Design And Economical Studies Of Cylindrical Reinforcement

Concrete Water Tanks

Done by :Ruba Ahmad Jaradat .Sabah Hussein Abo_Dalbouh .Eslam Nayf El-shorbasi  Supervisor:Dr. Abbas Zaki Ijjam

Introduction

 Nearly all water systems include some form of storage, most commonly a tank.

Water Storage describes how to store water for home, farm, and small communities. It will help you design storage for just about any use, including fire safety and emergency, in just about any context—urban, rural, or village.

  The classification of water tanks

A: due to its location

1.Water tanks resting on ground 2.Underground water tanks 3.Elevated water tanks 

The classification of water tanks

B : due to its shapes  

1. Circular tanks.2. Rectangular tanks.3. Bowel tanks.4. Spherical tanks.5. Conical tanks.6. Suspended bottom tanks.7. Intze tanks. 

The classification of water tanks

C : due to the material that used in construction 

JOINTS IN LIQUID RETAINING STRUCTURES MOVEMENT JOINTS

 

• There are three types of movement joints :

 1. Contraction Joint

 2. Expansion Joint

3. Sliding Joint

• Contraction Joints

• Temporary Joints

Cylindrical tanks design :

Given data for design ,as shown in the table :

Volume ---

Fs 150 N/mm2

ɣ water 9.81 N/m2

Thickness (t)

---

Freeboard 1.0 m

Es/Ec ≈ 14

N 3/7

J 6/7

B 1000mm

fc 15N/mm2

ȶ allowable 2N/mm2

Design of walls :

Step 1 : Determine the inner diameter of the tanks :

 

the total volume = π D2H/4then the diameter can calculated using the following eq.D= √(4 vol. / (π H))

Step 2 : load distribution

Find value of h :

H^2 /D.t

load distribution

Step 3 : Reinforcement against hoop stress

Maximum pressure (pmax)

P max = (H-h) γwater

Tension force from hoop stress (F/2) F/2 = p max * D/2

The reinforcement for this zone (As)

As = (F/2)/fs

Number of bars recording to the As

Using bars Φ 12mm | Φ 14mm | Φ 16mm ….

# of steel bars = As/As (one bar)

The spacing between the bars in one meter height Spacing = 1000/# of steel bars Check For tensile stress in concrete :

 Step 2.2 Reinforcement against cantilever actions:

 

Maximum force from cantilever action

 

Fmax = 0.5* ɣ water*H*h

 

Moment of cantilever (Mmax)

 

Mmax = ⅓*h*F max

= (1/6)* ɣ water*H*h2

 

Check for shear on base of wall :

Where,allowable = 2N/mm2 , d = t – 50mmminimum thickness against cantilever action :

Check for d d ≤ d provided d provided = t-50mm

reinforcement require against cantilever action :

The area of steel used to avoid shrinkage and temp. Changes is calculated as followed :

 

As min = 0.002 Ac

 

The reinforcement steel bars used the avoid shrinkage and temp. changes have to put at inner side of concrete .

 

 

B. design the base of the water tank :

well compacted ground have been considering in design without problems of differential settlement .

 

We used 200mm thickness as minimum with minimum reinforcement in both direction at top and at bottom "two layers". 10mm diameter @ 250 mm

 

Provided construction joint at 4m spacing in both directions.