Influence of strength reduction of timber in fire on structural resistance

Abstract

Present research was dedicated to investigation of strength of timber structures in fire conditions. Two kinds of timber specimens were used: oak and pine. Investigation included the following static test: tensile strength, compressive strength along fibres, compressive strength across fibres and bending strength. Specimens were tested under the following temperatures: 50°C, 100°C, 150°C, 200°C and 230°C. The result shows that pine specimens have better properties over entire temperature range in case of tensile and bending strength tests. Also for these strength types oak specimens shows a higher strength reduction rate than pine specimens. Whereas oak specimens have better properties over entire temperature ranges in case of compressive strength across fibres. Based on statistical analysis the linear expression for strength reduction coefficient was proposed.