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Benefits of pre-construction exploratory excavation

Toledo has a rich history dating back to the 18th?century. In the late 19th?and early 20th?centuries, Toledo became a railroad hub and manufacturing leader. The buried remnants of Toledo¡¯s past result in frequent field conflicts and changes during construction of any downtown infrastructure project.

Knowing the risks for infrastructure conflicts underneath downtown Toledo, we recommended pre-construction exploratory excavation to minimize delays and change orders. Why? Because when working in an urban environment, it¡¯s more efficient to perform pre-construction exploratory excavation than to redesign during construction. Conflicts can be discovered early, and changes can be coordinated before final construction begins.

I recommend pre-construction exploratory excavations when:

• The construction schedule is limited
• Construction delays are not an option
• New infrastructure is being installed in close vicinity to aging infrastructure
• Record drawings are not available

Expect the unexpected when digging in an urban area

When you¡¯re digging in an urban area, chances are likely that an unknown buried conflict will cause a need for a design change. Setting clear communication, documentation, and decision-making procedures early with the entire project team is key in these types of situations.

It¡¯s important to recognize locations with high risk of buried conflicts in advance, and to have the engineering team in place to adapt during construction. It¡¯s important for the same team that performed the final design to assist with construction¡ªand to plan for some redesign. It¡¯s also critical that the owner budgets for changes through a construction allowance or contingency and manages expectations within their organization. Plus, public outreach during all stages of the project will minimize conflicts with nearby businesses and residents¡ªit¡¯s in the best interest of all parties.

During the Downtown Storage Basin Project in Toledo, we uncovered an abundance of railroad ties, railroad tracks, building foundations, and abandoned utilities¡ªmany of which were not identified on record drawings or marked by utility locators. At the basin site, two abandoned pipes connecting our mass excavation area to the Maumee river were exposed, allowing the river to briefly flow into the excavation when the river elevation rose. Whenever conflicts came up, the project team used established communication procedures to discuss issues with the entire project team and work together towards formulating a solution.

Importance of coordination between all stakeholders

A collaborative and flexible project team that includes the owner, contractor, construction manager, and engineer is vital to successful construction in high traffic urban areas. In the case of the Toledo Downtown Storage Basin Project, we were fortunate to have top-tier professionals filling all these roles, which allowed the team to address conflicts in a concise and efficient manner.

Our team has continuously coordinated with utility companies to avoid, adjust, and redesign around utility conflicts at downtown intersections. Much of the drop shaft construction occurs near historic downtown Toledo structures. Dozens of instruments have been installed to continuously monitor noise, vibration, groundwater elevations, and soil movement to ensure safety and protect the integrity of these structures. Maintenance of traffic plans and intersection closures have been coordinated with adjacent construction projects, city events, and downtown businesses such as the Toledo Mudhens and Toledo Walleye.

The most important aspect of working in an urban area is assembling a project team with a common goal of successfully completing the project. A prepared owner, a quality contractor, and a responsive construction manager and engineering team can resolve almost any issue if the focus remains on this common goal.