Test Research And Analysis Of Prestressed Anchorage And Steel Strand

Prestressed technology is widely used in bridges, buildings, dams, airports and other facilities. With prestressed technology has drawn increasing attention, research related is gradually carried out. In prestressed engineer, the anchoring property and stress relaxation are two very important aspects.In this paper, the experimental study of the prestressed strand and anchorage has the following key elements:Part Ⅰ:strand tensile test. Draw three kinds of graph in the presence of intact strand and two kinds of strand which have fracture, according to changes in the characteristics of each strand of wire strain to distinguish between the existence of broken wire to provide reference for broken wire detection.Part Ⅱ:relaxation test. First, determinate the correspondence between strand loading force and the wire strain. According to the correspondence, fit the linear expression between the loading force and steel cable tensile strain. Then, proceed strand relaxation test, record the actual strain values at each time point during the relaxation strand, draw stress relaxation curve and calculate relaxation rate; give relational expressions between remaining test force and the time on the number. And finally, calculate elastic strain of strand by a linear relationship expression in stretch; Compare strand relaxation testing values with the measured strain values, explore plastic strain.Part Ⅲ:static anchoring test. Select a anchor with 9 holes, dispose strain gauges on the corresponding position in anchor. After designing anchorage static load test program, under the biasing force level, record the corresponding anchor strain, analysis the strain law of anchor.Part Ⅳ:Numerical anchorage calculations. Analysis cases, in line with the actual situation, establish anchor models and proceed numerical solution. The strain values are compared with the experimental strain above. One the premise of analogy, model size should be carry out to explore. According to the characteristics of the stress, the more reasonable size of the anchorage is given out.