| Human's daily life from transportation road to housing structure rely on the fabricating of concrete.If the concrete deteriorates,the results will be catastrophic.In order to reinforce these concrete structures with deterioration problems,many reinforcement methods have been investigated,such as concrete thickening method and steel-bonded reinforcement method.Fiber Reinforced Polymer(FRP)reinforcement material has the advantages that the above-mentioned reinforcement method does not have.This material has smaller quality,higher tensile strength,and significant fatigue resistance.It can avoid the influence of residual stress during reinforcement.At present,the research on the reinforcement of concrete structures by FRP embedded reinforcement method is still relatively limited.The type of FRP rods and the choice of embedding method have a great influence on the distribution of stress and cracks in the concrete structure,the effects of FRP rods in different kind of structure are also different.How to give full play to the excellent tensile properties of FRP rods to improve the bearing capacity of concrete structures is the key to this paper.In this paper,negative bending test was carried out on the concrete beams reinforced with FRP rods which aimed to give the ANSYS models powerful support and reference.The four reinforced concrete beams with a length of 1850 mm,a width of 250 mm and a height of160 mm were fabricated,two of them were used for contrasting.CFRP rods with a diameter of8 mm were wrapped by the GFRP layout and embedded in concrete beams with ultra-high-early-strength mortar to reinforce the specimens.The embedding depth was 10 mm.After the fully solidify of concrete,the specimens are loaded using the 2-point loading mode.The test result shows that there is no obvious relative sliding between the GFRP wrapped FRP reinforcement and the ultra-high-early-strength mortar.Base on the beam test,the FRP-NSM reinforced concrete cantilever slab was investigated.The size of reinforced concrete slabs is 4500 mm × 3050 mm × 160 mm.The CFRP rods with a diameter of 8mm were used for reinforcement,and the spacing between the CFRP rods was 200 mm.The reinforced concrete slab adopts the method of wheel load to simulate the actual situation of the tire on the deck.The results are as follows: CFRP rods bear the main tensile stress in the concrete cantilever slab,and there are no obvious concrete peeling and crush phenomenon occurs on the surface of slab.Then,the finite element software ANSYS was used to numerically analyze the beam and cantilever slab.The establishment process and steps of the finite element model were introduced.In this paper,the stress distribution and cracking results obtained by the beam model analysis are compared with the beam test results to verify the correctness of the model.On this basis,the cantilever slab models are analyzed.Finally,other 4 slab models were built,and the comparative study was carried out by changing the reinforcement material and diameter of each slab.The results of finite element analysis are as follows: the use of CFRP rods cannot change the position and occurrence of cracks in concrete,but it can slow the propagation of cracks;Under the premise of maintaining the total area of the reinforcement rods,changing the diameter and distribution of the rods has little effect on the slab before concrete cracking,but has a greater impact on the deflection of the slab after concrete cracking.The slab before concrete cracking has little effect,but it has a greater impact on the deflection of the slab after concrete cracking: under the same reinforcement method and static load,the reinforcement effect of CFRP reinforcement is better than that of steel rods. |
PDF Full Text Request