A review on acoustic emission monitoring for damage detection in masonry structures

Acoustic emission monitoring is widely used for damage detection in materials research and for site monitoring. Its use for masonry structures is however challenging due to the highly heterogenic nature of masonry and rapid signal attenuation. However, the non-invasive nature and high sensitivity of the technique also provide interesting opportunities, especially for historical masonry structures, to locate damage, identify severity of damage and rate of deterioration. Aim of this paper is to provide an extensive literature review on the application of the acoustic emission technique for masonry structures, addressing specific challenges and recent findings. AE-based methods for damage assessment in masonry are discussed in view of monitoring approaches, wave propagation, source location and crack development under static, fatigue and creep loading. Site applications are discussed for identifying crack location and crack propagation in historical masonry towers, buildings and masonry arch bridges. The paper concludes with future challenges identified in this research field

Debonding damage analysis in composite-masonry strengthening systems with polymer- and mortar-based matrix by means of the acoustic emission technique

Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historic masonry structures. A full characterization of the bond behavior and of the short- and long-term failure mechanisms is crucial to ensure effective design, compatibility with the historic substrate and durability of the strengthening solution. Therein, non-destructive techniques are essential for bond characterization, durability assessment and on-site condition monitoring. In this paper, the acoustic emission (AE) technique is evaluated for debonding characterization and localization on fiber reinforced polymer (FRP) and steel reinforced grout-strengthened clay bricks. Both types of strengthening systems are subjected to accelerated ageing tests under thermal cycles and to single-lap shear bond tests. During the reported experimental campaign, AE data from the accelerated ageing tests demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites, and debonding damage was successfully detected, characterized and located. In addition, a qualitative comparison is made with digital image correlation and infrared thermography, in view of efficient on-site debonding detection.The authors acknowledge the financial support of the Research Foundation-Flanders (FWO) for the mobility grant offered to Els Verstrynge.info:eu-repo/semantics/publishedVersio

Application of acoustic emission technique for bond characterization in FRP-masonry systems

The acoustic emission (AE) technique is used for investigating the interfacial fracture and damage propagation in GFRP-and SRG-strengthened bricks during debonding tests. The bond behavior is investigated through single-lap shear bond tests and the fracture progress during the tests is recorded by means of AE sensors. The fracture progress and active debonding mechanisms are characterized in both specimen types with the aim of AE outputs. Moreover, a clear distinction between the AE outputs of specimens with different failure modes, in both SRG-and GFRP-strengthened specimens, is found which allows characterizing the debonding failure mode based on acoustic emission data.(undefined

The need for conservation management in European 19th century urban housing

The prediction of the dynamic response of Unreinforced Masonry Structures (URMS) is a very complex task, since it is governed by material degradation and cyclic hysteric behaviour. Procedures based on nonlinear static analyses have been proposed for the seismic assessment of URMS, without properly considering hysteretic energy dissipation during the dynamic response. Even though dynamic nonlinear analyses provide satisfactory simulations of the seismic response, its application requires considerable computational effort and high user expertise for the accurate definition of the material properties, making it unsuitable for practical applications. However, simplified macro-element strategies, capable of simulating in-plane and outof-plane nonlinear responses, could represent a satisfactory engineering solution in the dynamic context. In this study the nonlinear static and dynamic in-plane behaviour of URMS was assessed by means of plane discrete models. The preliminary numerical investigation evidenced the need to define suitable hysteric constitutive laws for reliable nonlinear dynamic analyses of URMS.(undefined

Soil Settlement and Uplift Damage to Architectural Heritage Structures in Belgium: Country-Scale Results from an InSAR-Based Analysis

Soil movement may be induced by a wide variety of natural and anthropogenic causes, which are detectable in the local scale, but may influence the movement of the soil over vast geographical expanses. Space borne interferometric synthetic aperture radar (InSAR) measurements of ground movement provide a method for the remote sensing of soil settlement and uplift over wide geographic areas. Based on this settlement and uplift evaluation, the assessment of the potential damage to architectural heritage structures is possible. In this paper an interdisciplinary monitoring and analysis method is presented that processes satellite, cadastral, patrimonial and building geometry data, used for the calculation of settlement and uplift damage to architectural heritage structures in Belgium. It uses processed InSAR data for the determination of the soil movement profile around each case study, of which the typology is determined from patrimonial information databases and the geometry is calculated from digital elevation models. The impact on the historic structures is calculated from the determined soil movement profile based on various soilstructure interaction models for buildings. The resulting damage is presented in terms of a numerical index illustrating its severity according to different criteria. In this way the potential soil movement damage is quantified in a large number of buildings in an easily interpretable and user-friendly fashion. The processing of InSAR data collected over the previous 3 decades allows the determination of the progress of settlement- and uplift-induced damage in this time period. With the integration of newly acquired and more accurate data, the methodology will continue to produce results in the coming years, both for the evaluation of soil settlement and uplift in Belgium as for introducing related damage risk data for existing architectural heritage buildings. Results of the analysis chain are presented in terms of potential current damage for selected areas and buildings

Research on structural stability of the traditional timber houses in Bursa-Turkey

Bu çalışma, 13-15, Eylül 2016 tarihlerinde Leuven[Belçika]’ da düzenlenen 10th International Conference on Structural Analysis of Historical Constructions (SAHC) - Anamnesis, Diagnosis, Therapy, Controls Kongresi‘nde bildiri olarak sunulmuştur.Bursa has been exposed to many destructive earthquakes throughout the history; however, the traditional timber structural buildings are able to survive without significant damage until today. In this context, deteriorated, damaged and in good condition timber structure buildings which are located in various towns and villages of Bursa were examined in terms of construction systems, irregularities in plans and elevations, load bearing elements, cantilevers, material properties and the level of damages. In this study the researchers tried to find out the structural stability of these buildings by comparing their structural features obtained from the damaged and non damaged houses.As a result of the studies and investigations, it was observed that thanks to the system of using different joint techniques and wall bracing systems, the use of buttresses, capitals, metal connections, adobe in the design of timber structures, they have survived to the present day.KU Leuven, Raymond Lemaire Ctr ConservatArte ConstructoTrimbleCARMEUSELhoistVerstraete VanheckeMRT Grp MonumentABInBevKU Leuven, Civil Engn Dep

AE in Masonry

The purpose of this chapter is to highlight the strengths and pitfalls of using the Acoustic Emission (AE) technique for damage assessment in masonry structures, such as historical buildings and monuments, that are subjected to high sustained loads or are exposed to seismic risk. Firstly, an overview is presented of AE analysis techniques for damage detection in masonry, with specific reference to the issues that complicate AE sensing in masonry. Secondly, an overview of the authors’ experience with on-site AE monitoring in historical masonry structures is presented and illustrated with several case studies. In particular, the possibility to evaluate damage progress and structural stability from the evolution of AE activity is shown, and, if the position of the defects is not known to begin with, it can be located by making use of a multiplicity of sensors and triangulation techniques. Finally, AE monitoring during experimental campaigns, with AE-based prediction of creep and fatigue failure and a comparison of AE results with other crack measurement techniques during a test on a full-scale masonry wall, is presented

Investigation on single fiber pullout and interfacial debonding mechanisms with acoustic emission techniques

: Fiber pullout behaviour is of great significance in post-crack performance of steel fiber reinforced concrete. Firstly, in order to understand the debonding behaviour of the fiber/matrix interface during the pullout process, single fiber pullout tests are carried out in this study. Both hooked-end fibers and straight fibers with the same embedded length of 30mm are considered. Load versus relative displacement curves of different fiber type are studied. Secondly, to investigate the debonding behaviour along the interfacial zone, acoustic sensors are also applied. Based on the acoustic signal detected by the sensors attached on the concrete specimen, debonding mechanism is identified with parameter based AE signal analysis. Moreover, frequency and energy spectrum with regard to fracture behaviour of interfacial zone are further analyzed