| Assembled reverse rib floor is a large size or whole floor slab that is loaded by the 750mm mesh dense ribs made of 180mm rib beam and 50mm thick floor,which is prefabricated by the factory.This plate solves the practical problems of easy installation,maintenance and easy replacement of the pipeline.At the same time,because only the rib beam is connected with the surrounding components,the slab week is reduced.The number of ribs is raised to improve the efficiency of assembly structure production and installation.In order to popularize and apply the assembled concrete anti ribbed floor slab,the static test was carried out on the prefabricated rib beam and the full prefabricated ribbed slab of the rib beam,and the cracking process,the force mechanism and the design method of the prefabricated concrete counter ribs were studied in this paper.Through experiments and theoretical research,the following conclusions are reached.(1)Under the uniform load,the prefabricated part of the ribbed beam and the prefabricated counter-rib floor of the rib beam,the cracks at the bottom of the slab occur in the middle of the span,parallel to the direction of the long side.The cracks clearly show the crack characteristics of the two-way slab,but the number of cracks is The obvious difference is that the cracks in the prefabricated floor slabs of the ribs and beams are developed from the middle to the four corners as the load increases.The gaps between the bottoms of the slabs are large and the number of cracks is small;many.(2)When the uniform load is added to the load standard combination value,the mid span deflection of the rib beam partially prefabricated counter ribs is 3.25mm,the maximum crack width is 0.1mm,the mid span deflection of the ribbed beam is 3.84mm and the maximum crack width is 0.1mm,which is less than the standard cross deflection limit 17mm and the three grade crack width control limit value 0.2mm gauge respectively.Sure.(3)When the uniform load is added to the basic load combined value,the mid span deflection of the rib beam partially prefabricated anti ribbed slab is 3.86mm,the maximum crack width is 0.1mm,less than the limit state deflection limit of the bearing capacity 68mm and the crack width limit 1.5mm,and the mid span deflection of the ribbed beam is 4.53mm and the maximum crack width is 0.2mm.The specification limits the carrying capacity limit state,the deflection control limit 68mm and the crack width control limit 1.5mm.(4)Theoretical and computational analysis show that:? The internal force of the fabricated ribbed slab is in good agreement with the test results by the pseudo beam method.? It is clear that the resistance and reinforcement calculation can be carried out by using the existing standard design,and the design and structural requirements of the fabricated concrete reverse rib floor are also presented.(5)Ribbed prefabricated counter-rib floor slabs and ribs Some prefabricated counter-ribbed floors can be used for prefabricated building roof panels with reasonable design.The prefabricated counter ribs of the ribbed beams do not transfer the ribs.The factory manufacture is simple,and no additional steel bars are required for on-site installation.However,the on-site wet operation is slightly more than the prefabricated counter-rib floor slabs of rib beams.In view of the limited number of concrete anti ribbed slab test and the imperfect design calculation theory,it is still necessary to carry out further experiments,corresponding structural research and pilot project application,so as to provide scientific basis for the compilation of corresponding standards. |
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