Crux Subsurface Wins OPA and Bermingham Awards Crux Subsurface, Inc. is the recipient of both DFI’s 2014 Outstanding Project Award (OPA) and the 2014 C. William Bermingham Innovation Award. The OPA jury selected the Sunrise Powerlink Project in California as the winner. The Bermingham Award, which recognizes innovative contributions to deep foundation technology, was awarded for the steel micropile cap design used on the same project. The awards will be presented at DFI’s 39th Annual Conference, October 21-24, in Atlanta. The Sunrise project involved construction of a new 117 mi (188.3 km), 500 kV transmission line from Imperial Valley to San Diego, Calif. The line officially went into service in June 2012 and contributes to California’s Renewable Energy Mandate. The Electric, to define design and fabrication standards, and obtain approval to implement the steel caps in a timely manner. The steel caps were required to fasten to the micropiles without field welding, as hot work was prohibited on much of the alignment. The bolted connections between the piles and the cap needed enough fixity to limit foundation deflections to 1.0 in (25.4 mm) at the maximum factored foundation load. Finite element modeling was used to predict stresses and deflections and allowed the design team to review localized yielding and buckling potential of the unstiffened plates in the cap assembly, and ultimately reduce total weight of the pile cap. Two full scale prototype pile caps were constructed and installed on micropile foundations at a test site near the project alignment. A load test was conducted, applying 1,000 kips (454 tonnes) of compression load and 300 kips (136 tonnes) of lateral load simultaneously. Deflections in the micropiles and the pile caps were measured during the load test and compared with finite element analysis to confirm the model’s predictions. OPA Runner-Up Projects Micropile installation on the Sunrise Powerlink Project alignment crossed a number of rigorous and protected environments, including National Forest land and Peninsular big horn sheep habitat. Road access to these locations was either not feasible or not permitted, limiting 234 lattice tower sites to helicopter-only access. With up to 40 helicopters on contract, Sunrise is one of the largest helicopter‐assisted construction projects on record. Crux installed 3,732 micropiles to support steel pile caps for 234 of the 421 lattice tower structures on the alignment, totaling more than 99,000 ft (30,175 m) of pile. Customized drill rigs were flown to and from foundation sites, specially designed to break into components and allow for transport by helicopter. The C. William Bermingham Innovation Award was founded in 2012 to recognize the innovative spirit of Bill Bermingham, DFI past president, and his contributions to DFI and the deep foundations industry. On the Sunrise project, Crux Subsurface introduced a unique steel micropile cap design as an alternative to cast-in-place concrete caps. The steel pile caps required less construction time and provided the contractor and owner with more flexibility over the critical path of construction activities. Crux worked collaboratively with the owner, San Diego Gas & An OPA runner-up was the VDOT Midtown Tunnel which was part of the MLK Freeway Extension from Norfolk to Portsmouth, Va. Mueser Rutledge Consulting Engineers (MRCE) provided geotechnical and foundation engineering services during the design and construction of a new two-lane vehicular tunnel under the Elizabeth River. Several project challenges were overcome in order to enable construction: less than desirable soil conditions, excavation depths extending more than 80 ft (24.4 m) below river level, an existing roadway that crossed over the excavation, an adjacent sewer force main in close proximity and the existing Midtown Tunnel, which required a very rigid bracing system to keep lateral and vertical movements to a minimum. MRCE performed finite element modeling to assess the performance of the excavation support system, evaluated the impact of the construction on the existing tunnel and adjacent structures, and designed the support of excavation for the existing tunnel and adjacent structures during construction of the new tunnel. Haley & Aldrich, Inc. was another OPA runner-up for the firm’s work on the replacement of the Sakonnet River Bridge in Portsmouth, R.I. This was one of the first major bridge projects to use AASHTO LRFD in design and construction. Haley & Aldrich served as the project geotechnical engineer and designed steel pipe piles with recessed, internal plates to increase end-bearing and avoid driving 400 ft (122 m) into rock for the three river piers. The five new land piers were supported by 457 end-bearing H-section piles. One of the many design challenges was maintaining the existing bridge service during construction of the new replacement bridge. DEEP FOUNDATIONS • JULY/AUG 2014 • 37
