Adjustable Bolted Steel Plate Connection: Measured Behavior of Bolts during Field Installation and Numerical Parametric Investigation

Abstract

This paper presents an experimental investigation of bolt behavior in adjustable bolted steel plate connections during field installation and a numerical finite-element (FE) parametric investigation of the impact of (1) bolt diameter; (2) plate thickness; and (3) member flange thickness on the strains induced in the plates and bolts during field installation. The adjustable connection consists of prefabricated cold-bent plates that are further bent during field installation (via bolt tightening) to form moment-resisting joints between steel members. The connection is adjustable because the bolt-tightening field installation process changes the connection angle in situ to accommodate additional angles or manufacturing and erection tolerances. This paper presents the residual bolt surface strains, measured using the full-field photographic technique digital image correlation, providing unprecedented information on the behavior of high-strength bolts. A FE modeling approach for predicting strains in the plates and bolts is developed and validated against measured data. Parametric studies are then performed using the validated FE models with varying bolt diameter, plate thickness, and member flange thickness. Research results are relevant to any misaligned (i.e., nonflush) bolted connections, offering insight into strains from force fitting.