Experimental Research Of The Fatigue Performance Of RC Beams Strengthened With Pre-stressed C/GFRP Sheets

It is a new method to strengthen RC structures by pre-stressed C/GFRP sheets. At present, few research on carbon-glass hybrid fiber is conducted and most of that concentrate in mechanical properties of materials.while,the fatigue performance of RC beams strengthened by pre-stressed C/GFRP sheets is relatively less in china and abroad. In this thesis, fatigue tests of 6 RC beamsand theoretical research are conducted. The main research contents and conclusions are as follows:1. A existing anchorage devices to tension the fiber cloth is improved and designed to be simple,convenient and reliable.The experimental results show this process can meet the practicalengineering that needs large span and high stress of fiber cloth.2. Fatigue tests of 6 RC beams(4 beams strengthened by pre-stressed C/GFRP sheets under different pre-stress levels) and theoretical research are conducted. he experiment results indicate that pre-stressed CFRP sheets can increase the fatigue lifes of the strengthed beams, and with the increasing of pre-stress levels, the fatigue performance of strengthened beams improves.3. Through the analysis of fatigue test data of 6 test beams, the fatigue property and state of test beams is explained and shows how the hyhride fiber works in different stages.4. The feasibility that using optimized life-prediction model in life prediction of pre-stressed C/GFRP sheets strengthen RC beams is discussed.The results indicate that using stress amplitude of steel and deformation to predict life of pre-stressed C/GFRP sheets strengthen RC beams accords the actual situation.