Qudeer Hussain

Shear strengthening of RC deep beams with sprayed fibre-reinforced polymer composites (SFRP) and anchoring systems: part 1. Experimental study

This paper presents an experimental study on externally bonded sprayed fibre reinforced polymers (shortly as SFRP) RC deep beams to investigate the efficiency of SFRP in shear strengthening. Based on the experimental results, reinforced concrete deep beams strengthened by SFRP composites may fail by debonding of SFRP from the beam surface. To avoid such failures, various forms of anchoring systems have been proposed and tested to evaluate their performances in preventing the delamination of SFRP from concrete surface. A series of three-point loading tests was conducted on SFRP strengthened deep beams. The research parameters included SFRP material (glass and carbon), thickness, configuration, i.e. SFRP applied onto two or three sides, compressive strength of concrete and types of anchoring systems. Proposed anchoring systems (Through Bolts, Mechanical Expansion Bolts and Epoxy Chemical Bolts) were found to be effective to prevent the delamination of SFRP. Test results indicated that SFRP was capable of enhancing the ultimate load and deflection of RC deep beams provided that adequate anchoring system is installed. The performance of SFRP strengthening depends on several key variables such as SFRP material, thickness, strengthening configuration, strength of concrete, type of anchoring system and length of the anchor bolt.

Shear Strengthening of RC Deep Beams with Sprayed Fiber-reinforced Polymer Composites (SFRP): Part 2 Finite Element Analysis

This paper presents the finite element analysis conducted on SFRP strengthened reinforced concrete (RC) deep beams. The analysis variables included SFRP material (glass and carbon), SFRP thickness (3 mm and 5 mm), SFRP configuration and strength of concrete. The externally applied SFRP technique is significantly effective to enhance the ultimate load carrying capacity of RC deep beams. In the finite element analysis, realistic material constitutive laws were utilized which were capable of accounting for the non-linear behavior of materials. The finite element analysis was performed using computer software WCOMD. In the analysis, two dimensional eight-node reinforced concrete planar elements for concrete and planar elements with elastic-brittle behavior for SFRP were used to simulate the physical models. The concept of smeared cracking in concrete and steel was adopted over the element. The calculated finite element results are found to be in good agreement with the experimental results and to capture the structural response of both un-strengthened and SFRP strengthened RC deep beams. A comparison between the finite element results and experimental data proved the validity of the finite element models. Further, the finite element models were utilized to investigate the behavior of RC deep beams strengthened with different directions of SFRP Strips (vertical and horizontal). The vertical SFRP strips are found to be more effective than horizontal ones.

Compressive Behavior of Concrete Confined by Hemp Fiber Composite Jackets

This paper presents an experimental study on the strengthening of small scaled concrete columns externally confined with hemp fiber composite jackets. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study, two different types of columns i.e. circular and square were casted and tested under axial compression. The hemp fiber composite jacket of different thicknesses i.e. 2 and 4 layers were applied using epoxy resin. The test result show that hemp fiber composite jackets are very effective to enhance compressive strength and deformability of the confined concrete. There is found increase in ultimate load carrying capacity with an increase in the jacket thickness. The efficiency of hemp fiber composite jackets is found higher for circular columns then square columns.

Shear Strengthening of Reinforced Concrete Beams with HFRP Composite

This paper presents an experimental study on the strengthening of scaled reinforced concrete (RC) deep beam using hemp fiber reinforced polymer (HFRP) composite. HFRP is the composite material which compose of hemp fiber bonding with epoxy resin. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study 2 different fiber orientation has been apply to scaled deep beam and also different in thickness (fiber layer). Three scaled deep beam were strengthened using HFRP composite, remaining one beam was tested as control (unstrengthen) beam. The test result show that HFRP composite are effective to enhance ultimate load capacity for RC beam. The HFRP composite applied in U-Shape was result into higher ultimate load compare with the sample that applied with both side strengthen method

Flexural Behavior of Reinforced-Concrete (RC) Beams Strengthened with Hemp Fiber-Reinforced Polymer (FRP) Composites

This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.

Flexural Strengthening of RC Beams with Sisal Fiber Composites and Sisal Fiber Rods

The present study is conducted to examine the effectiveness of sisal fiber in flexural strengthening of reinforced concrete (RC) beams. In order to obtain this objective, two different strengthening configurations are adopted (use of sisal fiber composites and use of sisal fiber rods). A total of five flexural strengthened reinforced concrete beams are instrumented and tested using a four point bending setup. The results for strength, stiffness and failure modes are discussed for the both strengthening configurations. The results demonstrate that both sisal fiber composites and sisal fiber rods are effective in enhancing ultimate load carrying capacity of RC beams. The beams strengthened with sisal fiber rods showed higher increase in ultimate load as compared with the beams strengthened with sisal fiber composites layers.