1. Introduction to the form of column network
1. Large column net
As a regular size, 78m*8.The 0m column size has been widely used in underground garages. Three standard parking spaces of 2400mm*5300mm, together with a cross-sectional size of 600mm structural columns, create an extreme column spacing of 7800mm (net distance of 7200mm). The clear width of the lane is 5500mm and the lane setback line is 1250mm on each side to form a column grid size of 8000mm (8100mm).
Two-way large column network.
2. Large and small column nets
On the basis of the large column network, reasonably reducing the size of the column network can effectively reduce the cross-sectional size of structural components and improve the economy of the underground garage.
Under the premise of satisfying three standard parking spaces of 2400mm*5300mm, the column spacing of 7800mm (the net distance is 7200mm) and the net width of the 5500mm lane remain unchanged, and the depth of the original column network is changed to the lane depth of 6000mm and the body depth of 5050mm.
Large and small column grids. 3. a small column network
On the basis of the large and small column grids, we further change the size of the double-sided column grids to obtain the form of small column grids that meet the requirements of two standard parking spaces of 2400mm*5300mm. The column net adopts a column spacing of 5200mm (the net distance is 4800mm), and the original column network depth is changed to a lane depth of 5900mm and a body depth of 5100mm.
Column nets. 4. Improved small column network
In order to improve this reality, on the basis of the small column network form, an improved small column network form is derived, the column spacing remains unchanged at 5200mm, the lane depth is increased to 6900mm (each side is advanced by 500mm), and the body depth is reduced to 4600mm (each side is indented by 500mm).
Improved column mesh.
2. Similarities and differences between different column network forms
1.The influence of different column grid forms on the construction area of a single parking space
The construction area of a single parking space is one of the sensitive problems of the underground garage, under the condition that the plane size of the single parking space remains unchanged, the large column grid form adopts a 600x600 column section, and the small column network form adopts a 400x400 column section due to the reduction of the load area, so there is no difference in the construction area of a single parking space in different column grid forms.
2.Parking comfort analysis
The position of the column of different column net forms is different, has a certain influence on the turning radius of the vehicle, the parking comfort of the large column network is the best, the parking comfort of the small column network is general, and the parking comfort of the improved small column network form is improved to a certain extent than the parking comfort of the large and small column network and the small column network form.
Large column mesh. 
Large and small column grids. 
Column nets. 
Improved column mesh.
3.Visual perception analysis
In the structure of large column network, the column cross-section is larger, the number of columns is smaller, and the field of vision is broader. In the form of small column network structure, the column cross-section is smaller, the number of columns is larger, and the visual density is more dense.
Large column mesh. Column nets. 4.Floor height analysis
According to the trial calculation and the comprehensive results of the pipeline, the structural height of the large, large and small column grids with beams and floors is about 900mm, 800mm and 700mm. The structural heights of the large, large and small column grids and small column grids of beamless floors are about 450mm, 400mm and 300mm. Therefore, the structural height difference between the beamless floor and the beamed floor under different column mesh forms is 350mm 450mm, and the equipment height difference is 150mm 200mmThe difference in floor height is 150mm and 300mm
Analysis diagram of the height of the covered floor with beams.
Analysis diagram of the height of the covered floor with beams.
Comparison of the height of the structure.
5.Floor form
At present, the commonly used structural forms of underground garages are beamed floors and beamless floors, which are suitable for different column network forms. For the column network with large volume and regular volume, it is advisable to adopt the structural form of beamless floor;For irregular column grids, large changes in column spans, unstable business formats, and the possibility of more floor openings, it is advisable to adopt the form of beamed floors. There is no difference between different column grid forms on the floor form.
3. Economic analysis of different column grid forms
Compare the different column network forms in the case of beamless floor and beamed floor, without considering the foundation formSmall column mesh + beamless floorEconomical optimum.
In 1Under the premise of 5m soil cover and nuclear six-level civil air defense, it is estimated that the height of structural components and the amount of structural materials used in the beamless floor are less than those of the beamed floor, and the construction and installation cost of the beamless floor is more than 10% less than that of the beamed floor.
With the increase of column spacing, the cost of construction and installation increases accordingly. For the underground garage with beamed floors, the construction and installation cost of the large and small column networks is about % of the large column network. For the underground garage with beamless floors, the construction and installation cost of large and small column grids, small column grids, and improved small column networks is about % of that of large column networks.
Economical comparison based on large column mesh and beamed floors.
We also try to make quantitative analysis of different foundation forms, but due to the large difference in geological conditions of different projects and the huge number of combinations of foundation forms and column grids, we can only draw some qualitative analysis conclusions. When the foundation is a natural foundation, the economy of the small column network is the best, and the construction cost is reduced by more than 70 square meters. When the substrate is soft soil, karst, or it is necessary to consider anti-floating measures and other pile foundation or foundation treatment, it is still necessary to comprehensively consider the corresponding influencing factors to estimate the cost.
Conclusion
Through an in-depth analysis of the column grid form of the whole underground garage, it can be obtained:The economy of beamless floor is better than that of beamed floor, and the form of small column network is better than that of large column network and large and small column network structural formsQuantitative and qualitative analysis conclusions. In the process of selecting the column grid form, sometimes it is necessary to sacrifice economic benefits to obtain a more comfortable parking experience, and each project can choose the column grid size suitable for the project positioning according to its own situation.
*: Ocean Design Exchange