Economic And Technical Analysis Of Common Underground Garage Floor

As to a building, floor is an important component of the building. The same building,with different floors, will not only affect the calculation of internal force but also the cost ofthe building. In particular, to the underground structure, it is impossible to neglect thedifferent costs for different floors. With the condition of the same usable space, the choice ofdifferent floors will affect earth excavation、precipitation、retaining and protecting forfoundation excavation and so on. Therefore, it is necessary to integrate all these factors intoconsideration when choosing the floors for the underground structure. If it is decided whetherthe floor is built economically or not according to its cost, the conclusion will often be farfrom satisfactory.Focusing on which kind of structure is more economical, the thesis will compare thethree structures often adopted by common underground garage, that is beamless floor,beam-and-slab floor、hollow floor. Considering the cost of earth calculation, the thesis willcalculate the cost of the three floors respectively with three different spans of undergroundgarage（5.5m×5.5m、8.0m×8.0m、10.5m×10.5m）and two different additional load（0.5meterearth-sheltered、1.0meter earth-sheltered）. Finally from comparative analysis with the totalcost of various floor, conclusions were drawn as follows(the thickness of the floor are not lessthan150mm):(1) If the span was small (5.5m×5.5m,8.0m×8.0m), the structure of seamlessfloor can achieve obvious economic benefit. And if the slab span was larger (10.5m×10.5m),you can consider choosing the beamless or hollow floor. The economic benefit is basicallyequivalent.(2) If both the span and load was small(5.5m×5.5m),you should not use hollowfloor.(3) If the base was the rock foundation, beamless floor is adopted, so as the large span,which has economic benefit better than the beam-and-slab floor.(4)From the average of totalcost of unilateral structure, the cost of5.5m×5.5m seamless floor is the lowest.By referring to the conclusion of the thesis, the designer can choose the proper floorstructure according to the project directly rather than compare different structures bythemselves before the designing work, which improves the working efficiency.