QUOTE(mrPOTATO @ Dec 27 2011, 03:17 PM)
1st wanna clarify i not engineer, so its open to correction.
Limestone areas got cavities/floating stones/stone valleys etc to if just taruh 1 spun pile, it might not sit correctly in the abnormalities mentioned. Thats why have to taruh a few piles to 'diversify'

like diversify in financing. The strength of spun piles is higher, but when more rc piles is combined, it migh be stronger collectively like the saying breaking 1 chopstick vs a few chopsticks. Also the absolute max strength of spun pile is higher eg can take xxx tons load but mayb no need to use so high loading as only www tons is loaded on the foundation, it will be overdesigned.
actually span pile also common to taruh a few. not necessary one span pile under one column.
QUOTE(kochin @ Dec 27 2011, 06:10 PM)
wah, so many "anjing liar" (engineer) here.
given a choice, don't think it's a good idea to have more than one type of piles within the same project. due to the differential loading capacity of the piles, it MIGHT result in differential settlement (meaning block a settle by 12mm, car park settle by 20mm). this is where you would observe a very lengthy crack separating 2 areas.
also in limestone area, unless the anjing liar is very certain that the piles are seated firmly on solid bedrock, else the anjing liar should really look into designing all the foundation to rely on friction rather than end bearing.
friction means the foundation is supported by the 'grip' between the length of the piles against the soil.
end bearing as the name suggest relies on the solid material at the end of the pile where it sits.
cheerios!
"am not a qualified expert on this subject matter too but welcome any other specialist to correct me."
waaa... so details!. engineer spotted!
i belief the soil condition at the site vary. dat why they have to use different type of pile. probably one side have bedrock close to ground level where they can use end bearing and on the other side they have to use friction since the bedrock are deep. crack due to differential settlement may only happen at podium since podium build as one piece. my unit near lift core.. should be less crack, if this thing happen( i hope) .
one thin im worried is our site is to near to river. limestone & water dont mix well
anyway im too not qualified and expert about this. so u guys may correct me