Proposed Method of Bolt Tightening for Seismic Friction‐sliding Connections

Abstract

Seismic friction sliding structural connections have been a focus of research and development for over four decades. One of the challenges in the design and implementation of these connections is achieving accurate and precise clamping force through bolt tightening. An overestimated clamping force can lead to premature sliding, while an underestimated force can delay the onset of sliding and cause excessive damage during a severe earthquake. Achieving a precise clamping force during installation and maintaining it throughout the structure's lifetime is important. Well‐designed Belleville Springs (BeSs) have been identified as a component in enhancing the seismic behaviour of these connections, by ensuring stable sliding behaviour and maintaining clamping force under both static and dynamic conditions. However, there is a lack of standardized methods for tightening bolts with BeSs to achieve a desirable level of bolt tension within the elastic range. This paper presents findings from bolt tightening experiments conducted on various configurations and BeS types and arrangements. Parameters such as imposed torque on the nut, BeS deflection, and nut rotation were analyzed. A nut rotation‐based method is proposed to ensure that the desired level of bolt tension is achieved in both on‐site and workshop applications.