Which timber property describes the initial deflection of a member that increases with time?

• A. Orthotropic Behavior
• B. Splits
• C. Shakes
• D. Creep Characteristics

Answer: (D)

Creep describes how timber continues to deform under a sustained load, so the initial deflection increases with time. Under constant loading, wood slowly strains more as its molecular structure and moisture content respond to the load, so long-term deflection grows beyond the immediate elastic deflection. This time-dependent deformation is what creep characteristics capture, making it the best description for deflection that increases with time.

Orthotropic behavior is about wood’s directional properties—different stiffness and strength along the grain, across the grain, and in radial vs tangent directions—not specifically about how deflection grows over time. Splits and shakes are defects related to cracks in the wood from drying or stress, not a sustained-time deformation under load.