scholarly journals Monitoring and diagnosis of historical masonry buildings and future perspective = Monitoreo y diagnóstico de edificios históricos de mampostería y perspectiva futura

2021 ◽  
Vol 4 (1) ◽  
pp. 44
Author(s):  
Adolfo Preciado ◽  
Fabiola Colmenero
Keyword(s):  
Dynamic Properties ◽  
Construction Materials ◽  
Experimental Tests ◽  
Future Perspective ◽  
Historical Buildings ◽  
Vertical Loading ◽  
Thermal Cameras ◽  
Nuevas Tecnologías ◽  
Historical Masonry ◽  
Non Destructive

AbstractHistorical buildings still existing in different parts of the world were constructed with unreinforced masonry and have an acceptable capacity to transmit vertical loading, but they are very vulnerable against horizontal loading induced by earthquakes. In order to protect these buildings belonging to the patrimony of the humanity from this hazard, we need to understand the construction materials, structural elements and loading transmission mechanism. Moreover, to rehabilitate or retrofit them, it is necessary to develop an understanding process of the structure though monitoring and in-situ/laboratory experimental tests to stablish a diagnosis. The structural monitoring campaigns are helpful to investigate the mechanical and dynamic properties of the building. The use of installed thermal cameras and micro-sensors at strategic parts of the historical buildings represent a very interesting and non-destructive option to measure different parameters constantly and for long periods of time. The present paper aims at briefly describing the different involved processes in the monitoring and structural diagnosis of historical buildings which is fundamental in order to preserve them against the effects of earthquakes by means of rehabilitation works and strengthening. Moreover, it is presented a future perspective about non-destructive and non-invasive experimental tests and diagnosis with the use of new technologies.ResumenLos edificios históricos que aún existen en diferentes partes del mundo fueron construidos con mampostería no reforzada y tienen capacidad aceptable para transmitir cargas verticales, pero son muy vulnerables ante cargas laterales inducidas por sismos. Para proteger de esta amenaza a estas edificaciones que forman parte del patrimonio de la humanidad, debemos de entender los materiales constructivos, elementos estructurales y su mecanismo de transmisión de cargas. Para decidir entre rehabilitar o reforzar, se debe de realizar un proceso de entendimiento de la estructura a través de un monitoreo y pruebas experimentales en sitio y en laboratorio que permitan generar un diagnóstico. Los monitoreos estructurales sirven para investigar sus propiedades mecánicas y dinámicas. El uso de cámaras térmicas y micro-sensores en puntos estratégicos de los edificios históricos representan una opción muy interesante y no destructiva para medir diferentes parámetros de forma constante y por largos periodos de tiempo. El presente artículo tiene como objetivo describir de forma puntual los diferentes procesos involucrados en el monitoreo y diagnóstico estructural de edificios históricos que resulta fundamental para poder conservarlos ante los efectos de los sismos por medio de trabajos de rehabilitación y refuerzo. Además, se presenta una perspectiva futura sobre pruebas experimentales y diagnósticos no destructivos ni invasivos con el uso de nuevas tecnologías.

Influence of the Supplementary Cementitious Materials on the Dynamic Properties of Concrete

2014 ◽  
Vol 660 ◽  
pp. 162-167
Author(s):  
Elbachir Elbahi ◽  
Sidi Mohammed El Amine Boukli Hacene
Keyword(s):  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Natural Pozzolan ◽  
Frequency Method ◽  
Concrete Mixtures ◽  
And Control ◽  
Non Destructive

The resonance frequency method is one of many non-destructive tests which allow us to evaluate construction materials. It was used to determine the dynamic properties of concrete, required in structures design and control, also considered as the key elements for materials dynamic. In this study, we chose a non-destructive approach to quantify-in laboratory-, the influence of adding “crushed limestone” and “natural pozzolan” on local concrete’s dynamic characteristics. However, several concrete mixtures have been prepared with limestone aggregates. The experimental used plan, allowed us to determine the dynamic modulus of elasticity, the dynamic modulus of rigidity of different formulated concretes.

Experimental Assessment Techniques for the Dynamic Properties of Concrete

2017 ◽  
Vol 21 ◽  
pp. 226-233
Author(s):  
Mihai Sergiu Stratulat ◽  
Oana Mihaela Banu ◽  
Ana Maria Toma ◽  
Petru Mihai ◽  
Ionuț Ovidiu Toma
Keyword(s):  
Dynamic Properties ◽  
Measurement Techniques ◽  
Construction Materials ◽  
Rubberized Concrete ◽  
Destructive Testing ◽  
Recycled Materials ◽  
Assessment Techniques ◽  
Standardized Measurement ◽  
The Impact ◽  
Non Destructive

Recent progress in measurement techniques have given rise to increasing interest in non-destructive testing. Incorporating non-conventional, recycled materials in concrete (i.e. rubber crumbs from discarded tires), the heterogeneity is increased. Based on this, it is of importance to determine to what degree the accepted protocols, valid for traditional materials, are applicable to newly developed construction materials with particular interest to rubberized concrete. Several tests, including parameters missing from the standardized measurement techniques, such as the increasing rate of the frequency during the sweep for finding the resonant frequency of the specimen, were conducted on two types of concrete: traditional and rubberized concrete. The assessment of the dynamic properties was done by means of the forced vibration method and the impact method. The obtained results indicate the fact that current procedures should be applied with care when considering aggregate replacement in traditional concrete by other recycled materials.

A Contribution to the Treatment of Salt Damage in Historical Buildings

2015 ◽  
Vol 824 ◽  
pp. 127-132
Author(s):  
Iñigo Antepara ◽  
Igor Medveď ◽  
Jaromír Žumár ◽  
Robert Černý
Keyword(s):  
Building Materials ◽  
Historical Buildings ◽  
Research Teams ◽  
Porous Building Materials ◽  
Salt Damage ◽  
Advantages And Disadvantages ◽  
Historical Masonry

Salts and water may cause serious damage to historical masonries. Therefore, numerous conservation treatments have been developed by research teams for the consolidation and protection of porous building materials affected by salt attack. Here the focus is on methods for obtaining an effective desalination of historical masonry, indicating their advantages and disadvantages. It is pointed out that cellulose is a favourite material added to poultices used in desalination.

scholarly journals Control del proceso de deshumidificación de muros con georradar. Un edificio patrimonial como caso de estudio

2014 ◽  
Vol 4 (1) ◽  
pp. 74-83 ◽  
Author(s):  
Susana B. Gea ◽  
R. Quinteros ◽  
L. Nallim
Keyword(s):  
Physical System ◽  
Historical Buildings ◽  
El Sistema ◽  
High Investment ◽  
Non Destructive ◽  
The Church ◽  
Harmful Effects ◽  
Rising Damp

RESUMENEn edificios históricos son conocidos los efectos nocivos de la presencia de humedad en muros, que deteriora detalles de ornamentación, conjuntamente con los componentes de la mampostería que conforma su propia estructura. Es el caso de la Iglesia Nuestra Señora de la Viña (Salta, Argentina), edificio del s. XIX que presentaba manifestaciones patológicas características de las producidas por la presencia de humedad ascendente. Las tareas de recuperación de las superficies exteriores fueron realizadas una vez que el sistema instalado (por electrólisis) deshumidificó los muros. La elevada inversión realizada requiere de un control periódico de la eficacia del sistema. En este trabajo se presentan los fundamentos y los resultados obtenidos con el empleo de georradar como recurso no destructivo para controlar el sistema de deshumidifación, cuya principal ventaja es la de poder detectar en forma precoz a lo largo del tiempo alguna falla en el sistema, evitando en forma indefinida la aparición de nuevas manifestaciones patológicas por humedad ascendente.Palabras clave: patología; mampostería; humedad; radar.ABSTRACTIn historical buildings the harmful effects in masonry due to moisture are well known, as it affects ornamentation and the components of the masonry which is also the building’s structure. That is the case of the church Nuestra Señora de la Viña (Salta, Argenti na), a XIX cent. building which presented typical pathological symptoms caused by rising damp. An electro physical system was installed in order to dehumidificate the masonry and external surfaces were subsequently recovered. This high investment requires a periodical control of the system’s efficiency. This article presents the foundations of and the results obtained by using an impulse radar as a non-destructive resource to control the dehumidification system. Its main advantage is the early detecting of a failure in the system and so avoiding new pathological symptoms caused by rising damp.Keywords: Pathology masonry; moisture; radar.

scholarly journals SELECTED TECHNICAL AND LEGAL ASPECTS OF THE PNEUMATIC LAUNCHER OPERATION FOR HOPKINSON MEASURING BARS SET

2020 ◽  
Author(s):  
Kamil Sobczyk ◽  
Leopold Kruszka ◽  
Ryszard Chmielewski ◽  
Ryszard Rekucki
Keyword(s):  
Mechanical Test ◽  
Dynamic Properties ◽  
Construction Materials ◽  
Legal Aspects ◽  
Test Stand ◽  
Physical Experiments ◽  
University Of Technology ◽  
Split Hopkinson ◽  
Material Sample ◽  
The Military

The paper presents selected technical and legal areas of the exploitation of a pneumatic launcher as an essential part of the mechanical test stand of the split Hopkinson bar for testing the dynamic properties of construction materials. The process of impact loading of the tested material sample is carried out by means of a loading bar-projectile fired from this launcher. The concept of the first stage of the modernization of the pneumatic launcher used at the Institute of Civil Engineering of the Military University of Technology (MUT) for over 20 years was discussed in order to facilitate the performance of physical experiments. The formal and legal requirements for the design, construction and usage of a test stand with a pneumatic launcher in a laboratory room are presented.

Comparative dynamic investigation of cross-laminated wooden panel systems: Shaking-table tests and analysis

2017 ◽  
Vol 21 (10) ◽  
pp. 1421-1436 ◽  
Author(s):  
Viktor Hristovski ◽  
Violeta Mircevska ◽  
Bruno Dujic ◽  
Mihail Garevski
Keyword(s):  
Energy Dissipation ◽  
Earthquake Engineering ◽  
Dynamic Properties ◽  
Seismic Energy ◽  
Experimental Tests ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Equivalent Viscous Damping ◽  
Cross Laminated Timber ◽  
Engineering Seismology

Cross-laminated timber has recently gained great popularity in earthquake-prone areas for construction of residential, administrative, and other types of buildings. At the Laboratory of the Institute of Earthquake Engineering and Engineering Seismology in Skopje, comparative full-scale shaking-table tests of cross-laminated timber panel systems have been carried out as a part of the full research program on the seismic behavior of these types of wooden systems, realized by Institute of Earthquake Engineering and Engineering Seismology, Skopje, and the Faculty of Civil and Geodetic Engineering (UL FCG), University of Ljubljana. Two different specimens built of cross-laminated timber panels have been tested: specimen containing a pair of single-unit principal wall elements (Specimen 1) and specimen containing a pair of two-unit principal wall elements (Specimen 2). In this article, the results from the shaking-table tests obtained for Specimen 2 and numerically verified by using appropriate finite element method–based computational model are discussed. Reference is also made to the comparative analysis of the test results obtained for both specimens. One of the most important aspects of the research has been the estimation of the seismic energy-dissipation ability of Specimen 1 and 2, via calculation of the equivalent viscous damping using the performed experimental tests. It is generally concluded that Specimen 2 exhibits a similar rocking behavior as Specimen 1, with similar energy-dissipation ability. Both specimens have manifested slightly different dynamic properties, mostly because Specimen 2 has been designed with one anchor more compared to Specimen 1. Forced vibration tests have been used for identification of the effective stiffness on the contacts for Specimen 2. This research is expected to be a contribution toward clarification of the behavior and practical design of cross-laminated timber panel systems subjected to earthquake loading.

Characterization of Building Stones Involved in Historical Masonry

2011 ◽  
Vol 324 ◽  
pp. 388-391 ◽  
Author(s):  
Zbyšek Pavlík ◽  
Eva Vejmelková ◽  
Milena Pavlíková ◽  
Martin Keppert ◽  
Robert Černý
Keyword(s):  
Mercury Porosimetry ◽  
Moisture Diffusivity ◽  
Water Vapor Transport ◽  
Historical Buildings ◽  
Water Absorption Coefficient ◽  
The Czech Republic ◽  
Vacuum Saturation ◽  
Historical Masonry ◽  
Saturation Method

Basic physical properties, pore size distribution and hygric properties of several types of stones which are used in reconstructions of historical buildings on the territory of the Czech Republic, namely several types of sandstone and argillite, are investigated. Basic physical characteristics are measured using the water vacuum saturation method, pore distribution by mercury porosimetry. Values of water absorption coefficient and apparent moisture diffusivity are determined by methods utilizing the results of water sorptivity measurements. Water vapor transport properties are accessed by the cup method. The obtained data represents valuable information for the application of studied materials in reconstructions and renewal of historical buildings.

Structural behavior of a pre-stressed cable steel truss exposed to fire

2017 ◽  
Vol 8 (2) ◽  
pp. 117-130
Author(s):  
Yunchun Xia
Keyword(s):  
Design Methodology ◽  
Experimental Tests ◽  
Structural Behavior ◽  
Fire Behaviour ◽  
Steel Cable ◽  
Final Temperature ◽  
Content Type ◽  
Vertical Loading ◽  
Stress Changes ◽  
Steel Truss

Purpose This paper aims to present the results of a study on the behaviour of a pre-stressed cable steel truss exposed to fire under fire conditions, basing on the results of a large programme of experimental tests. Design/methodology/approach The research investigated the deformation and stress change on a pre-stressed steel cable, including the deflection and displacements at different joints and fire behaviour of the pre-stressed steel cable. In other words, the structural behaviours at different loaded pre-stress, the vertical loading, steel cable height, truss dimension and the final temperature were compared in case of fire. Findings The results showed that the strain of longitudinal chord was far larger than those of the transverse chords, the strains of lower chords were significantly larger than those of the upper chords, strain of the chord near the longitudinal centreline were also larger than those of the outside transverse chords. During heating, the displacement and strain gradually changed from linear to nonlinear with loading, and the yielded chord had also in an order those chords which were at mid-span and near to the longitudinal centreline, yielded at first. Originality/value Temperatures in the furnace and at several points of the pre-stressed cable steel truss, as well as deformations, deflections and the stress changes of upper chord and the bottom steel cable and the change of displacement at different joint were measured to achieve those goals and, consequently, to assess the deformation behaviours and temperature of the pre-stressed steel cable.

High Resolution 3D modelling of Cylinder shape bodies applied to 1000 ancient BC columns

2020 ◽  
Author(s):  
Giuseppe Casula ◽  
Silvana Fais ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Paola Ligas
Keyword(s):  
High Resolution ◽  
Building Materials ◽  
Laser Scanner ◽  
3D Modelling ◽  
Ultrasonic Tomography ◽  
Terrestrial Laser Scanner ◽  
Non Destructive Testing ◽  
Historical Buildings ◽  
Destructive Testing ◽  
Non Destructive

<p>A multi-technique high resolution 3D modelling is described here aimed at the investigation of the state of conservation of carbonate columns of the 1000 BC ancient church of Buon Camino located in the homonymous district of the town of Cagliari (Italy).</p><p>The integrated application of different Non-Destructive Testing (NDT) diagnostic methods is of paramount importance to locate damaged parts of the building material of artefacts of historical buildings and to plan their restoration.</p><p>In this study a multi-step procedure was applied starting with a high resolution 3D modelling performed with the aid of Structure from Motion (SfM) Photogrammetry and Terrestrial Laser Scanner (TLS) methodologies. For this delicate task we operated simultaneously a Nikon D-5300 digital Reflex 24.2 Mega pixel Camera and a Leica HDS-6200 Terrestrial Laser Scanner. Subsequently, starting from the information detected with the above methods deeper material diagnostics was performed by means of high resolution 3D ultrasonic tomography aimed at the capillary definition of the elastic properties in the inner parts of the building materials. Measurements of longitudinal wave velocity from ultrasonic data were performed using the transmission method, namely two piezoelectric transducers coupled on the opposite sides of the investigated columns. The ultrasonic data acquisition was planned designing an optimal survey and providing a very good spatial coverage of the investigated columns. The columns were then criss-crossed by a large number of ray paths forming a dense 3D net. The SIRT (Simultaneous Iterative Reconstruction Tomography) algorithm was used to produce the 3D rendering of the velocity distribution inside the investigated columns. With this method the damaged parts were located and it was possible to distinguish them from the unaltered areas. The information on the superficial material conditions obtained by SfM and TLS techniques were compared and integrated with the information of the inner materials obtained by 3D ultrasonic tomography.</p><p>The results of the above non invasive geophysical techniques have been interpreted in the light of the different textural and petrophysical features of the study carbonate building materials. The study of the main textural features, such as the relationship between bioclasts, carbonate matrix, or that of the cement and petrophysical characteristics such as the nature and distribution of porosity were found to be of fundamental importance in the interpretation of the geophysical data (e.g. TLS reflectance and longitudinal acoustic wave propagation). Therefore a detailed analysis of the textures and pore microstructure were carried out from petrographic thin-sections in Optical and Scanning Electron Microscopy (OM/SEM). The final result of our multi-step-technique integrated methodology is a sophisticated 3D model with a high resolution 3D image representing the internal and external parts of the investigated columns in order to account for their static load resistance and possibly plan their conservation and restoration. The described procedure can also be applied to other cases in which a diagnosis is needed of the state of conservation of the variously shaped, layered-stones and composed artefacts typical of ancient historical buildings.</p><p>Key words: 3D Modelling, 3D Ultrasonic Tomography, Terrestrial Laser Scanner, SfM Photogrammetry, Non-Destructive Testing, Diagnostic, Ancient Columns, Stones</p>

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