The Sigma Group New Corporate Office
Completed in December 2003, The Sigma Group, an engineering and environmental services consulting firm, constructed a new corporate office in the Menomonee Valley. Sigma purchased the vacant brownfield parcel from the City of Milwaukee. Construction began in March 2003 and was completed before the end of year. Prior to the construction phase, significant efforts were made to characterize the site, plan and design the building and grounds, and coordinate the project elements with State and City of Milwaukee agencies and local interest groups including the Menomonee Valley Partners.
HISTORY Consistent with most of the Menomonee River Valley setting, the Sigma property was originally a shallow marsh, which over time was filled with a variety of materials and adapted for industrial use. Historic records indicated coal and lumber companies utilized the site for box making, storage and warehousing. Around 1900, there was even a boat slip which was since filled with river dredgings, which extended south from the Menomonee River to within 30 feet of the corner of Canal Street and Emmber Lane. The site also had storefronts, railroad sidings and several variations of dock walls constructed of timber planks and piles anchored with buried tieback rods and stakes. More recently, the City used the land as a staging area for the construction of the Emmber Lane drawbridge.
ENVIRONMENTAL SITE ASSESSMENT Prior to acquisition, Sigma completed an environmental site assessment of the property conforming to ASTM Practice E 1527 and the Wisconsin Department of Natural Resources (WDNR) Phase I Property Environmental Assessment Guidance (SW-510-95). The process involved the review of many historical records and regulatory documents, local area geology and hydrogeology information and conducting a site inspection. The Phase I revealed recognized environmental conditions such as the release of hazardous and petroleum hydrocarbon substances.
The next step was to perform a soil, groundwater, methane and geotechnical investigation to characterize the subsurface conditions. This involved collecting soil samples from borings and test pits, installing and sampling monitoring wells to determine groundwater quality and to qualify the presence of methane gas being generated by underlying natural deposits and imported fill. Sigma elected to partner with the WDNR by participating in the Voluntary Party Liability Exemption (VPLE) 292 program. Upon project closure, Sigma will seek a certificate of completion from the WDNR.
CHALLENGES As a result of the environmental site assessment efforts, several challenging conditions needed to be addressed in planning and design as well as integrated with the construction process. Generally, these involved poor soil conditions requiring a series piles to support the building, the management of contaminated soils, and a means to control the methane that was being generated by the decay of both naturally occurring and land filled organic materials. An initial planning step was to formulate solutions that were presented to the WDNR who granted an exemption to construct on an abandoned landfill consistent with ss. NR 504 and 506.
For site grading, a soil management plan called out that excavated materials would remain on site and be utilized for non-structural berms and fill. The swampy soil conditions required a foundation design consisting of network of piles driven to between 50 and 90 feet and linked by pile caps and grade beams. To exhaust methane from possibly accumulating under the building, the plan calles for a network of slotted pipes embedded in a beneficial reuse product called Minergies produced by We energies, a mixture of fly ash and light weight concrete.
SITE FEATURES Situating the building on the site required consideration of various stake holder groups’ desire for urban style location placed close to the street at the corner of Canal Street and Emmber Lane. The backfilled former boat slip located in proximity to the corner, was a factor as the soil conditions were particularly poor and methane generation was the highest at this area of the site.
As aresult, the building footprint was shifted 200 feet east of the corner to avoid the higher cost of deeper piles and a more aggressive methane control system. The site also accommodates public access to the Menomonee River with a walkway that will border the site’s river edge and loop from Canal Street linking up with the Hank Aaron Trail.
BUILDING FEATURES The building and site incorporates several aspects of a “green building” the concepts of which are established by LEED (U.S. Green Building Council Leadership in Energy and Environmental Design). Representative features include natural day lighting, maximizing sunlight in occupied areas, specialized stormwater management, beneficial reuse of materials for constructing the floor slab, and a high efficiency HVAC system. A prominent building element is the use of bow truss structure for the main roof. This combined with the selection of the brick veneer and other building materials complement the neighboring Emmber Lane drawbridge and blend with the industrial look of the Menomonee Valley.
UP AND RUNNING On December 1, 2003, Sigma embarked on a new chapter with our first day of business on Canal Street. The Sigma Group was honored with the 2003 Mayor’s Design Award that recognizes design excellence throughout Milwaukee. Recipients of the award “have added value to their neighborhoods by restoring, constructing or enhancing their properties in a way that respects the urban fabric and contributes to the character of their surroundings."