Improving tensile fatigue life of centre-notched steel plates using CFRP sheets

Composite materials are used extensively in many industries today and have become popular in civil and structural projects worldwide. Composites can be used as a base material in construction and be designed to carry a portion or all of the applied loads. They can also be added to a structure in order to improve its loadbearing capacity or serviceability for higher loads. To date composites have been mainly used for the repair and rehabilitation of damaged structural members. Previous research shows that CFRP strengthening can effectively increase the sectional properties and loadbearing capacity of structural members. However, fatigue failure of structures such as bridges and offshore platforms is an issue, and few studies have been carried out on improving the fatigue behaviour of structures using CFRP material. In this research centre-notched steel plates are retrofitted and tested for fatigue. In addition some research has shown the benefit of the active effect of pre-tensioned CFRP, since pre-tensioning can increase the structural properties of cracked members. Our study shows the effect of pre-stressing CFRP patches in enhancing the fatigue life of cracked plates. Different configurations are tested for comparison of results.