Stamford Media Village

gzadan — Thu, 09 Apr 2020 12:47:06 +0000

Stamford Media Village gzadan Thu, 04/09/2020 - 08:47

Challenge

The 3-acre property, located in South Stamford, CT along the East Branch of the Stamford Harbor, was underlain by fill material dredged from the adjacent canal between the mid-1800s and the early to mid-1900 that had been impacted by historical manufacturing activities. The approximately 30,000-square foot two-story site building, which was constructed c. 1920s, was constructed on concrete piles above a crawlspace which contained soil contaminated with polychlorinated biphenyls (PCBs) at concentrations significantly above state and federal remedial action levels in certain locations and was subject to daily incursions from the tide. The proposed development included keeping the existing structure and adding two floors which required installing over 400 piles within the building footprint and through the PCB-contaminated soil. The combination of complex environmental and structural conditions, the waterfront setting, and the regulatory requirements for remediation required an experienced project team with a diverse set of technical skills.

Solution

During initial phases of the project, GZA participated in negotiations with the former owner regarding the extent of remediation warranted by site conditions and developed cost estimates for reaching regulatory closure under the Connecticut Transfer Act and for achieving compliance for PCBs under EPA’s Toxic Substance Control Act (TSCA). GZA designed and implemented remedial actions to address PCB contamination beneath the site building as part of the redevelopment including soil excavation and dewatering. A concrete slab was then installed to cap residual PCB impacts beneath the building and a deed restriction was recorded to prohibit disturbance of the cap.

Benefit

By skillfully responding to changes in site conditions and to the proposed project during construction, GZA was able to provide the flexibility, services and management skill required to help move this high-profile, challenging project forward to a projected on-time completion date. Stamford Media Village is involved with post-production of content for programs such as HGTV and History Channel and will be bringing around 400 jobs to this location once the building is completed.

Conduct environmental due diligence for acquisition
Review condition of bulkhead and marina
Perform investigations of soil and concrete to delineate release of PCBs
Integrate environmental remedial action planning with site development
Prepare final RAP to CT DEEP and EPA
Design and manage remediation of PCBs in soil through excavation
Design concrete slab to cap remaining PCBs
Prepare Dewatering Plan and obtain DEEP General Permits

Connecticut

Buildings & Real Estate Development

Waterfront and Coastal Engineering

Wolf Point East

gzadan — Fri, 06 Dec 2019 13:59:51 +0000

Wolf Point East gzadan Fri, 12/06/2019 - 08:59

Challenge

Wolf Point East is a 60+story residential tower under construction and located on the Chicago River with an estimated cost of $350 million dollars. The tower includes 6 levels of underground parking and a core structure which extends approximately 35ft and 53ft below grade respectively. The design of an Earth Retention System (ERS) presented challenges due to the small size and irregular shape of the lot; presence of adjacent parking structures which would remain operational during construction; Wolf Point Plaza; North Orleans Street; bracing layout and conflicts with column/shear wall lines; and the Chicago River on two sides. In addition, City Authorities required hand calculations for the design of the main members of the ERS system in preference to computer output.

Solution

GZA engineers performed the design using DeepXcav software and validated it through hand calculations. Hand calculations were performed in MathCAD with a special function tool that allows to report all the “numbers�� that go into every equation. After submission of the hand calculations to the City, the Engineer requested a 2D structural model of the internal bracing scheme to show the load distribution around the bracing. This analysis was performed using RISA3D structural software.

The ERS was composed of a steel sheet pile perimeter system down to elevation -50 (City of Chicago Datum (CCD)) and then a Core ERS composed soldier piles and lagging that extended from -29 to -59 (CCD). The two-level internal bracing system was composed of skewed 24 to 36-inch diameter Grade 3 pipe sections with varying wall thicknesses and heavy single & double W36 wales. The internal bracing system also supported the neighboring parking garage which extended to similar elevation below grade. Vertical transfer beams were used to span between the neighboring parking garage slabs to avoid unfavorable loading of its exterior walls with high corner brace loads. The design load on the braces reached up to 2,100kips and jacking loads were between 180 to 1050kips. The excavation included the removal of approximately 40,100 yd3 of material.

The tower structure is supported on large diameter drilled shaft foundations. The requirement for an internal braced ERS and the space for construction of large diameter shafts severely limited the remaining workspace. The core excavation required another 19-ft of excavation using internally braced soldier piles and lagging. GZA performed overall global stability analysis to ensure the main ERS, including the core ERS was stable. As the internal brace system and corner struts had to be supported on the neighboring parking garage, GZA designed a system to spread the loads to floor elevations and checked the parking garage slab against the applied thrust.

Benefit

The underground portion of the proposed building was constructed on schedule. The use of hand calculations in conjunction with geotechnical and structural software provided accurate estimates of the loads imposed on the ERS, which ultimately substantiated the installation of a more cost effective ERS resulting in savings in materials and labor during construction. The designed system was effective in providing the needed lateral support and allowed the below grade construction to be completed efficiently meeting the contractor’s requirements and satisfied the OUC concerns. The project received an SEAOI Excellence Award.

Related Insights

Article

Accelerating climate change demands ‘agile systems�� thinking �� and action

In an opinion piece for Commonwealth Beacon, Curt Spalding talks about the need for most agile environmental management to address the likely impacts of accelerating climate change. As Spalding notes...

Blog

PFAS Sampling as Part of Connecticut Wastewater Permitting

The Connecticut Department of Energy & Environmental Protection (CTDEEP) has recently been requesting facilities with wastewater discharges to sample for Per- and Polyfluoroalkyl Substances (PFAS)...

Blog

Unlocking Potential: The Crucial Role of Cleanup Grants for Historically Contaminated Properties

Revitalizing properties with an industrial past can feel daunting. Historical contamination often poses significant hurdles for redevelopment, with the polluter not identified or required to conduct...

Blog

Up to $25 Million Available for Transportation Safety Projects

The US Department of Transportation has announced the next round of funding for the Safe Streets and Roads for All (SS4A) grant program. Counties, cities, towns, transit agencies, and other special...

Pre-bid engineering services
Earth Retention System (ERS) design, including both internal bracing
Global stability analysis
Engineering services during construction
Structural analysis to distribute the brace loads applied to the neighboring parking garage

Illinois

Buildings & Real Estate Development

Geotechnical Engineering Services

Contractor Services

Waterfront and Coastal Engineering