Fiber Reinforced Plastic Reinforced Concrete Beams Force Performance

Fiber reinforced plastic rebar (FRP) is a new composite, which is composed of fiber acting as reinforced material, synthetic resin acting as matrix, and some adequate auxiliaries, and is formed through a pultrusion process and necessary surface process. It has a high strength to weight ratio, excellent non-corrosive characteristic, fatigue-resistant characteristic, strong designability and magnetic neutrality, so it can be used in the applications with special performance requirements or where reinforcing bars are subjected to severe chemical attack. For example, FRP reinforced concrete is used to support or surround magnetic resonance imaging (MRI) medical equipment, and FRP is also used for the constructions of some seawalls, industrial roof decks, base pads for electrical and reactor equipment, anchor in rock and ground engineering and concrete floor slabs in aggressive chemical environments In order to promote the wide usage of FRP and FRP reinforced concrete structures, financed cooperatively by National Natural Science Foundation (Item: The research on mechanical performance of FRP reinforced concrete beam reinforced; Number: 59978046) and Henan Illustrious Youth Science Foundation, connected with the analysis methods of modern steel reinforced concrete structure, the thesis further studies the flexural performance of FRP reinforced concrete beam through the systematic study on experimental data got from this kind of beams, systematically establishes the theoretical calculating system of the flexural performance of FRP reinforced concrete beam in cooperation with the up-to-date analytical methods for reinforced concrete, which suits the properties of FRP. The main achievements of this thesis are as follows:l.The effect of the FRP reinforcement ratio on cracking moment is analyzed. The calculating method and corresponding calculating formulas of flexural cracking moment of FRP reinforced concrete beam are put forward. The calculating results indicate that the plastic coefficient of FRP reinforced concrete beam is about 1.4.2.The effect of FRP reinforcement ratio on the ultimate moment of FRP reinforced concrete beam is studied, the conclusion is that the ultimate moment increases with the increase of the reinforcement ratio for FRP reinforced concrete beam in a certain range of reinforcement ratio. In terms of strength and ductility, the concept of specified yield point is put forward. Based on the principle that under the same condition (that is, the size of cross section, material strength and reinforcement ratio are identical), the resultant ultimate moment must be identical, the compression failure of FRP reinforced concrete beam is equal to the tension failure for the viewpoint of design and calculation.Then the capacity reduction factor Af of FRP that is equal to 0.7 is suggestedthough the calculation based on the test results. The calculating method of ultimate moment of FRP reinforced concrete beam is put forward, which is suitable to the characteristics of FRP and correspondent with the current design code in china.3.The test study indicates that the load-deflection curves of FRP reinforced concrete beams reinforced can be divided into two linear stages through the boundary point of initial cracking. Before the normal section cracks, the load-deflection curve is basically linear and the rigidity of the beam is larger. As soon as the normal section cracks, the crack firstly appears in the flexural region. At this moment, the load-deflection curve has a turning point. With the increase of the load, the rigidity of the beam decreases compared with that before cracking because of the development of cracks in flexural region, and the formation and development of diagonal cracks toward the loading point, the load-deflection curve is basically linear till the beam fails. Based upon the experimental data, the nonlinear and whole-process numerical analytical method of FRP reinforced concrete beams is explored. The experimental curve of load-deflection is imitated through computer and compa...