INSPECTION OF WOOD INTEGRITY USING WITHDRAWAL RESISTANCE OF WOOD-SCREW PROBES

-Inspection method of lumber used in existing wood structures based on bending strength-

Abstract

Inspection method of wood integrity using distribution of resistance to withdrawal of wood-screw type probes is proposed. The probes have a 5mm length thread and are screwed into wood. Withdrawal resistance of the probes in several depths is measured. Average withdrawal resistance provides integrity of wood. The distribution of withdrawal resistance of wood provides information of degradation in wood. Withdrawal resistance of wood-screw type probes and bending strengths of the specimens are compared. Based on allowable bending stress of wood, critical withdrawal resistance is proposed. Wood integrity is evaluated by comparing measured withdrawal resistance and critical withdrawal resistance.