Mechanical Properties Of Steel-concrete Composite Open-web Sandwich Panels With Special-shaped Shear Keys

The steel space grid box structure and its sub-structures,steel grid frame wall and steel open-web sandwich floor(SOSF),have been widely used in industrial and public buildings due to their excellent comprehensive mechanical properties.The SOSF is composed of a concrete slab,top and bottom chords,and shear keys.In order to further improve the load-bearing capacity of the SOSF and improve the force transmission efficiency of the structure,the traditional square tube shear key in the SOSF is changed into a flanged cruciform section shear key.A 5m×1m with 1/2 scale test model was designed.Taking model processing as an example,the manufacture method of this new structure is introduced.A graded static loading test was performed to measure deflection and strain.The calculation formula of the intersection beam analogy method(IBAM)considering the influence of shear stiffness is proposed.Finite element(FE)analysis uses two computational models: BEAM element model and SHELL element model.Comparing the results of the three methods,it is concluded that the maximum deviation of the deflection obtained by the IBAM,the FEM and the test is less than 5%,and the maximum strain error is less than 7%.It is proved that all three methods have high precision in the elastic range.The IBAM and the FEM can be used for further research.A steel-concrete composite structure with a special-shaped shear key was formed on the SOSF and the reinforced concrete slab was poured to continue the static loading test,and the deflection and strain were measured.The IBAM considering the reduction coefficient ? = 0.65,and calculate the results of it.A FE model was established by using SOLID-SHELL elements.By comparing the IBAM,the FEM and the test results,it is obtained that the deflection error between them is less than 5%.Although the strain result has a certain error,the trend is consistent.It can be considered that both the IBAM and the FEM have higher accuracy in the elastic range.In the subsequent research,only the FEM and the IBAM can be used to continue the in-depth research.During the tests,no macroscopic damage of the test model,local buckling of the steel profile and weld cracking were observed.The maximum strain of each measuring point remained below the yield strain of the material.The deflection test values are less than 1/300 of the span,indicating that the structure has good overall stiffness and safety margin.