Manhattan Bridge

New York's massive rehab of the historic Manhattan Bridge called for a new bikeway to be installed using a 15-foot cantilevered section that would jut out from the north span approach. To achieve this, four steel I-beams would need to pass through the approach's side elevation before being internally anchored to its foundation. Great care would be required in breaching the architecturally important granite facade, and given the worksite's bustling location, the NYCDOT required there be no traffic disruptions and only minimal construction dust and noise.

Working closely with the GC, Cutting Technologies (CTI) re- engineered the I-beam anchor system to provide 60% more load capacity, but with no additional cost. Since the foundation that would receive this system offered only a narrow mounting surface, the anchor pockets needed to be precision drilled within an extremely strict fault tolerance. Working with limited vertical access in a 6-feet-by-8-feet trench, CTI technicians core drilled each 3.5- inch-diameter anchor hole into the foundation to a full depth of 20 feet. Then, after setting and grouting the 150 ksi anchor rods, each was pre-stressed and tested to 200,000 pounds with a hydraulic jacking system.

Once CTI's techs precisely cut openings through the 4-feet-thick granite facade, each I-beam was rigged and carefully needled through before being secured to the foundation anchors.

By combining sound engineering with a safe, efficient work pace, CTI completed all drilling, cutting, rigging and installation within 15 days, and at half the cost of other bidders.