News and Events

Helping Healthcare Facilities Meet Seismic Requirements

posted 01.02.2019

Seattle Childrens Hospital

Healthcare facilities must meet a high standard of excellence. It’s the strong relationship of trust, combined with technical experience, that Mayes, A Terracon Company (Mayes) brought to Seattle Children’s Hospital’s continued expansion. The hospital serves the largest region of any children’s hospital in the U.S. (Washington, Alaska, Montana, and Idaho), and its location requires its facilities to meet special seismic zone requirements. The materials and structural recommendations for the hospital’s expansion are critical to its ability to deliver vital care to the region.

To continue to meet the needs of the communities it serves, the hospital has been adding new services and updating its facilities. Since 2000, three major building expansions have been completed, with a fourth expansion, “Building Care,” underway and expected to be complete in 2021. This expansion includes demolition of a parking area and helicopter landing zone, followed by moving of utility lines, and a bicycle and bus stop shelter. The expansion also includes the relocation of the helicopter landing zone to the top of Building Hope on the hospital campus.

Working with the design team, Mayes’ materials engineers provided input for concrete and structural steel specifications.  Mayes’ engineers have also provided welding procedure review, fabrication audits and preconstruction meetings.

Because Mayes worked on the hospital’s Phase 3 expansion, the team was ready to handle all the usual structural monitoring activities and perform inspections of the interior build-out to meet seismic requirements adopted from California’s Office of Statewide Health Planning and Development (OSHPD). Construction must meet a special seismic AWS D1.8 code requirement, which covers certain welded elements of the structure.

The new expansion includes a seismic force resisting system with special steel moment frames, which incorporate the latest AWS and AISC seismic welding requirements. Inspections and testing include reinforced concrete, shotcrete, structural steel fabrication, structural steel erection, fireproofing, auger cast piles, welding, ultrasonic testing, magnetic particle testing, and floor flatness testing.

Working on the latest expansion for Seattle Children’s Hospital is a point of pride for our team members, many of whom have trusted the staff with their own children’s’ care. Building upon a more than 15-year client-consultant relationship, the hospital’s commitment to excellence has been well served by the Mayes team’s focus on delivering innovative solutions.

“Serving the needs of the community, especially its most precious and vulnerable members, is the common goal behind the long-term success of this partnership,” said Laura Reinbold, Terracon national director of healthcare.


Lonny Morrison is a principal and senior project manager with our Mayes Terracon office in Seattle. He has more than 20 years of experience in special inspections and is certified in every discipline, while also holding a Masters of Special Inspection. His experience includes such projects as large-scale high-rise buildings constructed with both structural steel and concrete as well as wood framed structures. He also led a team of quality assurance inspectors on one of the largest projects in the world in Saudi Arabia.