Historical Masonry Structures Research Articles

Fiber Reinforced Cementitious Matrix (FRCM) for strengthening historical stone masonry structures: Experiments and computations

Seismic events highlight the inherent fragility and vulnerability of stone masonry buildings, which represent a large part of the existing historical and artistic heritage. In order to preserve these structures, numerous reinforcement techniques are typically used on masonry walls, including mortar injections, reinforced drilling, and reinforced concrete plaster. Nowadays new and less invasive strengthening techniques are preferred; among them Fiber Reinforced Cementitious Matrix (FRCM) system with lime-based mortar, which is considered to be more compatible with the intrinsic properties of these ancient structures as compared to cement-based mortar. This work aims to investigate experimentally and computationally FRCM applied as reinforcement to ancient stone masonry. In particular, the paper presents results from diagonal compression tests carried out at the University of L’Aquila (Italy) on stone masonry specimens strengthened with layers of Glass-FRCM (GFRCM). In comparison with unreinforced panels, those strengthened by the GFRCM exhibited a significant increase in shear modulus and shear strength. A computational framework based on the Lattice Discrete Particle Model (LDPM) was then used to reproduce the experimental results. The fracture behavior and the damage evolution in masonry panels were investigated under different assumptions on the GFRCM system features (bond behavior, mortar thickness, fiber anchors and fiber grid). The good agreement between experimental results and the LDPM simulations show that this approach predicts well the mechanical behavior and the damage evolution in stone masonry under quasi-static loading conditions. Moreover, it can be considered a viable tool for engineers in developing effective reinforcement techniques.

The Selected Issues of Adaptation of 19th and 20th Century Post-Industrial Buildings in Łódź

The paper deals with selected technical problems related to the adaptation for new uses of the structure of existing post-industrial buildings from the turn of the 19th and 20th centuries. A major difficulty is the fact that the strength and geometric properties of cast-iron, steel, and masonry elements often differ significantly from the values characterizing contemporary materials. Due to uncertainty regarding the load-carrying capacity of historical structures, in many cases there is a need to carry out destructive tests of elements taken from the buildings. As the example of cast-iron girders in the former spinning mill of “I. Poznański” demonstrated, such tests can prove a significant margin of load-carrying capacity and confirm the possibility of adapting the structure to new purposes. The paper also presents examples of strengthening the existing wooden ceilings by joining with the reinforced concrete structure, which allowed the keeping of the original elements and an increase of the allowable load. Selected problems related to the assessment of historical masonry structures were also described. The discussed examples of structural failures showed that they often resulted from incorrect assessment of the strength of historical masonry elements as well as improperly conducted construction works.

Lime-Based Mortar Reinforced by Randomly Oriented Short Fibers for the Retrofitting of the Historical Masonry Structure.

Recent seismic events prompted research to develop innovative materials for strengthening and repair of both modern and historic masonry constructions (buildings, bridges, towers) and structural components (walls, arches and vaults, pillars, and columns). Strengthening solutions based on composite materials, such as the Fiber Reinforced Polymers (FRP) or the Fiber Reinforced Cementitious Matrix (FRCM), have been increasingly considered in the last two decades. Despite reinforcement made of short-fibers being a topic that has been studied for several years from different researchers, it is not yet fully considered for the restoration of the masonry construction. This work aims to experimentally investigate the enhancement of the mechanical properties of lime-based mortar reinforced by introducing short glass fibers in the mortar matrix with several contents and aspect ratios. Beams with dimensions of 160 mm × 40 mm × 40 mm with a central notch were tested in three-point bending configuration aiming to evaluate both the flexural strength and energy fracture of the composite material. Then, the end pieces of the broken beams were tested in Brazilian and compressive tests. All the tests were performed by a hydraulic displacement-controlled testing machine. Results highlight that the new composite material ensures excellent ductility capacity and it can be considered a promising alternative to the classic fiber-reinforcing systems.

Tarihsel Yığma Yapıların Hâlihazır Koruma Durumunun İzlenmesi İçin Öneriler: Matrone Kilisesi ve Çardak Han Örneği

The aim of this study is to transfer the international developments related to the process of diagnosis and monitoring of historical masonry structures to the national area. The method chosen is to test the recommendations made at the international level on national cases and to discuss the results obtained by comparing them. A review of preliminary studies, on-site observations, measured surveys, material characterizations, mapping and visual analysis have been carried out. An examination of structural characteristics and observed failures have also been detailed. Related risks have been evaluated with criteria developed by taking into consideration condition classes defined in the UNI EN 16096, titled Conservation of Cultural Property – Condition Survey and Report of Built Cultural Heritage. According to the defined risks and classes, priorities of interventions were determined. Two historical masonry buildings which possess characteristics of different periods and present different damage types were selected: Matrone Church in Ildiri, Cesme, Izmir and Cardak Han in Cardak, Denizli. The condition reports of the selected buildings have been prepared. The critical points in the condition reporting of historical masonry buildings were determined: accurate comprehension of the authentic structural characteristics and related failures have priority in maintaining historical masonry structures. Identification of condition class and risk assessment of each historic masonry building should be made in accordance with a standard specific to the cases of our country, but in line with the European standards and current developments in the field of architectural restoration. Thus, it will be possible to evaluate the conservation state of our masonry assets in comparison with each other. The content and priority of interventions can be well planned with the participation of the necessary disciplines.

Ancient masonry structures within an integrated approach: the reinforced corbelled flat roofs of Umm el-Jimal

The historical development of structural engineering design remains a subject separate from other themes in the historical precedents in construction and building materials. Scientists and scholars deal with the engineering performance of historical masonry structures through the traditional ‘geometry’- Galileo’s ‘strength of materials’ theoretical dichotomy. Such approaches emphasize the role of two main aspects in understanding the stability of masonry buildings: form of the structure (arcuated or non-arcuated) and the performance of its building materials in tension and/or in compression. Both theories are questioned because they were not able to comprehensively acknowledge the role of a third important factor- the constructional and reinforcement systems. The study revisits Galileo’s ‘simple beam’ theory and exmines the effect of ‘strength of material’ in relation to the ‘geometrical’ and ‘reinforcement’ criteria. It uses the case of Umm el-Jimal in Jordan because the entire city is built using the sole building material: basalt stone. It explores the different applications of this material in generating reinforced flat structural design through employing diverse corbelling constructional techniques. The study recommends an integrative ‘material-geometry-construction’ approach for masonry structures to ensure a comprehensive understanding of its stability, equilibrium, and safety. It is an approach that could assist structural scholars in their attempts to take precedents as a means to advance contemporary theories in structural engineering.

Nonlinear Numerical Modeling of Complex Masonry Heritage Structures Considering History-Related Phenomena in Staged Construction Analysis and Material Uncertainty in Seismic Assessment

This paper presents the systematic use of numerical analysis as a tool for addressing some of the most common challenges encountered in the structural analysis of complex historical masonry structures, that is, the description of the effects of history-related phenomena and the uncertainty of material properties. The numerical strategy is based on the use of a constitutive model able to describe time-dependent strain accumulation, as well as damaging behavior under different stress states. This constitutive model is combined with a crack-tracking technique to represent tensile crack localization. The numerical model is applied to the study of two important monuments in Spain; the Mallorca Cathedral and the church of the Poblet Monastery. The staged construction analysis of the first case study allows for understanding the reasons of its current deformed condition, that is, critical construction process, strain accumulation given by long-term creep phenomena, and nonlinear geometric effects. The structural analysis of the second case study allows the structural diagnosis of the existing deformation and cracking patterns given by architectural alterations, insufficient buttressing of the naves, and past earthquakes. The application of a probabilistic analysis to the church of the Poblet monastery allows for considering the effects of the uncertainties of material properties and numerical parameters in the seismic vulnerability assessment.

Shake Table Testing of Two Historical Masonry Structures for Estimation of Their Seismic Stability

ABSTRACT Reliable estimation of seismic stability of structures built in seismically active regions is an objective that requires a complex investigation and different types of activities. For historical structures and monuments, this requirement is even more essential, because many of them represent unique heritage structures. In-situ testing of a monument for defining dynamic characteristics and seismic testing of scaled models represent the recommended activities to be considered as mandatory. Shake table testing of a scaled monument model provides valuable information about its seismic stability – weak parts and development of failure mechanism – as well as the crucial points of the structure that should be considered when designing the health monitoring system. This paper presents the results obtained by the shake table testing of scaled models of two historical masonry structures: the Old Bridge in Mostar and the ancient Protiron structure in Split. The monitored seismic response presented herein by the measured accelerations, relative and absolute displacements, and strains, as well as the damage identification during the shake table tests, provided essential information about their seismic stability, failure mechanism, and weak points. The obtained results have been used for verification of the analytical models for these two monuments, while the prospective of the conclusions derived from the tests has a possible implementation in planning their health monitoring system.

Safety Assessment of Masonry Arch Bridges Considering the Fracturing Benefit

The evolutionary analysis of the fracturing process is an effective tool to assess of the structural bearing capacity of masonry arch bridges. Despite their plain basic assumptions, it must be remarked that elastic analysis and plastic or limit analysis can hardly be used to describe the response and predict damage for moderate or service load levels in masonry arch bridges. Therefore, a fracture mechanics-based analytical method with elastic-softening regime for masonry is suitable in order to study the global structural behaviour of arch bridges, highlighting how the arch thrust line is affected by crack formation, and the maximum admissible load evaluated by means of linear elastic fracture mechanics is larger than the load predicted by elasticity theory. Such an increment in terms of bearing capacity of the arch bridge can be defined “fracturing benefit”, and it is analogous to the “plastic benefit” of the plastic limit analysis. The fracturing process, which takes into account the fracture initiation and propagation in the masonry arch bulk, occurs before the set-in of the conditions established by means of the plastic limit analysis. In the present paper, the study of the elastic-fracture-plastic transitions is performed for three monumental masonry arch bridges with different shallowness and slenderness ratios. This application returns an accurate and effective whole service life assessment of masonry arch bridges, and more in general it can be suitable for a great number of historical masonry structures still having strategic or heritage importance in the infrastructure systems.

The constructability of Cheops Pyramid

The aim of this paper is to forecast the methodology by which Cheops Pyramid as a historic building was built, based on notions of modular patterns discovered within the following planar illustrations, starting at the apex and descending to its grand base.Some of Cheops’ heritage in terms of form and function has existed for millennia, as its mark was recapped with a front line that was constructed thousands of years before. Such a voyage through the missing captures of the building techniques wouldn’t have occurred without the incidental outcome that resulted from overlaying the various pixelated plans of block arrangements on the floor maps of Cheops. This building is believed to exhibit norms similar to those governing the balance between matter and void in the universe.By assessing this historical masonry structure of Giza, we have come to find some regulatory approaches concerning how to asses the construction of such a building by predicting their interiors, spatial definitions, customs, and layouts. As there are no major records of their plans, the best practice anticipated in this paper is to modularize the figurative appearance of such buildings, by imitating themes of the repetitive patterns of past regional Egyptian architecture seen as pixels. This led to the fundamental solution to such a dilemma in building construction.

Visual programming for structural assessment of out-of-plane mechanisms in historic masonry structures

This work aims at proposing a novel procedure for the seismic assessment of historic masonry structures which is computationally efficient and does not rely on destructive material tests. Digital datasets describing the geometric configuration of historic masonry structures are employed to automatically generate a non-linear Finite Element (FE) model and investigate on possible collapse modes. A configuration of failure surfaces is therefore detected through the Control Surface Method (CSM), which is here proposed for the first time. In a following step of the analysis, structural macroblocks are identified, whereas an upper bound limit analysis approach is employed to estimate the structural capacity of the structure. Genetic Algorithms are also employed to detect the actual failure mode for the structure. The procedure is implemented into a visual coding environment, which allows one to parametrically explore all possible failure surfaces and immediately visualize the effects of the user assumptions. This is particularly suited to support a decisions-making process which strongly relay on engineering judgement. The procedure is validated by the analysis of two benchmark cases, whose results are presented and discussed.

Seismic Assessment in a Historical Masonry Minaret by Linear and Non-linear Seismic Analyses

Operational Modal Analysis (OMA) method is frequently used in order to determine dynamical properties of historical masonry structures. In this study, damage pattern of historical Alaca minaret which is selected as application is investigated under different ground motions by updating finite element models (FEM) depending on operational modal analysis test. Initial Finite element model was prepared in ABAQUS V10 program and numerical dynamic characteristics of minaret were determined. In addition, experimental dynamic properties of minaret were provided by operational modal analysis. Initial numerical model of brick masonry structure was calibrated via OMA method. Then, linear and non-linear seismic analyses of calibrated FEM of historical minaret were performed by using different earthquakes acceleration records that occurred in Turkey. Concrete Damage Plasticity model was taken into account in non-linear seismic analyses. As a result of the analyses, it is concluded that the stresses obtained with linear analyses aren’t as realistic as the non-linear analyses results and the earthquakes can cause some damages in the minaret.

- Dynamic Seismic and Wind Response of Masonry Minarets

Historical masonry structures i.e. minarets, towers, mosques or bastions are the heritage of past generations to the future societies as they carry the traces of the past communities. Among these structures, historical masonry minarets are one of the most generally constructed structure that reflects the beauty and magnificence of Islamic culture. Under severe winds and earthquakes, most of them were severely damaged or collapsed. Therefore, it is an inevitable duty for us to conduct and investigate their dynamic behavior under these vital actions of nature. In this study, the dynamic seismic and wind response of a historical minaret of İskenderpaşa Mosque that is selected from the technical literature is investigated by using different methods i.e. wind loading procedures of TS498, CICIND Model Code and Eurocode 1, the design spectrums of CICIND Model Code and Eurocode 8 for different types of soils, the time histories of real ground motions of Düzce and Kocaeli Earthquakes. At the end of the study, top joint displacements and stress distributions are obtained and interpreted. The findings of this study showed that the dynamic behavior of this historical masonry minaret is wind dominant (CICIND Model Code) and tensile and shear stress accumulations at the junction point of transition segment and cylindrical body of the minaret is the main reason for the collapse without showing any ductile behavior.

Testing methods for the assessment of material properties in historical masonry structures: a review

The current state of testing methods for assessing the mechanical properties of old masonry buildings is reviewed, with a focus on the methods adapted for heritage structures. For these buildings, an accurate assessment is needed in order to minimise the interventions extent while ensuring an adequate structural safety level. As old masonries are non-homogenous and exhibit a highly anisotropic behaviour, numerous parameters are required for correctly simulating the behaviour under a given load scenario. In earthquake-prone areas, numerous failure patterns, in-plane and out-of-plane, can occur for the structural walls, each of them depending on different characteristics of the material. If for new masonries the testing procedures are standardised, for old buildings less standardised tests exist, while investigations are often based on modified or empiric methods. The testing methods can be classified as destructive, minor destructive and non-destructive. The destructive methods are the most precise but are extremely intrusive and may not be acceptable for heritage listed buildings. The non-destructive methods mostly provide qualitative results. The minor-destructive tests are often the most adapted for the study of historical buildings, as they can provide relevant information while affecting only in a limited extent the existing elements.

Monitoring of a Historical Masonry Structure in Case of Induced Seismicity

ABSTRACT In case of induced seismicity, expectations from a structural monitoring system are different than in the case of natural seismicity. In this paper, monitoring results of a historical building in Groningen (Netherlands) in case of induced seismicity has been presented. Results of the monitoring, particularities of the monitoring in case of induced earthquakes, as well as the usefulness and need of various monitoring systems for similar cases are discussed. Weak soil properties dominate the structural response in the region; thus, the ground water monitoring as well as the interaction of soil movements with the structural response has also been scrutinized. The proposed study could be effectively used to monitor historical structures subjected to induced seismicity and provide useful information to asset owners to classify the structural health condition of structures in their care. It was shown that the in-plane cracks at the building would normally not be expected in this structure during small induced earthquakes happening in Groningen. One explanation provided here is that the soil parameters, such as shrinking of water-sensitive soil layers, in combination with small earthquakes, may cause settlements. The soil effects may superimpose with the earthquake effects eventually causing small cracks and damage.

An Experimental Study on the Effect of Water on Historic Brickwork Masonry

Architectural heritage is deeply threatened by extreme weather events due to ongoing climatic change. Since these phenomena are becoming more and more serious, their effects cannot be neglected when a reliable assessment of a historic masonry structure is required. In this paper, the phenomenon of rising damp was studied, focusing on the influence of water on the unit weight of masonry walls made from fired clay bricks and lime mortar. This study consists of a basic experimental research on the variations in the unit weight of masonry undergoing an ageing treatment, which was simulated through some cycles of capillary water absorption and temperature changes. The experimental study proves that penetrating damp causes an increase in masonry unit weight of more than 20%. This basic result is significant in the structural assessment of historic masonry buildings. Subsequent papers will analyze the interaction with strengths parameters.

On the accuracy of UAV photogrammetric survey for the evaluation of historic masonry structural damages

Photogrammetric surveys via Unmanned Aerial Vehicles are nowadays a valuable tool for historic masonry structures inspection, surveillance, mapping and 3D modeling issues. When structural damage mapping and structural assessment are of interest obtaining accurate and reliable geometric models is a crucial issue. Therefore, the flight plan, the georeferencing and the data processing steps need to be properly designed.In this paper, a procedure for the photogrammetric survey via Unmanned Aerial Vehicles of a masonry structures is used in order to obtain effective visual inspections and a 3D model of a historic masonry arch bridge located along the ancient Via Amerina (Todi, Perugia, Italy). The photogrammetric survey provides a detailed representation of the actual geometry, including lack of volumes and significant cracks along the vault and the spandrel walls, outlining a severe damage state affecting all the structure. Finally, a Total Station and a Laser Scanner were used to compare the results obtained by photogrammetry, highlighting the advantages, the limits and the weaknesses offered by their use.

Two-dimensional hygrothermal modelling of masonry walls accounting for imperfections at the masonry joint

Hygrothermal models are important tool for assessing the risk of moisture-related decay mechanisms such as freeze-thaw in historic masonry structures. There are several sources of uncertainty when modelling masonry, related to material properties, boundary conditions, quality of construction and twodimensional interactions between mortar and unit. This paper examines one potential source of uncertainty; the imperfect nature of mortar joints. This interface may feature hairline cracks or imperfect bonds which can be modelled as a fracture. This will alter the rate of liquid transport into and out of the wall and impede the liquid transport between mortar and masonry unit. This means that the “effective” liquid transport of the wall system will be different then if measured properties of the bulk material were modelled. A detailed methodology for modelling the interface as a fracture is presented including material property definition. Two-dimensional DELPHIN models of masonry walls were created to simulate this interaction with varying levels of fracture widths (apertures). A series of hygrothermal simulations were performed to demonstrate change in moisture profile from the baseline condition. A significant increase in moisture absorption was found. This was dependent on aperture size, material and the relative size of the masonry modelled.

Restoration and Strengthening of Historical Buildings: The Example of Minceta Fortress in Dubrovnik

Firstly, some important aspects of the restoration and structural strengthening of historical masonry buildings are briefly discussed. Particularly, as an illustration of the appropriate approach to solving such an issue, an example of the restoration of the Minceta fortress in Dubrovnik has been described. Based on the results of the extensive field and laboratory works with defined damages and cracking state in the fortress, as well as located sliding surfaces in foundation rock near deep excavation, the static and dynamic analysis of stress‐strain states and safety was performed at the characteristic time point in the history of the fortress. Different geometry models for discretization of the fortress and the foundation rock, as well as different constitutive models for masonry and rock, were considered. Based on the results of the case study, the solutions were proposed for the strengthening of the foundation rock, as well as for the restoration and the limited allowed strengthening of the fortress. It is believed that this study may be helpful in the restoration and strengthening of similar historical masonry structures.

Dynamic Response of Historical Masonry Minaret under Seismic Excitation

In order to study the dynamic response of historical masonry structures, a scaled down brick masonry model constructed in civil engineering department at Baghdad University to simulate a part of a real case study, which is Alkifil historic minaret. Most of the previous researches about masonry structures try to understand the behavior of the masonry under seismic loading by experimental and numerical methods. In this paper, the masonry units (bricks) simulated in scale (S= 1/6) with the exact shape of the prototype bricks. Cementitious tile adhesive was selected to be the mortar for the modeling. The height of the model designed to be 1.5 m with a 0.5 m diameter. Detailed construction steps were presented in this paper. Experts built the model with high accuracy. A shaking table and other dynamic testing facilities were used at the University of Baghdad. The model was tested using the time-compressed El Centro 1940 NS earthquake at different amplitudes. The first ground motion of (PGA= 0.05g) which considered as weak ground motion was used to check the adequacy of the conventional behavior of the masonry model and the limit of the elastic behavior of the model during weak earthquakes. Moderate ground motion (PGA=0.15g) was performed to investigate the response of the model with minor to moderate damages. The severe ground motions were not appropriate to use in such circumstances because of the possibility to overturn the model. The experimental results showed very adequacy of the model to withstand the weak and moderate earth motion with no observed cracks.

A digital tool based on Genetic Algorithms and Limit Analysis for the seismic assessment of historic masonry buildings

New technologies are changing the way engineers work within the construction sector. Newly developed software solutions have provided effective methods to explore the design space at the interface between Structural Engineering and Architecture, allowing more efficient design strategies. These technologies are based on the integration of parametric generation and visualisation of geometries with powerful numerical solvers, employing user-customised routines. While the construction industry is rapidly moving the design of new construction towards a fully digitalised process, the assessment and the analysis of existing structures with such tools are still largely unexplored. In this context, a visual script for the structural assessment of out-of-plane mechanisms in historic masonry structures subject to seismic loading has recently been proposed by the authors. This relies on two successive steps of analysis, which are integrated into a digital work-flow. Datasets describing the geometric configuration of masonry structures are employed to automatically generate a non-linear Finite Element (FE) model and investigate possible collapse modes. A preliminary global analysis is performed using the commercial software ABAQUS CAE. This, in combination with the Control Surface Method (CSM), allows identifying the most likely failure mechanisms which are described by the geometry of the macro-blocks. The parametric modelling of the macro-blocks geometry allows exploring the domain of possible solutions using the upper bound method of limit analysis. A Genetic Algorithms (GA) solver is used to refine the geometry of the macro-blocks and search the minimum of the upper-bound load multipliers, which guarantees equilibrium. The script is implemented in the visual programming environment offered by Rhino3D+Grasshopper. In this paper, a set of parametric analyses considering various input variables such as friction coefficient and opening incidence are performed to verify both the sensitivity and the accuracy of the proposed method.