Calculation of the volume of building excavation operations
After the destruction of the building, the excavation of the building should be done. At this stage, the amount of excavation volume is calculated based on the depth of the pit and the depot resulting from the destruction.
In small projects, excavation is usually left to the excavation contractor. At this stage, the contract is done in two ways.
The first method is that the volume of the pit (length*width*height) is the basis of payment based on cubic meters and a fixed amount for excavation is determined based on the volume of the pit.
In this method, the amount of excavation volume is calculated according to the foundation plan, and to calculate the volume of surface soil (demolition waste), an average height is considered for the soil depot (for example, three meters) and then the mentioned height is calculated in the length and width of the old building. They multiply to calculate the surface soil volume and the total volume of surface soil and pit soil is considered as the amount of excavation based on cubic meters.
For example, if the length of the new building is 20 meters, the width of the property is 10 meters, and the depth of the pit is 1.2 meters, the excavation volume will be 240 cubic meters. meters, the volume of earthmoving will be 450 cubic meters and the total volume of earthworks will be 690 cubic meters.
Now, if the excavation is to be done during the day, the soil should be transported by trucks and mini trucks because it is forbidden to drive trucks in the city during the day.
(until 10 pm).
Therefore, according to the fact that each pile has a carrying capacity of approximately 4 cubic meters of soil, the number of cars will be 172, and if the cost of transporting each pile is 200,000 tomans, the total cost of the contract will be approximately 34 million tomans.
However, if the excavation is done at night, if there is no restriction on the transportation by truck, it is calculated according to the conditions of the alley and passage in such a way that each truck can load 12 cubic meters, so the number of cars will be 57, and if the freight of the truck is 400 000 tomans, the excavation cost will be approximately 23 million.
As you can see, digging by truck is more economical due to the more appropriate transportation fee.
But sometimes we have to do earthmoving during the day for various reasons, including the sensitivity of excavation and the impossibility of working at night, or the limitation of the property and the traffic of trucks in the street.
In the lump sum method, the inflation of pit soil is usually not calculated because the soil resulting from demolition is profitable enough for the contractor, and due to the shape of the debris, this part of the soil shows a larger volume, which is not actually calculated to that extent.
In addition, in this method, the contractor’s profit and the loader’s cost are not calculated separately and are included in the shipping price.
In the second method, the basis of payment will be the number of loaded machines, and therefore, the number of machines should be recorded by the employer’s agents, and secondly, attention should be paid to the amount of soil loaded in each machine, because usually in this method, the machines are loaded less than the allowed capacity. And the pit contractor and the drivers are mischievous.
In estimating the initial cost in this method, the amount of soil inflation should be taken into account.
Excavation is more suitable by lump sum method.
In urban pits, approximately 50-60 ten-wheel truck services can be loaded with a mechanical shovel in one working shift (usually night to morning).
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This post is written by Mohammadsaadatmand23