QTS MAN1 DC-3

Summarize the project's program, features and achievements?

• Insulated Tilt-up Panel Building including Generator Yard
• Building Footprint: 140,000 SF
• 143 Tilt-up Panels
• Tallest Panel Height: 75'-5"
• Widest Panel Height: 36'- 5"
• Heaviest Panel: 75.17 T
• 136,000 SF Slab Metal Deck on Steel Framing
• Bracing of Exterior to Helical Anchors & Deadman Weights
• Timeline: December 2022 thru October 2023

MAN1 DC3 is a 140,000 SF data center located in Manassas, VA. The building was originally designed as a steel frame structure with an insulated precast panel skin but was successfully converted into an insulated tilt-up panel project.

Project Narrative

The majority of the QTS buildings in the area are an internal steel frame structure with a non-load bearing exterior precast skin. The buildings are built with steel frame being erected, the interior slabs being poured, and the precast being erected last. This process allows the Owner to provide the best slabs possible for their buildings since they are poured after the steel erection. The Owner tasked Southland Concrete to maintain the standard they expected for the slabs although the slabs were poured first for panel casting, and we would be erecting the panels & steel off those slabs. Additionally, the overall layout for the building was not conducive for tilt panel casting and erection. An irregular shaped exterior along with interior full height panels made for a difficult conversion from precast to tilt panel installation.

To help maintain the quality of slabs required by Owner we prioritized casting the slab on grade as a whole with as little leave-out as possible to help maintain a uniform finish with as little construction joints as possible. We also used less invasive products (glue down versus nail) for panel forming to make sure there was as little rework as possible on the slabs. We believe that we ended up supplying an exceptional finish for the slab on grade even though panels were cast on them and steel was erected off them.

Due to the irregular shape of the building we knew from the beginning that the data hall was the critical path for the project so we built the schedule around getting those panels cast and installed first. This sequencing meant that we couldn't install the admin/front of house foundations until after the data hall panels were erected. This also meant we would not be able to cast and erect the admin/front of house areas before steel erection so those panels were done afterwards like a typical precast skin. This required significant logistical work to make sure that the panels were cast in the optimal amount of area to make sure we had enough room around the tight site for all the panels.

Overall the project was extremely unique due to its conversion from a precast to a tilt-up exterior skin. Our field crews did an excellent job in managing all the logistical issues that came from this change while also delivering a top line data center that lived up to the high expectations required.

What obstacles were overcome related to the schedule, budget, program, specification, site, etc. on this project?

Southland Concrete was faced with some challenges regarding this large data center construction. The job was delayed due to the change in General Contractor which pushed our initial September start to December while also keeping the final completion date in place. Our initial scope of work only pertained to tilt-up panels, slab on grade and slab on metal deck, but thru the new GC we were awarded the opportunity to add both the foundation & generator yard work for our scope of work. This not only doubled our original contract, but also put us in contact with a new panel design engineer who we had no previous experience with.

The panel design had been completed prior to construction, but to our dismay in early January the team changed the design to the bus duct opening locations for the majority of the panels within the generator yard. This required significant rework to the first sets of panels being cast on site. With the lack of drawings provided, our crews had to re-sequence all the foundation and slab work to match the revised redesign. These redesign efforts caused various hiccups throughout our panel forming timeline. This project was always going to be a difficult tilt-up panel job due to the amount of ground concrete installed before slab on grade commenced. Due to poor soil conditions that required a significant amount of undercutting, our concrete scope nearly doubled from 5,000 CY to 9,000 CY of concrete to install the footings and foundation walls.

Please communicate any engineering complexities or unique features of the panel design for this project?

The building was originally designed as a steel frame structure with an insulated precast panel skin. Due to delays with precast acquisition the project was converted into an insulated tilt-up panel project. Converting the building from precast to tilt-up left little ‘laydown space' for the casting of the site panels. We had to work within the existing surrounding conditions which included wetlands on the eastern half of the project that significantly affected the amount of cast beds that could be used, as well as the location of these cast beds. Our teams had to strategize best areas to utilize to keep the project moving in a timely manner.

The Data Hall and front Admin Housing were constructed differently but had to be cohesive as a final product. A typical tilt-up build was executed for the Data Hall via panels erected first and steel tied in after, while the Admin section had the opposite approach with steel installation followed by precast pieces. This required extensive logistical work between our team, the panel design team, and to ensure we could cast and set all panels around this portion of the project. Through teamwork and communication our crew prevailed to completion.

What is the potential for this project's impact on the community and/or environment?

Although no specific impact to the community was implemented, this project and its Owner did take special attention to its surrounding environment. Water and its usage is a huge problem in the data center community as it uses a massive amount to cool down the heat produced. The cooling design placed within this building allows for a zero water usage rate. These measures are done by the use of a low-pressure pump system that uses air to remove the heat, as well as using rainwater collection systems and well water rather than municipal water. This means that thru various forms of water conservation that the wildlife, community, plants & farming, and drinking water remain in great quality and abundance. This is tracked thru a system to regulate its impact on the environment.