Behaviour of Timber Confined with CFRP under Compression
Rebecca S. Sweeney1
I. Introduction 2 University of New South Wales at the Australian Defence Force Academy This paper presents the results of a comprehensive theoretical and experimental investigation on the behaviour of timber confined with carbon fibre reinforcement polymers (CFRP) in compression. The use of CFRP strengthening systems has shown to increase strength and ductility of timber as demonstrated in the theoretical component of the research. The theoretical section of the research outlines the benefits for strengthening, seismic mitigation, historical retrofit and military applications. The compressive strength and stress-strain relationship were the main elements of the experimental research. The experimental component involved the wrapping of 20 samples and comparing results with three unwrapped samples. The CFRP wrapping enhanced the ductility of the samples, presenting a mitigation system for timber structures in regions susceptible to earthquakes. Improvements in ultimate strength of the CFRP confined timber was inconclusive due to the anisotropy of the timber, although the variability of the timber from defects such as cracks and knots was alleviated by the confinement. Contents
A. Timber 2 B. Carbon Fibre Reinforcement Polymers (CFRPs) and Matrix 3 C. Objective of Study 4
II. Literature Review 4
A. Introduction 4 B. Strengthening of Structures 4 1. Timber 4 i. Increase in compressive strength 4 ii. Orientation, type of confinement and number of layers 4 iii. Failure modes 5 iv. Protection from environmental degradation 5 2. Concrete 6 i. Increase in compressive strength and effects of orientation 6 ii. Effect of number of layers 6 iii. Environmental degradation 6 2. Steel 6 i. Increase in compressive strength and ductility 6 ii. Wrap orientation 7 iii. Protection from corrosion damage 7 C. Restoration of Historical Buildings 7 1. Considerations of rehabilitation of historical structures 7 2. Case studies of retrofitting 7 D. Seismic Strengthening 8 1. Timber in Earthquakes 8 2. CFRP as earthquake mitigation and reconstruction 8 E. Military and aid project applications 9 F. Conclusion 10
III. Materials and Methodology 10
A. Study area 10