Mechanical characterization of fibre reinforced polymersfor numerical fire endurance modelling

E. U. Chowdhury1, R. Eedson1, L. A. Bisby2, M. F. Green3, N. Bénichou4, and V.K.R.Kodur5

1 Graduate Student, Dept. of Civil Engineering, Queen’s University, Canada

2Assistant Professor, Dept. of Civil Engineering, Queen’s University, Canada

3 Professor, Dept. of Civil Engineering, Queen’s University, Canada

4 Senior Research Officer, National Research Council, Canada

5 Professor, Michigan State University, USA

ABSTRACT

Fibre reinforced polymer (FRP) materials are increasingly being applied in many areas of construction, particularly for rehabilitation of concrete, steel, and timber structures. However, concerns associated with fire remain an obstacle to the use of FRP materials in buildings and parking garages due to their susceptibility to degradation at elevated temperatures. Research is being conducted at Queen’s University in conjunction with the National Research Council of Canada (NRC) and industry partners to investigate the effects of fireon such FRP strengthened concrete structures. A major portion of the study involves numerical fire endurance modelling. For such models, the mechanical behaviour of FRP materials at high temperature is critical.

Thus, this paper presents an experimental investigation tocharacterize the mechanical properties ofsome currently available FRPs under various loading and thermal regimes ranging from ambient temperature to 600ºC. These tests will be conducted in an INSTRON Universal Testing Machine (UTM), which has an integrated, custom designed thermal chamber with an internal dimension of 250 mm (width) by 250 mm (depth) by 300mm (height) and has a maximum load capacity of 600 kN. Tensile, lap splice, and FRP to concrete bond tests will be conducted. Once the test specimens have achieved the desired temperature inside the thermal chamber of the INSTRON testing machine, load will be applied on them until failure occurs. Axial strain measurements of the test specimens during these tests will be taken using a high temperature axial strain gauge extensometer and deformation measurements using close-range photogrammetry. Results from these tests will be used to develop analytical models representing the stress-strain behaviour of FRP. Information from these tests will be used in calibrating coupled heat transfer and structural analysis numerical models for FRP strengthened members which are currently being developed at Queen’s University. In this paper, the experimental procedure and results of the initial mechanical testing will be presented.

1