Direct stiffness model of slant connection under thermal and non-symmetric gravity load

• We study beam with slant connection under thermal and non-symmetric gravity loads.
• Damping of thermally induced axial force is due to end-plates friction and crawling.
• Before thermal effect the axial force depends on the distribution of gravity load.
• The use of friction bolt raises axial force and movement initiation temperature.

Conventional steel beams exhibit lower structural performance when subjected to thermally induced axial expansion. In this regard, the design of a connection plays an utmost essential role in restrained beams. Most existing studies on the thermal behaviour of connections have so far focused only on vertical end-plate (conventional) type. This paper describes therefore the elastic mechanical behaviour of a newly proposed beam with a slant bolted end-plate connection under non-symmetric gravity load in the presence of an elevated temperature by means of direct stiffness finite element modelling. The presented direct stiffness method is relatively easy and useful to evaluate the behaviour of a steel beam with slant end-plate connection of various dimensions due to temperature increase. The performance of slant end-plate connections, with a proposed capability of damping additional thermally induced axial force, is determined under two resisting mechanisms. First, by friction force dissipation between two faces of slant end-plate connection and second, by small upward crawling on inclined plane. The applicability of the current model is ensured through a satisfactory verification with the results from the experimental test. Departing from the good agreement, a series of design charts in terms of axial force and temperature that initiates end-plate crawling has been produced for various friction factors and slanting angles.