scholarly journals Mechanical Properties of Steel-FRP Composite Bars under Tensile and Compressive Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Zeyang Sun ◽  
Yu Tang ◽  
Yunbiao Luo ◽  
Gang Wu ◽  
Xiaoyuan He
Keyword(s):  
Failure Modes ◽  
Flexural Rigidity ◽  
Compressive Loading ◽  
Concrete Structures ◽  
Frp Composite ◽  
Steel Bar ◽  
Calculated Stress ◽  
Frp Bar ◽  
Large Length ◽  
Ordinary Steel

The factory-produced steel-fiber reinforced polymer composite bar (SFCB) is a new kind of reinforcement for concrete structures. The manufacturing technology of SFCB is presented based on a large number of handmade specimens. The calculated stress-strain curves of ordinary steel bar and SFCB under repeated tensile loading agree well with the corresponding experimental results. The energy-dissipation capacity and residual strain of both steel bar and SFCB were analyzed. Based on the good simulation results of ordinary steel bar and FRP bar under compressive loading, the compressive behavior of SFCB under monotonic loading was studied using the principle of equivalent flexural rigidity. There are three failure modes of SFCB under compressive loading: elastic buckling, postyield buckling, and no buckling (ultimate compressive strength is reached). The increase in the postyield stiffness of SFCB rsf can delay the postyield buckling of SFCB with a large length-to-diameter ratio, and an empirical equation for the relationship between the postbuckling stress and rsf is suggested, which can be used for the design of concrete structures reinforced by SFCB to consider the effect of reinforcement buckling.

scholarly journals Moment-Curvature Behaviors of Concrete Beams Singly Reinforced by Steel-FRP Composite Bars

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Zeyang Sun ◽  
Yang Yang ◽  
Wenlong Yan ◽  
Gang Wu ◽  
Xiaoyuan He
Keyword(s):  
Bearing Capacity ◽  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Frp Composite ◽  
Steel Bar ◽  
Before And After ◽  
Frp Bar ◽  
Deformation Ability ◽  
Effective Depth ◽  
The Moment

A steel-fiber-reinforced polymer (FRP) composite bar (SFCB) is a kind of rebar with inner steel bar wrapped by FRP, which can achieve a better anticorrosion performance than that of ordinary steel bar. The high ultimate strength of FRP can also provide a significant increase in load bearing capacity. Based on the adequate simulation of the load-displacement behaviors of concrete beams reinforced by SFCBs, a parametric analysis of the moment-curvature behaviors of concrete beams that are singly reinforced by SFCB was conducted. The critical reinforcement ratio for differentiating the beam’s failure mode was presented, and the concept of the maximum possible peak curvature (MPPC) was proposed. After the ultimate curvature reached MPPC, it decreased with an increase in the postyield stiffness ratio (rsf), and the theoretical calculation method about the curvatures before and after the MPPC was derived. The influence of the reinforcement ratio, effective depth, and FRP ultimate strain on the ultimate point was studied by the dimensionless moment and curvature. By calculating the envelope area under the moment-curvature curve, the energy ductility index can obtain a balance between the bearing capacity and the deformation ability. This paper can provide a reference for the design of concrete beams that are reinforced by SFCB or hybrid steel bar/FRP bar.

Bond performance between SFCBs and grouted sleeves for precast concrete structures

2021 ◽  
pp. 136943322110015
Author(s):  
Yunlou Sun ◽  
Zeyang Sun ◽  
Liuzhen Yao ◽  
Yang Wei ◽  
Gang Wu
Keyword(s):  
Concrete Structure ◽  
Failure Modes ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Bond Slip ◽  
Analysis And Design ◽  
Bond Performance ◽  
Steel Bar ◽  
Critical Issues ◽  
Hybrid Reinforcement

A precast concrete structure reinforced by steel-fiber-reinforced polymer (FRP) composite bars (SFCBs) shows good durability and controllable post-yield stiffness, which makes this kind of structure suitable for marine infrastructure. The connection technology is one of the critical issues of a precast concrete structure with hybrid reinforcement. This paper presents an experimental study on the bond-slip testing (27 pullout specimens) of composite bars connected by a grouted deformed pipe splice (GDPS) connector with different bond lengths. The reinforcement included SFCBs and pure FRP bars. The test results showed that the failure modes could be classified into three categories: rebar pullout before or after the inner steel bar yielded, rupture of the FRP wrapped on the SFCB, and mixed failure of bar pullout with a partial fiber fracture. The average bond strength of the ordinary steel bar was approximately 146.8% that of the SFCB connector with the same anchored length. When the anchored length of the SFCB specimen was 15 d ( d: bar diameter), the specimen could be fully anchored to fracture. An explicit hardening bond-slip model considering the post-yield stiffness of the SFCB was used to predict the bond-slip behavior of the GDPS connector, and the experimental and analytical results agreed well with each other, which demonstrates that the proposed model could provided a reference for the analysis and design of connectors for SFCB-reinforced precast concrete structures.

scholarly journals Constitutive modeling for FRP composite materials subject to extreme loading

2018 ◽  
Vol 45 (2) ◽  
pp. 205-230
Author(s):  
Robert Asaro ◽  
David Benson
Keyword(s):  
Composite Materials ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Compressive Loading ◽  
Theory Model ◽  
Fiber Fracture ◽  
Deformation And Failure ◽  
Frp Composite ◽  
Physically Based ◽  
Interlaminar Shear

A physically based, finite deformation, rate and temperature dependent theory and model have been developed to simulate the deformation and failure of FRP composite materials and structures. Failure modes include: inter alia, fiber crushing and kinking as occurs during extreme compressive loading; fiber fracture as occurs in for example fragmentation; interlaminar shear as occurs at elevated temperatures and that leads to kinking; debonding and delamination including the coupling with laminate kinking; and debonding as occurs in cored FRP panels. The theory/model is capable of describing quasi-static (including creep) as occurs at elevated temperatures, and dynamic deformation and failure as occurs during shock, blast or impact. The model is implemented within LS DYNA and specific example simulations are described that illustrate the theory/model capabilities. In Part I, fragmentation is not covered in detail. Fiber fracture and fragmentation are to be covered to detail with specific examples in Part II.

Structural Materials. Steel Bar Corrosion of Concrete Structures Affected by Combined Deteriorating Causes.

1996 ◽  
Vol 45 (9) ◽  
pp. 1048-1054
Author(s):  
Yukio KITAGO ◽  
Shigehiro KOBAYASHI ◽  
Yasutaka KIKUCHI ◽  
Toyoaki MIYAGAWA ◽  
Manabu FUJII
Keyword(s):  
Concrete Structures ◽  
Structural Materials ◽  
Steel Bar

Load Testing to Collapse Limit State of Barr Creek Bridge

2000 ◽  
Vol 1696 (1) ◽  
pp. 92-102 ◽  
Author(s):  
Nicholas Haritos ◽  
Anil Hira ◽  
Priyan Mendis ◽  
Rob Heywood ◽  
Armando Giufre
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Flexural Rigidity ◽  
Load Capacity ◽  
Limit State ◽  
Dynamic Test ◽  
Service Condition ◽  
Flat Slab ◽  
Testing Program ◽  
Static Testing

VicRoads, the road authority for the state of Victoria, Australia, has been undertaking extensive research into the load capacity and performance of cast-in-place reinforced concrete flat slab bridges. One of the key objectives of this research is the development of analytical tools that can be used to better determine the performance of these bridges under loadings to the elastic limit and subsequently to failure. The 59-year-old Barr Creek Bridge, a flat slab bridge of four short continuous spans over column piers, was made available to VicRoads in aid of this research. The static testing program executed on this bridge was therefore aimed at providing a comprehensive set of measurements of its response to serviceability level loadings and beyond. This test program was preceded by the performance of a dynamic test (a simplified experimental modal analysis using vehicular excitation) to establish basic structural properties of the bridge (effective flexural rigidity, EI) and the influence of the abutment supports from identification of its dynamic modal characteristics. The dynamic test results enabled a reliably tuned finite element model of the bridge in its in-service condition to be produced for use in conjunction with the static testing program. The results of the static testing program compared well with finite element modeling predictions in both the elastic range (serviceability loadings) and the nonlinear range (load levels taken to incipient collapse). Observed collapse failure modes and corresponding collapse load levels were also found to be predicted well using yield line theory.

Numerical Simulation of Ring-Shape Rock Failure under Compressive Loading

2011 ◽  
Vol 378-379 ◽  
pp. 15-18
Author(s):  
Yong Bin Zhang ◽  
Zheng Zhao Liang ◽  
Shi Bin Tang ◽  
Jing Hui Jia
Keyword(s):  
Numerical Simulation ◽  
Fracture Process ◽  
Failure Modes ◽  
Failure Process ◽  
Compressive Loading ◽  
Orientation Angle ◽  
Crack Orientation ◽  
Ring Specimen ◽  
Ring Shape ◽  
Good Agreement

In this paper, a ring shaped numerical specimen is used to studying the failure process in brittle materials. The ring specimen is subjected to a compressive diametral load and contains two angled central cracks. Numerical modeling in this study is performed. It is shown that the obtained numerical results are in a very good agreement with the experiments. Effect of the crack orientation angle on the failure modes and loading-displace responses is discussed. In the range of 0°~40°, the fracture paths are curvilinear forms starting from the tip of pre-existing cracks and grow towards the loading points. For the crack orientation angle 90°, vertical fractures will split the specimen and the horizontal cracks do not influence the fracture process.

Crack Propagation and Local Failure Simulation of Reinforced Concrete Subjected to Projectile Impact Using RBSM

2016 ◽  
Author(s):  
Yoshihito Yamamoto ◽  
Soichiro Okazaki ◽  
Hikaru Nakamura ◽  
Masuhiro Beppu ◽  
Taiki Shibata
Keyword(s):  
Reinforced Concrete ◽  
Crack Propagation ◽  
High Velocity ◽  
Failure Modes ◽  
Concrete Structures ◽  
Constitutive Models ◽  
Local Failure ◽  
High Velocity Impact ◽  
Velocity Impact ◽  
Projectile Impact

In this paper, numerical simulations of reinforced mortar beams subjected to projectile impact are conducted by using the proposed 3-D Rigid-Body-Spring Model (RBSM) in order to investigate mechanisms of crack propagation and scabbing mode of concrete members under high-velocity impact. The RBSM is one of the discrete-type numerical methods, which represents a continuum material as an assemblage of rigid particle interconnected by springs. The RBSM have advantages in modeling localized and oriented phenomena, such as cracking, its propagation, frictional slip and so on, in concrete structures. The authors have already developed constitutive models for the 3D RBSM with random geometry generated Voronoi diagram in order to quantitatively evaluate the mechanical responses of concrete including softening and localization fractures, and have shown that the model can simulate cracking and various failure modes of reinforced concrete structures. In the target tests, projectile velocity is set 200m/s. The reinforced mortar beams with or without the shear reinforcing steel plates were used to investigate the effects of shear reinforcement on the crack propagation and the local failure modes. By comparing the numerical results with the test results, it is confirmed that the proposed model can reproduce well the crack propagation and the local failure behaviors. In addition, effects of the reinforcing plates on the stress wave and the crack propagation behaviors are discussed from the observation of the numerical simulation results. As a result, it was found that scabbing of reinforced mortar beams subjected to high velocity impact which is in the range of the tests is caused by mainly shear deformation of a beam.

Self-monitoring Properties of Concrete Columns with Embedded Cement-based Strain Sensors

2011 ◽  
Vol 22 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Huigang Xiao ◽  
Hui Li ◽  
Jinping Ou
Keyword(s):  
Cyclic Load ◽  
Failure Modes ◽  
Concrete Structures ◽  
Concrete Columns ◽  
Strain Sensors ◽  
Strain Sensing ◽  
Self Monitoring ◽  
Good Strain ◽  
Displacement Transducers ◽  
Monotonic Load

Cement-based strain sensors (CBCC sensor) were fabricated by taking the advantage of piezoresistivity of CB-filled CBCC. CBCC sensors were centrally embedded into concrete columns (made with C40 and C80 concretes, respectively) to monitor the strain of the columns under cyclic load and monotonic load by measuring the resistance of CBCC sensors. The comparison between the monitored results of CBCC sensors and that of traditional displacement transducers indicates that CBCC sensors have good strain-sensing abilities. Meanwhile, CBCC sensors exhibit different failure modes that break later than C40 concrete columns, but a little earlier than C80 concrete columns. Therefore, the strength-matching principle between embedded CBCC sensors and concrete columns is proposed in this article to guarantee the sensing capacity of CBCC sensors in various concrete structures. The analytical results agree well with the experimental phenomena.

scholarly journals Effects of Cyclic Freeze–Thaw on the Steel Bar Reinforced New-To-Old Concrete Interface

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1251
Author(s):  
Tao Luo ◽  
Chi Zhang ◽  
Xiangtian Xu ◽  
Yanjun Shen ◽  
Hailiang Jia ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Concrete Structures ◽  
Freezing Temperature ◽  
Frost Damage ◽  
Freezing And Thawing ◽  
Shear Properties ◽  
Freeze Thaw ◽  
Steel Bar ◽  
Concrete Interface

Frost damage of concrete has significant effects on the safety and durability of concrete structures in cold regions, and the concrete structures after repair and reinforcement are still threatened by cyclic freezing and thawing. In this study, the new-to-old concrete interface was reinforced by steel bar. The shear strength of the new-to-old concrete interface was tested after the new-to-old combination was subjected to cyclic freeze–thaw. The effects of the diameter of the steel bar, the compressive strength of new concrete, the number of freeze–thaw cycles and the freezing temperatures on the shear properties of new-to-old concrete interface were studied. The results showed that, in a certain range, the shear strength of the interface was proportional to the diameter of the steel bar and the strength of the new concrete. Meanwhile, the shear strength of the reinforced interface decreased with the decreasing of the freezing temperature and the increasing of the number of freeze–thaw cycles.

PERFORMANCE OF CONNECTED PRECAST LIGHTWEIGHT SANDWICH FOAMED CONCRETE PANEL UNDER FLEXURAL LOAD

2015 ◽  
Vol 75 (9) ◽  
Author(s):  
Noridah Mohamad ◽  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Josef Hadipramana ◽  
Norwati Jamaluddin
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Core Layer ◽  
Crack Pattern ◽  
Control Panel ◽  
Structural Behaviour ◽  
The Core ◽  
Steel Bar ◽  
Mode Of Failure ◽  
Foamed Concrete

This paper investigates the structural behaviour of two connected Sandwiched Precast Lightweight Foamed Concrete Panel (PLFP) in term of their load bearing capacities and failure modes. Three (3) connected PLFP panels were cast using foamed concrete as the wythe and polystyrene as the core layer. Each connected panel were cast from two single panels connected using L-bar connection. The panels were strengthened with steel bar reinforcement embedded in both wythes which were connected to each other by the steel shear truss connectors. The connected PLFP panels were tested under flexural load. A single PLFP panel was cast as a control panel and tested under axial load. The results were analysed in term of the panel’s ultimate load, crack pattern and mode of failure. Results showed that the two connected PLFP panels were able to sustain slightly lower ultimate load compared to single PLFP panel. Crack at 45 degree angle at top half of panel and small crack at surface between joint of the connection were observed.

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