Property redevelopment can be a tricky business. This is especially true for sites with a history of industrial use that are impacted by uncontrolled fills, construction materials, abandoned structures and utilities, and industrial waste. Put those materials near or below the groundwater surface and you’ve got quite a brew. Dealing with such impacts is not cheap, but many projects incur unnecessary costs because they aren’t coordinated from a shared environmental and geotechnical perspective. Excess costs come from two sources:
- Basic site investigation rework
- Failure to leverage both environmental and geotechnical expertise when evaluating site redevelopment alternatives
Rework is generally the product of poor logistics or inexperience and can be mitigated through better planning. Leveraging environmental and geotechnical expertise requires more experience, a solid understanding of regulations governing design and construction, and industry savvy.
Collaboration During Site Investigation
Environmental professionals characterize environmental site contamination as well as develop and perform remediation plans—it’s what they were trained to do. But many environmental site investigations come up short on difficult sites. Site contamination is often characterized with little or no thought regarding how the contaminated material(s) can be avoided, relocated, repurposed, etc., to support redevelopment. As a result, geotechnical consultants often redrill at additional cost to obtain geotechnical information that should have been gathered during the environmental investigation.
Similarly, while geotechnical engineers understand what it takes to characterize subsurface geologic conditions to support construction of buildings and pavements, they often fail to recognize potential impacts to projects related to environmental issues that may be evident in surface features (abandoned fuel pumps), borehole samples (odorous or discolored soil), or test pits (entrained demolition debris). Whether environmental or geotechnical, such omissions can ruin a project.
Once a site has been characterized, it is critical to understand all environmental and geotechnical constraints, how they affect each other, and how they affect the project’s bottom line cost and the risk of future structural problems. Unfortunately, the traditional environmental investigation and remediation process doesn’t do this well on its own, nor does conventional geotechnical engineering.
For example, environmental consultants can rigorously delineate limits and estimate the volume of uncontrolled fill impacted with chemicals at concentrations above applicable regulatory standards, but what are the disposal options once it’s excavated? Are there options for on-site relocation of the fill that won’t limit redevelopment options or prevent redevelopment from occurring at all? And what about sites with uncontrolled fill impacted by contaminated groundwater? Is there a ground improvement or building support alternative available to reduce or eliminate groundwater management costs associated with dewatering?
These questions can pose complex challenges. This is where experience and industry savvy come into play. For instance, it may be possible to place fill containing construction debris outside foundation oversize planes and/or at depth below pavements to reduce potential impacts to building or pavement performance. Many times, additional excavation work can be performed to accommodate placement of contaminated soils at depth below buildings or pavements to prevent off-site disposal of contaminated soils.
Move Construction Obstacles with Experienced Staff
No matter how well a site is characterized, unforeseen conditions are possible, even typical. Most building contractors are not trained to think about environmental issues, but are focused on the myriad of details related to construction of the new structure and associated infrastructure. That is why it is critical to have experienced field staff present during construction who understand both the environmental regulatory framework and the plans for building construction. The presence of experienced field staff facilitates prompt resolution of minor issues and proper assessment and communication of larger issues. They are the first line of defense when these issues arise in the field.
It is critical to bring environmental and geotechnical professionals together early in the planning process for redevelopment sites. Working together, these professionals can design field investigations that capture as much environmental and geotechnical information as possible. Braun Intertec can help implement this approach to assist the owner in its efforts to maximize the performance of new structures while minimizing total project costs. Contact Michael Beck at Braun Intertec for more information.