| In the field of engineering reinforcement,basalt fiber composite material is another new material after carbon fiber composite material,but its price is low,which is the basis of BFRP grid for beam reinforcement test in this experiment.In view of the high strength of fiber reinforced polamer(FRP)and small elastic modulus,the application of prestressed FRP in structural strengthening has been studied.The new pre-stress tension theory and test be adopted in this test are very ideal,and the strain reverse control stress is adopted to successfully avoid the influence of friction on the pre-stress in the process of tension,as well as the influence of prestress loss caused by deformation of anchoring part and elastic shrinkage of concrete.In this test,a total of 5 beams are designed,among which 1 is a contrast beam,1 is a non-prestressed reinforcement of basalt fiber reinforced polamer(BFRP)grid,and the other 3 are prestressed reinforcement.Tested each beam in the monotonous mechanical performance under the action of static loads,including pure bending curvature,stiffness,fracture the formation process of three bearing capacity,ductility and energy consumption,etc.,and has carried on the comparison,thus determine the beam bottom width,size of prestressed reinforcement on the influence of the reinforcement effect,and the result of the test made an in-depth theoretical analysis.The test results show that the pure bending section of the beam still conforms to the assumption of plane section,and with the increase of load,the neutral surface will move up;When the width of BFRP grid reinforcement is equal,the stiffness of prestressed beams with large strength will be improved more;Under the condition of equal prestress of the whole BFRP grid,the larger the reinforcement width is,the greater the stiffness is and the greater the bearing capacity is;The ductility of the reinforced beam is very ideal,and the ultimate deflection is similar to that of the contrast beam,with obvious signs before failure.In the use of beam members,the yield of steel is equivalent to the beam has been in a state of destruction,can not continue to load,so in the normal use of the process,the yield load calculation is very important.Suitable reinforcement beam reaches the yield load,concrete is beam top still work normally,not reached ultimate strain,when calculating so large amount of calculation,according to this characteristic,through the use of programming,concrete is more accurate to calculate the compressive stress size and centroid position,so as to breakthrough the bottleneck of the yield load calculation.Figure 37;Table 24;Reference 73... |
