Experimental Research And Analysis On Static And Fatigue Performance Of The Assembled Monolithic Hollow-ribbed Floor

The assembled monolithic hollow-ribbed floor is a new type of floor structure system,which is developed from the traditional ribbed floor and the cast-in-situ concrete hollow floor.This new type of floor combines many advantages of two traditional floor structure system and at the same time has solved many problems of traditional floor.It is an important innovation of floor structure field in our country.In this dissertation,the author has carried out experiment research and analysis on the static performance of the new type of post-constructed hollow-ribbed floor,the shear performance of the large-size reinforced concrete ribbed beam with thin web and the normal section bending fatigue performance of the traditional assembled monolithic hollow-ribbed floor.At last,the corresponding calculation methods and design suggestions are put forward.The author has carried out short-term static loading test of the new type of post-constructed hollow-ribbed floor with corner post support,the new type of floor under vertical load of main process of loading,crack distribution,failure pattern,deformation and bearing capacity characteristics were investigated.Analysis of the cracking load of the new floor.According to the failure pattern of the test floor,the author put forward the failure mechanism of the new floor and deduces the calculation formula of ultimate load balance.According to the deformation characteristics of the test floor,the author proceed from the theory of elastic deformation of the floor and using the method of introducing stiffness reduction coefficient,that is to replace the initial stiffness with the actual stiffness,put forward two kinds of simplified calculation method of the elastic-plastic stage deformation of the floor.The elastic force and deformation of the new type of post-constructed hollow-ribbed floor can be divided into two stages,that is before and after the installation of post-constructed precast slab.In this dissertation,the author has carried out comparative experiment research and finite element analysis on the two stages of the elastic force and deformation.Through measuring the strain of steel and concrete and vertical deformation of the floor.Analysis of the influence of post-constructed precast slab on the force and deflection performance of hollow-ribbed floor.According to the test result,the results of theoretical analysis and reference to the relevant literature,the author put forward a calculation method of elastic bending stiffness of the post-constructed hollow-ribbed floor with corner post support of medium and short span,this method considers the contribution of precast slab stiffness.In order to solve the problem of shear strength in inclined section of the large-size reinforced concrete ribbed beam with thin web.The author has carried out experiment research on the shear performance of four large-size reinforced concrete ribbed beams with thin web under concentrated load.Analysis of the main process of loading,deformation characteristics,cracking load,failure pattern and shear bearing capacity,take the shear strength test results comparative with the main code calculation results,the author proceed from the perspective of security and applicability,put forward a recommended design calculation code of shear bearing capacity.The author has carried out experimental research on static and normal section bending fatigue performance of twelve traditional assembled monolithic hollow-ribbed slabs.Analysis of the main process of loading,crack development and distribution,failure pattern,fatigue life,fatigue stiffness degradation,residual bearing capacity degradation and fatigue damage.Analysis of the influence of different hollow box type,fatigue load parameters and the reinforcement ratio of precast slab,put forward the relevant design suggestions.On the basis of fatigue test and summarize the relevant research achievements of fatigue.The author has carried out theoretical analysis on the fatigue performance of the assembled monolithic hollow-ribbed slabs,put forward the design and calculation method of normal section bending fatigue strength.Analysis of the law of fatigue stiffness degradation,put forward the calculation method of fatigue stiffness and the prediction method of the performance of fatigue based on the fatigue stiffness degradation.It provides a reliable basis for the application of the new floor in the construction of the multistory parking lot,industrial factory building and the composite bridge decks.