The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Mohammed Jameel - One of the best experts on this subject based on the ideXlab platform.
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Nondestructive test methods for Concrete Bridges: A review
Construction and Building Materials, 2016Co-Authors: Sardar Kashif Ur Rehman, Zainah Ibrahim, Shazim Ali Memon, Mohammed JameelAbstract:NDT methods applicable to Concrete Bridges are reviewed. The methodology, advantages and disadvantages along with up to date research on NDT methods are presented. Different damage levels, having less dependence on inspector judgment, are suggested. Moreover, a flow chart based on damage level along with NDT methods and potential remedial measures are proposed for periodic health monitoring of structures. NDT methods are also suggested to address specific problems related to structures. Finally, the relation between some of the well-known NDT methods and most common problems encountered by the field engineers is proposed. Hence, the importance of structural health monitoring is highlighted.
Wei Zhang - One of the best experts on this subject based on the ideXlab platform.
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FEM Study on Shear Stiffness of Sloping Segmental Joints in Cantilever Casting Concrete Bridges
Applied Mechanics and Materials, 2012Co-Authors: Wei Zhang, Zong Lin Wang, Shi Zhu TianAbstract:Based on the conclusion of shear stiffness experiment of vertical segmental joint in cantilever casting Concrete Bridges (CCCB), finite element models (FEM) study was conducted to assess the shear stiffness of sloping segmental joints in this paper. Through the comparison of calculating relative vertical displacement at joint between vertical and sloping joint, it can be educed that the shear stiffness of slope joint between 5o ~15o increasing as the increasing of slope angle is consistently higher than vertical joint.
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Shear Stiffness of Segmental Joints in Cantilever Casting Concrete Bridges
Advanced Materials Research, 2011Co-Authors: Wei Zhang, Zong Lin Wang, Fadhil Naser AliAbstract:Joints between segments in cantilever casting Concrete Bridges require special attention in design and construction. These joints introduce discontinuity in the bridge; furthermore weaken the connection stiffness and strength of corresponding section, which may lead to excessive downwarping of bridge. Experiments were conducted to assess the shear stiffness of segmental joints section. The parameters studied included monolithic non-joints, joints roughened, joints roughened with shear-key. It was found that the shear stiffness of jointed section is largely lower than that of non-jointed section; however, the shear-key can effectively enhance the shear strength and especially shear stiffness of the joints section. Measures are proposed for shear-key design, and may provide a rational basis for the design of cantilever casting Concrete Bridges.
Joan R Casas - One of the best experts on this subject based on the ideXlab platform.
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Diagnostic Load Testing of Concrete Bridges, Principles and Example
2018Co-Authors: Joan R Casas, Piotr Olaszek, Juliusz Ciesla, Krzysztof GermaniukAbstract:Load testing of Concrete Bridges is a practice with a long history. Historically, and particularly before the unification of design and construction practices through codes, load testing was performed to show the travelling public that a newly built bridge was safe for use. Nowadays, with the aging infrastructure and increasing loads in developed countries, load testing is performed mostly for existing structures either as diagnostic or proof tests. For newly built Bridges, diagnostic load testing may be required as a verification of design assumptions, particularly for atypical bridge materials, designs, or geometries. For existing Bridges, diagnostic load testing may be used to improve analysis assumptions such as composite action between girders and deck, and contribution of parapets and other nonstructural members to stiffness. Proof load testing may be used to demonstrate that a structure can carry a given load when there are doubts with regard to the effect of material degradation, or when sufficient information about the structure is lacking to carry out an analytical assessment.
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PROBABILISTIC RESPONSE OF PRESTRESSED Concrete Bridges TO FATIGUE
1996Co-Authors: C Crespo-minguillon, Joan R CasasAbstract:This paper presents a model developed in the frame of doctoral research of the first author, for the analysis of the tensional sectional response of a partially prestressed Concrete bridge to fatigue action. It accounts for the non-linear constitutive relations in the materials within the section, and for the natural uncertainties inherent to the main variables involved in this problem. It also gives a statistical definition of the SN curves and of the variable "Miner Summation at Failure" for the steel components of Concrete Bridges.
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A STUDY ON THE FATIGUE BEHAVIOUR OF SEVERAL PARTIALLY PRESTRESSED Concrete Bridges
1994Co-Authors: C Crespo-minguillon, Joan R CasasAbstract:This paper presents the preliminary results of a wider study for the probabilistic assessment of the fatigue damage of partially prestressed Concrete Bridges, as compared with fully prestressed Concrete Bridges. The following steps are required to study the fatigue safety of partially prestressed Concrete Bridges: (1) study and their randomness, including traffic loads, thermal gradients and settlements; (2) analyse the response of a section under the effects of external actions, accounting for the randomness of the geometry and material properties; (3) study the behaviour of materials subjected to repetitive loads; and (4) define the limit state function. Results are given for three Concrete one-span 12.7m wide Bridges, each designed for three different degrees of prestressing and for two lanes of traffic in one direction. The fatigue safety of these Bridges is analysed, using: (1) a probabilistic simulation approach; and (2) the criteria of the fatigue specifications proposed in the European EC-2 standard. Only the fatigue damage of reinforcing and prestressing steel is analysed, and it is assumed that the fatigue damage of Concrete will be less than that of steel. For the covering abstract see IRRD 869077.
Sardar Kashif Ur Rehman - One of the best experts on this subject based on the ideXlab platform.
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Nondestructive test methods for Concrete Bridges: A review
Construction and Building Materials, 2016Co-Authors: Sardar Kashif Ur Rehman, Zainah Ibrahim, Shazim Ali Memon, Mohammed JameelAbstract:NDT methods applicable to Concrete Bridges are reviewed. The methodology, advantages and disadvantages along with up to date research on NDT methods are presented. Different damage levels, having less dependence on inspector judgment, are suggested. Moreover, a flow chart based on damage level along with NDT methods and potential remedial measures are proposed for periodic health monitoring of structures. NDT methods are also suggested to address specific problems related to structures. Finally, the relation between some of the well-known NDT methods and most common problems encountered by the field engineers is proposed. Hence, the importance of structural health monitoring is highlighted.
Dan M. Frangopol - One of the best experts on this subject based on the ideXlab platform.
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full scale experimental and numerical investigation on the ductility plastic redistribution and redundancy of deteriorated Concrete Bridges
Engineering Structures, 2021Co-Authors: Xiaoming Wang, Dan M. Frangopol, Xiangyuan Mao, You Dong, Huan Wang, Pei Tao, Shengpeng TangAbstract:Abstract Due to structural degradation, the performance of Concrete Bridges may degrade with time and result in catastrophic consequences. A novel approach is developed for evaluating the time-variant reliability of multi-girder Concrete Bridges considering the effects of the load-carrying mechanism and redundancy. By considering three failure modes at both the component and system levels, a new performance indicator is proposed for quantitatively evaluating the load elastic distribution and plastic redistribution among multiple girders. The adverse effects of material deterioration on the structural capacity, ductility, redundancy, load-carrying capacity, and failure mechanism are also investigated and incorporated into the analytical procedure, in which an incremental nonlinear finite element analysis of a 3D fiber beam element is used. Furthermore, the results associated with full-scale destructive tests of two in situ deteriorated Bridges, a reinforced Concrete (RC) and a prestressed RC (PRC) T-girder bridge, are adopted to evaluate the accuracy of the proposed approach. The feasibility and satisfactory performance of the proposed framework are evaluated using these two real-world Bridges. The results demonstrate that the load-carrying mechanism and redundancy significantly affect the structural ultimate load-carrying capacity and time-variant reliability of deteriorating structures.
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Time-variant performance indicators for Concrete Bridges exposed to corrosion
2014Co-Authors: Fabio Biondini, Dan M. FrangopolAbstract:The life-cycle performance of Concrete Bridges exposed to corrosion is investigated based on a set of time-variant probabilistic performance indicators including structural reliability, redundancy, robustness and resilience. The performance indicators are quantitatively evaluated based on a methodology for life-cycle nonlinear static and seismic analysis of deteriorating Concrete structures under uncertainty. The methodology accounts for the diffusion process of aggressive agents, such as chlorides, and the mechanical damage coupled to diffusion, including corrosion of steel reinforcement and deterioration of Concrete. The applicability of the proposed approach is shown through various examples, including the life-cycle reliability analysis and maintenance planning of a bridge pier, the redundancy and robustness evaluation of an arch bridge, and the seismic resilience assessment of a continuous box-girder bridge.
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Lifetime Performance Analysis of Existing Reinforced Concrete Bridges. I: Theory
Journal of Infrastructure Systems, 2005Co-Authors: Ferhat Akgül, Dan M. FrangopolAbstract:In this first part of a two-part paper, a general methodology for lifetime performance analysis of existing reinforced Concrete Bridges is presented. The framework for the methodology is established by identifying four distinct categories: limit state equations, random variables, deterministic parameters, and constant coefficients. The limit state equations are derived by strictly adhering to the load and capacity formulas and requirements set forth in AASHTO specifications. Generality is pursued by establishing parametric limit state equations such that the formulas are applicable to any type of reinforced Concrete bridge having similar superstructure components. The methods presented in this paper for reinforced Concrete Bridges are part of a larger study focusing on lifetime performance evaluation of multiple bridge types in an existing bridge network. For time-variant performance analysis, special emphasis is placed on the chloride penetration modeling in slab and girders. In the companion paper, the lifetime performance of reinforced Concrete slabs and girders in an existing bridge network is investigated and results are presented for three Bridges located in Colorado.
