Features of determining the estimated length of positive arches made of laminated wood

Abstract

The issue of loss of stability of arched structures is very important in engineering practice and design. This issue is especially key from the point of view of reliability and safety and economic losses, since structures of this type are usually used in buildings with a consequence class of at least CC2. [1].Laminated timber arches are long-span com-pression-bent elements in which the loss of stability plays a major role in determining the cross-sectional dimensions. In contrast to beams, an arch has a much larger ratio between the length of the element and its cross section, which in turn increases the risk of loss of stability. The loss of stability of an arch and its cor-rectly determined design length are directly related. The design length is defined as the value at which an arch can lose its stability under the influence of external loads. The main aspects of this relationship are: the value of the design length of the arch; mechanisms of loss of stabil-ity; dependence on the material and shape; ac-curacy of engineering calculations.It should be noted that recommendations for determining the design length of an arch are contained exclusively in the methodological lit-erature and outdated regulatory documents, such as [7]. In the latest current regulatory doc-ument [8], this issue is resolved by checking the strength and stability of the element, without limiting the flexibility. Since the flexibility of the element depends on its design length, the is-sue of determining this parameter remains open and relies directly on the design engineer, or rather, on his experience and competence. This issue is very relevant, given that a minor error in determining the design length significantly affects the results of testing compressed-bent elements.As a result of the work carried out, we analyzed the determination of the design lengths of hollow arches with different shapes and types of loading using two calculation methods: analytical formulas and the finite element method using the LIRA-SAPR-2019 software. Based on the calculations, recommendations for determining the design lengths of arches are given.