The Prestressed Carbon Fiber Board Experimental Study Of Damaged Reinforced Concrete Beam

Due to construction defects, improper curing and overload,a lot of bridge structure are damaged.For component of the average damage, the reinforcement repair is economical and essential, but the severely damaged components are often demolished and rebuilt.In practical engineering, a lot of bridge components,especially the medium and small span beam bridge,are not seriously damaged but still demolished for various reasons, causing the waste of resources.Actually the bearing potential of these bridge components can be extended through all kinds of new technology.Therefore, this research team studies the feasibility of restoring or improving the bearing capacity of severely damaged members by strengthening them with prestressed carbon fiber plates. And the study is on the basis of reinforce the T beam component seriously cracked in trial(crack width is above 1 mm).Based on the existing damaged beam, in this research the component B1-S is designed without any crack repair,and then it is reinforced by using prestressed carbon fiber boards.In the test, components B0 and B1 are contrasted respectively and stress behaviors of the damaged beam after reinforcement are analyzed.The test results show that the bearing capacity of the damaged beams can be restored or improved by means of reinforcement,that is,to transform the damaged beam is feasible.On the basis of the results,the mechanical performance and failure mode of damaged concrete beams reinforced by prestressed carbon fiber plates are analysed theoretically.The analysis shows that the mechanical model based on the assumed flat section can better predict the performance of the damaged structure reinforced by prestressed carbon fiber plates; Through the analysis of several kinds of limit states,three kinds of failure modes for the test beam reinfored by prestressed carbon fiber plates;And thus the initial prestress on the size of the upper and lower limit is derived,which makes a practical guiding significance to reinforce the construction.Meanwhile according to the assumed conditions, the formula of bearing capacity of components when they are normally used is deduced. through the calculation formula, the bearing capacity of component B1- S is calculated and the results and the test value is very subtly different, which shows that the prestressed carbon fiber plates have very good reinforcement effect on damaged structure.The conclusion of this experimental study and theoretical analysis provide technical support and theoretical basis for reinforcement and reconstruction of old bridge, especially in both the damaged structure.