Experimental Study On Shear Resistance Of After-fire Reinforced Concrete T-shaped Beam Retrofitted With Prestressed Steel Strips

With the wide application of new building materials, the probability of fire disasteroccurrence get bigger and bigger. The mechanical properties of structural members willchange after fire disaster, for instance, steel tensile strength and concrete compressivestrength will fall, which lead shear capacity of reinforced concrete beams to be declinedand deflection to get big. But these building could be used after strengthened.It takesshorter times and low cost to strengthen than to build. prestressed steel strengtheningmethod derive from packaging technology, the method has advantage of simpleoperation. Now experimental study on Seismic performance of RC column and shearcapacity of RC beams retrofitted by prestressed steel strip have been done for thistechnology, But the former research don’t involve after-fire strengthening method,whichrestrict the using of after-fire building strengthening.In this paper the analysis and study are carried on the shear resistance of after-firereinforced concrete T-shaped beam retrofitted with prestressed steel strips through firetest and static test. The main content is as follows:1. A description of achievement get from native and foreign researchers, such asthe mechanical characteristics of steel, concrete and the bond performance betweenconcrete and steel after fire are presented. From them, the performance parameters suitfor this paper are determined.2. Twelve T-shape beams have been made in this experiment, one is normaltemperature control beam, the other beams are under fire in the furnace. fire exposuretime include60min、90min and120min. 3. Experimental data is collected from static test of T-shaped beam retrofitted withprestressed steel strips, these data include the value of load, bending, steel stripstrain.Through the analysis of the data,summarize the regularity how the layer numbersof steel strip,the spacing of steel strip and fire exposure time influence the shearcapacity, stiffness and failure mode.4. Through theoretical analysis and data processing, obtain the formula of shearcapacity of normal beam and strengthening beam.In the end, the main research achievements are summarized and suggestions arepresented for the further study and engineering application.