A proposed strengthening model considering interaction of concrete-stirrup-FRP system for RC beams shear-strengthened with EB-FRP sheets

2018 ◽  
Vol 37 (10) ◽  
pp. 685-700 ◽  
Author(s):  
Weiwen Li ◽  
Chengyue Hu ◽  
Zejie Pan ◽  
Wei Peng ◽  
Yong Yang ◽  
...  
Keyword(s):  
Effective Strain ◽  
Polymer System ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded

Many factors can affect the shear capacity of fiber-reinforced polymer in reinforced concrete beams shear-strengthened with externally bonded fiber-reinforced polymer composites. Undoubtedly, the interaction of concrete-stirrup-fiber-reinforced polymer system is one of the key factors. However, most of the existing fiber-reinforced polymer design guidelines do not take account of this important factor on predicting fiber-reinforced polymer shear capacity. This study provides an advanced strengthening model that comprehensively considers the interaction among concrete, stirrup, and fiber-reinforced polymer for calculating the fiber-reinforced polymer effective strain. The advanced strengthening model provides a more accurate prediction for the fiber-reinforced polymer shear contribution compared with existing design guidelines.

Data analysis on fiber-reinforced polymer shear contribution of reinforced concrete beam shear strengthened with U-jacketing fiber-reinforced polymer composites

2016 ◽  
Vol 36 (2) ◽  
pp. 98-120 ◽  
Author(s):  
Chunyang Ji ◽  
Weiwen Li ◽  
Chengyue Hu ◽  
Feng Xing
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Guidelines ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Beam Size ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Effective Depth

Lots of studies have investigated the shear contribution of the fiber-reinforced polymer of reinforced concrete beams with externally bonded fiber-reinforced polymer (FRP). In this paper, based on more than 200 collected experimental results of reinforced concrete beams shear strengthened with U-jacketing fiber-reinforced polymer composites, four existing design guidelines on the fiber-reinforced polymer shear contribution of strengthened reinforced concrete beams are compared in terms of the effect of the shear span-to-effective depth ratio, beam size, and stirrup ratio. These three influence factors are found to play significant roles in the prediction accuracy of different design guidelines. This paper, therefore, proposes an advanced shear strength model, which considers the effect of shear span-to-effective depth ratio, beam size, and stirrup ratio. The proposed model can provide better predictions of fiber-reinforced polymer shear contribution.

Externally bonded carbon fiber–reinforced polymer composites for seismic retrofit of reinforced concrete coupling beams designed according to old codes

2018 ◽  
Vol 22 (6) ◽  
pp. 1412-1425 ◽  
Author(s):  
Sara Honarparast ◽  
Georges El-Saikaly ◽  
Omar Chaallal
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Polymer Composites ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded ◽  
Carbon Fiber Reinforced

A large number of existing buildings have seismic-resistant systems designed according to old code provisions. These structural systems exhibit non-ductile behavior and can present a significant risk in the case of a moderate or significant seismic event. Reinforced concrete–coupled shear walls designed to old codes and standards are among those deficient structures that need to be seismically upgraded. This article aims to investigate a new retrofitting and upgrading method using externally bonded carbon fiber–reinforced polymer composites for existing or/and damaged reinforced concrete coupling beams that can improve the seismic performance of them during earthquakes. To this end, an experimental test was conducted to evaluate the seismic behavior of two identical reinforced concrete–coupled shear wall specimens under reverse cyclic loading. To simulate the old existing building, the specimens were designed and constructed according to the old 1941 National Building Code of Canada with a conventionally reinforced coupling beam. One of the specimens was tested as a control, and the other was strengthened using externally bonded carbon fiber–reinforced polymer composites to evaluate the improvement in its seismic performance. Results show that the retrofit using externally bonded carbon fiber–reinforced polymer resulted in significant enhancement in strength and energy dissipation capacity compared to the conventionally reinforced coupling beam from the control specimen. In addition, externally bonded carbon fiber–reinforced polymer sheets resulted in much improved hysteretic and ductile behavior and in lesser strength and stiffness degradation.

scholarly journals Application of Sustainable Bamboo-Based Composite Reinforcement in Structural-Concrete Beams: Design and Evaluation

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 696 ◽  
Author(s):  
Alireza Javadian ◽  
Ian F. C. Smith ◽  
Dirk E. Hebel
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Design Guidelines ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Structural Concrete ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Composite Reinforcement

Reinforced concrete is the most widely used building material in history. However, alternative natural and synthetic materials are being investigated for reinforcing concrete structures, given the limited availability of steel in developing countries, the rising costs of steel as the main reinforcement material, the amount of energy required by the production of steel, and the sensitivity of steel to corrosion. This paper reports on a unique use of bamboo as a sustainable alternative to synthetic fibers for production of bamboo fiber-reinforced polymer composite as reinforcement for structural-concrete beams. The aim of this study is to evaluate the feasibility of using this novel bamboo composite reinforcement system for reinforced structural-concrete beams. The bond strength with concrete matrix, as well as durability properties, including the water absorption and alkali resistance of the bamboo composite reinforcement, are also investigated in this study. The results of this study indicate that bamboo composite reinforced concrete beams show comparable ultimate loads with regards to fiber reinforced polymer (FRP) reinforced concrete beams according to the ACI standard. Furthermore, the results demonstrate the potential of the newly developed bamboo composite material for use as a new type of element for non-deflection-critical applications of reinforced structural-concrete members. The design guidelines that are stated in ACI 440.1R-15 for fiber reinforced polymer (FRP) reinforcement bars are also compared with the experimental results that were obtained in this study. The American Concrete Institute (ACI) design guidelines are suitable for non-deflection-critical design and construction of bamboo-composite reinforced-concrete members. This study demonstrates that there is significant potential for practical implementation of the bamboo-composite reinforcement described in this paper. The results of this study can be utilized for construction of low-cost and low-rise housing units where the need for ductility is low and where secondary-element failure provides adequate warning of collapse.

A Study on Effective Strains in Different FRP Shear Strengthening Schemes for Analytical Optimized Truss Models

2014 ◽  
Vol 935 ◽  
pp. 168-171
Author(s):  
Hor Yin ◽  
Wee Teo
Keyword(s):  
Effective Strain ◽  
Design Guidelines ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Shear Strengthening ◽  
Reinforced Polymer ◽  
Truss Model ◽  
Minimum Total Energy ◽  
Current Design ◽  
Optimized Model

This paper presents an optimized truss model based on the principle of minimum total energy theorem. Six most recent effective strain ɛfrp,e models including three design guidelines were selected for the analysis. Three reinforced concrete beams strengthened with different fiber reinforced polymer (FRP) schemes were chosen. Comparing with current design guidelines, the results of these three beams indicate that the optimized model is promising and encouraging.

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