Research On Pullout Behaviour Of Stud In Steel-concrete Composite Structures Under Polar Low Temperature

Steel-concrete composite(SCC)structures that combining advantages of steel and concrete become popular in engineering infrastructures.Recently,this structural system has been used in a wide variety of engineering constructions in cold regions or harsh environment.Headed studs,as the most commonly used shear connectors,are key components in the SCC structures that determine the structural performances.Due to such important roles,the behaviour of headed studs in SCC structures built in the Arctic and cold regions need to be carefully studied and determined for the design of such type of SCC structures.In order to investigate the mechanical properties and pullout behaviour of headed studs,60 headed studs and 16 pull-out specimens were prepared.Finite element model was also developed to simulate the ultimate strength behaviour of pullout specimens under low temperatures.60 tensile tests were performed on headed studs at low temperatures ranging from-80°C to +20°C.Mechanical properties of headed studs at low temperatures,i.e.,strain-stress behaviours,yield and ultimate strength,yielding,ultimate,and fracture strains were reported,analysed,and discussed.Based on the experimental results,regression analyses were also carried out to develop empirical prediction equations for the yield and ultimate strength of headed studs at low temperatures within 20°C ~-80°C.Empirical prediction equations were also recommended and their accuracies equations were checked through validations of predictions against experimental results.16 tests of the influence of temperature,effective embedded depth of headed studs and concrete strength on the tensile load capacity of headed studs was carried through.The experimental results were evaluated in terms of capacity,initial stiffness as well as failure mode.The experimental results show that three kinds of damage can be distinguished,namely concrete cone failure,splitting failure and steel failure.As the temperature decreased from +20°C to-80°C,both the tension load capacity of headed studs and stiffness of headed studs increased with the decreasing temperature.The tension load capacity of headed studs and stiffness of headed studs increased with increasing effective embedded depth of headed studs and concrete compressive strength.Finally,finite element model was developed to simulate the pullout behaviour of headed studs.The accuracy of FEM simulations were checked by the test results.The numerical study performs subsequently a parametric investigation on 60 headed studs.