| Stainless steel bars have the characteristics of high strength,superior corrosion resistance,good impact resistance and ductility,etc.The use of stainless steel bars can greatly enhance the durability of reinforced concrete structures and reduce maintenance costs in the later period.There have been few studies on the shear performance of stainless steel reinforced concrete beams with web reinforcement.In this paper,through the shear performance test of 12 stainless steel reinforced concrete beams with web reinforcement,the effects of hoop reinforcement ratio and shear-tospan ratio on the damage pattern,cracking in oblique sections,crack development,deformation performance of specimen beams,hoop strain,longitudinal strain,concrete strain and shear load capacity of stainless steel reinforced concrete beams with web reinforcement were investigated.Compared the calculation methods of the existing codes,a shear calculation formula which suitable for stainless steel reinforced concrete beams with web reinforcement is proposed.The main results are as follows:(1)The basic mechanical properties of stainless steel reinforcement were measured by metal tensile testing at room temperature,and the test results showed that: stainless steel reinforcement have higher tensile strength,yield strength and elongation after break than ordinary reinforcement,but their modulus of elasticity is smaller.(2)By observing the test phenomenon of stainless steel reinforced concrete beams with web reinforcement under concentrated loading,it was found that the damage form of stainless steel reinforced concrete beams with web reinforcement is basically the same as that of ordinary reinforced concrete beams,and its damage form can be summarized as follows: the first vertical crack will appear near the span of the beam,and as the load continues to increase,a new one is produced within the purely curved section that gradually expands to both sides of the beam in the span The first diagonal crack then appears in the shear span section,the load continues to increase,and the critical inclined crack forms and develops rapidly until the beam is damaged.(3)The effect of hoop ratio and shear-to-span ratio on the ultimate breaking load of stainless steel reinforced concrete beams with web reinforcement was analyzed.The test results show that the ultimate damage load of the beam will be increased by15%～20% when the hoop ratio is increased from 0.25% to 0.34%,which means that the increase of hoop ratio can significantly increase the shear ultimate load capacity of stainless steel reinforced concrete beams with webs;when the shear-to-span ratio is increased from 1 to 2.5,the ultimate damage load of the beam is reduced by35%～40%,which shows that the shear-to-span ratio has a great influence on the ultimate damage load of the beam,and the ultimate damage load of the beam decreases significantly with the increase of shear-to-span ratio.As the shear-to-span ratio increases the ultimate damage load of the beam decreases significantly.(4)The variation of hoop strains and concrete strains in stainless steel reinforced concrete beams with webs under concentrated loading was analysed.The results show that the hoop strains and concrete strains in the middle part of the shear span zone are greater than those near the support and loading point,which corresponds to the test phenomenon that the diagonal crack is narrow at both ends and wide in the middle.(5)The shear load capacity of 12 stainless steel reinforced concrete beams with web reinforcement was obtained through the test,and with reference to the Chinese code shear load capacity calculation formula for diagonal sections,regression analysis was carried out on the test data in this paper,and a good correlation was finally determined for the diagonal section shear calculation formula for stainless steel reinforced concrete beams with webs. |
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