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Torsional Capacity of Slip Joints with Polygonal Hollow Sections
Author(s) -
Bräutigam Katharina,
Knoedel Peter,
Ummenhofer Thomas
Publication year - 2019
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.1067
Subject(s) - flange , structural engineering , slip (aerodynamics) , collar , joint (building) , transmission line , engineering , aerospace engineering , electrical engineering
ABSTRACT Polygonal steel sections are widely used for lighting towers and are more and more adopted for transmission line towers. They convince with an inconspicuous appearance compared to steel lattice towers. Therefore, instead of flange connections “invisible” joints are preferred, such as slip joints. The European design rules for overhead electrical lines (1) cover the use of these joints very generally by a constant ratio of the overlapping length L and the section's diameter D . It is neither distinguished between load conditions nor between cross‐sectional shapes. The ratio value L/D = 1.5 is based on bending tests without regard to torsional moments. In the design of transmission line pylons, torsional loading occurs in the load case of a single‐side loss of a transmission line. Thus, there is a need to improve the knowledge on the load bearing effect of a slip joint connection within this special load case. In this paper the torsional capacity of slip joints is investigated to identify the capability of polygonal cross sections to carry this additional load, particularly in comparison with circular hollow sections. On the basis of numerical and analytical analysis, an adaption for the design of the slip joints is proposed.