Construction of a new six-story building adjacent to Seattle Public Utility’s Massachusetts Substation required management of Construction Vibrations to protect sensitive power station equipment that would be subject to potentially damaging vibrations SubTerra was retained by SODO Builders to evaluate potential impacts, evaluate the potential contribution of pre-drilling to minimize vibration levels and remotely monitor vibrations during construction.

SubTerra, used eight Minimate Plus seismographs to create attenuation models based off of six test piles and determined that mitigation was  necessary.  By carefully studying the relationship between distance, depth and peak particle velocity, SubTerra was able to recommend pre-drilling piles to a depth of 30 feet within a 40-foot radius of the sensitive equipment.  The recommendation was successful and SODO Builders was able to com-plete the project without interruption to the city’s power supply.