Proceedings of DFI-India 2018: 8th Conference on Deep Foundation Technologies for Infrastructure Development in India, (DFI)
A Model Study of Micropile Groups Subjected to Lateral Loading under Different Relative Density
Zakir Hussain, Research scholar, Binu Sharma, Professor and Takiur Rahman, M.E. Student
Many old structures like high rise buildings and bridges are unsafe and need to be strengthened in highly seismic prone zones. Strengthening of existing foundations of structures is difficult as it involves excavation, temporary support system below the foundation level, limited head room, risk of collapse of the structure during excavation. In such cases micropiles are the best solution for strengthening of vulnerable structures. Different investigations report different and contradictory group effects on micropiles subjected to vertical and lateral loading. This work is a model study to investigate the behaviour of micropile groups subjected to lateral load installed in loose sand (relative density 30%) and in dense sand (relative density 80%). The group behaviour is found to be a function of relative density of sand, length to diameter (L/D) ratio and spacing of the micropile groups. In loose sand ultimate lateral load carrying capacity of micropile groups as well as efficiency is highest in 2D spacing followed by 4D and 6D spacing. Positive group effect is seen at 2D spacing for 30% relative density and at 6D spacing for 80% relative density and also by a few piles of higher L/D ratio at 4D spacing at 80% relative density. Rest of the piles show a negative group effect.
|article #3165; publication #1050 (India2018)|