Study On The Influence Of The Dense Degree Of Embedded Pipelines In Laminated Layer On The Flexural Bearing Capacity Of Reinforced Concrete Composite Floor Slabs

Prefabricated concrete structure system is one of the most important choices in modern construction industry,anddeveloping this kind of system is a major revolution of construction method.It is helpful to save resources,reduce pollution and improve labor productivity.Prefabricated concrete floor slabs is an important part of prefabricated concrete structure,whichare mainly using the structural form of laminated floor slabs.During the construction,a variety of water and electricity pipelines will be placed on prefabricated floor slabs before pouring cast-in-place concrete.With the improvement of the level of electrical intelligence,the pipelines layingare gradually concentrated,and weaken the concrete cross section,which has an impact on the bearing capacity of concrete composite floor slabs.This influence is even more serious especially in the intersection of multiple pipelines and at the intersection of pipelines.In structural design,it does not take into account the influence ofthe dense degree of embedded pipelines in laminated layer on the flexural bearing capacity of reinforcedconcrete composite floor slabs.In this paper,by static loading test and finite element analysis,the laminated floor slabs embedded pipeline is studied,the bearing capacity(ultimate bearing capacity,crack,deflections)and failure mechanism are analyzed.This paper mainly does the following work and obtains the related conclusions:(1)Review the domestic and foreign literatures which is related to the laminated artifacts,and summarize the research status about laminated floor slabs at home and abroad.(2)Adequately appreciate the regularity of the change of stress on the cross section and the failure mechanism of laminated floor slabs in the bending process,and complete the theoretical calculation of ultimate bearing capacity of each group of testingconcrete floor slabs.(3)Two groups of laminated floor slabs of single layer pipelines arranged horizontally but with different embedding spacing,two groups of laminated floor slabs of single-layer pipelines arranged vertically but with different embedding spacing,two groups of laminated floor slabs of single-layer pipelines arranged with lateral inclination of 45°but with different embedding spacing,a group of laminated floor slabs of double-layer pipelines arrangedvertical cross and a group of the identical size of laminated floor slabs without pipelines,through the static loading test and the comparative analysis to the above eight group of laminated floor slabs,study onthe influence of single-layer pipelines of different embedding spacing on bearing capacity of laminated floor slabs in three directions,and then study on the influence of double-layer pipelines on bearing capacity of laminated floor slabs in relation to single-layer pipelines.The experimental result shows that the influence of the bearing capacity of the laminated slabs varies with different buried directions of the single layer pipelines.For the laminated floor slabs of single-layer pipelines arranged with the same height,the embedding spacing of pipelines has great influence on the bearing capacity of the laminated slabswhen pipelines arranged horizontally.thebearing capacity of the laminated slabs arrange pipelines with large separation distanceis better than that with small separation distance.The bearing capacity of the laminated slabs arrange pipelines with large separation distance and withsmall separation distanceare almost the same when pipelines arranged vertically,so the spacing of pipelines has little impact on the bearing capacity of the laminated slabs.The influence of the spacing of embedded pipelines on the bearing capacity of laminated floor slabs is between transverse arrangement and longitudinal arrangement when the laminated floor slabs of pipelinesarranged with lateral inclination of 45°.The bearing capacity of laminated floor slabs with double-layer pipelines is a little smaller than that of single-layer pipelines.(4)Nonlinear numerical simulation to eight sets of laminated floor slabsby finite element software(Abaqus),the result shows that the simulation result is in good match with the test result,the conclusion of simulation issimilar to experiment,which reflects the actual stress of the testingconcrete slabs.