Analysis of Mechanical Properties of Four-Section Composite Columns of Pinus sylvestris var. Mongolia of Ancient Wooden Architecture under Axial Compression Load

Abstract

In order to study the influence of the cross-sectional area of hidden dovetail mortise (cross-sectional area of the projecting part after dovetail installation is completed) and length of tenon joint dimensions (axial length with dovetail installation completed) on the axial compressive behavior of four-section composite columns, the length of tenon joint dimensions was set to 30 mm, 60 mm, and 90 mm, and the cross-sectional area of hidden dovetail mortise was set to 360 mm2, 562 mm2 and 810 mm2 as experimental variables. Some column models were designed and fabricated accordingly. Axial compression tests were conducted to observe failure modes, load–displacement curves, stress–strain curves, load–strain curves, ultimate bearing capacity, and stiffness of the timber column. The results of the study show that the influence of dark drum mortise and tenon cross-section size and tenon length on the axial compressive mechanical properties of four-section jointed wood columns should not be ignored; the load-carrying capacity of the wood columns decreases with the increase in tenon cross-section size and decreases with the decrease in tenon length; the stability decreases with the increase in tenon cross-section size; and the deformability of specimens of the tenon length group as a whole is obviously superior to the tenon cross-section area group. The increase in ultimate load-carrying capacity of the columns was 7–11.9% when the concealed cross-sectional area of the hidden dovetail mortise was reduced in the range of 30.5–55.5%. When the length of the tenon joint dimensions was reduced from 90 mm to 60 mm, its ultimate bearing capacity decreased by 9%; when it was reduced from 60 mm to 30 mm, its ultimate bearing capacity was almost unchanged, which indicated that after the length of tenon joint dimensions was lower than 60 mm, the influence on the ultimate bearing capacity of the column was more negligible. It is recommended that the length of tenon joint dimensions of 60 mm should be taken as the design standard value of the ultimate bearing capacity for the four-sectioned composite columns of the Pinus sylvestris var. Mongolia (PSVM).