Factors Affecting Strength of Epoxy‐Repaired Timber

Abstract

An investigation into the factors affecting the strength of epoxyrepaired timber structures has been conducted. Two aspects are evaluated: repair methodology, and effects of member configuration. The structural repair sequence of timber consists of four basic steps: (1) Special member preparation; (2) joint sealing; (3) epoxy injection; and (4) finishing. Each of these steps is described in detail with recommended procedures to aid the engineer in both the design and inspection of epoxy repair. To evaluate the various joint configuration parameters affecting the behavior of epoxy‐repaired timber, over 200 full size repaired members and over 100 shear blocks of Southern pine were tested. The parameters studied include effects of: mechanical connectors; length of overlap; member thickness; grain orientation; timber age; and glue line thickness. It was found that the shear bond strength is on the order of the shear strength of the wood. It was also determined that the primary factors affecting strength are the ratio of lap length to member thickness and grain orientation.