Simplified method for evaluating the behavior of strain hardening cementitious composite flexural strengthening reinforced concrete members

Various factors, including increase in traffic volume and weight, structural aging, and environmental impact, cause damage in structural members. This raises the importance of the maintenance, rehabilitation, and strengthening of reinforced concrete members. External post-tensioning is one of the widely-used strengthening techniques in many countries due to its advantages over other strengthening methods. Although flexural strengthening of existing structural members is a well-established method, shear strengthening of structural members, especially with existing shear cracks, has attained very little attention from researchers. Similarly, external fiber-reinforced polymer (FRP) bonding for shear strengthening of structural members, especially with existing shear cracks, is a relatively new area of research. This paper presents the results of an experimental study on the shear strengthening of reinforced concrete (RC) beams with existing shear cracks by external post-tensioning and external FRP bonding. The test result showed that the combined strengthening technique of external post-tensioning and external FRP bonding can effectively increase the shear capacity of RC beams with existing shear cracks.

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Analytical and Experimental Study of Flexural Strengthening of RC Members using Mechanically Fastened FRP Strips

Advanced Composites Letters ◽

10.1177/096369351102000104 ◽

2011 ◽

Vol 20 (1) ◽

pp. 096369351102000

Author(s):

Angeliki Papalou ◽

Thanasis C. Triantafillou

Keyword(s):

Reinforced Concrete ◽

Reinforced Concrete Beams ◽

Fiber Reinforced Polymer ◽

Flexural Strengthening ◽

Concrete Members ◽

Four Point Bending ◽

Reinforced Polymer ◽

Mechanically Fastened ◽

Frp Strips ◽

Increasing Load

The main objective of this work is to investigate the behaviour of reinforced concrete members strengthened for flexure using mechanically fastened fiber reinforced polymer (FRP) strips. Experiments were conducted on strengthened reinforced concrete beams loaded to failure with an increasing load in four-point bending. An analytical-numerical model was developed predicting the behaviour of the strengthened concrete beam and reproducing its large ductility before failure.

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Flexural Strengthening with Externally Poured Ultra High Toughness Cementitious Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.579 ◽

2011 ◽

Vol 675-677 ◽

pp. 579-582

Author(s):

Nan Wang ◽

Shi Lang Xu

Keyword(s):

Reinforced Concrete ◽

Flexural Behavior ◽

Structural Behavior ◽

Cementitious Composites ◽

Surface Cracks ◽

Flexural Strengthening ◽

Existing Structures ◽

High Toughness ◽

Concrete Members ◽

Flexural Bearing Capacity

The flexural behavior of reinforced concrete (RC) members strengthened with postpoured Ultra High Toughness Cementitious Composites (UHTCC) was investigated in this paper. The flexural behavior, failure mode and crack propagation during loading process of composite specimens were studied, and their structural behavior was also compared to that of original members. The experimental results showed that post-poured UHTCC materials enhanced flexural bearing capacity and toughness of existing concrete members. And introducing UHTCC material into strengthening enabled the composite specimens sustain the loading at a larger deflection without failure. It also revealed that post-poured UHTCC layer dispersed larger cracks in upper concrete into multiple tightly-spaced fine cracks, which prolonged the appearance of harm surface cracks and improved the durability of existing structures.

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A Simplified Method for Estimating the Amount of Energy Dissipated by Flexure-Dominated Reinforced Concrete Members for Moderate Cyclic Deformations

Earthquake Spectra ◽

10.1193/1.2197547 ◽

2006 ◽

Vol 22 (2) ◽

pp. 459-490 ◽

Cited By ~ 21

Author(s):

Honggun Park ◽

Taesung Eom

Keyword(s):

Reinforced Concrete ◽

Compressive Force ◽

Cyclic Behavior ◽

Dissipated Energy ◽

Structural Walls ◽

Element Analysis ◽

Axial Compressive Force ◽

Concrete Members ◽

Simplified Method ◽

Energy Dissipated

In advanced earthquake analysis/design methods, the cyclic behavior of reinforced concrete (RC) members, which is characterized by strength, deformability, and the amount of dissipated energy, must be estimated with reasonable precision. However, presently, the amount of dissipated energy is estimated by either empirical equations, which are not sufficiently accurate, or experiments and sophisticated numerical analysis, which are difficult to use in practice. In the present study, nonlinear finite element analysis was performed to investigate the behavioral characteristics of flexure-dominated RC members subject to moderate plastic displacements. The results showed that flexural pinching can occur due to the effects of axial compressive force and asymmetrical rebar arrangement. However, axial force has little effect on the energy dissipation. The arrangement and ratio of reinforcement have substantial effects. Based on the findings, a simplified method to estimate the energy dissipated by flexure-dominated members was developed, and was verified by comparing its results with those of existing experiments on beams, columns, and structural walls.

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