Experimental Study On Shear Behavior Of Steel Fiber Reinforced High-strength Concrete Corbel

As a support structure,The corbel is widely used in practical engineering.It has higher requirements on crack resistance and bearing capacity.According to the research results at home and abroad on corbels,when the sectional dimension is curtained,The crack resistance?bending and shearing strength can be improved by improving the strength of concrete.However,the brittleness increases with the increase of concrete strength grade.Adding steel fiber into concrete can improve the crack resistance,ductility,toughness and durability of concrete members.For corbel which has higher requirements on the cracking resistance,Steel fiber reinforced high-strength concrete has attracted many scholars concern at home and abroad.So far,foreign scholars have done a lot of research on steel fiber reinforced concrete,The effects of shear span ratio,steel fiber content and stirrup ratio were considered in the experiments.A series of calculation formulas which are based on bending model,truss model and mathematical statistical analysis are put forward,But their applicability remains to be further verified.Compared with the foreign countries,in recent years,the domestic research on the steel fiber reinforced high-strength concrete corbels is less,There is no design method of steel fiber reinforced high-strength concrete in the current norm.Therefore,under the support of the national natural foundation of China,9 concrete corbels of steel fiber reinforced high strength test is carried out in this paper.The shear span ratio 0a/ h(28)0.3 is the control point,The effects of shear span ratio,steel fiber content and reinforcement ratio are investigated,The main results are as follows:1.With the decrease of shear span ratio,the cracking load and bearing capacity of the positive and oblique sections are improved,and the crack width,midspan deflection and ductility decrease under the same load.2.The main reinforcement ratio and stirrup ratio has little effect on the bracket' Normal section cracking load,but a greater impact on the diagonal cracking load,bearing capacity,ductility.3.With the increase of steel fiber,Normal section cracking load is increased,when the fiber content is 0.75%,the oblique crack load is the maximum,the number of cracks is increased with the incorporation of steel fibers,but the width is decreased.4.The damage properties of ordinary concrete corbel and steel fiber reinforced high-strength corbel is same.5.Formulas for calculating cracking load of normal section is put forward according to common concrete component cracking moment,the influence coefficient of steel fiber is 0.6.6.The prediction results according to domestic norms and ACI specification for steel fiber reinforced high-strength concrete corbels bearing capacity are safe.