ABSTRACT
One of the road infrastructures in the Philippines is currently undergoing engineering rehabilitation to reinforce the structures, which is a 5-kilometer viaduct across a basin swamp in Central Luzon. The soil formation in this area is composed of low-bearing, compressible soft fine-grained soils. A deep foundation system consisting of bored piles was utilized to support the load demands. To verify the theoretical capacities and optimize the pile design, dynamic pile testing was conducted. Further assessments were carried out, particularly the mobilized shaft resistances within the soft fine-grained layers on which cyclic softening may occur. Susceptibility to this phenomenon was derived using the recent methods developed by Boulanger and Idriss, supplemented by Pehlivan’s study of liquefaction on fine-grained soils. Capacities of the bored piles were then derived considering the effects of liquefaction-like behavior of clays. A case study on the bridge project is presented, comparing theoretical and measured shaft resistance.
