Research On The Behavior Of Timber Beams Strengthened With CFRP

Timber structure is the main structural style of traditional ancient buildings in China. However, large numbers of exiting ancient timber buildings such as houses,bridges, temple, and towers have been being in service for lots of years, and their structures have been greatly damaged so that the seismic capacity is not enough to resistant the major earthquake. So reinforcement of the traditional ancient buildings is extremely urgent. Based on the principle that repairs as old as before which suggestde by Mr. Liang sicheng,Using the technology of CFRP strengthening is an effective way to strengthen and rehabilitation timber structure. The perfect effect in strengthening and appearance can be obtained using the technology. However, there is not the technical specification for strengthening timber structures with carbon fiber reinforced polymer home and abroad, so that the design of strengthening timber structures accords to nothing. It is restrained heavily for the technology to be applied widely in engineering.On the basis of the study upon the present situation about CFRP strengthened wood member, through 8 specimens approved that the CFRP have obvious strengthen effect to the wood beam.,Both tehsility and ductility had been strengthed in vary degrees, the limit bearing capacity is increased about 18%～30%, and the strengthen effect is more obvious when Paste two layer of CFRP. At the same time, we find that the strengthen effect have great discreteness. The natrue of the wood such as water-content coefficient, wooden knot, heart-centre, crack, decay and so on, has noticeable function on the ultimate capacities of the wooden beam.In view of the wooden beam's several kind of destruction condition, the formula of the ultimate capacities about the rectangle wooden beam which is reinforced by the CFRP is deduced in the thesis. the boundary destruction shape was given in the paper to judge the destroy way of the reinforced wooden beams, Ultimate capacities of the experimental beams are calculated using the formula presented in the paper, and compared the experimental value with the calculation, found that the two value is basically coincidence.A C program for the full-range analysis of the timber beams with externally bonded CFRP sheets has been developed. And the curve of the M-φis drawed , then compared the experimental value with the calculation,A good agreement between the results from the program and test can be found. The parametric study about those beams has been conducted using the program. The result indicated that the influence of the height is more obviously than the width of the timber beams. The result is agree with the actual situation. the two of the experimental value and the calculation is basically coincidence. All proved that the program is true.