Danbro’s articles have extensively promoted the indispensable virtues of helical technology and the hard-working wizards, the helical installers, who use it to achieve frequently difficult/sometimes near-impossible feats of construction magic. While reviewing some of our more than 300 Case Studies, several jumped out as particularly good illustrations of what one can accomplish with a helical pile that couldn’t get done with any alternative foundation support system.
This is the first of a two-part series of articles involving project sitemares.
South Cape May Meadows
This Nature Conservancy project, undertaken by RENOVA, the installer, involved the most restrictive environmental rules ever undertaken by any Danbro Installer and, probably, any helical installer anywhere!
According to RENOVA’s Project Description, the project “included the installation of 2,675 linear feet of elevated boardwalk, 650 helical piles, and the seamless installation of a 50’ x 6’ Bedford ReadySpan™ pedestrian bridge, which connects key pathways in the preserve…”
Furthermore, in compliance with the strict regulations established by the Nature Conservancy to protect the preserve’s sensitive environment, RENOVA “implemented comprehensive environmental protection measures. These measures included erosion and sediment controls, high-visibility fencing, and ground protection matting to minimize construction impacts.”
The ground protection matting was utilized in those very limited areas where a machine could touch terra firma, including the termination point at the beach and at the entrance to the preserve at Sunset Boulevard.
Otherwise, installation was done by lowering one preconstructed section in place at a time and moving forward on that section to repeat the process.
In a project defined by challenges, the most difficult part was crossing over an approximately 40’ + estuary in the middle of the walkway. As RENOVA’s Project Description explained: “The pedestrian bridge vendor noted that the installation would be “one of the most challenging” they had ever seen, as the bridge spanned over a body of water and was in a remote area of the preserve.”
South Cape May Meadows | Danbro Distributors
304 Johnson Avenue, Jersey City, NJ
The original project, undertaken by another contractor, involved constructing a foundation for a new public housing building. H-piles were originally chosen for the foundation, but the installation was agonizingly slow, so a decision was made to pre-auger the H-piles to speed the process. Unforeseen complications arose!
Due to WOH soil, a high-water table, and recent rain, the augured holes collapsed, causing the existing structure of an adjacent (i.e., less than 3 feet away) occupied public housing building to settle.
Helicals to the rescue!
Hale Built, the helical installer, undertook the underpinning project for the existing building.
The first step was to install a rack bracing system, using steel girders and carbon fiber strips, to stabilize the existing four-story brick building. This temporary fix allowed the new construction project to proceed.
The second step was to underpin the existing building.
Access (overhead) and mobilization (muck) were at issue for the excavation of the existing structure which was further hampered by the installed H-piles that were in the way.
A high-water table created a sloppy mess with soil constantly collapsing back into the hole.
IDEAL 4.5” pipe piles with 7′ leads (10’ 12’ 14’) and 5′ extensions were installed to 55’ to underpin the structure, arrest the settlement, and achieve the 50-ton capacity.
Out of an abundance of caution, grout was added just below the footer to encase the pile/bracket connection to protect and stabilize them further in the questionable soil environment.
All of this drama took place under the scrutiny of the press and all of the government/quasi-government entities!
304 Johnson Ave (Hale Built) | Danbro Distributors
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