Load-carrying capacity of bolted joints of timber structures under static loading

Abstract

The paper is devoted to the study of the single loads effect on the load-carrying capacity and deformability of bolted joints of wooden structures. The introduction substantiates the relevance of the topic, gives a general description of the work, its scientific novelty and practical value. The authors propose an experimental technique for determining the load-carrying capacity of bolted joints when separating the deformation of the dowel hole and that of tensile strain of bolts. The operation of such joints was experimentally and theoretically investigated. The study resulted in statistical confirmation of satisfactory convergence between the theoretical data obtained by the proposed method and the experimental data of the authors, as well as the recommendations on practical application of the suggested calculation method were developed. The deformations of the bolt and the wood were experimentally separated, the diagrams of the deformation of the stretched zone of the bolt were made, and the percentage ratio of the bolt deformations to the total deformations of the entire joint was calculated. To describe the process of the bolt joint deformation due to the action of single static loads, it is recommended to use a hyperbolic dependence, which well reflects the relationship between the load-strain values (F-Δ). A new method is proposed for calculating the bearing capacity of bolted joints, which is based on the use of the initial modulus of strain capacity E0 and the strain capacity coefficient of the joint β. According to this technique, the load-carrying capacity of bolted joints with various geometric characteristics was calculated. The ratio of theoretical values of load-carrying capacity to the experimental values by, on average, 30% showed a greater convergence when compared to the load-carrying capacity calculated according to the current regulatory documents.