A Case Study of Ground Vibrations Due to Pile Driving in Mobile, Alabama

Ground vibrations generated by construction activity, including pile driving, have the potential to cause damage to nearby structures. Determining the expected vibration levels at a project site can become an important aspect in planning construction projects. There are several parameters that affect the expected vibration levels, including the distance from the source, the site specific soil conditions, and the pile installation method. Due to the variability in soil conditions, site specific investigations are often required to determine ground vibration characteristics. An investigation into ground vibrations due to pile driving was initiated by the Alabama Department of Transportation (ALDOT) at a project site near the Mobile River, just south of downtown Mobile, Alabama. The investigation included the installation of one concrete pile and two steel H-piles that are commonly used by ALDOT. The soil conditions at the project site predominantly consisted of dense, gravelly sand. The vibration monitoring program that was developed consisted of measuring ground vibrations at a horizontal distance of approximately 50, 100, and 150 feet from each pile. The largest vibrations observed throughout the project were at 50 feet from the concrete pile. As anticipated, the vibration magnitude was significantly reduced at 150 feet from the pile. The vibration data obtained from the project was used in conjunction with existing vibration prediction equations to potentially use in future construction projects at this site.