Round robin testing initiative for fiber reinforced polymer (FRP) reinforcement

An international Round Robin Testing (RRT) programme on FRP reinforcement was conducted within the framework of the Marie Curie Research Training Network, ENCORE, and with the support of Task Group 9.3 of the International Federation for Structural Concrete (fib). Eleven laboratories and six manufacturers and suppliers participated in this exercise. As part of this extensive experimental endeavour, one or more of the following tests were performed by the participating laboratories: 1) tensile tests on FRP bars and strips; 2) tensile tests on FRP laminates; 3) double bond shear tests on FRP laminates (Externally Bonded Reinforcement, EBR) and FRP bars/strip (Near Surface Mounted reinforcement, NSM). This paper will discusses the results of the RRT initiative, among which the experimental results of bond tests on concrete specimens strengthened with EBR and NSM FRP

FRP reinforcement in RC structures

fib Bulletin 40 deals mainly with the use of FRP bars as internal reinforcement for concrete structures. The background of the main physical and mechanical properties of FRP reinforcing bars is presented, with special emphasis on durability aspects. For each of the typical ultimate and serviceability limit states, the basic mechanical model is given, followed by different design models according to existing codes or design guidelines

Confined Concrete Columns Stability with Longitudinal CFRP Reinforcement

The stability and strength of concrete columns confined by tangential CFRP wrapping and longitudinal external CFRP sheet is studied. Plain and confined columns of slenderness l = 40 are tested. Two batches of concrete with different ultimate compressive strengths 25 and 50 MPa are investigated. The total number of specimens is 24 (sixteen 300 mm high cylinders for material properties and eight 1500 mm high columns, all specimens with diameter 150 mm). Unconfined and with one and two CFRP sheet layers confined concrete columns are tested. Further longitudinal CFRP sheet in one and two layers are added on the confined columns. The theoretical prediction of ultimate strength and stability of columns coincides rather well with experimental results. It is concluded that additional external strengthening of CFRP confined concrete columns by attaching longitudinal CFRP sheets is efficient. The two methods applied lead to similar results, that the additional longitudinal reinforcement is efficient for improving stability of confined columns in region of moderate slenderness 3

Confined Concrete Columns Stability with Longitudinal CFRP Reinforcement

The stability and strength of concrete columns confined by tangential CFRP wrapping and longitudinal external CFRP sheet is studied. Plain and confined columns of slenderness l = 40 are tested. Two batches of concrete with different ultimate compressive strengths 25 and 50 MPa are investigated. The total number of specimens is 24 (sixteen 300 mm high cylinders for material properties and eight 1500 mm high columns, all specimens with diameter 150 mm). Unconfined and with one and two CFRP sheet layers confined concrete columns are tested. Further longitudinal CFRP sheet in one and two layers are added on the confined columns. The theoretical prediction of ultimate strength and stability of columns coincides rather well with experimental results. It is concluded that additional external strengthening of CFRP confined concrete columns by attaching longitudinal CFRP sheets is efficient. The two methods applied lead to similar results, that the additional longitudinal reinforcement is efficient for improving stability of confined columns in region of moderate slenderness 3

Tests to estimate the cooperation between confined concrete and column reinforcement up to compressive failure

The stability and strength of reinforced concrete columns confined by tangential external CFRP wrapping is studied. The plain and confined columns of slenderness λ = 66.7 and λ = 16 with or without longitudinal steel bar (with diameter 12 mm and 16 mm) reinforcement are tested. Two batches of concrete with different ultimate compressive strength are investigated

Tests to estimate the cooperation between confined concrete and column reinforcement up to compressive failure

The stability and strength of reinforced concrete columns confined by tangential external CFRP wrapping is studied. The plain and confined columns of slenderness λ = 66.7 and λ = 16 with or without longitudinal steel bar (with diameter 12 mm and 16 mm) reinforcement are tested. Two batches of concrete with different ultimate compressive strength are investigated