The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Nizar Lajnef - One of the best experts on this subject based on the ideXlab platform.

  • a new solution of measuring thermal response of Prestressed Concrete Bridge girders for structural health monitoring
    Measurement Science and Technology, 2017
    Co-Authors: Pengcheng Jiao, Wassim Borchani, Hassene Hasni, Nizar Lajnef
    Abstract:

    This study develops a novel buckling-based mechanism to measure the thermal response of Prestressed Concrete Bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to Concrete Bridge girders, the electrical signals are used to detect the thermal response of Concrete Bridges. Finite element simulations are conducted to obtain the displacement of Prestressed Concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler–Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on Concrete Bridge girders. The proposed solution sufficiently measures the thermal response of Concrete Bridges.

Masoud Motavalli - One of the best experts on this subject based on the ideXlab platform.

  • determining the remaining tendon force of a large scale 38 year old Prestressed Concrete Bridge girder
    Pci Journal, 2006
    Co-Authors: Christoph Czaderski, Masoud Motavalli
    Abstract:

    A reliable method to determine the remaining prestressing force is often needed in routine inspection of Bridges, during rehabilitation of structures, or when retrofitting for increased vehicle capacity. This article reports on a study that was undertaken to determine the remaining tendon force of a large-scale (17 meters long), 38-year-old Prestressed Concrete Bridge girder. The authors used a semi-destructive test method and compare measurements of the prestressing force losses determined by their method with calculations methods based on fib guidelines and Swiss code. They found that calculated and measured prestressing force losses were generally in good agreement. A long-term prestressing force loss of about 20% was determined. The authors conclude that their material tests on the prestressing steel showed that 38 years of constant stress had no discernable effect on its tensile strength. This article reports on the first part of an extensive test program that will be carried out on five similar test beams.

  • damage identification using modal data experiences on a Prestressed Concrete Bridge
    Journal of Structural Engineering-asce, 2005
    Co-Authors: Olaf Huth, Glauco Feltrin, Johan Maeck, Nedim Kilic, Masoud Motavalli
    Abstract:

    Large scale tests with progressive damage on a Prestressed Concrete highway Bridge have been performed to investigate the sensitivity of several damage detection, localization, and quantification methods based on modal parameters. To investigate the quality of modal parameters, the data set of one damage step was analyzed by several output-only identification techniques. Although the Bridge was severely cracked, natural frequencies as well as mode shapes display only minor changes. However, the relative changes of mode shapes are larger than those observed for natural frequencies. A novel damage indicator, called mode shape area index, based on changes of mode shapes, has been developed and found as the most sensitive damage detection approach. Damage detection or localization via changes of the flexibility matrix performed better than natural frequencies or mode shapes alone. The application of the direct stiffness calculation and a sensitivity-based model update technique showed results having a high level of ambiguity about the location and quantification of damage also at the highest damage level. Evaluating the information collected in this study the test results indicate that an early stage damage identification in Prestressed Concrete Bridges is hardly possible because of the nearly complete recovery of stiffness after closing of cracks in Prestressed Concrete and the effect of environmental parameters on modal data.

Hyun Mock Shin - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Performance Assessment of Hollow Reinforced Concrete and Prestressed Concrete Bridge Columns
    International Journal of Concrete Structures and Materials, 2012
    Co-Authors: Dai-jeong Seong, Hyun Mock Shin
    Abstract:

    The aim of this study is to assess the seismic performance of hollow reinforced Concrete and Prestressed Concrete Bridge columns, and to provide data for developing improved seismic design criteria. By using a sophisticated nonlinear finite element analysis program, the accuracy and objectivity of the assessment process can be enhanced. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), is used to analyze reinforced Concrete and Prestressed Concrete structures. Tensile, compressive and shear models of cracked Concrete and models of reinforcing and prestressing steel were used to account for the material nonlinearity of reinforced Concrete and Prestressed Concrete. The smeared crack approach was incorporated. The proposed numerical method for the seismic performance assessment of hollow reinforced Concrete and Prestressed Concrete Bridge columns is verified by comparing it with the reliable experimental results. Additionally, the studies and discussions presented in this investigation provide an insight into the key behavioral aspects of hollow reinforced Concrete and Prestressed Concrete Bridge columns.

  • Analytical Study on Joints in Precast Segmental Prestressed Concrete Bridge Piers
    Journal of The Earthquake Engineering Society of Korea, 2007
    Co-Authors: Hyun Mock Shin
    Abstract:

    This paper presents an analysis procedures of Joints in precast segmental Prestressed Concrete Bridge piers. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced Concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked Concrete and a model of reinforcing steel. An unbended tendon element based on the finite element method, that can represent the interaction between tendon and Concrete of Prestressed Concrete member, is used. A joint element is newly developed to predict the inelastic behaviors of segmental joints. The proposed numerical method for joints in precast segmental Prestressed Concrete Bridge piers is verified by comparison with reliable experimental results.

  • Analytical Study on the Inelastic Behavior of Precast Segmental Prestressed Concrete Bridge Piers
    Journal of The Earthquake Engineering Society of Korea, 2005
    Co-Authors: Hyun Mock Shin
    Abstract:

    The purpose of this study is to investigate the inelastic behavior of precast segmental Prestressed Concrete Bridge piers. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced Concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked Concrete and a model of reinforcing steel. An unbonded tendon element based on the finite element method, that can represent the interaction between tendon and Concrete of Prestressed Concrete member, is used. A joint element is newly developed to predict the inelastic behaviors of segmental joints. The proposed numerical method for the inelastic behavior of precast segmental Prestressed Concrete Bridge piers is verified by comparison with reliable experimental results.

Hiroaki Kayanoki - One of the best experts on this subject based on the ideXlab platform.

  • Extradosed Prestressed Concrete Bridge with High-Strength Concrete, Japan—Yumekake Bridge
    Structural Engineering International, 2020
    Co-Authors: Hiroshi Akiyama, Masao Nakayama, Hiroaki Kayanoki
    Abstract:

    The Yumekake Bridge is an extradosed Prestressed Concrete Bridge over the Kumano River in a steep ravine located near the UNESCO World Heritage Site of Sacred Sites and Pilgrimage Routes in the Kii Mountain Range in Japan. This Bridge is the nation's first extradosed Prestressed Concrete Bridge with high-strength and self-compacting cast-in-place Concrete having specified design strength of 60 MPa for the tower and the box girder. The high-strength materials are also employed for the piers. This solution ensured slenderness and seismic resistance. The special features of the Bridge are reported in this paper.

  • extradosed Prestressed Concrete Bridge with high strength Concrete japan yumekake Bridge
    Structural Engineering International, 2011
    Co-Authors: Hiroshi Akiyama, Masao Nakayama, Hiroaki Kayanoki
    Abstract:

    The Yumekake Bridge is an extradosed Prestressed Concrete Bridge over the Kumano River in a steep ravine located near the UNESCO World Heritage Site of Sacred Sites and Pilgrimage Routes in the Kii Mountain Range in Japan. This Bridge is the nation's first extradosed Prestressed Concrete Bridge with high-strength and self-compacting cast-in-place Concrete having specified design strength of 60 MPa for the tower and the box girder. The high-strength materials are also employed for the piers. This solution ensured slenderness and seismic resistance. The special features of the Bridge are reported in this paper.

Pengcheng Jiao - One of the best experts on this subject based on the ideXlab platform.

  • a new solution of measuring thermal response of Prestressed Concrete Bridge girders for structural health monitoring
    Measurement Science and Technology, 2017
    Co-Authors: Pengcheng Jiao, Wassim Borchani, Hassene Hasni, Nizar Lajnef
    Abstract:

    This study develops a novel buckling-based mechanism to measure the thermal response of Prestressed Concrete Bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to Concrete Bridge girders, the electrical signals are used to detect the thermal response of Concrete Bridges. Finite element simulations are conducted to obtain the displacement of Prestressed Concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler–Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on Concrete Bridge girders. The proposed solution sufficiently measures the thermal response of Concrete Bridges.