Experimental Study Of Axial Tension Member With The Prestressed Concrete Mandril

Most damage of construction is due to the crack,so people always consider the beginning of crack as the sign of danger,it always makes people fear.With the development of economy in our country,the dimensions of construction is larger and larger,and the engineering is growing towards large-scale and complexity,because the refresh of material of concrete,the strength of concrete is improved,but a lot of crack appears in the engineering.In recent years,As the further development of economy in our country,the need of steel in the engineering is increscent,but the supply of steel in our country can not satisfy with the need,the price of steel is continuously rising,so it gives us a problem,we must save steel in designing construction and simultanentily controlling the crack of construction.So it gives us a new question on crack study.A way to avoiding crack or reducing crack width of concrete or reducing distortion of member is using prestressed concrete.The writer tried to make full use of the merit of the prestressed concrete and designed prestressed concrete mandril to control crack of structure.The prestressed concrete mandril,which was firstly applied high pressure on a small concrete bar,and then was made in concrete,so it would act as reinforced bar and resist load.In this thesis the writer designed 24 mmnbers and had experimental study of them,reached the conclusion that the effect of resisting crack of the prestressed concrete mandril was good when the load was not large,it can enhance the capacity of resisting crack and reduce the crack distance and crack width,but when the loads was large,the effect of resisting crack was not good,when we used the prestressed concrete mandril and reinforced bar together in member,the effect of resisting crack was very good.The writer analysed the adherence mechanism and wreck mechanism of the prestressed concrete mandril in anxial tension members,and according to the character of the prestressed concrete mandril, the writer constructed the bond model of it.Then the writer introduced the analysis theory of crack including the bond-slip theory,the non-slip theory,the synthesis theory and mathematics stat method.The different theory had different theory base,they considered that the primary affection of crack width was different.In this test,the crack distance and crack width of members which placed reinforced bar were match to the compute value of the code GB 50010-2002 very well.To the members which...