Ductility of Welded Steel Columns

AUTC project number: 410001

PI(s):

Mervyn Kowalsky (NCSU)

Funding:
  • US Department of Transportation (RITA)
  • Alaska Department of Transportation & Public Facilities
  • Start Date: Jul 1, 2010
  • End Date: Dec 31, 2012

Project Summary

This research, a joint effort between AUTC and North Carolina State University, is a continuation of an ongoing project that investigated bridge and marine structure design practices, aiming to identify improved connection design approaches to produce the necessary ductility and energy absorbing capacities required for satisfactory designs in Alaska. Through earlier testing, researchers not only proved what methods were inadequate (such as the current practice of fillet-welding the cap beam to the pile as well as an alternative welding methods) but also confirmed that a new method of using a plastic hinge-relocating concept was more successful. This method utilized a round steel column capital in which the top portion welded to the cap beam is thicker than the bottom thinner portion welded to the pile. The approach successfully reduced the inelastic demands of the cap beam weld, and forced the inelastic action to occur in the pile itself. Current research includes optimizing the new design to improve displacement capacity and ductility in bridge and marine structure design, as well as investigating additional connection designs proposed by ADOT&PF engineers. The research will result in a series of design recommendations consistent with the various levels of seismicity found within Alaska. The primary benefit will be the improved design and performance of steel bridges and marine structures containing similar connections.