Allega Cos. answers Corps contract commanding nearly 120,000 tons of wave-worthy precast
A weather front emanating from Superstorm Sandy in October 2012 tested infrastructure well inland of metro New York and New Jersey, the area hardest hit by precipitation, wind and storm surge. Among federal and state agencies contending with long-term responses to Sandy-level exposure is the U.S. Army Corps of Engineers Buffalo District. It capped the 2015 and 2016 construction seasons closing repair and upgrade contracts—Oswego Harbor Detached Breakwater, New York; Cleveland Harbor East Breakwater, Ohio—using non-proprietary precast concrete structures known as dolosse, in tandem with limestone or granite armor block.
District engineers outlined finished structure air content, flexural and compressive strength, plus surface quality specifications for respective Oswego and Cleveland project precasters, Lakelands Concrete Products of Lima, N.Y., and Allega Cos. of Valley View, Ohio. Both determined that highly fluid, self-consolidating mixes are the best solution for accelerated production of structures that will be submerged or subject to frequent Great Lakes wave exposure through a service life plausibly extending into the next century. Early indicators suggest the dolosse installations contribute to a Corps roster proving the efficacy of SCC for structures prone to extreme weather or temperature events, sharp freeze-thaw cycles, and rare, but catastrophic loads.
Dolosse resist breakwater or shoreline erosion from waves and undercurrent through their mass and energy-dissipating geometry. Known as dolos individually, the monolithically cast structures comprise three members of octagonal cross section: Uniformly sized shanks connect fluke ends. The latter are flared, tapered members running in opposite directions, along X and Y axes. Dolosse are fabricated in four- to 16-ton sizes, sans lifting hardware, and placed by sling so each structure interlocks such that even the most forceful waves or undercurrents meet long plain or reinforced precast concrete chains of inordinate tonnage.
The Corps Buffalo District used a formula factoring statistical 20-year wave height and 10-year water level to determine 16-ton and 6.5-ton dolos sizes for the New York and Ohio installations. Located near the southeastern corner of Lake Ontario and serving the first U.S. port from the St. Lawrence Seaway, the upgraded Oswego Harbor structure marks the District’s first use of 16-ton dolosse. Lakelands Concrete fabricated 997 of the 11-ft. long structures with conventional reinforcement (Concrete Products, July 2015). The dolosse represented the bulk of a $19 million contract Michigan’s Durocher Marine completed in November 2015.
Slightly trailing the New York engineering and casting schedule were preliminaries for the much more ambitious Cleveland Harbor work, centered in Lake Erie about two miles east and one-half mile north of downtown Cleveland. Buffalo District engineers specified the 6.5-ton dolosse, plain and 8.3-ft. long, for 4,400 feet of breakwater structure, which sustained more than $31 million in damage attributable to the Superstorm Sandy-spurred weather system. The Corps found that the intensity of the winds over Lake Erie created extraordinarily rare waves, measured at nearly 18 feet offshore of Cleveland.
|Great Lakes Dock & Materials customized a precast handling device in house, and turned to a GPS-guided, crane cable-mounted topographical 3D system, Posibloc, for precise dolos placement. Companion Visibloc technology recorded each unit’s location, so the crane operator could target subsequent placements for optimal density and interlocking. Although not Posibloc-prescriptive, the Cleveland Harbor contract required a system a) with positioning technologies and sensors to produce a 3D image of dolos being placed; b) capable of guiding the crane operator to place units in designated positions with interlocking control; and, c) equally accurate above and under water.|
|The contractor deployed two 100-dolosse barges for June 2015–November 2016 breakwater repairs and upgrades. Anthony Allega Inc. began fabrication in April 2015, whereby Great Lakes Dock & Materials approached peak season with a two- to three-month dolosse inventory. SITE PHOTOS: Andrew Kornacki, Corps Buffalo District|
|MasterGlenium HRWR assured self-consolidating properties in the mixes for the dolosse, each requiring 3.25 yd. Between its rapid placing rate and zero vibration requirements, the self-consolidating concrete proved critical to a 300- to 350-dolosse weekly production schedule. Allega Cos. mobilized fabrication at its headquarters property, running on both sides of the Interstate 480 crossing at Valley View, Ohio. PLANT PHOTOS: Concrete Products|
After securing the precast contract, Allega Cos. mapped a dolosse production and storage plan at its headquarters, south of Cleveland and about 15 miles from a precast off-loading point. The site is the base of fleet and plant equipment supporting Anthony Allega Inc., a building and heavy/civil contractor operating mainly in Ohio; and Allega Concrete Corp., a four-plant, northeastern Ohio ready mixed producer.
Seasoned in precast barrier and sound wall fabrication, Anthony Allega enlisted Canal Fulton, Ohio-based Lindsay Concrete Products to fabricate 50 forms, enabling 300 dolosse output on a six-day schedule. Through lead Cleveland Harbor contractor Great Lakes Dock & Materials LLC, Muskegon, Mich., the Corps initially called for 12,577 dolosse. Anthony Allega was set to cover that quantity over an April 2015–October 2016 production window. Site assessments, coupled with the availability of additional funding, compelled Buffalo District engineers to increase the precast order to 18,257 dolosse. The schedule for two shifts of casting plus form stripping and maintenance crews went from six to seven days a week in 2016.
The option of self-consolidating mix specifications allowed Anthony Allega and Lindsay Precast to design freestanding dolos forms, with the 1.67-ft. octagonal end of a fluke serving as the lone charging port. Individual stands bear two hinged form sections: one main, with full 8.3-ft. fluke and shank tapering from 2.67 to 1.67 ft.; the other with remaining fluke and clamped end. Anthony Allega staged production between a 200-yd./hour batch plant and storage area equal to 2,000 dolosse.
|Lindsay Precast Concrete demonstrated handling and stripping features of a prototype prior to a nod from Anthony Allega for 49 additional dolos forms. After testing a handful of form oils, the producer opted for Hill & Griffith’s Grifcote FR-50.|
BASF Admixture Systems assisted the producer on a self-consolidating mix design exhibiting 21- to 22-in. spread. Polycarboxylate-type high range water reducers from the MasterGlenium family imparted high fluidity in mixes designed with air entraining agents (6 percent target); varying accelerator dosages; St. Marys Type I cement; Ontario Stone coarse aggregate; and, Shelley Co. sand. At 12 hours, the concrete typically developed 2,600-psi compressive and 935-psi flexural strengths, the latter nearly double the threshold required for form stripping targets. Each 50-dolos production cycle required just over 180 yd. of concrete.
Anthony Allega cast the final lot in late October 2016. Dolos with stenciled red numbers 1 and 18,257 were loaded on the last trailer to a Great Lakes Dock & Materials staging area. Crews completed the final dolosse barge run before Thanksgiving, enabling Corps Buffalo District officials to formally dedicate the Cleveland Harbor East Breakwater Repair in early December.