Economic And Technical Analysis Of The Underground Garage

In recent years, with the economic development, China's urbanization process is accelerating, the number of new district in the city is increasing; at the same time as the ceaseless improvement of residents, urban residents of motor vehicle is growing,the original ground parking spaces have been unable to meet the new vehicle. From the point of developers, how to solve the parking problem of new motor vehicle has become one of the key factors influencing the village selling performance good or bad.The problem will be solved well by the underground garage which does not need more ground area occupied by cells while increasing the number of parking spaces, the development of underground garage has become the main direction of development.However, garage, roof loads(overburden load and fire live load), column grid size,layout and parking spaces roof slab form factors will be considered in the construction of the underground whose cost accounts for a significant proportion of the construction costs of the entire cell. Thus the designer is required to take reasonable measures to reduce the cost of construction of the underground garage by developers. The problem how to save underground garage construction costs reasonably is considered by the designer. This article mainly from the factors of above, focus on the study of the impact of several factors on the underground garage building cost and put forward reasonable solution, the main work is as follows:1. several kinds of reasonable column spacing are determined by car size, parking space size, parking mode and the number of cars parked between pillars. Finally, three reasonable column network dimension determined by the way of parking and column spacing.2. Two different kinds of distributions of parking stall are laid out in the same column grid, namely annular column grid layout and layout using the principle of individual. Two kinds of parking layout of economy are analyzed by comparing the cost of single parking stall. It concluded as follows: the cost of application of the principle of individual layout pattern is the lowest which is beneficial to saving the cost of the garage.3. Three kinds of rationality column grid are arranged in accordance with the uniform conditions of the garage, namely small column grid(5400mm×5000mm),medium-column grid(7800mm×7800mm) and big column grid(10200mm×5000mm).First, the single parking area of three kinds of column grids is calculated, second, the cost of the material per unit area under the roof of each column grid combined with the actual situation is calculated. Last, parking spaces cost comparison of three column grid economy under each column grid by calculating, and give concluded. Finally,three column grid of economy is compared by calculating the cost of column grid, and the following conclusions: the cost of per unit area in small column grid(5400mm×5000mm) is the lowest.4. By PKPM software, underground garage roof structure chosen ordinary non-girder floor and girder floor are modeled, the major materials(steel, concrete and template) cost of the floor under the different size of column grid and different thickness of overburden soil is calculated. Finally, the main material costs were compared for each floor, the following conclusions:(1) when the thickness of covering ?1.0m, non-girder floor used small column grid(5.4m×5.4m) and middle-column grid(7.8m×7.8m) is more economical, girder floor used large column grid(10.2m×10.2m) is relative economical.(2) under the same conditions of soil thickness, non-girder floor and girder floor general with increasing column spacing, the unit material cost increases, but the material price growth rate of non-girder floor is much higher than the growth rate of girder floor.5.The roof of the underground garage fire lanes live load value: through the calculation of fire wheel pressure diffusion effect and fire lane load reduction coefficient, different plate span and different thickness of the covering soil fire lane equivalent uniform distributed load are calculated. Through the practical engineering,fire live load reduction of materials before and after the underground garage roof member economic influence are compared, draws the conclusion: the fire load reduction can significantly reduce the cost of roof material and save the cost of underground garage.