Wednesday, April 8, 2009

Salem Senior Center

Project: Salem Senior Center
Location: Salem, Oregon
4412 SW Corbett
Portland, Oregon
97239
General Contractor: Todd Construction
Square footage: 32,000 sq. ft.
Status: Completed 2008.

The Salem Senior Center was my third project I worked on since I joined Lewis and Van Vleet. It was new a 2-story senior center located near downtown Salem, to the north.

The building is constructed primarily of steel. The roof originally was constructed with open-web wood chord/metal web joist with plywood sheathing. But after some number crunching by the architect and developer, they opted to use open-web steel joist with metal roof decking. Centered in the roof is a clerestory to provide light below.
The second floor was framed with a series of wide flange beams framing into wide flange girders with a composite floor diaphragm. The configuration of the building was such that the upper floor plan was square in nature and the lower floor more rectangular, in that a portion extended out beyond. This provide a location for mechanical units and the same sort of framing was extended to that area. It allowed to surface to be concrete as well, providing some damping below.

On the first floor plan, they had a great hall, but the wall from the second floor rest about in the center of the hall. The architect and owner did not want a column in the center of the hall, so we designed a plate girder to span the length of the hall, nearly 64 feet. The flange width needed to be 10 inches maximum 2 1/2 inches thick. The depth was kept at 60 inches with a 1/2 inch thick web, to avoid interference with the window system. At one point, we suggested a truss fabricated of HSS sections, but it was too difficult to coordinate windows around web openings.

The lateral system was a series of moment frames with two braced frames. In the end, it turned out to be all moment frames because of openings and such required by the architect/owner. They were designed as special moment frames in accordance to AISC standards and utilized the "dog bone" style connection.

Initially I started the design using RAM Structural System. I had never used this program so it was a learning experience for me. I did not have enough time to really assuage the troubles I was having with designing the moment frames within this program. After discussing it with Lance, I opted to use RAM Structural System to design only the composite gravity loads and then did the moment frames in RISA 3D. This worked well in the end.

The building turned out to be a real nice addition to the community. I had stopped by one Sunday when they were having a wood carving fair. I engaged one of the men there about the place and told him I was the structural engineer on the project. He then informed me, the only real complaint was that the janitorial room was 3/4's smaller than over at the other building.

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