Methods for measuring deteriorated thicknesses of wood by static penetration tests used different steel pins

Abstract

Although the drilling resistance tests and dynamic pin penetration tests were commonly used for measuring deteriorated thickness of woods, there are some faults for inspection of in-situ wooden structures. We tried to develop a simple and high accurate measuring apparatus for deteriorated thickness by static penetration using 7 types steel pins. Firstly, we developed a static penetration test apparatus with electric motor operation and measured penetration thickness and penetration force as it penetrated wood with constant penetration speed. The required penetration forces for measuring by static penetration tests were analyzed for measuring the deteriorated thickness using 7 types steel pins compared with the deteriorated thicknesses which were obtained by the drilling resistance tests. The accuracy of measurement of the deteriorated thicknesses were examined for every 7 types steel pins. Secondary, we developed a simple static penetration test apparatus with a penetration force measurement device to measure penetration thickness which can be used even in water. The measurements of deteriorated thickness were conducted by three persons using the simple static penetration test apparatus. The tests results indicated that the wedge-shaped steel pin with 3 mm in diameter can measure deteriorated thickness with the highest accuracy with the simple static penetration test apparatus. The buckling phenomena were observed in measurement by using steel pins with 2 mm in diameter. The investigation revealed that the wedge-shaped steel pin with 3 mm in diameter is mostly suitable for the simple static penetration test apparatus to measure deteriorated thickness for in situ wooden structure.