English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

During designing of reinforced concrete beams, it is important to know formulas from design codes and also to understand the physical meaning of a phenomenon. The applying the real deformation laws of materials is unusual and irrational for an engineer. In this paper proposed calculation method is a compromise between high accuracy and volume of costs. Generally, reinforced concrete structures at different deformation stages are considered: elastic, inelastic, when cracks occurred by using a cracked structural member at the destruction moment. On each of the stages it is important to properly determine the values of mechanical state parameters. Both in valid design codes of West Europe (EN 1992, etc.) and in East Europe (Russian SNiP, Ukrainian DBN, etc.) the stress distribution in a cross section is simplified and expressed by a triangle or rectangle shape. Such approximate is acceptable for many civil engineers, but it is non-universal and inaccurate, and sometimes may be incorrect. Nowadays the finite element method is very popular in a structural analysis. However, it has some deficiencies: an exact model may be complex enough; an approximation level of results depends on skills of a designer; each next problem needs to be re-modelled, etc. In design and expertise companies, in addition to finite element software, to verify the given results, more accurate analytical engineering methods are applied, one of which is presented by this paper, i.e. the ZI method. Ehsani et al. [1] experimentally investigated 4 reinforced concrete beams, two of which contained 2% of steel fibres. There were load-strain graphs presented. The authors compared the given results for structural members with different mechanical properties of materials. Slaitas et al. [2] during experiments tested 6 reinforced concrete beams. The flexural strengths were calculated by 7 various methods (one of which was the ZI method). There were bearing capacity reserves and crack depths investigated. A comparison was made. Some experimental investigations of this problem were early presented by Jokūbaitis et al. [3] and others [4]. In Golyshev et al. [5, 6] and Gvozdev‘s [7] a review of XX century analytical methods and experimental tests in East Europe is presented. Filatov and Suvorov [8] presented a stepperinteractive algorithm, which considers the stress state of a normal section, by using diagrams - of real materials. The damaged zone with cracks was also investigated. Modern computer algebra software was applied. The proposed decision is precise in load-history aspects, but it is complicated enough for an engineer. Raue and Timmler presented [9] a geometrically and physically non-linear model, which is based on the analysis of the potential energy. An example of a column under compression and bending was presented, taking into account the development of cracks. Such general model is difficult for the direct usage by engineers in practice, because of integration and optimization processes. The presented paper is an extension in the applied direction of monographs [10, 11] about the ZI method, key solutions of which are based on the classic engineering theory of the beam section stress/strain state (Fig. 1).

Investigation of Mechanical State of Reinforced Beams with Cracks by the ZI Method: Algorithm and Calculation Results