MPC
Project Details

Title:	Moment-Rotation Tests of High Performance Steel I-Girders
Principal Investigators:	Bryan A. Hartnagel
University:	Colorado State University
Status:	Completed
Year:	1999
Project #:	MPC-177

Abstract

Bridge designers now have a new choice of steel available for consideration when planning a bridge. High performance steel (HPS) grade 70W is currently available for bridge construction. The HPS70W was developed under a cooperative research program between the Federal Highway Administration (FHWA), the U.S. Navy, and the American Iron and Steel Institute (AISI). However, current bridge design provisions limit the flexural strength of girders with yield strength greater than 50 ksi (350 MPa) to the yield moment capacity. The flexural capacity of similar bridge girders designed with yield strength less than or equal to 50 ksi (350 MPa) is equal to the plastic moment capacity if certain restrictions are met. Further, if the designer chooses, an inelastic analysis of the girder is allowed with steel yield strengths less than or equal to 50 ksi (350 MPa). Inelastic analysis and design methods offer larger cost savings compared to the elastic analysis provisions. Even with the disadvantage on the flexural capacity, HPS is still competitive with Grade 50 steels because of material savings obtainable with HPS. If these restrictions could be lifted or even relieved, the use of HPS would provide significant cost savings.

Project Deliverables

• [Final Report] Pier Moment-Rotation of Compact and Non-Compact HPS70W I-Girders — MPC-03-148