关键词: 国产落叶松, 国产齿板, 轻型木桁架, 有限元模拟, 承载性能

Abstract: [Objective] The load-carrying capacity of light wood trusses made with domestic Larix kaempferi was investigated in this study, which provided a scientific basis for the development of light framing wood construction in China.[Method] Six parallel chord trusses were fabricated with Larix kaempferi and domestic truss plates in two types. The ultimate load, stress distribution and failure mode of light wood trusses were studied by static load test, then the results were compared with that of finite element model.[Result] The results indicated that the ultimate loads of P and L type light wood trusses were 22.45 kN and 22.94 kN, respectively, which were 2.27 and 2.32 times as large as the design load. The variation coefficients of P and L light wood trusses were 7.9% and 7.1%. The failure mode of P type light wood truss was brittle failure, and the failure mainly occurred at the trisection points of truss where concentrated load applied and two ends where the diagonal member connected with the top chord. Out plane deformation always observed in the L type light wood truss when the load reached about twice of the design load, and it reached its load-carrying capacity when the lateral deformation was large enough. Through the SAP 2000 finite element simulation, it could be found that the joint deflection was almost consistent with the experimental results. The maximum deflection was in the mid-span and decreased gradually to both ends. The maximum bending moment and the maximum axial force were obtained at the trisection points of the truss and the ends joints connected with diagonal member, which was coincided with the experimental results.[Conclusion] Both of the two kinds of light wood trusses possess good load-carrying capacity under design load, but they show a certain degree of dispersion due to the wood heterogeneity and the processing types. The bearing capacity of L type light wood truss is higher than that of P type light wood truss, but it is more prone to lateral deformation for the out of plane,which stiffness is small and need to be strengthened in application. The P type light wood truss is more stable to practical application. Moreover, the weakest point of the parallel chord light wood truss exists at the end joint and the joint where concentrated load applied, which is consistent with the test results. SAP 2000 can be used to predict the stress and deformation of light wood truss in practical application.

Key words: domestic larch (Larix kaempferi), domestic truss plate, light wood truss, finite element simulation, load-carrying capacity