Engineering Surveys and Services (ES&S) was contacted by the City of Sedalia to inspect a basement cellar located beneath a downtown city sidewalk. The room measured 42’ long x 6’ wide x 8’ deep and had deteriorating stone walls on three sides and an 18” thick, poured concrete wall supporting the adjacent structure. The concrete cap covering the cellar had deteriorated enough that exposed rebar had begun corroding, causing multiple holes in the sidewalk. These holes created public safety concerns. Because of the location of the impacted area, construction needed to be non-intrusive so as to not disrupt surrounding businesses. Additionally, any material used to fill the cellar would need to be very light-weight to prevent additional stresses from impacting the adjacent structures.
ES&S worked closely with Foundation Recovery Systems (FRS) to design an economical solution for the situation. FRS recommended filling the cellar with StableFILL cellular concrete which is light weight, extremely flowable, and has excellent compressive strength characteristics. Due to its flowable nature, FRS was able to fill the entire room by pumping Stablefill through two existing manhole openings in the concrete sidewalk. The entire room was filled with 77 cubic yards of cellular concrete, weighing approximately 30 pounds per cubic foot (PCF) and a compressive strength of over 13,000 pounds per square foot (PSF). The pumping operation took just over two hours and the sidewalk remained open to the public.
The following week, FRS returned to the site and injected PolyRenewal™ beneath the sidewalk to fill any existing voids and to uniformly support the sidewalk slab. PolyRenewal™ is two-component polyurethane which is injected in liquid form through small, dime sized holes drilled into the slab. Once injected, PolyRenewal™ expands into rigid, light weight foam which is used to fill voids, stabilize slabs and lift concrete. With an average placed density of nearly 4 PCF, PolyRenewal™ boasts a compressive strength of over 9,000 PSF.
The entire project was completed in two partial days with virtually no impact to the public or businesses.
Project Engineer: Engineering Surveys and Services (ES&S)
Products Installed: PolyRenewal™
Certified Installer: Foundation Recovery Systems (FRS)