Numerical Analysis of Initially Imperfect Pretensioned Bolted Connections

Abstract

Bolted steel end-plate rigid connections are used to transfer straining actions between different parts of steel structures. However, during structural assembly some of these connections are erected with initial imperfections in form of gap between connected parts. This paper investigates numerically initially imperfect end plate connections subjected to major external bending moment and major shearing force. A finite element model (FEM) is developed to represent the behavior of these initially imperfect connections. The presented FEM is verified against experimental testing presented by the authors in previous work. The effect of the gap angle between connected parts on the connection bending strength and moment-curvature relationship is investigated by varying its value from 1.5° to 6°. The results of initially imperfect connections are compared to those of perfect ones and it is concluded that the loss in bending strength of imperfect connections varies from 11.5 % to 22 % for gap angles from 1.5° to 6° respectively.