Research And Application On Structural Performance Of New Assembled Hollow-ribbed Slab

The new assembled hollow-ribbed slab is a new slab structure,which is composed of prefabricated box and cast-in-place ribbed beam.It has the advantages of simple construction,low cost,seismic resistance and good integrity.Compared with the ordinary assembled hollow-ribbed slab,some improvements have been made in the prefabricated assembly box in this paper:first,the trapezoid section is used in the new assembly box in the hollow-ribbed slab,which can appropriately increase the cracking load of the ribbed beam;second,concealed columns are set at the four corners of the box side plate,and concealed column bars are placed in the concealed columns,which plays the role of shear resistance and integrity improvement in the transportation process.In order to study the overall structural performance of the improved slab,the main research analysis and results are as follows:First of all,the improved assembly box and a 9000mm × 8400mm × 300mm standard span slab are simulated by finite element method.The analysis results show that the design of the top plate,side plate and hidden column of the assembly box is reasonable and can meet the requirements of normal use,transportation and demoulding.Under three different load combinations,the standard span ribbed slab can meet the requirements of the code,and the assembly box and the ribbed beam can work together,so the slab has a good integrity.Secondly,in this paper,the cross beam system method,look-up table method and PKPM are used to build a five story model to analyze the influence of different ribbed beam sections on the internal force calculation of the slab.It is found that among the three sections,the negative bending moment and shear force value of the ribbed beam support of the I-section is the smallest,the bending moment and shear force value of the midspan is the largest,and the deflection is the smallest,which is closer to the simulation value of ABAQUS.Therefore,compared with other sections,it is more accurate to consider the rib beam section as I-section when calculating the internal force of the slab.Finally,when calculating the internal force of the new assembled hollow-ribbed slab,the function of the assembling box should be fully considered.In order to make the calculation easier,the stiffness contribution coefficient ? of the assembling box is obtained ?e=0.759.The modified cross beam system method and the look-up table method can be used to simplify the calculation,and the deflection value of the modified cross beam system method is closer to the result of software simulation.