The Experts below are selected from a list of 27507 Experts worldwide ranked by ideXlab platform

Lawrence F. Kahn - One of the best experts on this subject based on the ideXlab platform.

  • testing of a full scale unreinforced Masonry Building following seismic strengthening
    Journal of Structural Engineering-asce, 2007
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    To investigate the effectiveness of several seismic strengthening techniques, a full-scale unreinforced Masonry (URM) structure was subjected to slowly applied lateral load reversals after the application of fiber reinforced plastic overlays, near surface mounted rods, and vertical posttensioning. Results showed that all techniques were effective for improving the seismic resistance of the previously tested URM Building structure. Each system either increased the lateral in-plane strength and/or provided continuity of pier and spandrel elements over increased lateral displacements. In addition, the response of the test structure (overall height to base ratio of approximately one) showed that global issues such as flange effects, the effects of overturning moment, and global rocking can be substantial and must be considered.

  • lateral load tests on a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Tianyi Yi, Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A full-scale two-story unreinforced Masonry (URM) Building was tested in a quasistatic fashion to investigate the nonlinear properties of existing URM structures and to assess the efficiency of several common retrofit techniques. This paper presents the main experimental findings associated with the nonlinear properties of the original URM structure. The test structure exhibited large initial stiffness and its damage was characterized by large, discrete cracks that developed in Masonry walls. Significant global behavior such as global rocking of an entire wall, and local responses such as rocking and sliding of each individual pier were observed in the Masonry walls with different configurations. In addition, formation of flanges in perpendicular walls and overturning moments had significant effects on the behavior of the test structure. A comparison between the experimental observations and the predictions of FEMA 356 provisions shows that major improvements are needed for this latter methodology.

  • analyses of a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A variety of elastic and inelastic analytical approaches were used to investigate the response of a full-scale unreinforced Masonry (URM) structure tested in the laboratory. Elastic analyses, employing a three-dimensional finite element model, revealed little coupling between parallel walls, and pointed to the appropriateness of two-dimensional analytical tools for further simulation of the test structure. The nonlinear analytical methods employed included, in order of increasing complexity, a rigid body analysis, a two-dimensional nonlinear pushover analysis, and a three-dimensional nonlinear finite element analysis. All methods considered important structural characteristics such as failure modes of perforated walls, flange effects, and global overturning moment effect. All methods predicted the experimental behavior fairly well. Strengths and weaknesses of these analytical approaches are discussed, and recommendations for analyzing old URM Buildings are presented.

Guido Magenes - One of the best experts on this subject based on the ideXlab platform.

  • shake table test of a strengthened stone Masonry Building aggregate with flexible diaphragms
    International Journal of Architectural Heritage, 2019
    Co-Authors: Gabriele Guerrini, Ilaria E. Senaldi, Francesco Graziotti, Guido Magenes, Katrin Beyer, Andrea Penna
    Abstract:

    A unidirectional shake-table test was performed on the half-scale prototype of a natural stone Masonry Building aggregate, to investigate the seismic performance of this type of historical construc...

  • Experimental seismic performance of a half-scale stone Masonry Building aggregate
    Bulletin of Earthquake Engineering, 2019
    Co-Authors: Ilaria E. Senaldi, Gabriele Guerrini, Paolo Comini, Francesco Graziotti, Andrea Penna, Katrin Beyer, Guido Magenes
    Abstract:

    This paper focuses on the unidirectional dynamic shake-table test performed on a prototype of a natural stone Masonry Building aggregate. The half-scale prototype was designed to reproduce the features of existing unreinforced stone Masonry Building aggregates, typical of the historical centres in many European cities, including the city of Basel, Switzerland. The three-storey-high aggregate prototype consisted of two weakly connected structural units, with double-leaf undressed stone Masonry walls incorporating a limited percentage of river pebbles. The specimen included flexible timber floor diaphragms and side-gabled timber roofs with different heights above the two units. Scaling the material mechanical properties of the specimen was necessary to satisfy similitude relationships without altering accelerations and material densities. An incremental, unidirectional dynamic test was performed up to near-collapse conditions of the prototype, using input ground motions selected to be compatible with realistic seismic scenarios for the region of Basel. This paper summarizes the main characteristics of the specimen and illustrates the evolution of its dynamic response and damage mechanisms.

  • experimental seismic performance of a full scale unreinforced clay Masonry Building with flexible timber diaphragms
    Engineering Structures, 2018
    Co-Authors: Stylianos Kallioras, Gabriele Guerrini, Francesco Graziotti, Andrea Penna, Umberto Tomassetti, Beatrice Marchesi, Guido Magenes
    Abstract:

    Abstract This paper presents the results of a unidirectional shake-table test performed on a full-scale, single-storey unreinforced Masonry Building. The specimen represented a typical detached house of the Groningen region of the Netherlands, consisting of double-wythe clay-brick unreinforced Masonry walls, without any specific seismic detailing. The Building prototype included large openings and a reentrant corner, causing a discontinuity in one of the perimeter walls. The floor was made of timber beams and planks, resulting in a flexible diaphragm. The roof, characterized by a very steep pitch, consisted of a series of timber trusses connected by wood purlins and boards. The two facades perpendicular to the shaking direction were designed to represent two typical gable geometries. An incremental dynamic test was conducted up to the near-collapse state of the specimen, using input ground motions compatible with induced-seismicity scenarios for the examined region. This paper summarizes the main characteristics of the specimen and the shake-table experimental results, illustrating the dynamic response of the structure, the evolution of the damage mechanisms, and the attainment of significant limit states.

  • Seismic damage diagnosis of a Masonry Building using short-term damping measurements
    Journal of Sound and Vibration, 2017
    Co-Authors: Leonidas Alexandros S. Kouris, Andrea Penna, Guido Magenes
    Abstract:

    Abstract It is of considerable importance to perform dynamic identification and detect damage in existing structures. This paper describes a new and practical method for damage diagnosis of Masonry Buildings requiring minimum computational effort. The method is based on the relative variation of modal damping and validated against experimental data from a full scale two storey shake table test. The experiment involves a Building subjected to uniaxial vibrations of progressively increasing intensity at the facilities of EUCENTRE laboratory (Pavia, Italy) up to a near collapse damage state. Five time-histories are applied scaling the Montenegro (1979) accelerogram. These strong motion tests are preceded by random vibration tests (RVT's) which are used to perform modal analysis. Two deterministic methods are applied: the single degree of freedom (SDOF) assumption together with the peak-picking method in the discrete frequency domain and the Eigen realisation algorithm with data correlations (ERA-DC) in the discrete time domain. Regarding the former procedure, some improvements are incorporated to locate rigorously the natural frequencies and estimate the modal damping. The progressive evolution of the modal damping is used as a key indicator to characterise damage on the Building. Modal damping is connected to the structural mass and stiffness. A square integrated but only with two components expression for proportional (classical) damping is proposed to fit better with the experimental measurements of modal damping ratios. Using this Rayleigh order formulation the contribution of each of the damping components is evaluated. The stiffness component coefficient is proposed as an effective index to detect damage and quantify its intensity.

  • damage assessment of unreinforced stone Masonry Buildings after the 2010 2011 canterbury earthquakes
    International Journal of Architectural Heritage, 2015
    Co-Authors: Ilaria E. Senaldi, Guido Magenes, Jason Ingham
    Abstract:

    The sequence of earthquakes that has affected Christchurch and Canterbury since September 2010 has caused damage to a great number of Buildings of all construction types. Following post-event damage surveys performed between April 2011 and June 2011, an inventory of the stone Masonry Buildings in Christchurch and surrounding areas was carried out in order to assemble a database containing the characteristic features of the Building stock, as a basis for studying the vulnerability factors that might have influenced the seismic performance of the stone Masonry Building stock during the Canterbury earthquake sequence. The damage suffered by unreinforced stone Masonry Buildings is reported and different types of observed failures are described using a specific survey procedure currently in use in Italy. The observed performance of seismic retrofit interventions applied to stone Masonry Buildings is also described, as an understanding of the seismic response of these interventions is of fundamental importance ...

Franklin Moon - One of the best experts on this subject based on the ideXlab platform.

  • testing of a full scale unreinforced Masonry Building following seismic strengthening
    Journal of Structural Engineering-asce, 2007
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    To investigate the effectiveness of several seismic strengthening techniques, a full-scale unreinforced Masonry (URM) structure was subjected to slowly applied lateral load reversals after the application of fiber reinforced plastic overlays, near surface mounted rods, and vertical posttensioning. Results showed that all techniques were effective for improving the seismic resistance of the previously tested URM Building structure. Each system either increased the lateral in-plane strength and/or provided continuity of pier and spandrel elements over increased lateral displacements. In addition, the response of the test structure (overall height to base ratio of approximately one) showed that global issues such as flange effects, the effects of overturning moment, and global rocking can be substantial and must be considered.

  • lateral load tests on a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Tianyi Yi, Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A full-scale two-story unreinforced Masonry (URM) Building was tested in a quasistatic fashion to investigate the nonlinear properties of existing URM structures and to assess the efficiency of several common retrofit techniques. This paper presents the main experimental findings associated with the nonlinear properties of the original URM structure. The test structure exhibited large initial stiffness and its damage was characterized by large, discrete cracks that developed in Masonry walls. Significant global behavior such as global rocking of an entire wall, and local responses such as rocking and sliding of each individual pier were observed in the Masonry walls with different configurations. In addition, formation of flanges in perpendicular walls and overturning moments had significant effects on the behavior of the test structure. A comparison between the experimental observations and the predictions of FEMA 356 provisions shows that major improvements are needed for this latter methodology.

  • analyses of a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A variety of elastic and inelastic analytical approaches were used to investigate the response of a full-scale unreinforced Masonry (URM) structure tested in the laboratory. Elastic analyses, employing a three-dimensional finite element model, revealed little coupling between parallel walls, and pointed to the appropriateness of two-dimensional analytical tools for further simulation of the test structure. The nonlinear analytical methods employed included, in order of increasing complexity, a rigid body analysis, a two-dimensional nonlinear pushover analysis, and a three-dimensional nonlinear finite element analysis. All methods considered important structural characteristics such as failure modes of perforated walls, flange effects, and global overturning moment effect. All methods predicted the experimental behavior fairly well. Strengths and weaknesses of these analytical approaches are discussed, and recommendations for analyzing old URM Buildings are presented.

Roberto T Leon - One of the best experts on this subject based on the ideXlab platform.

  • testing of a full scale unreinforced Masonry Building following seismic strengthening
    Journal of Structural Engineering-asce, 2007
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    To investigate the effectiveness of several seismic strengthening techniques, a full-scale unreinforced Masonry (URM) structure was subjected to slowly applied lateral load reversals after the application of fiber reinforced plastic overlays, near surface mounted rods, and vertical posttensioning. Results showed that all techniques were effective for improving the seismic resistance of the previously tested URM Building structure. Each system either increased the lateral in-plane strength and/or provided continuity of pier and spandrel elements over increased lateral displacements. In addition, the response of the test structure (overall height to base ratio of approximately one) showed that global issues such as flange effects, the effects of overturning moment, and global rocking can be substantial and must be considered.

  • lateral load tests on a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Tianyi Yi, Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A full-scale two-story unreinforced Masonry (URM) Building was tested in a quasistatic fashion to investigate the nonlinear properties of existing URM structures and to assess the efficiency of several common retrofit techniques. This paper presents the main experimental findings associated with the nonlinear properties of the original URM structure. The test structure exhibited large initial stiffness and its damage was characterized by large, discrete cracks that developed in Masonry walls. Significant global behavior such as global rocking of an entire wall, and local responses such as rocking and sliding of each individual pier were observed in the Masonry walls with different configurations. In addition, formation of flanges in perpendicular walls and overturning moments had significant effects on the behavior of the test structure. A comparison between the experimental observations and the predictions of FEMA 356 provisions shows that major improvements are needed for this latter methodology.

  • analyses of a two story unreinforced Masonry Building
    Journal of Structural Engineering-asce, 2006
    Co-Authors: Franklin Moon, Roberto T Leon, Lawrence F. Kahn
    Abstract:

    A variety of elastic and inelastic analytical approaches were used to investigate the response of a full-scale unreinforced Masonry (URM) structure tested in the laboratory. Elastic analyses, employing a three-dimensional finite element model, revealed little coupling between parallel walls, and pointed to the appropriateness of two-dimensional analytical tools for further simulation of the test structure. The nonlinear analytical methods employed included, in order of increasing complexity, a rigid body analysis, a two-dimensional nonlinear pushover analysis, and a three-dimensional nonlinear finite element analysis. All methods considered important structural characteristics such as failure modes of perforated walls, flange effects, and global overturning moment effect. All methods predicted the experimental behavior fairly well. Strengths and weaknesses of these analytical approaches are discussed, and recommendations for analyzing old URM Buildings are presented.

Francesco Graziotti - One of the best experts on this subject based on the ideXlab platform.

  • shake table test of a strengthened stone Masonry Building aggregate with flexible diaphragms
    International Journal of Architectural Heritage, 2019
    Co-Authors: Gabriele Guerrini, Ilaria E. Senaldi, Francesco Graziotti, Guido Magenes, Katrin Beyer, Andrea Penna
    Abstract:

    A unidirectional shake-table test was performed on the half-scale prototype of a natural stone Masonry Building aggregate, to investigate the seismic performance of this type of historical construc...

  • Experimental seismic performance of a half-scale stone Masonry Building aggregate
    Bulletin of Earthquake Engineering, 2019
    Co-Authors: Ilaria E. Senaldi, Gabriele Guerrini, Paolo Comini, Francesco Graziotti, Andrea Penna, Katrin Beyer, Guido Magenes
    Abstract:

    This paper focuses on the unidirectional dynamic shake-table test performed on a prototype of a natural stone Masonry Building aggregate. The half-scale prototype was designed to reproduce the features of existing unreinforced stone Masonry Building aggregates, typical of the historical centres in many European cities, including the city of Basel, Switzerland. The three-storey-high aggregate prototype consisted of two weakly connected structural units, with double-leaf undressed stone Masonry walls incorporating a limited percentage of river pebbles. The specimen included flexible timber floor diaphragms and side-gabled timber roofs with different heights above the two units. Scaling the material mechanical properties of the specimen was necessary to satisfy similitude relationships without altering accelerations and material densities. An incremental, unidirectional dynamic test was performed up to near-collapse conditions of the prototype, using input ground motions selected to be compatible with realistic seismic scenarios for the region of Basel. This paper summarizes the main characteristics of the specimen and illustrates the evolution of its dynamic response and damage mechanisms.

  • experimental seismic performance of a full scale unreinforced clay Masonry Building with flexible timber diaphragms
    Engineering Structures, 2018
    Co-Authors: Stylianos Kallioras, Gabriele Guerrini, Francesco Graziotti, Andrea Penna, Umberto Tomassetti, Beatrice Marchesi, Guido Magenes
    Abstract:

    Abstract This paper presents the results of a unidirectional shake-table test performed on a full-scale, single-storey unreinforced Masonry Building. The specimen represented a typical detached house of the Groningen region of the Netherlands, consisting of double-wythe clay-brick unreinforced Masonry walls, without any specific seismic detailing. The Building prototype included large openings and a reentrant corner, causing a discontinuity in one of the perimeter walls. The floor was made of timber beams and planks, resulting in a flexible diaphragm. The roof, characterized by a very steep pitch, consisted of a series of timber trusses connected by wood purlins and boards. The two facades perpendicular to the shaking direction were designed to represent two typical gable geometries. An incremental dynamic test was conducted up to the near-collapse state of the specimen, using input ground motions compatible with induced-seismicity scenarios for the examined region. This paper summarizes the main characteristics of the specimen and the shake-table experimental results, illustrating the dynamic response of the structure, the evolution of the damage mechanisms, and the attainment of significant limit states.

  • Dataset from the dynamic shake-table test of a full-scale unreinforced clay-Masonry Building with flexible timber diaphragms
    Data in brief, 2018
    Co-Authors: Stylianos Kallioras, Gabriele Guerrini, Umberto Tomassetti, Simone Peloso, Francesco Graziotti
    Abstract:

    This paper provides information related to the sensor measurements obtained from an unreinforced Masonry Building subjected to incremental dynamic shake-table tests at the EUCENTRE facilities in Pavia, Italy. These tests provide a unique data set that captures at full scale the in-plane and out-of-plane behavior of unreinforced Masonry walls, and the influence of flexible diaphragms on the dynamic global response of a complete Building. The authors made this information available to assist in the development of analytical and numerical models, necessary to estimate the dynamic response and the engineering parameters for the performance-based seismic assessment of unreinforced Masonry Buildings. All recorded data (acceleration and displacement time histories) and the videos of the tests can be requested online on the EUCENTRE repository at the URL www.eucentre.it/nam-project referring to EUC-BUILD-2. For further interpretation of the sensor recordings, and for a detailed discussion on the seismic performance of the Building specimen, the reader is referred to the article entitled "Experimental seismic performance of a full-scale unreinforced clay-Masonry Building with flexible timber diaphragms" (Kallioras et al., 2018) [1].