Research On The Embedded Steel Bars Technology And Performance Of Concrete Structures

With the rapid development of the industry of reinforcement and reconstruction in china and abroad, research and application of the consolidate theory and technology about reinforced concrete structure become an important subject in structural engineering, while joining of new-old concrete also is needed to be studied content urgently with the embedded steel bar technology in reinforcement and reconstruction.Based on the analysis of the embedded steel bars working mechanism and mechanical properties, researched on structural test and finite element numerical simulation and verified by an with engineering example, some conclusions are as follows: (1)Stress distribution law of embedded steel bars which is a maximum closed to the edge of orifice and decreased successively along the length direction in ultimate pullout capacity; Frictional stress of interface between the embedded steel bars and the binder showed normal distribution approximately, and whose peak diverts from the near orifice to the length direction gradually with the increase of loads. (2)Influence area of circumferential stress is limited along the length direction about embedded steel bars, which is not proportional to the length. Embedded steel bars bearing external loads react with in a certain range barely, and overlong length can't improve the pulling force. (3)Pull out experiment is adopted through the inorganical binder of embedded steel bars developing Xi'an University of Science and Technology, which obtained the conclusion that reasonable length of embedded steel bar is greater than or equal to 15d(d is the diameter of embedded steel bars). (4)When the diameter of embedded steel bars is constant, increasd the diameter will increase ultimate pullout capacity to a certain degree. But if the aperture of embedded steel bars is increased excessively, the ultimate pullout capacity is small relatively increasing extent. The paper suggests that the value of aperture of embedded steel bars is d+(6~14)mm. (5)When the spacing of embedded steel bars is 6d, the interaction is small relatively between steel bars and which can be neglected, and the tensile failure mode and bearing capacity are all considered according to single embedded steel bars; Besides, the smaller spacing of embedded steel bars is, the smaller ultimate pullout capacity about holistic specimens will be. The paper suggests that the spacing of embedded steel bars is greater than or equal to 6d.These research results have gained some effects in engineering application, as for the further research of the embedded steel bars technology and performance of concrete structures and improving the strengthening design code about concrete structure, which have a certain reference value, and can provide design and construction renference to consolidation and reconstruction engineering.