Experimental Study On Flexural Behavior Of Concrete Beam Prestressed With External CFRP Tendons

CFRP (Carbon Fiber Reinforcement Polymers) is one kind of new material, which is of high strength, non-corrosion and light weight etc. Using carbon fiber reinforced polymers (CFRP) bars or tendons provides an alternative solution to replace ordinary reinforcing steel, and becomes one of the research hot spot at present. Based on the nation natural science fund subsidiary item (50478052), this paper focus on the study of the simply supportly concrete beams prestressed by CFRP tendons, and the major content includes: (1) This paper systematically introduced prestressing force and CFRP's development history, research present situation as well as development foreground in the real engineering outside the body at present. Conclude in each country standard and recent years document to the body calculation formula of prestressing limit stress (or stress increment), and compared applicability and reasonable nature that had already had the formula, (2) This paper disposes that 4 concrete beam prestressed by CFRP tendons and 1 ordinary reinforced concrete beam have carried. The concrete grade and CFRP and initial prestress as well as the beginning state of beam body (building or reinforces) etc are chosed as the parameter. the following conclusion are drawn: testing beam with the utilization steel cuts with scissors the thread and resemble as the destruction model of prestressing force muscle concrete roof beam outside the body; After the stress of CFRP have appeared in the body the non-prestressing force reinforcing steel subdues; The crack of ordinary reinforced concrete beam will lack, and height and crack interval width are prolonged to the crack; Exerting outside the body behind the prestressing force, the bearing capacity of roof beam is notably raised, and also has better ductility. (3) The limited unit theory of the linkage based on adopts the numerical analysis of parameterization, the full course nonlinear analysis that the simple beam of prestressing force is in progress from the feed to destruction to the body, and the derivation calculation formula in the analysis course; The increment of establishment in order to load is the computer program of foundation, and uses that this procedure has been in progress the parametric analysis, prestressing force muscle is fixed up the influence of the equal prestressing force concrete roof beam bearing capacity of parameter to the body to the concrete intensity grade to effective prestressing force dimension at the beginning of including the body. In addition still to the body analysis has been in progress to the ductility of prestressing force concrete roof beam.