Pile Foundation - မွတ္စု

Load Transfer Mechanism

1. Structural Load (e.g columns, walls .. )
2. Pile Cap
3. Pile (material)
4. Soil (geotechincal)

1. Structural Load ဆိုတာကေတာ့ super-structue ေတြကေန တြက္ခ်က္ရယူထားတဲ့ column or walls loading ေတြဘဲျဖစ္ပါတယ္။ number of pile ေရြးခ်ယ္ရမွာ သတိျပဳမယ့္ အေရးႀကီးအခ်က္ကေတာ့ Unfactored Load (service load) ကို အသံုးျပဳရပါမယ္။

2. Pile Cap ဆိုတာကေတာ့ column or wall ေတြရဲ႕ loading ေတြကို Pile ေတြဆီ ေျပာင္းလဲေပးမယ့္ ၾကားခံ structure တစ္ခုဘဲျဖစ္ပါတယ္။ column or wall loading သက္ေရာက္မႈေၾကာင့္ high shear forces and punching shear ေတြျဖစ္ေပၚမႈကို ခံႏိုင္ရည္ ရွိေအာင္ ဒီဇိုင္းလုပ္ေပးဖို႕ အေရးႀကီးလွပါတယ္။

3. Pile Structural Capacity (material)

• Bored Cast In-situ Pile
  

Qa = 0.2 fcu A (or) 0.25 fcu A (< style="font-style: italic;">

Precast Reinforced Concrete Piles

Qa = 0.25 fcu A

• Precast Concrete Spun Piles

Qa = 0.25 (fcu - prestress after losses) A

fcu (max) = 60 Grade, only for spun pile

• Steel Piles

Qa = 0.3 fy A (driven piles)
Qa = 0.5 fy A (jacked-in piles)

• Timber Piles

Qa = 0.25 fc A

Qa = allowable working load
A = cross-sectional area of pile
fcu = concrete strength
fy = yield strength of steel (Grade 43A = 275 N/mm2, 50A = 355 N/mm2)
fc = compressive strength of timber