Study On Shear Behavior Of Stud Connectors At Low Temperature

The steel-concrete composite beam structure can give full play to the advantages of steel and concrete materials,which is widely used in the alpine region of the western plateau of China.It is very important to find out the stress mechanism of the stud shear connectors in low temperature environment,and to apply the steel-concrete composite beams to bridges in alpine regions.In order to study the shear resistance of stud connectors at low temperature,15 test pieces were designed and manufactured,and the test pieces were cooled by a low temperature test machine.The self-made heat preservation device was used to maintain the low temperature state,then the test pieces were tested.At the same time,the finite element software ABAQUS was used to establish the three-dimensional finite element model,and the test results were verified.The shear performance of the stud connection,shear resistance,peak slip and shear stiffness at low temperature was studied.The shear capacity of the studs is increased by 13% at-20°C and 27% at-40°C,respectively,but the peak displacement of the stud connectors decreases with decreasing temperature,indicating the te plasticity and ductility of stud connectors deteriorate at low temperature;The shear stiffness of the stud connector increases with the decrease of temperature,for the stud connectors with diameters of 16 mm,19mm and 22 mm,the shear stiffness is increased by 54.8%,52.9% and 43.0% at-40°C respectively;The main factor affecting the shear capacity of stud connectors at low temperatures is the temperature of concrete,which accounts for 65% of the increase in bearing capacity,while the temperature of the studs has a relatively small influence on bearing capacity of the stud connectors,which accounts for 35%.Through the fitting of the test and finite element data,the low-temperature influence coefficient of the shear capacity of the stud is introduced,and the bearing capacity of the stud connector under low temperature conditions is established.The calculation formula provides a reference for the design of the combined structure in the severe cold area.