Study On The Force Performance Of Post-tensioned Prestressed Assembled Concrete Foundations And Shear Performance Of Contact Surfaces

With the development of building industrialization,assembled structure has been widely used in the aboveground structure,but the application of underground foundation structure is relatively less,which restricts the development of assembled structure.Based on the independent foundation under cast-in-place column,the assembly design and experimental research are carried out in this paper.The main research contents are as follows:(1)According to the stress characteristics and foundation form of independent foundation under cast-in-situ column,referring to the segmental construction of prestressed concrete beam bridge,the precast concrete foundation form using post-tensioned prestressed assembly technology is proposed.Taking an actual independent foundation under concrete column as an example,the split design and connection design are carried out.The finite element software Abaqus is used to analyze the mechanical performance of this design example under construction and normal working conditions,and the ultimate load of the foundation is applied to study its failure mode.(2)For the designed fabricated concrete foundation,two 1:1.5 scale test models with unbonded and bonded prestressed tendons are designed and manufactured.The static loading test are carried out by applying vertical load on the foundation floor.The stress process and failure mode of the two foundations are studied,and the stiffness and bearing capacity are evaluated.Based on the experimental study,the numerical simulation analysis of the test specimen is carried out,and the mechanical properties of the two foundations are further studied.(3)Thirteen double shear specimens are designed and fabricated,and the direct shear tests are carried out to study the effects of different joint structures on the stress process,failure mode and shear capacity of the joint surface,including dry and adhesive bonding of joint surface,bonded and unbonded prestressed tendons,whether the joint surface contains shear key grooves,and the different compressive stress levels of joint surfaces.(4)Twelve existing formulas for calculating the shear capacity of the joint surface with shear keys are summarized,and the reliability of the existing formulas is evaluated through the test results in this paper and the test data collected in other relevant literature.