Study And Analysis On Cast-in-site Hollow Floor With Thin-wall Core Box System

In this dissertation ,we will see another slab which is formed by adding a slab downstairs to the waffle slab ,and is named the cast-in-site concrete hollow floor with thin-wall box.This kind of slab can decrease the comsuption of the materials , reduce its own weight,and has good globality.So this kind of slab may be popular in the future.Combined with a project financially supported by the Construction Bureau of Hunan Province, some studies about this floor have been carried out in this dissertation. The valuable results achieved are outlined as follows:(1) The pseudo-plate method has been modified for three times, and then it has been used to analyse two examples.Compared with the ANSYS results, we can see the modified pseudo-plate method is feasible in the research of the hollow floor.(2) In this dissertation, the working performances of the cast-in-site concrete hollow floor with thin-wall box under the verical load with simply supported, has been investigated by the software ANSYS (10.0). The stress﹑deflection﹑crack are all indicated both in the elastic and the elasto-plastic stage,espercially when they are in the typical location.In the end, the calculate fomula of the max slab deflection and the rigitidy variability are advanced during the whole Non-linear process.(3) As we know,if we choose the differentσ?εfunctions to anlyse the reinforced concrete slab ,we will gain the different results .In this dissertation,twoσ?εfunctions are choosed to compare the chinese and the ACI code in the max definition of the concrete function.Meanwhile,it is found that in the elastic stage ,the section can keep plane-section,and the slab'defection will not change along z direction.(4) Membrane effect, which may be affected by the concrete intensity﹑the ratio of reinforcement﹑theσ?εfunction and so on, exsists in the the hollow floor with thin-wall box.It has influence on the strcture's limit load.In this dissertation, the phenomenon are confirmed by the simulation of the ansys software.(5) In this dissertation, the section parameters of the hollow floor are analysed systematically, and the optimum interval is obtained in the end.(6) Comparing the hollow floor with thin-wall box and the waffle slab with the same consumption of concrete, it is found that the former's max deflection is only about 30 percentage of the latter under the same condition.Comparing the hollow floor with the solid slab,which has the same section in height and in inertia moment, it proves that the slab which is studyed by this dissertation has good performances.