Fig. 3

Cross-section of the beams and columns used for determining the instability factors \( k_{c}^{G} \) and k _c. a Wooden rectangular cross-section. b Wooden circular cross-section. c Wooden narrow I-section. d Wooden narrow box cross-section. e Wooden wide I-section. f Wooden wide box cross-section. g Narrow I-section with a web made from wood-based material. h Narrow box cross-section with walls made from wood-based material. i Wide I-section with a web made from wood-based material. j Wide box section with walls made from wood-based material