Project 1

To calculate the gross water demand of the residential society, we need to first calculate the total number of persons living in the society. Based on the given information, we have:

Total number of 2BHK flats = 200 Total number of 3BHK flats = 100

Number of persons in each 2BHK flat = 3 Number of persons in each 3BHK flat = 4

Total number of persons in 2BHK flats = 200 x 3 = 600 Total number of persons in 3BHK flats = 100 x 4 = 400

Total number of persons in the society = 600 + 400 = 1000

Now, we can calculate the total water demand per day for the society as follows:

Total water demand = Total number of persons x Gross water demand per person per day

Gross water demand for drinking = 5 liters/person/day Gross water demand for cooking = 45 liters/person/day Gross water demand for bathing = 30 liters/person/day Gross water demand for toilet flushing = 25 liters/person/day Gross water demand for cloth washing = 35 liters/person/day Gross water demand for miscellaneous use = 10 liters/person/day

Total gross water demand per person per day = 150 liters

Total water demand per day for the society = 1000 x 150 = 150000 liters/day

Now, let's consider the constraints and site data provided. The width of the road is 6 meters and thus the width dimension of the underground water tank cannot exceed 6 meters.

Assuming a rectangular tank shape, let's consider different depths for the tank and calculate the corresponding area of the tank base that would be required to store the daily water demand of the society.

For a founding depth of -3.00 m LVL, the S.B.C is 7.5 tonnes/sqm. Let's assume a tank depth of 3 meters for this case. The required area of the tank base would be:

Area = Total water demand per day / (Depth x S.B.C) Area = 150000 / (3 x 7.5) Area = 6666.67 sqm

This area exceeds the maximum width constraint of 6 meters and thus this option is not feasible.

For a founding depth of -4.00 m LVL, the S.B.C is 8 tonnes/sqm. Let's assume a tank depth of 4 meters for this case. The required area of the tank base would be:

Area = Total water demand per day / (Depth x S.B.C) Area = 150000 / (4 x 8) Area = 4687.5 sqm

This area is also greater than the maximum width constraint of 6 meters and thus this option is not feasible either.

For a founding depth of -5.00 m LVL, the S.B.C is 8.5 tonnes/sqm. Let's assume a tank depth of 5 meters for this case. The required area of the tank base would be:

Area = Total water demand per day / (Depth x S.B.C) Area = 150000 / (5 x 8.5) Area = 1764.71 sqm

This area is less than the maximum width constraint of 6 meters and thus this option is feasible.

Therefore, the minimum founding depth required for the underground water tank to store the daily water demand of the residential society is -5.00 m LVL and the required depth of the tank is 5 meters.

To create a 3D model of the underground water tank, you can follow the steps below:

1. Create the geometry of the tank in STAAD Pro using the center line approach.

2. Apply the soil properties and the soil bearing capacity at the different founding depths.

3. Define the support conditions for the tank, such as fixed or pinned supports.

4. Apply the loads on the structure, including the dead load and live load of the top cover slab, the weight of the soil and water, and the water demand load.

5. Specify the material properties of the tank, such as the concrete grade and the reinforcement details.

6. Mesh the structure using an average mesh size of 500 mm.

7. Run the analysis to obtain the bending moments, shear forces, and deflections in the tank.

8. Check the results to ensure that they are within the allowable limits for the soil settlement and the structural integrity of the tank.

9. Make necessary changes to the model and re-run the analysis until the results are satisfactory.

10. Once the model is finalized, generate the necessary drawings, including the plan, elevation, and section views, for construction purposes.

Note that this is a complex problem, and it requires expertise in stru