12-09-2013, 03:01 PM
Design of Underground Water Tank
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ABSTRACT
The Underground tanks are used to store water, liquid petroleum, petroleum
products and similar liquids. The force analysis of the tanks is about the same
irrespective of the chemical nature of the product. All tanks are designed as crack
free structures to eliminate any leakage.
This project gives in brief, the theory behind the design of liquid retaining structure
i.e. rectangular underground water tank.
This report includes requirement of water tank, survey, excavation methods,
Reduced Levels, Average Depth of UGWT, Soil on which it is constructed, Depth of
water Table, Type of Mix Design and Capacity of the tank.
Introduction
Gyanganga society is a residential society being constructed by Goel Ganga
Developers formally known as Goel Ganga pvt. Ltd. Ii is being constructed in
Rahatani village in PCMC Municipal Corporation.
Society has proposed 5 buildings each of seven floors having 4 flats per floor.
Thus in this project an attempt has been made to design a water tank for storing
drinking and utility water to serve daily requirement of the entire society.
The project work consisted of the following
1. Requirement
2. Survey
3. Excavation
4. Design Requirments
5. Approval from RCC Consultant
6. PCC and Water Proofing
Requirement
Water is one of the basic necessarily for a human.An absolute ―minimum water
requirement‖ for humans is independent of lifestyle and culture, can be defined
only for maintaining human survival.
Different sectors of society use water for different purposes i.e. drinking, cooking
food, bathing and washing clothes, sanitation and many other daily use utilities.
The water required for each of theseactivities varies with climatic conditions,
lifestyle, culture, tradition, diet, technology and wealth.
Water requirements for a society varies upon various factors i.e. No of buildings in
society, No of floors in each building, No of flats on each floor etc etc. Moreover if
society consists of row houses then water requirement for society increases as per
gardening needs. Amenities like common garden, swimming pool, gymnasium, play
ground, jogging park and club house have become additional factors of increased
water requirement of a society now a days.
Working Procedure:
The extent of soil and rock strata is found by making trial pits in the
construction site. The excavation and depth is decided & approved according
to the concerned site‘s R.C.C consultant.then, excavation is carried out as
follows-
Setting out or ground tracing is the process of laying down the excavation
lines and center lines etc. on the ground before the excavation is started. The
center line of the longest outer wall of the building is marked on the ground
by stretching a string between wooden or mild steel pegs. Each peg may be
projected about 25 to 50 mm form the ground level and 2m from the edge of
the excavation. The boundary is marked with the lime powder. The center
lines of other walls are marked perpendicular to the longer walls & the
excavation work is started with the help of JCB machine. Digging is done up
to a depth(Approved by R.C.C consultant) of 3.5 meters
DESIGN REQUIREMENT OF
CONCRETE (I. S. I)
In water retaining structure a dense impermeable concrete is required
therefore, proportion of fine and course aggregates to cement should be
such as to give high quality concrete.
Concrete mix weaker than M20 is not used. The minimum quantity of
cement in the concrete mix shall be not less than 30 kN/m3
The design of the concrete mix shall be such that the resultant concrete is
sufficiently impervious. Efficient compaction preferably by vibration is
essential. The permeability of the thoroughly compacted concrete is
dependent on water cement ratio. Increase in water cement ratio increases
permeability, while concrete with low water cement ratio is difficult to
compact. Other causes of leakage in concrete are defects such as
segregation and honey combing. All joints should be made water-tight as
these are potential sources of leakage.
CONCLUSION
Storage of water in the form of tanks for drinking and washing purposes,
swimming pools for exercise and enjoyment, and sewage sedimentation
tanks are gaining increasing importance in the present day life. For small
capacities we go for rectangular water tanks while for bigger capacities
we provide circular water tanks.
Design of water tank is a very tedious method. Particularly design of
under ground water tank involves lots of mathematical formulae and
calculation. It is also time consuming. Hence program gives a solution to
the above problems.
There is a little difference between the design values of program to that of
manual calculation. The program gives the least value for the design.
Hence designer should not provide less than the values we get from the
program. In case of theoretical calculation designer initially add some
extra values to the obtained values to be in safer side.