The development consists of a modern 45,800 square foot industrial warehouse structure ideally located near I-95 on Wilson Avenue in Norwalk, Connecticut. To reach proposed grades, seven to ten feet of filling was required to raise the east portion of the site to building slab elevation. Thirty feet of rock and earth excavation was also required to bring the west portion of the site down to proposed grades. A retaining wall was constructed around the eastern portion of the site to accommodate the difference between the proposed site grades and existing ground surface on the adjoining properties. The weight of the fill material and building presented a challenge due to the increase of stress in the underlying soil, compressibility of underlying soils, and variable composition and thickness of existing surficial fill. GEODesign designed a preload and surcharge fill to “pre-settle” the site and permit use of normal shallow foundations. This design avoided the expense of other ground improvement methods or pile foundations.
We also assisted in the due diligence process before purchase by reviewing historic environmental reports for the site and adjoining properties. Our environmental professionals assisted our client as a prospective purchaser by coordinating with the buyer’s and seller’s attorneys and environmental consultant. We reviewed environmental testing results and observed environmental restoration of subsoils.
The Solutions Unearthed
- Historic reports including a search of Department of Energy and Environmental Protection files were reviewed to develop a site conceptual model of prior site uses.
- We worked with attorneys to conclude that the site was not an establishment and thus, was not subject to the Connecticut Transfer Act.
- To address the concern for site subsidence and differential settlement, we recommended pre-compressing the site to promote settlement to occur before constructing the building and reduce post-construction secondary settlement.
- The pre-compression fill placement performed successfully as demonstrated by a settlement monitoring program.
- We provided construction special inspection services for earthwork and foundation construction.
Client: 320 Wilson Avenue, LLC