Macro scale material characterisation in support of meso scale modelling of masonry under uniaxial in-plane loading

The amount of detailed experimental data on the mechanical properties of brick masonry in the literature is limited regarding the orthotropic strength and fracture energy. A combined experimental/numerical methodology is proposed for the derivation of the macro scale properties of masonry. The experimental aspect deals with the mechanical characterisation of the individual materials, small masonry samples and masonry wallettes, including the relation of couplet to wallette strength. The numerical aspect is the calculation of the macroscopic properties of the masonry through discrete cracking calculations in two orthogonal directions. The numerical analysis results are compared with the experimental stress-strain results and Digital Image Correlation analysis. The Young's modulus and compressive fracture energy for the masonry composite are derived. The results are analysed in view of the resulting anisotropy of masonry and the obtained failure modes.Peer ReviewedPostprint (author's final draft

Crack growth in masonry::Numerical analysis and sensitivity study for discrete and smeared crack modelling

One of the most common obstacles faced by engineers when making numerical models to assess damage in historical masonry lies in defining the most suitable constitutive models when there is shortage of either material characterization or experimental data. This paper presents the implementation of a 2D finite element model (FEM) of a masonry wall by means of two strategies: a discrete cracking meso-model and a continuum smeared cracking macro-model. A sensitivity study is performed to investigate the effect of material properties variation on both modelling strategies, each of which considers the highly non-linear behaviour as well as the brittle cracking of the masonry. The numerical models are validated through the results obtained from an experimental testing campaign which considered a brick masonry wall subjected to cyclic three-point bending. The results of both modelling strategies compared with experimental results are presented, as well as the criteria considered for material characterization and the sensitivity analysis. Results indicate the suitability of both models to reproduce experimentally observed load capacity, failure mechanism and horizontal deformations. However, the meso-model showed higher accuracy in terms of failure mechanism and plastic deformations. The sensitivity analysis indicated that some material parameters, such as fracture energy, cohesion and tensile strength, significantly govern the final cracking. This is an important criterion for adequately choosing the parameters for further models in which crack width is considered, e.g. for settlement-induced cracking analysis.</p

Numerical Modeling of a Church Nave Wall Subjected to Differential Settlements::Soil-Structure Interaction, Time-Dependence and Sensitivity Analysis

Historic masonry structures are particularly sensitive to differential soil settlements. These settlements may be caused by deformable soil, shallow or inadequate foundation, structural additions in the building and changes in the underground water table due to the large-scale land use change in urban areas. This paper deals with the numerical modeling of a church nave wall subjected to differential settlement caused by a combination of the above factors. The building in question, the church of Saint Jacob in Leuven, has suffered extensive damage caused by centuries-long settlement. A numerical simulation campaign is carried out in order to reproduce and interpret the cracking damage observed in the building. The numerical analyses are based on material and soil property determination, the monitoring of settlement in the church over an extended period of time and soil-structure interaction. A sensitivity study is carried out, focused on the effect of material parameters on the response in terms of settlement magnitude and crack width and extent. Soil consolidation over time is considered through an analytical approach. The numerical results are compared with the in-situ observed damage and with an analytical damage prediction model.The authors acknowledge the funding received by BRAIN.be, Belspo in support of the GEPATAR research project (“GEotechnical and Patrimonial Archives Toolbox for ARchitectural conservation in Belgium” BR/132/A6/Gepatar).Peer ReviewedPostprint (author's final draft

Numerical analysis of settlement-induced damage to a masonry church nave wall

Differential soil settlements can induce structural damage to heritage buildings, causing not only economic but also cultural value losses. In 1963, the Saint Jacob’s church in Leuven was permanently closed to the public because of severe settlement-induced damage caused by insufficient bearing capacity of the founda- tion. Currently, the church is stabilized using a temporary shoring system. This work aims at implementing a practical modelling approach to predict damage on church nave walls subjected to differential settlements. For that purpose, a finite element model of the Saint Jacob’s church nave was generated and validated through on- site monitoring data including levelling, damage survey and laser scanningThis work was done within the framework of the GEPATAR project (“GEotechnical and Patrimonial Archives Toolbox for ARchitectural conservation in Belgium” BR/132/A6/Gepatar), supported by BRAIN.be, Belspo.Postprint (published version

Comparison of numerical modeling and measured data for a tunnel built in soft rocks

status: publishe

Macro Scale Material Characterization In Support Of Meso Scale Modelling Of Masonry Under Uniaxial In-Plane Loading

Abstract: The amount of detailed experimental data on the mechanical properties of brick masonry in the literature is limited regarding the orthotropic strength and fracture energy. A combined xperimental/numerical methodology is proposed for the derivation of the macro scale properties of masonry. The experimental aspect deals with the mechanical characterisation of the individual materials, small masonry samples and masonry wallettes, including the relation of couplet to wallette strength. The numerical aspect is the calculation of the macroscopic properties of the masonry through discrete cracking calculations in two orthogonal directions. The numerical analysis results are compared with the experimental stress-strain results and Digital Image Correlation analysis. The Young’s modulus and compressive fracture energy for the masonry composite are derived. The results are analysed in view of the resulting anisotropy of masonry and the obtained failure modes.status: publishe

Structural behavior and damage investigation of a neo-gothic masonry arcade

This study deals with the structural analysis of a heritage neo-gothic arcade located in Stromov-ka Park in Prague. This building has been of great importance to Czech citizens since the late 17th century. However, it has endured more than sixty years of negligence, natural disasters, and close range tunneling con-struction. The arcade is composed by a series of brick masonry segmental cross vaults and arches reinforced with embedded wrought iron, outer sandstone columns and inner opuka masonry pillars. The specific aim of the study was to assess the stability and structural behavior of the arcade and furthermore to establish the causes of the observed damage pattern. Analyses included Graphic Statics by means of a pseudo-3D thrust analysis and Non-Linear Finite Element Analysis (FEA) taking into account the construction process and the action of the embedded iron reinforcement. The findings of this study, using both previous approaches, deter-mined the structural importance of the embedded iron reinforcement on the overall stability of the arcade and concluded that the main reason for the current crack pattern came up from the structural system as designed.status: publishe

Settlement-induced damage monitoring of a historical building located in a coal mining area using PS-InSAR

status: publishe

Numerical Modeling of a Church Nave Wall Subjected to Differential Settlements: Soil-Structure Interaction, Time-Dependence and Sensitivity Analysis

© 2019, © 2019 Taylor & Francis. Historic masonry structures are particularly sensitive to differential soil settlements. These settlements may be caused by deformable soil, shallow or inadequate foundation, structural additions in the building and changes in the underground water table due to the large-scale land use change in urban areas. This paper deals with the numerical modeling of a church nave wall subjected to differential settlement caused by a combination of the above factors. The building in question, the church of Saint Jacob in Leuven, has suffered extensive damage caused by centuries-long settlement. A numerical simulation campaign is carried out in order to reproduce and interpret the cracking damage observed in the building. The numerical analyses are based on material and soil property determination, the monitoring of settlement in the church over an extended period of time and soil-structure interaction. A sensitivity study is carried out, focused on the effect of material parameters on the response in terms of settlement magnitude and crack width and extent. Soil consolidation over time is considered through an analytical approach. The numerical results are compared with the in-situ observed damage and with an analytical damage prediction model.status: publishe

Methodology for Heritage Conservation in Belgium based on Multi-Temporal Interferometry

Soil differential settlements that cause structural damage to heritage buildings are precipitating cultural and economic value losses. Adequate damage assessment as well as protection and preservation of the built patrimony are priorities at national and local levels, so they require advanced integration and analysis of environmental, architectural and historical parameters. The GEPATAR project (GEotechnical and Patrimonial Archives Toolbox for ARchitectural conservation in Belgium) aims to create an online interactive geo-information tool that allows the user to view and to be informed about the Belgian heritage buildings at risk due to differential soil settlements. Multi-temporal interferometry techniques (MTI) have been proven to be a powerful technique for analyzing earth surface deformation patterns through time series of Synthetic Aperture Radar (SAR) images. These techniques allow to measure ground movements over wide areas at high precision and relatively low cost. In this project, Persistent Scatterer Synthetic Aperture Radar Interferometry (PS-InSAR) and Multidimensional Small Baseline Subsets (MSBAS) are used to measure and monitor the temporal evolution of surface deformations across Belgium. This information is integrated with the Belgian heritage data by means of an interactive toolbox in a GIS environment in order to identify the level of risk. At country scale, the toolbox includes ground deformation hazard maps, geological information, location of patrimony buildings and land use; while at local scale, it includes settlement rates, photographic and historical surveys as well as architectural and geotechnical information. Some case studies are investigated by means of on-site monitoring techniques and stability analysis to evaluate the applied approaches. This paper presents a description of the methodology being implemented in the project together with the case study of the Saint Vincent’s church which is located on a former colliery zone. For this building, damage is assessed by means of PS-InSAR.status: publishe