-story drifts that when subjected to very rare earthquake (VRE) shaking are up to approximately 40% lower in both transverse and longitudinal directions compared with the uncontrolled structure. Owing to the effective control of seismic damage to both structural and non-structural components, the TVMD-equipped structure achieves a 42% reduction in median repair cost and a 46% reduction in median repair time at VRE compared with the uncontrolled building. The seismic performance assessment results also illustrate the advantages of TVMD control compared with conventional viscous dampers.

Investigating the damage to masonry buildings during shield tunneling: A case study in Hohhot Metro

After prolonged service, masonry buildings constructed in the 1970s and 1980s often experienced significant deterioration in strength and stiffness. Excessive ground deformation caused by shield tunneling frequently leads to cracking in adjacent masonry buildings. Most studies have focused on the settlement and tilting caused by shield tunneling on masonry structures, failing to reflect the specific damages caused by shield tunneling. This paper employs a jointed masonry model in numerical simulations to simulate masonry buildings, considering the actual measurement data from the Hohhot Metro Line 1 project. It discusses a thorough investigation into the potential damages and cracking on masonry buildings that may occur during shield tunneling in masonry structures. It provides a detailed study of the specific forms of cracking in masonry buildings. Then, a comprehensive and in-depth analysis is conducted on the impact of bricklaying methods, mortar adhesive strength, and synchronous grouting pressure on buildings in the context of shield tunneling through structures. The results show that using the jointed masonry model can effectively reflect the cracking and damage situation of masonry structures during shield tunneling construction, providing valuable guidance for actual shield tunneling operations. The area of cracking damage caused by shield tunneling construction gradually increases from the top to the bottom of the building. It is concentrated above the doors and windows of the structure. Potential cracks around door and window openings extend from the upper-middle part of the openings towards both sides, forming a regular figure-eight distribution. With changes in the masonry construction method, grouting pressure, and mortar bond strength, the settlement and damage levels of the building also undergo alterations. Specifically, as the mortar bond strength increases from 30 kPa to 50 kPa, the maximum tensile strain of the masonry construction decreases to 0.11 %. Simultaneously, when the construction method of the building bricks transitions from A to B, the damage at the door and window openings on the west wall of the building gradually intensifies, resulting in a rise in the maximum tensile strain to 0.109 %. Furthermore, as the grouting pressure increases from 50 kPa to 300 kPa, the maximum settlement of the building walls decreases by 51 %, and the maximum tilt reduces by 48 %. However, this study did not account for the lintels and sills in the masonry building, which may lead to an overestimation of simulated strain data.

Damage Evaluation and Seismic Assessment of a Typical Historical Unreinforced Masonry Building in the Zagreb 2020 Earthquake: A Case Study—Part I

The city of Zagreb, the national capital and economic hub of Croatia, is situated in a seismically active region and hosts a significant array of historical buildings, from the medieval to Austro-Hungarian periods. These buildings possess varying but generally high degrees of vulnerability to seismic loading. This was highlighted in the Zagreb earthquake of 22 March 2020, emphasizing the need for seismic retrofitting in order to preserve this architectural heritage. In this paper, the seismic capacity of one such unreinforced masonry building is considered through a number of analysis methods, including response spectrum, pushover, and out-of-plane wall failure analyses. Given the advantages and disadvantages of the individual methods, their applicability and value in a seismic analysis is considered. Ambient vibration measurements before and after the Zagreb 2020 earthquake, used for model calibration, are also presented. Conclusions are drawn from each individual analysis and later compared. In conclusion, no single analysis method considers all relevant failure modes, and a combination of nonlinear static or dynamic analysis and out-of-plane analysis is recommended. Due to the large volume of the material, it is published in two parts, with ground motion record selection, dynamic analysis, and a comparison of the results published in part two.

Seismic safety evaluation of coir and nylon fiber-reinforced masonry building models subjected to bi-axial shaking table test

The unsatisfactory performance of unreinforced masonry (URM) buildings during seismic events has led the research community to explore various strengthening techniques. However, most techniques used are based on external strengthening and are not easy to implement in real-life situations. Therefore, the current study focuses on improving the seismic behavior of masonry structures through the incorporation of a novel fiber-reinforced mortar in construction. Two different waste fibers, i.e., coir and nylon fibers, were used as reinforcement in the mortar, and the same mortar was used for both mortar joints and plaster. The objective is to improve the seismic performance of URM buildings while reducing carbon footprint and landfill problems. The scale-down building models were built with both clay and fly ash bricks. Then, these building models were subjected to seismic loading through a bi-axial shake table. The failure mechanism of the models was thoroughly examined. Furthermore, the seismic performance of both types of building models was assessed using various parameters, including failure pattern, crack formation, maximum sustained peak ground acceleration (PGA), arias intensity, acceleration amplification factor, energy flux ratio, etc. It was observed that the strengthened masonry models sustained significantly higher seismic loading (up to 45.5% in terms of first crack strength) than their unreinforced counterparts. The failure of strengthened models was ductile, and these strengthened models successfully avoided the sudden and brittle failure of URM models. There was also a notable improvement in the other parameters mentioned above. Overall, the current study's strengthening technique proved effective, sustainable, easy to implement, and economical.