Field Tests on Micropiles Under Dynamic Lateral Loading

Micropiles are increasingly used as foundation support of new buildings in seismic areas as well as for the seismic retrofitting of structures that have experienced seismic damage. Hence, it is essential to enhance the knowledge of the dynamic behavior of micropiles under horizontal loading. In the present paper, first steps of an extensive experimental study carried out on two vertical micropiles in alluvial silty soil are reported. One of the vertical micropiles is injected throughout valves a-manchèttes placed along the steel core of the shaft, while the other one is simply grouted. In particular, experimental results of ambient vibration tests and impact load tests are reported and a comparison between the behavior of the vertical injected and non-injected micropiles is provided. Experimental data of impact load tests are also compared with results obtained from an analytical model.