3d modeling

Clark Construction uses 3D modeling and laser scanning to solve healthcare project challenges

When it opens in 2023, a new healthcare facility for MedStar Georgetown University Hospital in Washington, DC, will feature the latest medical and technological advancements.

The new 477,213 square foot medical and surgical building will feature 156 patient rooms, 32 exam rooms and a rooftop helipad with direct access to 31 operating rooms. An intraoperative MRI system with a ceiling mounted rail system connecting the diagnostic room and adjacent operating rooms will bring the MRI magnet directly to the patient. In addition, the project includes a 600-space underground parking garage, 18 elevators and 6 acres of new green space.

The site is on the grounds of the former Kober-Cogan building, which was closed in May 2010 after the discovery of mold in teee building and previously housed the hospital’s psychiatry ward.

This presented unique challenges for the project team, led by Bethesda, Maryland-based Clark Construction. Miles of water pipes, many of which were undocumented, ran directly under the location of the new pavilion to supply both MedStar Georgetown University Hospital and the campus buildings of Georgetown University. The project team had to move these utilities outside of the building footprint to allow the project to begin.

“Clark’s team designed and engineered a 250-foot-long service bridge to support chilled water and electrical services from the central utility plant to the existing MedStar Georgetown Hospital,” said Bradley Hunter, project manager at Clark Construction Group. “The installation of the bridge required close coordination with the mechanical and electrical contractors who installed the utilities on pre-fabricated supports which were then suspended from steel beams measuring 60 feet, allowing the excavation to begin. below.”

Clark designed a temporary service bridge to support the existing hospital’s active utility services.

Authorization granted by Clark Construction

Clark Construction, in conjunction with architects HKS and Shalom Baranes Associates, assembled a BIM model of the existing utilities. As the design progressed and the base structure and caisson locations were defined, “we did additional drilling at all caisson locations and further informed the BIM excavation model,” Hunter said. .

This first step allowed Clark’s team to better inform the cost model with respect to deep foundations and to begin revising the excavation plan. With nearly 1,000 piles to install for support during excavation, Clark recorded the actual ground and service conditions encountered in real time with each pile and entered the information into the BIM model. This greatly improved Clark’s understanding of the site and allowed the excavation plan to continue to be revised and resequenced ahead of field crews, Hunter said.

“At the end of the pile installation, we were able to have a very complete profile of the planned excavation well in advance of the final phase of the excavation,” Hunter said. “Using this information, we were able to develop mitigation strategies with the goal of minimizing impacts on the project’s critical path.”

The team turns to on-site technology

Clark conducted a preliminary survey with traditional survey instruments, such as the Leica MS50, which combines total station functionality, GNSS connectivity, digital imagery and 3D laser scanning in a single instrument. 3D technology carried out checks of slab edges, precast concrete, joints and floor flatness. The technology also coordinates existing buildings to make connections to the facade.

After completing and setting checkpoints around the site, the team began the scanning and layout process, said Kathleen Lavelle, project manager at Clark Construction Group.

“For the 3D laser scanning, we again use our Leica MS50 which has full scanning capabilities. We use our survey control points to link the scan data to site coordinates. Once the scan is complete, the Infinity program of Leica is used to clean the scan.” Lavelle said. “It can be exported to different file formats depending on the software used to work with the data.”

The survey team used Leica MultiWorx, a companion application to Autocad Civil 3D. This scanned data can be used to generate existing conditions and as-built drawings as needed.

Managing an influx of people

Due to its location next to a university and a health center, the Clark team had to think of solutions to manage the flow of students, patients and visitors, especially at the start of the pandemic. of COVID-19 to accommodate social distancing guidelines.

To accomplish this, the construction team constructed a temporary pedestrian bridge to maintain access along the east side of the construction site. Additionally, an on-site concrete batching plant, producing over 35,000 cubic yards of concrete, has helped ease traffic congestion by reducing the number of deliveries to the project site. The plant took about 3,500 trucks off the road and ensured the quality of the concrete on site, according to Lavelle.

Removing trucks from the road has also helped reduce noise levels, another challenge as the construction site is near several residential neighborhoods, said Andree Yaap, project manager at Clark Construction Group.

Clark also worked closely with HKS and the owner to assess which elements of the project could be fabricated offsite. Using a formal rating and evaluation process, the team selected which items to prefabricate based on what would bring the most benefit to the project, Yaap said.

The project includes more than 700 prefabricated materials, including 156 bathroom modules, operating room ceilings, patient head walls, electrical rooms, clinical rooms, MEP skids and supports, and interior partitions , Yaap said.

A range of ready-to-install patient bathroom modules.

Authorization granted by Clark Construction

Building components were fabricated across the country, with bathroom modules being built in Texas, operating room ceilings being built in Oregon, headwalls being built in Oklahoma, and wall panels under construction in Virginia, Yaap said.

“Clark’s efforts have accelerated lead times and reduced costs,” Yaap said. “Other benefits include improved quality resulting from assembly in a controlled environment, reduced construction activity on site, and reduced noise levels, neighborhood traffic and congestion.”