The Experts below are selected from a list of 18123 Experts worldwide ranked by ideXlab platform
Hrvoje Smoljanovic - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis of 3d dry stone Masonry Structures by combined finite discrete element method
International Journal of Solids and Structures, 2017Co-Authors: Hrvoje Smoljanovic, željana Nikolic, Nikolina živaljic, A MunjizaAbstract:Abstract The evaluation of damage mechanism and the failure of dry-stone Masonry Structures subjected to seismic load is one of the most important aspects of seismic assessment of existing Masonry buildings. Discontinuities between the blocks, their mechanical interaction, large displacement and rotation are the main causes of degradation and collapse of these Structures. This paper presents the application of the combined finite-discrete element method (FDEM) in the analysis of 3D dry-stone Masonry Structures which is able to capture such mechanisms and structural damage both at joint and at block level. Moreover, the proposed approach includes friction forces based on Coulomb-type of law accounting for friction effects across dry joints and open cracks, in order to correctly simulate the mechanical behaviour of dry-stone Masonry. The capabilities of presented approach are demonstrated in a series of numerical tests, starting with sliding and rocking of single blocks, examination of dry joints shear behaviour, walls subjected to in-plane and out-of-plane load, and finally the simulation of the simple spatial stone Masonry Structure.
-
shaking table test of scaled model of protiron dry stone Masonry Structure
Procedia Engineering, 2017Co-Authors: željana Nikolic, Lidija Krstevska, Pavao Marovic, Hrvoje SmoljanovicAbstract:Abstract A great number of buildings which are classified as cultural heritage are historic Structures made of stone blocks with dry joints. Some of them, which were originally built with mortar in the joints, have experienced mechanical degradation over time and the behaviour of these Structures becomes similar to those made of dry stone Masonry. Most of these Structures have been damaged due to seismic activity. With the aim of increasing their resistance, many of dry stone historical Structures were further strengthened by clamps and bolts. In order to evaluate the resistance of these Structures, experimental investigations of the behaviour of existing stone Masonry Structures is very important. This paper presents experimental investigations of the behaviour of the model of stone Masonry Structure Protiron in the Peristyle square of the Diocletian’s Palace in Split, Croatia, under the seismic excitation. The Protiron was originally built at the turn of the fourth century only from stone blocks and bolts. At the beginning of the 20th century it was strengthened with clamps. A physical model of the Protiron for experimental shaking table testing was constructed in scale 1:4. The testing was performed on the 5×5 meters seismic shaking table at the Dynamic testing laboratory of the Institute of Earthquake Engineering and Engineering Seismology (IZIIS) in Skopje, Macedonia. The testing consisted of several phases: (1) definition of dynamic characteristics of the model; (2) seismic testing in linear range; (3) seismic testing in non-linear range by representative earthquake until failure of the model. The tests provided a clear insight into the seismic resistance and behaviour of the system, the mechanism of damage and failure under intensive tests, especially in the efficiency of the connecting elements (clamps) between the Masonry units (stones), which had a special role in increasing the seismic energy dissipation and protection of the Structure from collapse.
A Munjiza - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis of 3d dry stone Masonry Structures by combined finite discrete element method
International Journal of Solids and Structures, 2017Co-Authors: Hrvoje Smoljanovic, željana Nikolic, Nikolina živaljic, A MunjizaAbstract:Abstract The evaluation of damage mechanism and the failure of dry-stone Masonry Structures subjected to seismic load is one of the most important aspects of seismic assessment of existing Masonry buildings. Discontinuities between the blocks, their mechanical interaction, large displacement and rotation are the main causes of degradation and collapse of these Structures. This paper presents the application of the combined finite-discrete element method (FDEM) in the analysis of 3D dry-stone Masonry Structures which is able to capture such mechanisms and structural damage both at joint and at block level. Moreover, the proposed approach includes friction forces based on Coulomb-type of law accounting for friction effects across dry joints and open cracks, in order to correctly simulate the mechanical behaviour of dry-stone Masonry. The capabilities of presented approach are demonstrated in a series of numerical tests, starting with sliding and rocking of single blocks, examination of dry joints shear behaviour, walls subjected to in-plane and out-of-plane load, and finally the simulation of the simple spatial stone Masonry Structure.
Dora Foti - One of the best experts on this subject based on the ideXlab platform.
-
a new experimental approach to the pushover analysis of Masonry buildings
Computers & Structures, 2015Co-Authors: Dora FotiAbstract:The present paper proposes a new approach for the pushover analysis of Masonry Structures: the shear strength of a Masonry building is determined using experimental values combined with an analogy with rock masses. The shear strength criterion of Mohr-Coulomb is used, the values for the cohesion and friction angle being obtained by the non-linear criterion of Hoek-Brown for rock masses. The results of the proposed method are in good agreement with the values of the shear strength obtained using the Italian Code (NTC 08) for an LC3 level of knowledge of a Masonry Structure.
-
non destructive techniques and monitoring for the evolutive damage detection of an ancient Masonry Structure
Key Engineering Materials, 2014Co-Authors: Dora FotiAbstract:In the present article non-destructive testing evaluation of the existing damage evolution has been applied to some buildings of the medieval town of Craco (Matera, Italy) and, in particular, to the Normand tower. Actually the little town of Craco is totally abandoned as a consequence of the activation of the landslide motions of its soil depth. Nevertheless, the Normand tower still stands because it is located on a stable and stiffer foundation ground. The tower was built in the XII century. It is 20 m tall and has a symmetric square plan, with dimensions 11 m x 11 m; it was built for defense against enemy attacks. Inside the tower a cistern in reinforced concrete was placed in 1949. It is not connected to the structural walls of the tower; however it represents an obstacle for installing the damage detection equipment and sensors. In this article a preliminary study on the Masonry Structure of the Normand tower is carried on. A finite element numerical model has been developed and a modal analysis has been performed. The final aim of the research is to find out the evolutionary stage of the cracks and to propose a possible retrofit of the tower.
-
structural safety control of Masonry buildings non linear static seismic analysis with a non linear shear strength criterion
2012Co-Authors: Dora Foti, M Debernardis, V PaparellaAbstract:This paper has the purpose of comparing the shear strength obtained using the values proposed by the code for a level of knowledge LC3 [1,2] of a Masonry Structure with those experimentally obtained from the mechanical tests with flat jacks and the compression tests on stone elements. The shear strength criterion of Mohr-Coulomb has been utilised, applying for the cohesion and friction angle the values obtained by the non-linear criterion of Hoek-Brown for rock masses [3]. For the last criterion an analogy has been assumed between rock mass and Masonry; it has been properly adapted to the specific case of the Masonry Structure examined in the paper.
željana Nikolic - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis of 3d dry stone Masonry Structures by combined finite discrete element method
International Journal of Solids and Structures, 2017Co-Authors: Hrvoje Smoljanovic, željana Nikolic, Nikolina živaljic, A MunjizaAbstract:Abstract The evaluation of damage mechanism and the failure of dry-stone Masonry Structures subjected to seismic load is one of the most important aspects of seismic assessment of existing Masonry buildings. Discontinuities between the blocks, their mechanical interaction, large displacement and rotation are the main causes of degradation and collapse of these Structures. This paper presents the application of the combined finite-discrete element method (FDEM) in the analysis of 3D dry-stone Masonry Structures which is able to capture such mechanisms and structural damage both at joint and at block level. Moreover, the proposed approach includes friction forces based on Coulomb-type of law accounting for friction effects across dry joints and open cracks, in order to correctly simulate the mechanical behaviour of dry-stone Masonry. The capabilities of presented approach are demonstrated in a series of numerical tests, starting with sliding and rocking of single blocks, examination of dry joints shear behaviour, walls subjected to in-plane and out-of-plane load, and finally the simulation of the simple spatial stone Masonry Structure.
-
shaking table test of scaled model of protiron dry stone Masonry Structure
Procedia Engineering, 2017Co-Authors: željana Nikolic, Lidija Krstevska, Pavao Marovic, Hrvoje SmoljanovicAbstract:Abstract A great number of buildings which are classified as cultural heritage are historic Structures made of stone blocks with dry joints. Some of them, which were originally built with mortar in the joints, have experienced mechanical degradation over time and the behaviour of these Structures becomes similar to those made of dry stone Masonry. Most of these Structures have been damaged due to seismic activity. With the aim of increasing their resistance, many of dry stone historical Structures were further strengthened by clamps and bolts. In order to evaluate the resistance of these Structures, experimental investigations of the behaviour of existing stone Masonry Structures is very important. This paper presents experimental investigations of the behaviour of the model of stone Masonry Structure Protiron in the Peristyle square of the Diocletian’s Palace in Split, Croatia, under the seismic excitation. The Protiron was originally built at the turn of the fourth century only from stone blocks and bolts. At the beginning of the 20th century it was strengthened with clamps. A physical model of the Protiron for experimental shaking table testing was constructed in scale 1:4. The testing was performed on the 5×5 meters seismic shaking table at the Dynamic testing laboratory of the Institute of Earthquake Engineering and Engineering Seismology (IZIIS) in Skopje, Macedonia. The testing consisted of several phases: (1) definition of dynamic characteristics of the model; (2) seismic testing in linear range; (3) seismic testing in non-linear range by representative earthquake until failure of the model. The tests provided a clear insight into the seismic resistance and behaviour of the system, the mechanism of damage and failure under intensive tests, especially in the efficiency of the connecting elements (clamps) between the Masonry units (stones), which had a special role in increasing the seismic energy dissipation and protection of the Structure from collapse.
Hong Hao - One of the best experts on this subject based on the ideXlab platform.
-
numerical derivation of homogenized dynamic Masonry material properties with strain rate effects
International Journal of Impact Engineering, 2009Co-Authors: Xueying Wei, Hong HaoAbstract:Masonry is a composite material composed of bricks and mortar disposed in a regular arrangement. It is commonly used as load bearing or partition walls in building Structures. Owing to limitations of computer power, detailed distinctive modelling of brick and mortar of a realistic Masonry Structure or a Structure with Masonry infilled walls is usually not possible. Moreover, no dynamic Masonry material model can be found in the open literature. Dynamic Masonry material properties are important for an accurate prediction of Masonry failure and fragmentation under dynamic loads. In this paper, a continuum damage model with strain rate effect is developed for Masonry materials based on the homogenization method. The equivalent elastic properties, strength envelope and dynamic increase factors (DIFs) of strength and moduli for the homogenized Masonry material are numerically derived from the simulated responses of a representative volume element (RVE). A numerical model of an RVE is analyzed with detailed distinctive modelling of brick and mortar with their respective dynamic material properties obtained from laboratory tests. The homogenized material model can be used to analyse large-scale Masonry Structures subjected to dynamic loading.
-
experimental study of dynamic material properties of clay brick and mortar at different strain rates
Australian Journal of Structural Engineering, 2008Co-Authors: Hong Hao, Boris TarasovAbstract:It is well known that most construction materials behave differently under highspeed and static loading conditions. The strain rate effect on many materials, such as metals, concrete and rock, has been intensively investigated. However, the strain rate effect on Masonry materials, such as clay bricks and mortar mixed with cement, lime and sand, cannot be found in open literature. Understanding the strain rate effects on Masonry materials is important for accurately modelling Masonry Structure damage to high-velocity impact and blast loads. This paper reports experimental results of the strain rate effect on clay bricks and mortar materials. Uniaxial compression tests were carried out on brick and mortar specimens at various strain rates ranging from quasi-static (10-6 /s) to dynamic up to a strain rate of 200 /s. The strain rate effect on the yield and ultimate strength, yield and ultimate strain, elastic modulus, and Poisson's ratio of clay brick and mortar material are determined from the testing results. Empirical relations of dynamic increase factors (DIF) for the material properties are derived and presented. Discussions and comparisons of the DIF of brick and mortar obtained in this study are also made with other geomaterials, such as concrete and rock.