Mechanical Behavior And Finite Element Analysis Of Concrete Bar Planted Steel Beams Under Fatigue Loading

Bar planting technology is a simple and effective connection anchoring technology.In engineering practice,there are more and more cases in which bridges,crane beams and other structures subject to fatigue loading are reconstructed,extended or reinforced through the bar planting technology.However,the research on their mechanical properties is not yet in-depth.At present,researches on bar planting technology mainly focus on the drawing mechanism of planted bar,while the research on the stress mechanism of planted bar system as a whole is comparatively less.In engineering practice,the steel bars built by flexural reinforced concrete members are no longer under one-way stress,but in a complex stress state.At present,the bar planting technology has been widely used in engineering,and the limitations of the actual test have an impact on the performance analysis of the concrete anchorage beam,so it needs to be studied in depth and combined with the finite element analysis to make the study more complete.First,in order to investigate the mechanical properties of concrete planted beams under fatigue loading,4 planted bars are made and planted into beams with root anchorage depths of 20 d,25d and 30d(d stands for the diameter of the planted bar),and the planting ends of the bar planted beams are without stirrups,then the test is to,damage their static load.Meanwhile,3 planted bars are made and planted into beams with root anchorage depths of 20 d,25d and 30 d,and the planting ends of the bar planting beams are without stirrups,then another 3 planted bars are made and planted into beams with root anchorage depths of 20 d,25d and 30 d,and the planting ends of the bar planting beams are with additional stirrups.The fatigue loading tests are carried out on the six embedded steel beams mentioned above.Using ANSYS software,the tested beams with three different anchorage depths are simulated,,the flexural mechanical properties are modeled and analysed,span load deflection curves and the stress curves of implanted bars under changing load are drawn,and then the effect of the stirrups on mechanical properties of beams is analysed.Stimulating the fatigue load test,more static load data acquisition nodes are considered in order to confirm the experiment;load frequency parameters are also increased to find out the impact of frequency on mechanical properties of beams.The fatigue loading test of bar planted beams and ANSYS simulation show theaddition of stirrups at the end of the anchorage beams can alleviate the stress concentration at the end of the beams,improve the ductility,cracking load and ultimate load of anchorage end,and reduce the planted bar strain and residual deformation;and low frequency reduces overall mechanical performance of the beams under test.