The Experts below are selected from a list of 1707 Experts worldwide ranked by ideXlab platform

Atorod Azizinamini - One of the best experts on this subject based on the ideXlab platform.

  • THE NEBRASKA HIGH PERFORMANCE Steel TWO-BOX GIRDER SYSTEM
    2020
    Co-Authors: K D Price, P A Cassity, Atorod Azizinamini
    Abstract:

    The Nebraska High Performance Steel (HPS) Two Box Girder project has been developed as a prototype structure for the replacement or new construction of typical grade separation bridges. These bridges represent a large market potential. The objectives for this prototype design are to simplify and accelerate construction, reduce cost, and increase life expectancy. This paper describes the prototype bridge design currently underway for a new two-span grade separation bridge near Omaha, Nebraska. The superstructure consists of twin box girders erected span-by-span without field splices. The design utilizes ASTM A709 HPS Grade 70W material. The deck is a full depth composite slab, precast, and posttensioned, designed for zero tension, with a wearing surface. Time dependent effects are fully accounted for. This paper describes the bridge analysis, design, and various constructibility issues. It is expected that the bridge will be constructed in 2002. Testing of various components will occur during design, and monitoring of the bridge performance will be provided in-service.

  • High-Performance Steel Cost Comparison Study
    Transportation Research Record, 2012
    Co-Authors: Richard Horton, Edward H. Power, Kristi Van Ooyen, Atorod Azizinamini
    Abstract:

    In 1996, the American Iron and Steel Institute, the Office of Naval Research, and the FHWA introduced new High-Performance Steel (HPS) grades with superior strength, weldability, and toughness. Since then, HPS-70W has been used successfully on bridges across the country and is increasingly gaining popularity with bridge design professionals. As HPS-70W Steel becomes a more viable alternative, designers are faced with two basic questions: When is HPS-70W Steel economical? What are the advantages of its use? To determine the economy of HPS-70W Steel, a study was conducted to compare the relative cost of Steel designs using HPS-70W and conventional-grade 50W. Investigated were the conditions in which HPS-70W Steel would offer economic advantages over grade 50W Steel as well as its other advantages. The study considered three two-span continuous bridge arrangements with 45.75-m (150-ft), 61-m (200-ft), and 76.25-m (250-ft) span lengths. Variable bridge cross sections were considered with 2.75-m (9-ft) and 3.6...

  • high performance Steel research front historical account of research activities
    Journal of Bridge Engineering, 2004
    Co-Authors: Atorod Azizinamini, Karl E Barth, Robert J. Dexter, Camille Rubeiz
    Abstract:

    This paper provides a summary of the major research studies conducted or being conducted in the U.S., to address design issues related to use of high performance Steel (HPS) in bridge construction. Emphasis of the paper is on the work related to HPS-485W Steel, which has specified minimum yield strength of 485 MPa (70 ksi). Design issues that are addressed in this paper include (1) flexural capacity of compact and noncompact HPS sections in negative bending; (2) issues related to ductility of HPS composite girders in the positive sections (this section presents a simplified ductility check for composite plate girders); (3) tensile ductility of HPS plates; (4) shear capacity of the hybrid Steel plate girders; (5) live load deflections; and (6) brief overview of the work that is underway to develop innovative bridge configurations capable of incorporating the advantages of HPS.

  • High Performance Steel: Research Front—Historical Account of Research Activities
    Journal of Bridge Engineering, 2004
    Co-Authors: Atorod Azizinamini, Karl E Barth, Robert J. Dexter, Camille Rubeiz
    Abstract:

    This paper provides a summary of the major research studies conducted or being conducted in the U.S., to address design issues related to use of high performance Steel (HPS) in bridge construction. Emphasis of the paper is on the work related to HPS-485W Steel, which has specified minimum yield strength of 485 MPa (70 ksi). Design issues that are addressed in this paper include (1) flexural capacity of compact and noncompact HPS sections in negative bending; (2) issues related to ductility of HPS composite girders in the positive sections (this section presents a simplified ductility check for composite plate girders); (3) tensile ductility of HPS plates; (4) shear capacity of the hybrid Steel plate girders; (5) live load deflections; and (6) brief overview of the work that is underway to develop innovative bridge configurations capable of incorporating the advantages of HPS.

  • High Performance Steel Cost Comparison Study
    High Performance Materials in Bridges, 2003
    Co-Authors: Richard Horton, Edward H. Power, Kristi Van Ooyen, Atorod Azizinamini
    Abstract:

    In 1996, the American Iron and Steel Institute, the Office of Naval Research and the Federal Highway Administration (FHWA) introduced new High Performance Steel (HPS) grades with superior strength, weldability and toughness. Since then, HPS-70W has been used successfully on bridges across the country and is increasingly gaining popularity with bridge design professionals. As HPS-70W Steel becomes a more viable alternative, designers are faced with two basic questions: When is HPS-70W Steel economical? What are the advantages of its use?

A M T Hassan - One of the best experts on this subject based on the ideXlab platform.

  • experimental and numerical studies of size effects of ultra high performance Steel fibre reinforced concrete uhpfrc beams
    Construction and Building Materials, 2013
    Co-Authors: Goran H Mahmud, Zhenjun Yang, A M T Hassan
    Abstract:

    Abstract Ultra High Performance Steel Fibre Reinforced Concrete (UHPFRC) is a relatively new construction material with high strength, fracture toughness and ductility. Although many aspects of UHPFRC have been investigated extensively, the size effects on structural strength of UHPFRC members remain largely unknown. This is mainly due to the lack of sufficient and reliable experimental data. This study investigates the size effects on flexural strength of similar notched UHPFRC beams under three-point bending tests. Nonlinear finite element simulations using the concrete damage plasticity (CDP) model in ABAQUS were also conducted, using material properties extracted from uniaxial tensile and compressive laboratory tests. It was found that the size effect on the beam nominal strength is little due to high ductility of UHPFRC. The numerical simulations using the CDP model can predict load–displacement curves and crack propagation process with good agreement with experimental data.

Jun Li - One of the best experts on this subject based on the ideXlab platform.

  • Mesoscale Analysis on Ultra-High Performance Steel Fibre Reinforced Concrete Slabs under Contact Explosions
    Composite Structures, 2019
    Co-Authors: Yun Peng, Chengqing Wu, Jun Li, Xiangwei Liang
    Abstract:

    Abstract This paper develops a more efficient and applicable three-dimensional mesoscale model to simulate ultra-high performance Steel fibre reinforced concrete (UHP-SFRC) slabs under contact explosions. In the proposed mesoscale model, UHP-SFRC consists of two components involving concrete matrix and Steel fibres. The straight Steel fibres are randomly distributed and orientated in the concrete matrix using the self-coding program. The proposed mesoscale model is firstly validated with a series of static and dynamic tests, and then it is adopted in the numerical simulation of contact explosions. With the verified mesoscale model, parametric studies are conducted to investigate the effects of slab thickness and TNT charge weight on the crater damage of UHP-SFRC slabs under contact explosions. Based on the results of parametric studies, a damage identification multi-classifier is constructed to recognize and predict the damage of UHP-SFRC slabs under contact explosions by using the support vector machine (SVM).

  • Numerical study of ultra-High-Performance Steel fibre–reinforced concrete columns under monotonic push loading:
    Advances in Structural Engineering, 2017
    Co-Authors: Shenchun Xu, Chengqing Wu, Jun Li
    Abstract:

    A finite element model is developed to investigate the behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns under combined axial compression and horizontal monotonic push loading. The effects of Steel fibre content, axial compression ratio, reinforcement ratio (or rebar ratio), stirrup ratio and shear span ratio on the structural behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns are investigated in detail. The numerical model shows good agreement in bond–slip behaviour of specimens based on CEB model results and numerical results, and such behaviour should be taken into consideration in engineering practice. The results indicate that the developed finite element model could predict the structural behaviour and failure mode of ultra-High-Performance Steel fibre–reinforced concrete columns effectively. It is found that the reinforcement ratio, axial compression ratio, shear span ratio and volume fraction of Steel fibre have a great influence on both the struc...

  • Numerical study of ultra-High-Performance Steel fibre–reinforced concrete columns under monotonic push loading:
    Advances in Structural Engineering, 2017
    Co-Authors: Shenchun Xu, Chengqing Wu, Jun Li
    Abstract:

    A finite element model is developed to investigate the behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns under combined axial compression and horizontal monotonic push loa...

  • Mesoscale study of Steel fibre-reinforced ultra-high performance concrete under static and dynamic loads
    Materials & Design, 2017
    Co-Authors: Yu Su, Pengtao Wu, Chengqing Wu, Jun Li, Xibing Li
    Abstract:

    Abstract In this paper, a three-dimensional numerical model to study the static and dynamic behaviour of ultra-high performance Steel fibre reinforced concrete is developed. Ultra-high performance Steel fibre reinforced concrete is assumed to be a two-phase model consisting of concrete matrix and Steel fibres. The concrete matrix is modelled with homogeneous material and the straight round Steel fibres are assumed to be dispersed with random locations and orientations in the matrix. The interfacial transition zone (ITZ) effect is studied based on the single fibre pull-out tests, and parameters describing the fibre-matrix one dimensional bond-slip behaviour are obtained and discussed based on both experimental and theoretical results. After the three-dimensional model is validated with static split tensile tests, split Hopkinson pressure bar (SHPB) split tensile tests are numerically modelled and the stress-time history is interpreted in the mesoscale level. The proposed model qualitatively and quantitatively predicts the material static and dynamic behaviours, and also gives insights on the fibre reinforcement effect in the concrete matrix.

Zhenjun Yang - One of the best experts on this subject based on the ideXlab platform.

  • experimental and numerical studies of size effects of ultra high performance Steel fibre reinforced concrete uhpfrc beams
    Construction and Building Materials, 2013
    Co-Authors: Goran H Mahmud, Zhenjun Yang, A M T Hassan
    Abstract:

    Abstract Ultra High Performance Steel Fibre Reinforced Concrete (UHPFRC) is a relatively new construction material with high strength, fracture toughness and ductility. Although many aspects of UHPFRC have been investigated extensively, the size effects on structural strength of UHPFRC members remain largely unknown. This is mainly due to the lack of sufficient and reliable experimental data. This study investigates the size effects on flexural strength of similar notched UHPFRC beams under three-point bending tests. Nonlinear finite element simulations using the concrete damage plasticity (CDP) model in ABAQUS were also conducted, using material properties extracted from uniaxial tensile and compressive laboratory tests. It was found that the size effect on the beam nominal strength is little due to high ductility of UHPFRC. The numerical simulations using the CDP model can predict load–displacement curves and crack propagation process with good agreement with experimental data.

Chengqing Wu - One of the best experts on this subject based on the ideXlab platform.

  • Mesoscale Analysis on Ultra-High Performance Steel Fibre Reinforced Concrete Slabs under Contact Explosions
    Composite Structures, 2019
    Co-Authors: Yun Peng, Chengqing Wu, Jun Li, Xiangwei Liang
    Abstract:

    Abstract This paper develops a more efficient and applicable three-dimensional mesoscale model to simulate ultra-high performance Steel fibre reinforced concrete (UHP-SFRC) slabs under contact explosions. In the proposed mesoscale model, UHP-SFRC consists of two components involving concrete matrix and Steel fibres. The straight Steel fibres are randomly distributed and orientated in the concrete matrix using the self-coding program. The proposed mesoscale model is firstly validated with a series of static and dynamic tests, and then it is adopted in the numerical simulation of contact explosions. With the verified mesoscale model, parametric studies are conducted to investigate the effects of slab thickness and TNT charge weight on the crater damage of UHP-SFRC slabs under contact explosions. Based on the results of parametric studies, a damage identification multi-classifier is constructed to recognize and predict the damage of UHP-SFRC slabs under contact explosions by using the support vector machine (SVM).

  • Experimental investigation on the cyclic behaviors of ultra-High-Performance Steel fiber reinforced concrete filled thin-walled Steel tubular columns
    Thin-walled Structures, 2019
    Co-Authors: Shenchun Xu, Chengqing Wu, Ruizhe Shao
    Abstract:

    Abstract This paper presents an experimental investigation on the cyclic behaviors of ultra-high performance Steel fiber reinforced concrete filled thin-walled Steel tubular columns under combined axial compression and cyclic lateral displacement loading. The failure modes, hysteretic behaviors, envelop diagrams, ductile performance, stiffness degradation and energy dissipation capacity were analyzed in detail. Notably, the cyclic behaviors of referenced high strength concrete and normal strength concrete filled thin-walled Steel tubular columns were also studied to get a better illustration of the cyclic behaviors of ultra-High-Performance Steel fiber reinforced concrete filled thin-walled Steel tubular columns. Furthermore, the effects of Steel tube thickness, axial compression ratio, volume ratio of Steel fiber and slenderness on the cyclic behaviors of ultra-High-Performance Steel fiber reinforced concrete filled thin-walled Steel tubular columns were also investigated in detail. The test results indicate that the high strength concrete filled thin-walled Steel tubular columns represent a poor cyclic behavior. However, replacing high strength concrete with ultra-high performance Steel fiber reinforced concrete to infill thin-walled Steel tubes can get an excellent cyclic behavior. Moreover, the cyclic behavior of ultra-high performance Steel fiber reinforced concrete filled thin-walled Steel tubular columns is also much better than that of normal strength concrete filled thin-walled Steel tubular columns.

  • Numerical study of ultra-High-Performance Steel fibre–reinforced concrete columns under monotonic push loading:
    Advances in Structural Engineering, 2017
    Co-Authors: Shenchun Xu, Chengqing Wu, Jun Li
    Abstract:

    A finite element model is developed to investigate the behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns under combined axial compression and horizontal monotonic push loading. The effects of Steel fibre content, axial compression ratio, reinforcement ratio (or rebar ratio), stirrup ratio and shear span ratio on the structural behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns are investigated in detail. The numerical model shows good agreement in bond–slip behaviour of specimens based on CEB model results and numerical results, and such behaviour should be taken into consideration in engineering practice. The results indicate that the developed finite element model could predict the structural behaviour and failure mode of ultra-High-Performance Steel fibre–reinforced concrete columns effectively. It is found that the reinforcement ratio, axial compression ratio, shear span ratio and volume fraction of Steel fibre have a great influence on both the struc...

  • Numerical study of ultra-High-Performance Steel fibre–reinforced concrete columns under monotonic push loading:
    Advances in Structural Engineering, 2017
    Co-Authors: Shenchun Xu, Chengqing Wu, Jun Li
    Abstract:

    A finite element model is developed to investigate the behaviour of ultra-High-Performance Steel fibre–reinforced concrete columns under combined axial compression and horizontal monotonic push loa...

  • Mesoscale study of Steel fibre-reinforced ultra-high performance concrete under static and dynamic loads
    Materials & Design, 2017
    Co-Authors: Yu Su, Pengtao Wu, Chengqing Wu, Jun Li, Xibing Li
    Abstract:

    Abstract In this paper, a three-dimensional numerical model to study the static and dynamic behaviour of ultra-high performance Steel fibre reinforced concrete is developed. Ultra-high performance Steel fibre reinforced concrete is assumed to be a two-phase model consisting of concrete matrix and Steel fibres. The concrete matrix is modelled with homogeneous material and the straight round Steel fibres are assumed to be dispersed with random locations and orientations in the matrix. The interfacial transition zone (ITZ) effect is studied based on the single fibre pull-out tests, and parameters describing the fibre-matrix one dimensional bond-slip behaviour are obtained and discussed based on both experimental and theoretical results. After the three-dimensional model is validated with static split tensile tests, split Hopkinson pressure bar (SHPB) split tensile tests are numerically modelled and the stress-time history is interpreted in the mesoscale level. The proposed model qualitatively and quantitatively predicts the material static and dynamic behaviours, and also gives insights on the fibre reinforcement effect in the concrete matrix.