Project # 2: Measurement of Slip in Slip-Critical Connections with Different Specification Holes

One of the most discussed issues in the steel construction industry is that of slip-critical connections. In fact, the current design provisions might be too conservative, especially for long connections, thereby impacting the usefulness of bolted connections in those situations. While slip resistance has been investigated by numerous researchers, the issue of the actual amount of slip that occurs, as a function of the type of bolt holes used (i.e., standard versus oversize), has been studied very cursorily. This project aims at filling some gaps in the existing database of experimental tests, so that a better model can be devised for slip-critical connection behavior. This project will comprise experimental testing on single lap-splice specimens, with different hole patterns, and employing either standard (STD) or oversize (OVS) holes. Specimens will be tested cyclically in tension up to the design slip load, and then brought to failure monotonically. Variables include the actual location of the bolts in the holes (in general, in multi-bolt connections, clearances will vary from bolt to bolt), the amount of tension in the bolts during testing, and the friction coefficient of the faying surfaces. As a deliverable, this project will provide more data points for the existing multi-bolt experimental database, and data reduction with regression analysis will try to provide a predictive analytical model to reproduce the slip behavior of a multi-bolt connection.

Information about some of the facilities available and activities pursued (PDF 1.1 MB)