Performance of laterally loaded helical piles in clayey soils established from field experience

Despite the wide use of helical piles with large diameters, the available studies documenting their lateral performance are few. To date, helical piles with shaft diameters up to 1200 mm have been successfully used in Alberta, Canada. The results of a lateral pile load test programs and the field monitoring of helical and driven piles with shaft diameters varied between 219 and 508 mm, installed in firm to very soft clay to very hard clay till were presented in this study. Load testing programs were carried out at five different sites. Effect of pile installation on the lateral capacities of helical piles was also evaluated. Direct comparison between lateral resistances of helical and driven piles was performed. The results of the load tests were compared to a p–y curve model using LPILE 2016 (LPILE. 2016. A program for the analysis of piles and drilled shafts under lateral loads. Austin, TX: Ensoft Inc.). Based on the results of this study it was found that helical piles can develop considerable resistance to lateral loads and their lateral resistances are almost exclusively controlled by the shaft size.