Washington Aggregates and Concrete Association (WACA) recognized some of our structures during their annual Excellence in Concrete awards event. Here is a closer look at DCI’s projects that either won or were nominated by the trade association in the last two years. The project summaries also give you an idea of what our engineers specifically do when reviewing designs of various concrete structures.
The Matilda Building
The 88,000-sf Matilda Building won this year’s “Tilt-Up Structures” category. Our Spokane office contributed to the structural and civil engineering for the four-story mixed-use project, which comprises of three residential levels over one commercial level. DCI designed the primary building structure, including foundation, floor, and roof plans, as well as provided construction support.
To build the facades, the general contractor (DIVCON, Inc.) formed three-story tilt-up wall panels. Once the walls were erected, the walls were braced to the building slabs with helical anchors to allow for structural steel installation. For cost efficiency, the contractor attached the fourth floor tilt-up wall panels separately. The walls were braced to the cast-in-place inserts in the fourth floor slab.
NextIT – Pinecroft
This two-story office building won last year’s WACA “Tilt-Up Structures” category. DCI’s Spokane office worked on the 40,000-sf NextIT building which is in Spokane Valley’s Pinecroft Business Park. The developer chose tilt-up construction for economy, construction efficiency, and architectural finishes. The surface of the exterior tilt-up panels features “stamped” texture for aesthetic variety. Different colored concrete mix was also poured for the exterior tilt-up panels to make a distinctive pattern (and eliminate the need for painting).
The DCI team reviewed concrete mixes for appropriate aggregate size and water/cement ratio. Our engineers also designed the foundation and column plan, floor and roof framing plan, spread footing schedule, reinforcement details, and panel connections.
Point Defiance Regional Treatment Facility
This concrete stormwater treatment project won last year’s “Sustainable Merit” category. The Point Defiance Regional Treatment Facility is a 5,500-sf bio-retention facility improving the quality of stormwater before discharging into Tacoma’s Commencement Bay. The treatment facility consists of cascading precast concrete pools with trough and weir systems to evenly distribute water during the treatment process, which involves treatment media and an underdrain system. The treatment facility processes up to 6,000,000 gallons of stormwater per day.
DCI worked with Oldcast Precast, Inc. to craft the details of the precast tanks. The DCI Spokane team calculated reinforcement beams, determined hydrostatic load, and generated the fabrication drawings.
Block 52e (Apollo)
The LEED Gold-certified Block 52e (also known as The Apollo) in Seattle’s South Lake Union neighborhood is a 12-story, 317,000-sf office building. This year, the building was nominated as a running finalist for WACA’s “Cast-In-Place Parking Structures” category. For the building to achieve LEED points for parking, all four levels had to be below-grade. The project site has a high water table that is hydraulically connected to Lake Union. DCI’s Seattle team worked with Graphite Design Group and GLY Construction to come up with a concrete “bathtub” structure for the parking as a solution to the soil conditions. To resist hydrostatic pressure, waterproof concrete was prepared with Hycrete W1000. DCI specified a thicker concrete slab at parking Level P4 which gradually dropped beyond 22 feet below-grade. The parking garage walls are made of concrete core and post-tensioned concrete slabs.
1124 First Hill Medical Pavilion
Nominated as a running finalist in the “Cast In Place Structures” category this year, 1124 Columbia Medical Office Building in downtown Seattle includes a new six-story medical office tower and expansion of an existing underground parking structure. The existing three-story underground parking garage expanded to five levels, providing a total of 415 parking stalls. The garage also shares a structural system with the six-story medical office building. DCI’s designs made it possible to nearly double the size of the parking garage while maintaining three perimeter walls, saving time and money compared to a total rebuild.
The designs mostly utilize mild-reinforced concrete slabs, with post-tensioned concrete beams used in select areas to achieve the long spans necessary to accommodate the building’s layout. The use of mild-reinforced slabs makes the building flexible for future tenant improvements.
Learn more about concrete structure and construction from these online sources:
Structural concrete basics
Concrete framing and load capacity
Rose Bechtold, Communications Specialist | Rose comes from a journalism and technical writing background. She is in her element while in research mode and naturally immerses herself in expert knowledge by interviewing staff members about new subjects. In her spare time, Rose practices plein-air sketching of buildings and random scenes around town.
