A tale of two challenges – and solutions – in water treatment construction

Spartanburg Water is one of the most established water systems in South Carolina. Established in 1929 as the Spartanburg Metropolitan District, the utility has a history of providing high-quality drinking water to customers. Spartanburg Water relies on three water treatment facilities and a well-maintained network of pumping stations, lakes and transmission lines.

Built 96 years ago, the RB Simms Wastewater Treatment Plant (RB Simms) features pipes and structural elements that are over 100 years old. In 2019, it was time to modernize this facility. When Spartanburg Water selected Harper General Contractors to provide Construction Manager at Risk (CM at Risk) services for major upgrades at RB Simms, our team spent a great deal of time with the client carefully planning our project approach. . We knew, however, that this project involved significant strains on an aging infrastructure and would require a top-notch project team that could think quickly and creatively to deliver the best possible outcome.

Main photo (top of page): Aerial view of the construction of the new 64″ raw water main at Penstock Crossing.

Working near aging infrastructure using horizontal drilling in granite next to a dam

As construction and AEC professionals know, innovative solutions and quick thinking are critical tools for project success. Unapproved plans, unforeseen circumstances, and changing demands may require the design and construction team to come up with a new solution to keep the project on track. A significant issue that needed to be addressed during the RB Simms upgrade was the facility’s location next to Municipal Reservoir No. 1 and its associated dam, creating a particular challenge when operating or factory update. Working closely with HDR, Inc. (HDR) as the design engineer for the project, our team developed an approach focused on mitigating any disturbance to the reservoir while still being able to complete our project on time.

In order to complete this project, we had to install a new ozone system. This system would be located very close to the 100 year old dam and the pipelines associated with this system would have to run from the water to the treatment facility. Although the ground along the new driving path was solid granite, the team did not approve of the blasting due to its proximity to the dam. Our team had to go back to the drawing board to find a solution that would allow us to connect the pipe to the water and to the plant, without using the unapproved path.

The solution allowed the Harper team to contract a tunnel boring machine (TBM) to drill horizontally through 250 feet of granite along the reservoir. Our team dug a 40’x26′ pit to prepare the grinder. Although we made significant changes to the plan, we were not willing to compromise our client’s project schedule. Digging the shaft required 24/7 operations for several weeks to meet the project schedule. And at times, that included using hand tools to remove the granite. Halfway down the shaft, the team constructed a rest area to provide tool storage and an accessible evacuation area if needed. The 40-foot shaft included ventilation, dewatering equipment, soil nailing, conduits, pipes, and poured-in-place concrete as additional safety measures. The omission of just one of the safety features could potentially compromise the integrity of the drill shaft. Even though we had a change of plans and an extremely tight schedule, our team prioritized safety and quality and did not skimp on the delivery of this well. After drilling 20′-30′ per day, the machine started at its designated end point, and the team successfully connected the two pipes.

The extra time and attention spent on finding an innovative solution to this predicament has kept this project moving forward. The extra care, prioritization of safety and quality, and maintaining the budget allowed this project to be a success.

Aerial view of the construction of the microtunneling borehole adjacent to the dam fault.

Exceeding customer expectations with virtual construction

As we began to make significant improvements to RB Simms, we quickly knew that virtual building would be part of our approach. Recognized for its time and cost saving benefits, virtual construction has become an increasingly popular tool used in the construction industry in recent years. In the water and sanitation sector, this resource is just beginning to emerge on projects.

A significant issue that needed to be addressed was the existence of existing infrastructure layers on the site, creating a particular challenge when operating or updating the plant. HDR and Harper came to the table with unique approaches focused on maintaining facility operations during construction, addressing concerns about existing infrastructure and plant location, and collaborating with our client. throughout the process.

Maintaining operations during construction was a major concern for Plant 64-MGD. Simple solutions, such as building a new chemical feed storage area at the rear of the plant, have eased the coordination of deliveries. However, installing new water pipes under the existing infrastructure presented a more daunting challenge. The available plans and site layout gave a general idea of ​​what lay underground and the plant operators filled in many of the gaps. Still, the Harper team wanted to be sure they wouldn’t cut an electrical wire or puncture an existing water pipe during construction.

We performed extensive imaging and layout exercises to understand how the proposed construction would interact with underground utilities. This was accomplished using imaging technology, including total station robotics, LiDAR imaging, and traditional sample probing. The result was a 3D model of the entire construction site, showing the existing power, water and utility lines laid over the proposed additions. We reviewed the model, quickly identified potential conflicts, and revised the drawings accordingly. Seeing the finished product before procurement or construction and adjusting plans accordingly has saved time and money by eliminating rework and purchasing additional materials.

An example of the benefit of this approach was identifying that the new water and ozone lines crossed or were adjacent to an existing 100-year-old 78-inch penstock. The precise site layout provided the team with the data needed to lay the pipes around the penstock without any service interruption. Before a shovel hit the ground, Harper’s field and project management teams knew the exact location of the penstock, where they needed to dig to avoid hitting the structure, and precisely where the pipe would connect a time he would cross the penstock.

Another collaborative application for virtual construction was to combine real-time images with approved drawings. Our project manager collected 300-600 high quality aerial images per month using Drone Deploy. The project team placed applicable images on their corresponding drawings to show progress and confirm layout and measurements. These images guided the pre-planning meetings with the commercial partners, in particular with the BIM model (Building Information Modeling). During monthly owner/engineer/contractor meetings, these images provided Spartanburg Water with a visualization of the project to guide conversations about progress and next steps.

Overall, virtual construction allowed this project to move forward with limited disruption to plant operations. Underground imaging avoided costly conflicts between new pipes and existing pipes. Real-time images overlaid on the drawings ensured accurate foundations and pipe placement. BIM models provided the backdrop for rapid decision-making as all parties could see and discuss the proposed end product. And, most importantly, we were able to develop an approach using virtual construction to address our customers’ concerns, prioritize their requests, and exceed their expectations.

The RB Simms water treatment facility was recently completed, giving Spartanburg Water the updated facility needed to continue producing high quality drinking water for its customers for years to come.

BIM model detailing the construction of the 64 inch raw water main at the penstock crossing.

About Harper

Throughout our 72 year history, Harper has had the opportunity to develop strong professional relationships with clients throughout the Carolinas. By bringing our clients’ vision to life, Harper leaves a lasting impression on community members. The core of our business is focused on working with owners and design professionals in an open and transparent manner, letting the owner know how every project dollar is being invested. An award-winning company, Harper is consistently recognized in the areas of quality, safety, environmental stewardship and community involvement. For more information, visit harpergc.com or contact us.

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