was performed from a berm at the north side of the garage prior to the installation of the wale and rakers along the DDP line. This sequence was used because the equipment to install the RIs would not be able to access the area once the wales and rakers were set. The remainder of the RIs for the slab support and foundation support were installed using two drill rigs from the subgrade elevation. A load transfer platform (LTP) that was 12 to 18 in (305 to 457 mm) in thickness was constructed beneath each foundation location after the RIs were installed. Experience Counts Cross-section of jet grout underpinning of the active 108 in (2,743 mm) diameter outfall pipe Ground Improvement Rigid inclusions were installed for ground improvement within a portion of Garage 2A to support the floor slabs at level P2 as well as to support the spread footings at level P2 to an average allowable bearing pressure of 8,000 psf (383 kPa). Post-construction settlement of no more than 1 in (25 mm) was specified. Prior to production work, load tests on two individual RIs were performed to verify the design capacity. The first phase of the installation of RIs On large, complex projects such as this, experience is key to a smooth operation. Keller’s history of successful geotechnical work throughout the Washington, D.C. area, its ability to undertake multiple aspects of the foundation package under one contract, and the various crews’ familiarity with working together were key to the overall smooth running of the project. During peak operations at the jobsite, more than 50 Keller personnel were employed across the various tasks. Any issues that arose could be quickly resolved through close cooperation among all parties (owner, GC and Keller), which translated into schedule and economic advantages to the owner and general contractor. To complete the significant amount of work in such a congested space on an accelerated schedule required collaboration and communication among all parties involved, including the several other subcontractors. The ongoing foundation work is expected to be completed by February 2020. Brandon M. Robinson, P.E, is a project manager for Hayward Baker, a Keller company, and has 10 years of experience in specialty geotechnical construction including ground improvement, soil mixing, jet grouting and excavation support systems. He has a B.S. degree in civil engineering from the University of Delaware and an M.S. degree in civil engineering from the University of Maryland. Joseph K. Cavey, P.E., is vice president of Hayward Baker’s Mid-Atlantic Region and is a registered professional engineer in Maryland, Virginia, Penn- sylvania and Washington, D.C. He has a B.S. degree from Bucknell University and an M.S. degree in civil engineering from Northwestern University. Since joining Hayward Baker in 1994, he has worked on numerous anchor, piling, grouting, underpinning and ground improvement projects throughout the U.S. George A. King, Jr., is area manager for all groundwater control projects undertaken by Moretrench, a Keller Company, in the Washington, D.C. area. He has 38 years of experience in the installation and operation of dewatering systems utilizing wellpoints, deep wells, ejector systems, monitoring wells and horizontal drains. During peak operations, more than 50 Keller crew members were deployed at various tasks across the site 18 • DEEP FOUNDATIONS • SEPT/OCT 2018
