Precision Drilled Piers: Malcolm Drilling’s Role in Bridge Replacement
The Niles Boulevard Bridge, spanning the Union Pacific Railroad and BART tracks at the Fremont/Union City border, required a seismic retrofit following the Loma Prieta earthquake. After assessing the cost and constraints of retrofitting the existing structure, it was determined that replacing the bridge was the optimal solution. The new cast-in-place, prestressed concrete box girder bridge was constructed adjacent to the existing bridge while ensuring that all tracks remained operational during construction.
Malcolm’s role in the new bridge involved the installation of three drilled piers, each measuring 9 feet in diameter and reaching a depth of 100 feet. The proximity of the piles to the existing tracks and the loose ground conditions necessitated the use of full-depth temporary casing, installed using the oscillator method.
This project demanded a highly detailed work plan, complete with drawings that meticulously documented the position and movement of equipment by the hour when trains were not running and by the minute when trains were in operation. Furthermore, any work or equipment that could potentially obstruct the existing tracks had to maintain a minimum distance of 25 feet from the rails when trains were active. Keeping these factors in mind, Malcolm conducted the majority of its work during weekend nights when train operations were suspended.
Despite the unique challenges presented by this project, Malcolm successfully delivered a high-quality, integrity-tested product within the established timeline and budget.
