Experimental And Theoretical Study On A New Assembled Two-way Hollow-ribbed Slab

Combining the merits of the concrete hollow-ribbed slab and the laminated slab,a new assembled two-way hollow-ribbed slab is developed.The slab combines the cavity inner mold with the prefabricated part of the laminated board and is produced in large scale in the factory.A certain width of gap is reserved where the reinforcement is embedded between the boxes to form vertical and horizontal ribs.After the board was transported to the site and installed into place,secondary pouring was carried out to form a well-integrated two-way ribbed cavity floor.The floor incorporates the advantages of industrial production and traditional ribbed cavity floors,which can effectively reduce the amount of wet work at the construction site and reduce environmental pollution.In order to understand the working performance of the slab,this paper conducts a full-scale static loading test and a finite element comparison analysis to study the two-way force characteristics,as well as its actual working state under load.The main research contents and results are as follows:Firstly,a full-scale test model of 8700mm×8700mm was made.The static load test was conducted to study the performance of the new-type prefabricated two-dimensional rib cavity superimposed floor under vertical uniform load.The test results show that the load and deformation of this new type of prefabricated two-dimensional multi-rib cavity laminate floor have a linear change,and the residual deformation is not large.It has good elastic properties,and the two-way force performance is obvious so that it can be calculated by two-way board.Secondly,the finite element model of a new type of assembled two-way ribbed cavity superimposed floor was established.The static characteristics of the finite element model were numerically simulated and compared with the experimental data.At the same time,the stress performance of test plate,ribbed floor cover and common solid plate under different conditions was compared and analyzed.The results show that the numerical simulation results are basically consistent with the test results,and further confirm that the new type of floor slab not only has the same force deformation characteristics as ordinary solid slabs,but also has better overall performance than the multi-rib floor slab.Thirdly,the rigidity of the test plate in two directions is analyzed.The calculation model of the test plate is equivalent to the ordinary cast-in-place hollow plate.The design calculation method for the internal force and deformation of the test plate is given.The results show that the short-term stiffness formula and deflection deformation formula of the test plate are obtained,and the feasibility of the calculation method is verified by comparing with the experimental values and the finite element calculation results.Fourth,the ultimate bearing capacity of the new assembled two-dimensional multi-rib cavity laminated floor was calculated and analyzed.The plastic stranding method was used for calculation,taking into account the effect of the thin film effect.The results show that the ultimate load are 55.40kN/m~2 and 108.31kN/m~2 under the condition of four edges simply supported and four sides clamped respectively,and the results are verified by finite element software.