The Experimental Study On Shear Performance Of The Interfacial Between New And Existing Concrete With Groves And Tranversal Remforcement

The new and old concrete interface in cutting groove, with planting steel bar, is a new kind of interfacial structure, which is able to improve its shear performance. The method of cutting groove with planting steel bar has been used on a bridge of FoKai Highway as it adopted the way of increasing prestress additionally to be more solid. However, The Chinese Official Organization has not established the standard for calculating shear-bearing capacity on the interface in cutting groove. So,it has important social significance and significant economic benefits to research the performance of the new and old concrete bonding.The article according to the different way of old and new concrete interface treatment, made24specimens, set up different interface treatment,including chiselling interface,cutting groove,and planting reinforced bars, using those old and new concrete specimens static load test,From the aspects of bearing capacity, concrete strain, failure pattern and so on to analysis the influence of interface treatment effect, have made progress in the following aspects:(1)The result of this test indicates that:cutting groove could improve the shear performance of new and old concrete interface; With the increasing width of cutting groove, its shear performance has been improving to occupy the65%-75%of total value; The testing units indicate obvious brittle damage, and at last the spline has been broken by shear; planting steel bar could expand the interface’s tractility, and the shear performance is going well with the increasing rate of planting steel bar,its shear performance has been improving to occupy the65%-75%of total value,the specimen of cutting groove with planting steel bar not only improve the interface shear capacity, but also increases the ductility of the interface because of the embedded steel bar, its shear performance has been improving to occupy the72%of total value,and at last the spline has been broken by shear,and the reinforced had yield;(2)Summarize the existed theoretical formula of the concrete interface shear bearing capacity these had put forward by scholars, calculate the shear bearing capacity of the chiseling method specimen, cutting groove specimen, planting bar steel specimen, and make a comparison between the calculation result and experimental result, we can see from the result of table that the chiseling specimens theoretical Value can use this section the third formula to calculation, the ratio of the calculated value and experimental value is1, the cutting groove specimens can use this section the third formula to calculation, the ratio of the calculated value and experimental value is73%～85%, the planting steel bat specimens can use this section the section or the third formula to calculation,, the ratio of calculation value and experimental value was83%～90,88%～98%;(3)the AASHTOLRFD formula gives the interface shear bearing capacity calculation formula of the overall plant steel specimen and chisel plant steel specimen and no chisel plant steel specimen,cutting grooved planting steel bar specimens interface shear bearing capacity calculation without mentioning, after analysis and calculation is deduced from the result of the experiment,advise the value of the cutting grooved planting steel specimens interface bearing capacity calculation formula about c and μ(c=340,μ=1.2);(4)The research achievements of old and new concrete interface shear bearing capacity of the further research, the research showed that cutting grooved planting steel bar specimens of old and new concrete not only can delay specimens cracks, with obvious characteristics of ductility, improved the old and new concrete interface bonding quality and integrity, has a certain academic value and engineering applied value.