Three-stage analysis of adjustable steel props with load-dependent support conditions according to EN 1065

Adjustable telescopic steel props (ATSPs) are innovative temporary supports widely-used in construction sites. In Turkey, ATSPs should be designed based on EN 1065, which requires a three-stage nonlinear analysis involving rather complex calculations. Accordingly, almost all companies producing ATSPs in Turkey prefer either conducting tests or receiving technical support from international companies. This study aims to derive differential equations required to determine the actual characteristic strengths of ATSPs using the calculation method defined in EN 1065 and solve them analytically using the load dependent support conditions. The use of the derived analytical solutions for the determination of the strength of a typical ATSP is also illustrated in the paper. It has been shown that there are four fundamental limit states that should be checked in each stage of an ATSP analysis: (i) flexural failure of the tubes, (ii) bearing failure of the inner tube, (iii) shear failure of the pin and (iv) elastic buckling of the prop. If the analysis ends without reaching any of these limit states, it is assumed that the support of the ATSP has failed. The analytical solutions derived in this study are expected to guide ATSP design and contribute to future studies on optimal prop design.