Research Of Structural Behavior And Design Method Of Steel Fiber Recycled Brick Concrete Two-way Composite Slab

The composite slab can effectively improve the construction efficiency and reduce the amount of template,and is widely used in practical engineering.With the policy of promoting the development of building industrialization in recent years,it is of practical significance to study the slab in depth.At the same time,the social problems bring by city transformation and development cause resource consumption and construction waste.Consequently,the utilization of recycled materials has become the responsibility.Based on the above problems,the research group made a systematic and in-depth research on the new one-way composite slab based on different construction.In order to improve the theoretical system of composite slab,this paper designs a new type of two-way composite slab based on different construction.The prefabricated floor of the specimen is made of steel fiber regenerated brick coarse aggregate concrete,and the construction of steel truss and concrete ribs are set up to improve the structural behavior.By establishing a finite element numerical model,the rationality of the numerical model is verified by comparing the experimental results.Numerical expansion analysis based on the change of key parameters is carried out to study witch the influence of the parameters on the structural behavior of the specimen;based on the calculation formula of the bearing capacity,deflection and width of crack at present,by introducing the correction factor,the factors of the reinforced truss and steel fiber regenerated brick aggregate are considered reasonably,and the design and calculation method of a new type of two-way composite slab based on different construction is put forward.The main contents of the study are as follows:1.Through the static test of 2 prefabricated floor,4 composite slab and 1 cast-in-situ boards,the structural behavior of different material floor(NPS-1,RPS-2)are studied respectively.Moreover,the different construction of steel fiber recycled brick concrete two-way composite slab(RLS-2,RLS-3,RLS-4)and common concrete two-way slab(NCS-1,NLS-1)are studied.In addition,the structural behavior is studied of the influence of different floor materials(NLS-1,RLS-2).Based on the analysis from the changes and development of contrast test,the strain of the reinforced bar,the strain of the reinforced concrete,the mid span deflection and the characteristic load,the following conclusions are drawn:1)the steel fiber recycled brick concrete and the common concrete precast floor are all in elastic working state during construction stage,and the deflection is less than the standard limit value,which can satisfy the requirement of bearing capacity on the construction stage.2)the steel fiber material can effectively improve crack resistance and specimen ductility.The steel truss and concrete rib can effectively improve the overall stiffness and bearing capacity of specimen.The reinforcement of the steel truss is more prominent.The specimens are arranged by the bearing capacity from large to small as:RLS-4,RLS-3,RLS-2,NLS-1,NCS-1.3)lower chord bars and plate bottom tensile reinforce each other to resist bending moment.2.By using ABAQUS software,this paper set up a finite element numerical model of the two-way composite slab,and analyzed the strain,the deflection and the damage distribution of the specimen under same load and boundary condition.Moreover,the rationality of the finite element model is verified by comparing with test results.In addition,numerical expansion analysis is carried out based on the change of length and height parameters of reinforced truss.The results showed that:1)when the length of steel truss is less than 1/2 of the length of plate,it can still improve the bearing capacity of member effectively.The longer the truss,the better the bearing capacity;2)the change on height of steel truss can be ignored before normal use limit state.When after normal use limit state,it is necessary to ensure the high superposition of steel truss.It should be noted that the higher the steel truss is,the greater stiffness of the specimen is.However,the influence brought by changing truss height is not as much as changing truss length.3.According to the existing theory of ordinary concrete structure,the contribution of the steel truss to the bearing capacity of the specimen is considered,and the ultimate bearing capacity of the specimen is calculated,which proves the applicability of the calculation theory and the reasonableness of the cooperative work of the steel bar truss.The cracking load of the specimen is analyzed and calculated,and the reference value of~?mfor the specimen is put forward,and its rationality is verified.Considering maximum crack width of the specimens,the relevant formulas for steel fiber recycled brick and truss are established,and their rationality is verified.