To construct a house in North-eastern part of Thailand (Esarn) usually we use spread foundation instead of piling as in Bangkok because in Esarn part soil in the level start from 2 meters is sand not clay. But some projects use 4-5 meters long concrete piles with solid square shape. For not higher than 2 stories house we use rectangular spread shape foundation size 1.50x1.50 meters. This footing can carry column weight 10-12 tons. To make the footing we excavate soil to the level 1.5-2.00 m. below original soil level. At this level we should see a hard sand-graveled layer that if tested by load bearing capacity test we will get the load bearing of 30 tons/sq.m.
Why some house use piling system instead.?
Most of people think that piling foundation is more expensive than spread one. To validate this I used to compare price of them and I found that piling footing is not cost higher than rafting footing and sometime it's cheaper! Because if you use only one pile for each footing so pile cap is just a small one sizing 0.6x0.6 m. It's mean less excavation , less concreting , less labor cost , and less time used. And now pile cost is much lower than before because of higher technology used , higher efficiency in factory. What should be considered is how big working area you have to let hammer machine to mobilize and move around to drive piles. If you are in the very limited area and driving pile might damage adjacent building you have another choice by using bored pile which higher cost.
No comments:
Post a Comment