New research shows how concrete can be integrated into high-rise timber floors

There has been an increase in buildings using large amounts of timber.

Research by Oregon State University in the United States looked at how architects and builders can overcome the technical difficulties of designing and constructing largescale timber buildings.

Normally, concrete flooring is used in high-rise buildings. The difficulty when using timber is that there is a limit to the span of wooden floors and the load that can be carried. The answer, according to the researchers, is to incorporate concrete into timber floors.

The researchers constructed an 8’ x 36’ wooden test floor made from cross-laminated timber. This represented a floor for an 11-story building. The floor was then stress tested for load, bending, shearing and cracking. This was done both before and after adding a 2.25-inch concrete slab on top of the timber.

Stress testing revealed that the floor that had the concrete layer was stronger and only failed after 82,000lb of pressure was applied, which is eight times the normal load for floors. In real world conditions, the timber would need to be treated with fire resistant chemicals and this could weaken it. This means that timber floors need to be made thicker than the test, the timber layer of which was 6.75 inches.

The researchers concluded that for high-rise timber construction buildings, a concrete flooring slab would need to be added to strengthen the timber floors, especially in earthquake regions where extra strength is required.