Analysis On Mechanical Performance Of Fabricated Foundations

With the fast growth of China's construction industry,the building materials strength and construction mechanization level continue to improve,the industry's requirements for construction speed and construction environment are also higher and higher.Therefore,the country put forward the slogan of “construction industrialization”,and the prefabricated building has become more and more common.The most widely used structural form is the prefabricated concrete structure.In the current prefabricated component manufacturing industry,prefabricated columns,prefabricated beams,and prefabricated panels are produced in a wide variety of applications,but the development of prefabricated concrete components for building foundations is rare.Therefore,this paper takes the independent foundation as an example,and designs the fabricated foundation.The ABAQUS is used as the calculation tool to analyze the mechanical performance of the fabricated foundation model under three forms of engineering loads.The main contents of the study are as follows:(1)Taking the independent foundation under the column in a four-story office building as an example,the fabricated foundation has been designed.Two kinds of prefabricated concrete components,GJ-A and GJ-B,were designed,and the matching connection scheme was selected.The tendon-anchorage group was selected as the connecting piece.(2)The research on the connection of prefabricated components in the prefabricated foundation is mainly to analyze the role of the tendon-anchorage group in the connection,calculate the tensile control stress of the prestressed steel bar in the calculation scheme,and calculate the tendon-anchorage group parameters and number of placements.Analyze the frictional force between the contact surfaces of GJ-A and GJ-B,and calculate the maximumstatic friction force required between the contact surfaces in the foundation.(3)The finite element analysis of the cast-in-place foundation model and the fabricated foundation model is carried out under the most unfavorable combination of vertical loads.The analysis results show that the tensile strength of the concrete material in the fabricated foundation is significantly reduced due to the forces in both directions of prestressing and substrate reaction.Under the most unfavorable combination of vertical loads,the stress level of steel materials,concrete materials and tendon materials in the fabricated foundation model is less than the material strength design value;The vertical deformation of the foundation is about0.695 mm,and the relative displacement between the prefabricated components is within0.386 mm.Under the combination of vertical loads,the mechanical properties of the fabricated foundation meet the engineering needs of the example.(4)The finite element analysis of the cast-in-place foundation model and the fabricated foundation model is carried out under the most unfavorable combination of horizontal loads.Under the most unfavorable combination of vertical loads,the stress level of steel materials,concrete materials and tendon materials in the fabricated foundation model is less than the material strength design value;The relative displacement between the prefabricated components in the fabricated foundation is within 0.543 mm;The longitudinal direction of the prefabricated member should be consistent with the direction of the bending moment,which can reduce the vertical deformation of the foundation,and the overall deformation of the foundation is within 1.432 mm.Under the combination of horizontal loads,the mechanical properties of the fabricated foundation meet the engineering needs of the example.(5)Finite element analysis of the fabricated foundation model.A fixed end constraint is applied to the base tip and a uniform load is applied to the base bottom until the model is broken.In this paper,the analysis results show that the determinant of the failure of the fabricated foundation model is that the rebar of GJ-A.When the model is destroyed,The load value is 419.3KPa,the connection between the prefabricated components works normally: the maximum stress of the tendon is 760.9MPa,and the relative displacement between the prefabricated components is less than 1mm.