Experimental Research And Finite Element Analysis Of RC Beam With Non-contact Splicing Of Bars

The reinforced concrete is widely used in civil engineering, there is a large number of situations about bar-connecting during the construction of reinforced concrete members.《Code for Design of Concrete Structures》(GB 50010-2002) recommends three kinds of reinforcing bars connection: tieing splicing; welding and mechanical joint. The tieing splicing of reinforcement is easily operated and reliable, so it is popular in the construction.The tieing splicing of reinforcement has contact and non-contact forms. As the gap between the splicing bars is too narrow to hold concrete aggregate, the concrete cann't bond bar wholly, which cann't realize the largest anchoring bond action, so the contact bar splicing form isn't carrying the coaction principal of concrete and steel very well. The non-contact bar splicing form has a clear distance as big as a concrete coarse aggregate between the splicing bars, concrete can bond bar wholly, so the splicing bars could transfer load to each other through anchoring bond action between concrete and the bars, the load-transfer principal is obviously more effective.There is few research about this obviously logical splicing form in our country, so it is necessary to do the research about splicing of bars with non-contact form. The main contents in this paper are as follows:1 Introduction of bar splicing construction mechanism and correlated prescribe of the national and foreign Codes.2 In order to study the load-transfer performance of splicing of bars with non-contact form, five full size test specimens of RC beams were made. Of the five, two's with 25% splicing of bars (a non-contact and a contact), two's with 100% splicing bars (a non-contact and a contact) and one's with continuous bars. The flexual performances of these beams were tested under symmetrical concentrated forces. The process of the test and the failure of specimens are presented, the ultimate load carrying capacity and load-deflection curve of specimens and the stress distribution of steels in lapping area were analyzed.3 The purpose,method and fundamental theory of nonlinear finite element analysis of reinforced concrete are introducted.4 Using ANSYS software to proceed a nonlinear finite element analysis of five simple beams of reinforced concrete, and compare the results with experiment data. The process of the test is simulated, numerical analysis results and experimental results are compared.The results showed that the load-transfer performance of non-contact bar splicing form is effective and reliable; with the same ratio of reinforcement and lapping length, the load-transfer performance of steel bars with non-contact bar splicing form is obviously superior to contact splicing form; the flexural capacity of the beam which with 25% lapping ratio is superior to the beam with 100% lapping ratio; the crack-resistance performance and flexural capacity of the beam with continuous bars is superior to other beams.