Wood Beam Relative to Flood Plane 1

CBSE · Feb 14, 2017

Have a bit of an issue that came up with an Architect. The detail they wanted was the CMU going to the bottom of the floor joists as shown in the attached with the joists resting on top of the glulam beams. The problem is, they drew everything so that the free board was 12" between bottom of joist and top of flood line. My glulam beams to support the floor will be in the water in the event of a flood, with the detail drawn as shown.

I can't find a definitive answer in literature that doesn't say this is NOT OKAY/OKAY. Anyone have literature saying something definitive? It only happens at interior bearing on CMU columns, which is basically the entire building except the exterior walls.

CBSE · Feb 14, 2017

I should add, this is a Flood Design Class 2. It's not on the coast, it is in the middle of the state and the flood would be from a river over-flowing its banks.

SlideRuleEra · Feb 14, 2017

The American Institute of Timber Construction (AITC) says it's ok if the proper steps are taken:

1. The glulam beam has to be treated with a preservative acceptable for residential use.

2. Fasteners and hardware have to be corrosion resistant. This is as much to prevent damage from the wood preservative as it is from moisture / water.

See Table 2, on page 6, of AITC 109 Standard for Preservative Treatment of Structural Glue Laminated Timber.

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