Bulldozing Around Site-Specific Challenges During an Interceptor Force Main Damage Event

Buried sewer force main failures occur periodically and primarily due to pipe material degradation or contractor damage events. Failure and damage events require prompt action to minimize environmental impacts and to return the force main to service. Challenges associated with sewer force main failures are driven by environmental and operational factors specific to the location within their respective system. In August 2024, HRSD experienced a damage event resulting from the alleged theft of a bulldozer from a nearby construction site that was driven through an easement unsuitable for heavy machinery. Due to marshy soil conditions within the easement and the limited cover along the interceptor force main alignment, the steel tracks of the 35,000-lb dozer were wrapped circumferentially around an essential 42-inch PCCP force main raising concern for imminent failure in an area with limited accessibility to perform repairs. This event triggered immediate action requiring prompt emergency preparation and planning as well as engineering and construction support to mitigate the following challenges: - emergency sequencing / planning - stakeholder coordination - site constraints and equipment access - limiting environmental impacts - repair material resourcing / transition - unfavorable soil conditions - system isolation and bypass / pipe repair design (limited planning) - existing pipeline protection - dozer removal procedures HRSD staff worked closely with their engineer and contractor to address these challenges, safely remove the dozer, and perform the necessary repairs within an expedited time frame by utilizing a design-build approach due to unknown conditions.