Murphy Elevator Project faces soil challenges requiring new foundation design

During the recent Round Lake CUSD 116 Board of Education meeting, significant updates were shared regarding the Murphy Elevator Project, particularly concerning unexpected soil conditions that have impacted construction timelines and methods.

The project team encountered unsuitable soils beneath the construction site, specifically a soft gray clay that resembled a muddy riverbank. This discovery occurred after excavation reached a depth of 10 feet below the finished floor elevation, which is the level at which the elevator will operate. The construction manager described the soil as a "soupy mess," prompting further investigation.

To address these challenges, the team initially dug a test hole to assess the soil conditions, only to find similar soft clay extending deeper. A geotechnical engineer was brought in to recommend a new excavation strategy, which involved digging in one-foot increments to a maximum depth of 20 feet. However, even at this depth, the same unsuitable conditions persisted, leading to concerns about safety and practicality.

As a result, the project will now utilize a deep foundation system designed to support the three-story elevator shaft. The original building relied on wood timber piers, which were driven deep into the soft soil, similar to the construction of a commercial fishing dock. The new solution involves the use of helical piers, which are large screw-like structures that will be driven into the ground to provide the necessary support.

This adjustment in construction strategy highlights the complexities involved in the Murphy Elevator Project and underscores the importance of thorough site assessments in ensuring the safety and stability of educational facilities. The board's commitment to addressing these challenges reflects a proactive approach to maintaining the integrity of the project and ensuring its successful completion.