Moisture Content – Strength Relationship for Lumber Subjected to Bending

The moisture content – strength relationship for lumber was investigated by performing a dry out test. It was found that the increase in strength, as moisture content went down was discernible for initially strong material, whereas weak material did not increase in strength as indicated in the present building codes. However, stiffness did increase over the whole range of initial stiffness as moisture content dropped. It was also found that the present grading rules do not provide consistent overload factors for the different grades.