Experimental Studies on Model Single Pile and Pile Groups Subjected to Torque

Abstract

Many structures namely tall buildings, offshore platforms, bridge bents and electric transmission towers are subjected to lateral loads of considerable magnitude due to wind and wave actions, ship impacts, or high-speed vehicles. Significant torsional forces can be transferred to the foundation of transmission towers due to the laterally loaded high tension wires. Inadequate consideration of torque in design of the piles against these loads result into disastrous consequences. The design and analysis of pile foundations present a complex problem to the engineers because of several factors that affect the foundation behaviors. Such factors include mode of loading, soil properties, pile geometry, placement and method of construction. The mode and magnitude of loads transferred from the superstructure influences the selection of pile foundation to resist the imposed loads. The present work considers a mechanism of applying torque to a model single pile and model (m × n) pile groups; secondly, to find out experimentally the torque-twist curves of a model single pile and model (m × n) pile groups; and to analyse basis of pile-soil-pile interactions in model (m × n) pile groups subjected to torque. The experiments on a model single pile (1 × 1) and model (m × n) pile groups consisting of (1 × 2), (1 × 3) and (2 × 2) piles were performed to analyse the effect of torque on a model single pile and model (m × n) pile groups. The experiments were performed in loose and dense sand. The results of application of torque on a model single pile were compared with that of model (m × n) pile groups.