Experimental Study On The Shear Capacity Of Concrete Beams With GFRP Hybrid Stirrups

FRP material has the characteristics of easy material acquisition,less pollution,high tensile strength and strong corrosion resistance,which can effectively solve the problem of deteriorating the performance of reinforcing steel bars in concrete structures.It is considered as an ideal material for gradually replacing steel bars,and its popularization and application can serve as a strategy for slowing down national One of the tight iron ore resources,and meets the requirements of the country’s green development.At present,there are few researches on the shear resistance of concrete structures with FRP tendons.According to the research results of the existing GFRP stirrups,due to the low elastic modulus of GFRP tendons,there are bending and shearing sections in the loading process of the tested beams.There are many problems with oblique cracks and large slit widths.In order to promote the engineering application of FRP bars,and to better understand the configuration,shear mechanism and failure characteristics of stirrups in FRP reinforced concrete beams,the shear performance of GFRP hybrid ferrule concrete beams with GFRP stirrups and steel stirrups at equal intervals was studied.Considering the effect of different stirrup ratios and shear-span ratios,an ordinary steel stirrups concrete beam and five GFRP mixed ferrule concrete beams were tested.The test results of the test were used to analyze the stirrup strain,longitudinal strain and concrete strain of the test beam.And mid-span deflection and other characteristics with the load changes.By comparing and analyzing the variation law of the maximum width of oblique cracks and the variation of shear ultimate bearing capacity of each test beam,the variation rule of the maximum width of oblique cracks and the ultimate shear capacity of GFRP reinforced concrete beams are investigated.Impact of changes.At the same time,the variation of the maximum width of the oblique cracks and the ultimate shear capacity of the GFRP stirrups concrete beams with respect to the GFRP stirrups concrete beams is compared and analyzed.The similarities and differences between the two are discussed.According to the test phenomena and results analysis,the shear force model of GFRP mixed ferrule concrete beam is established.Based on this model,the ultimate shear capacity calculation formula is deduced.By comparing the calculated value of the formula with the measured value of the ultimate bearing capacity,the two are consistent.better.At the same time,based on the development law of cracks and the law of width variation,combined with the relevant research results combined with the characteristics of GFRP concrete beams,the calculation formulas for the cracking load of shear cracks and the maximum width of oblique cracks are given,and the calculated values and cracking loads are calculated.The comparison of the measured values of the maximum width of oblique cracks and the results show that the calculation formula has applicability.The finite element model of GFRP mixed ferrule concrete beam was established using ANSYS software.Through the model analysis and test results verification,the applicability of the GFRP mixed-hoofed concrete beam model was determined,and then the concrete strength and longitudinal strength of the beam subjected to the shear ultimate bearing capacity were determined.The rib reinforcement ratio and other factors were expanded.