A training manual in conducting a workshop in the design, construction, operation, maintenance and repair of hydrams |
Session 10: Hydram construction - concrete (18 hours over a 7 day period) |
CAVITY WALL THICKNESS |
DOME COVER THICKNESS |
NUMBER OF BOLTS AND SIZE |
The side wall thickness (Ts) in a concrete Hydram without reinforcement shall be equal to the diameter of the cavity (Dc) in inches times the drive head (H) in feet divided by 10 or shall be equal to the cavity diameter, whichever is greater.
The top or bottom wall thickness (TL) should be 1.25 times the cavity diameter.
The total bolt area (TBA) should equal the drive pipe diameter (inches) squared times the drive head in feet divided by 50 or :
If D in mm. and H in meters then
To determine the proper number of bolts, find the area of the bolt size you wish to use and divide it into the total bolt area.
Diameter of bolt:
mm. |
6.3 |
8 |
9.5 |
11 |
12.7 |
14 2 |
15.8 |
19. |
22.2 |
25.4 |
in. |
1/4 |
5/16 |
3/8 |
7/16 |
1/2 |
9/16 |
5/8 |
3/4 |
7/8 |
1 |
Area of bolt:
.027 |
.045 |
.068 |
.093 |
.126 |
.162 |
.202 |
.302 |
.419 |
.551 |