Hong Kong Builder
39
-Concrete ready
for depositing
Layer of Concrete deposited during upward blow of hammer
Rise of Tube per upward blow
Fall of Tube per downward blow
Layer of compressed concrete rammed 80 times per minute
Fig. 4
between the concrete and the inner walls of the tube. Thus the tube moves up whilst the concrete remains stationary.
The effect of the light cushioned downward blow is shown in Fig. 5. The friction between the concrete and the tube now helps to make the concrete move downwards, the tube and concrete acting virtually as a solid ram exerting a considerable tamping pressure over the whole section of the pile. During this operation the layer of concrete is compacted and rammed outwards to fill the
Fig. 5
space left by the tube; a corrugated surface is also formed on the pile, increasing the friction between the pile and the surrounding ground.
This cycle of upward and downward blows is repeated 80 times per minute, a pile of dense concrete being formed at the rate of up to 4 ft. per minute.
Fig. 3 shows the completed 17 in. lia. Vibro pile, which may be finished at any desired level below the ground surface, according to the amount of concrete filled into the tube.
WE MANUFACTURE
STEEL
WINDOWS
& DOORS
IN
LIGHT, MEDIUM AND HEAVY SECTIONS
WE SUPPLY STANDARD SIZES
AND SHAPES DIRECT FROM STOCK
OR MADE TO ORDER FROM
YOUR SPECIFICATIONS
NEW
ALL METAL WINDOWS
FOR THE
CENTRAL MARKET
HONG KONG
WERE MANUFACTURED AND SUPPLIED
BY US
HONG KONG METAL WINDOW MFG., CO.
6 FUK WING ST..
TELEPHONE 58644.
KOWLOON