Remedial Construction Management, Former MGP

GZA was selected by the client to provide construction management services for an Excavation Interim Remedial Measure (IRM) at a former manufactured gas plant (MGP). The facility operated from the late 1800s until approximately 1930, when most above-ground MGP-related structures were removed. The property was subsequently redeveloped as a shopping center and parking lot, which were recently demolished to accommodate current redevelopment plans. The IRM addresses MGP-related contaminants remaining in soil within the footprint of the proposed new building.

Challenge

Excavation requires installation of support of excavation, groundwater dewatering and treatment, and completion of all excavation activities within a temporary membrane structure. The work must comply with New York State Department of Environmental Conservation (NYSDEC) and New York State Department of Health (NYSDOH) regulations. Installation of the support of excavation and temporary membrane structure also required full designs and New York City Department of Buildings job filings so the contractor could obtain installation permits.

Solution

Before construction, GZA conducted constructability reviews, assisted with contractor bid reviews, and reviewed the site-specific groundwater flow model prepared by the Design Engineer. With construction underway, GZA provides full-time, on-site construction administration and management support, including review of contractor submittals and work plans, oversight of compliance with project specifications and schedule requirements, review of payment applications and change orders, and administration of weekly progress meetings. GZA also assists the client in coordinating the Design Engineer, contractor, NYSDEC, NYSDOH, property owners, community, and government officials. During IRM activities, GZA’s responsibilities expanded to include full design and Department of Buildings job filings under the self-certification process for the support of excavation and temporary membrane structure.

Benefit

GZA’s integrated construction management, design, and permitting support helps the client address the technical, regulatory, and coordination requirements of the ongoing IRM. These services support excavation of MGP-impacted soil within the proposed building footprint while maintaining oversight of construction requirements and facilitating the permitting needed for installation of critical temporary structures.