Study On Shear Strength Of Glass Fiber Self-compacting Concrete Deep Beams

Deep beam can play an important role in many places in modern society,but it also has some defects.The construction process is complicated due to its mass volume.The components are subjected to a large shear force during loading process and are more likely to crack.The high fluidity of self-compacting concrete can solve the difficult in the construction of deep beams.The whole formwork can be filled by itself without vibration,making the construction of deep beams more efficient.The application of glass fiber can also solve the problem of deep beam cracking.The glass fiber not only has strong toughening and anti-cracking ability compared to normal fiber,but also has a lighter weight with cheaper price Therefore,this paper focus on researching the shear performance in the deep beam with glass fiber and self-compacting concrete.Through the shear tests of 8 groups of different deep beams,the anti-cracking ability and ultimate bearing capacity of the deep beams were explored under the changes of different glass fiber volume ratio,different vertical distribution of reinforcement ratio and different horizontal distribution of reinforcement ratio.Meanwhilr,the ultimate bearing capacity of the deep beams under different shear spans was simulated by finite element method,and the modified formula was obtained.The main conclusions are as follows:1.When the volume fraction of glass fiber increases from 0% to 0.5%,1% and 1.5%,the cube compressive strength changes by 0.8%,3% and-7.8%,respectively.When the volume fraction of glass fiber increases from 0% to 0.5%,1% and 1.5%,the splitting tensile strength increases by 18%,9.6% and 6.7%,respectively.2.The increase of the volume ratio of glass fiber can improve the Initial shear fracture strength of the deep beam.Compared with the members with 0% volume ratio,the Initial shear fracture strength of 0.5%,1% and 1.5% increases by 5%,15.3% and 12.8%,respectively.3.The increase of the volume fraction of glass fiber increases the ultimate shear strength of the member.0.5%,1% and 1.5% increase the ultimate shear strength by 4%,16% and 11.2%compared with 0%.With the increase of reinforcement ratio of vertical distribution bars,the ultimate shear strength of the member with 0% horizontal distribution bars increases by 7.8%and 10%,respectively.With the increase of reinforcement ratio of horizontal distribution bars,the ultimate shear strength of the member with 0% volume ratio increases by 12% and 21%,respectively.4.The simulation results show that the reduction of the shear span ratio will increase the shear capacity of the deep beam.Compared with the deep beam with shear span ratio of 0.875 and 0.8125,the shear span ratio is increased by 6% and 11.8%.5.According to the experimental results and finite element simulation results,the modified shear cracking load formula of glass fiber reinforced self compacting concrete deep beam is proposed.The modified formulas based on tensile strength and vertical distributed reinforcement are compared and analyzed,and the modified formula based on tensile strength is more suitable for this test.