Shear characteristics of interfacial timber-to-timber joints for log-wall structures with large-diameter beech dowels: Experimental and theoretical evaluation

The construction of log-wall generally involves the assembly of glulam members with tongue and groove connections. However, significant relative slip was observed between glulam members under lateral loads, resulting in low lateral stiffness of log-wall. This simplified connection greatly hinders its application in multi-story buildings. To address this problem and enhance the interfacial constraints and overall lateral stiffness of log-wall, the large-diameter beech dowels were innovatively introduced to connect glulam members. This paper investigated the shear characteristics of the connection joints by push-out tests. The key parameters investigated were wood species, dowel spacing, number of beech dowels and prestress levels. The test results demonstrated that the failure mode was predominantly a combination of bending and shear fracture failure of beech dowels. The introduction of large-diameter beech dowels was found to significantly enhance the shear properties of the joints. In addition, the application of prestressing technology also significantly increased the ultimate load and initial slip modulus by 36.7 % and 138.8 %, respectively. The effect of the dowel spacing on the shear properties is mainly determined by the lateral constraints, and the effect is less than 10 %. Furthermore, the theoretical solution of the dowel shear capacity was predicted according to the European Yield Model (EYM) and the slip modulus was determined based on the beam-on-elastic-foundation theory (BEFT). The theoretical values showed good agreement with the experimental results. •Innovatively application of large-diameter beech dowels for log-wall structures.•Failure modes and shear properties of timber-to-timber joints with beech dowels were studied.•Effects of wood species, dowel spacing, number of beech dowels and prestress on shear properties.•Theoretical formulas were used to predict the shear capacity and initial slip modulus.