Wednesday, February 08, 2017

Combined Pile - Raft foundation effective for Tall Buildings

Combined Pile - Raft foundation effective for Tall Buildings

High rise buildings are usually founded on piled foundation, which is subjected to a combination of vertical, lateral and overturning forces. 


Combined pile- raft foundations 

  • can be particularly effective form of foundations for tall buildings because the raft is able to provide a reasonable measure of both stiffness and load resistance.
  • It is possible to reduce no of piles in Piled raft foundation. 
  • Another feature is that the pressure applied from the raft on to the soil can increase the lateral stress between the underlying piles and the soil, and can increase the ultimate load capacity of a pile as compared to free- standing piles.

Following points should be consider while designing high- rise buildings:

  • Ultimate capacity of the Foundation under vertical, lateral and moment loading combinations.
  • Influence of the cyclic nature of the wind
  • Earthquake 
  • Overall settlements
  • Differential settlements
  • There should be good cooperation and interaction between the geotechnical designers and the structural designers. 

(Ref: C&CR magazine)