piles mainly for marine works are as during the Japanese occupation, but since At depth desired, the casing is anchor-
1947 approximately 250 projects have ed to the driving frame,
tollows:
I. Cast-in-situ piles require less rein
forcement,
2. The concrete of the cast-in-situ piles may be leaner (as the pile does not need to be handled or driven as such),
3.
4.
5.
Time is saved in curing,
There is no wastage due to cutting off large portions of piles,
raised very been built on these piles, among them slightly and concrete plug is expelled. being the Bank of China, Shamrock Hotel, Small quantities of concrete are dumped the North Point Housing Scheme, Li down the casing (alongside the ram) and Cheng Uk Resettlement Flats, Shek Kip successively driven out under falling ram Mei Resettlement Flats, Hong Kong Police blows of 150,000 foot lbs. (more or less, Headquarters, Chinese Chamber of Com- as required). This action highly densifies merce, etc., etc.
the surrounding soil, forms an enlarged concrete bulb and provides the charac- The general idea of the system is as teristic high load carrying capacity of follows:-
Franki Displacement Caissons.
The casing is precisely located and
There is no risk of damaging the adjusted for true verticality, and a quan- tity (3 to 5 cubic feet) of dry mix or pile by driving.
crushed rock according to circumstances is dropped into bottom of tube and tamp- ed until the mix compacts against the sides producing sufficient friction for driv-
6. The pile driving plant is
tively lighter.
'FRANKI' PILES
compara-
After the expanded base of the caisson is formed, the rough (or reasonably smooth, if desired) shaft is built by ram- ming into the soil successive quantities of concrete while progressively raising the casing (10"-18" increments). Maximun! skin friction may be developed by ram-
'Franki' piles is a system of piling ing. The 13" diameter solid cylinder ming the compacted concrete out against which belongs to the class of cast-in-situ ram, having tamped the plug tight, is now the already compressed soil with blows of
raised ΙΟ to 20 feet piles.
as required, and 30,000 to 40,000 foot lbs. forming a allowed to drop freely on the plug forcing shaft of 23" to 25" diameter, depending it into the ground and causing the casing upon original soil density and values to be pulled along.
The system was invented in 1911 by a Belgian engineer, Edward Frankignoul Eventually it gained universal recognition because of its outstanding advantages.
desired.
-
The Earth penetrated is pushed aside and
is Franki Displacement Caisson compacted to make room for casing now complete the steel casing has been In Hong Kong the system has been Boulders encountered are usually smashed removed to be used over and over again. operating since 1918 when the Hong Kong or pushed aside by heavy impact of the The finished pier is a rough concrete Engineering & Construction Co. Ltd. ob- 7,000 lb. ram put directly on them column encased in a sheath of tightly- tained a licence from the Societe des through the compacted concrete. The compacted earth completely integrated Pieux Franki (Belgium) to drive 'Franki' casing quickly moves downward, to de- with the entire soil mass. The caisson piles in Hong Kong, Macao and China. signated depth, because of the high driv- exploits the maximum bearing capacity Since then, many buildings have been ing force of the falling ram (much greater of the soil because of the enlarged, pres built in Hong Kong on 'Franki' piles. than steam or pneumatic haminers). Mark sure-injected footing, the rough bulbous One of the first ones was the Peninsula on ram cable shows height of concrete in shaft and because of the densification of Hotel. The record of pre-war structures casing, assuring against entrance of water, the adjacent soil as a result of the method built on 'Franki' piles has been lost mud or soil at all times.
of execution.
Australian manufacture of plywood and veneer is developing in ways unparalleled by many of the country's other industries.
One of the most outstanding aspects is the production of Reswood, sheets of which sized 7 ft by 25 ft without splice are claimed to be the biggest being produced in the world. Completely waterproof, it is being put to uses never before envisaged for plywood.
As formwork for major concreting projects, Reswood is in keen demand throughout the world. Photograph (above) shows it being used in the building of a new dam at Warragamba, New South Wales.
Size of a normal sheet of Reswood was graphically demonstrated at the Toronto Trade Fair, in this exhibit of a monster Australian aboriginal boomerang shown in the photograph (right).
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