In marketing, there is an old saying: “Success has many fathers, but failure is an orphan!” The same is probably true for many other experiences in business and life. This was very true of a recent project on DeGraw Street in Brooklyn, NY. The plans called for the addition of a new penthouse level to the eponymous Amanda Moffatt Pottery property. Ms. Moffatt is an internationally renowned ceramicist. www.amandamoffatpottery.com
The search for an alternative pile began with an email from Paul South, Project Manager of Taffera Fine Building & Finishes, to Danbro Distributors. Mr. South stated that the original design called for 9” micro piles to carry the load for a new penthouse structure above the one-story, low-slung side of the building. He indicated that Taffera was working with the engineer to produce an updated design that would not require using a pile driver, as large equipment would not fit within the existing building structure (136.75” from slab to underside of joist, 146.75” to sheathing). Mr. South indicated that the engineer was considering alternatives, perhaps smaller 5” or 6” diameter piles, that they have been told could be done with smaller equipment. “If this is a feasible approach,” Mr. South stated, “the engineer has agreed to modify the details shown in the current (attached) drawings to what’s noted below.”
As is usually the case when builders are seeking an alternative foundation solution, site conditions were driving the search. Mobilization, no vibration, low noise, and limited access are well-known considerations for utilizing helical piers. Additionally, in this case, the need for no water, dirt, or mud blowing about in an existing building cried out for a different approach.
Based on the drawing, loads, and site limitations, Danbro put together a cost-effective working design and passed it along to our manufacturer for verification of our approach and a VE design. Then, the design was passed to Baxt Ingui Architects (engineer of record) for their input and ultimate structural design. The original micro pile plans called for both compression (40 ton) and lateral (2.5-ton) load tests to verify the ultimate capacity; that requirement carried over to the helical piles.
As I have noted in numerous other articles, the last proud papa was the most important one of the lot. When Danbro has a complex job in a tough urban environment like Brooklyn, we turn to the likes of Persi Contracting to get it done! Savvy helical professionals like Persi are used to challenging high-profile jobs with curious owners, builders, engineers, architects, and code officials looking on. Neither 5” or 6” diameter piles were necessary to carry the residential load. Forty-three 3.5” pipe piles (300 wall) were installed to 27’ inside an existing building to support the columns supporting the new penthouse. Persi used a mini-excavator with a 12K drivehead to deal with the restricted access inside the building. Click here to see other Persi projects.
In addition to eliminating some thorny site issues, the use of helicals as an alternative foundation element cut a month off the original schedule. Paul South with Taffera summed up the experience for all parties who had a hand in this successful endeavor: “The helicals proved to be a very positive experience. We eliminated a lot of headaches, saved time, and most importantly, money for our client. Given the kind of work we do, this system will probably come in handy again somewhere down the road.”
Kudos are in order for Baxt Ingui, who recognized the various site challenges with the original design and were open to exploring an alternative piling system. Hats off also to Persi Contracting whose execution justified everyone’s faith in this successful helical endeavor. Once again, helicals proved to be a viable go-to when the mobilization and mess associated with micro piles proved to be exceedingly difficult and too costly. Ultimately, a successful project was claimed by many happy fathers who were more than satisfied with the helical solution!