Structural Fuse Concept for Bridges

Graduate Students: Samer El-Bahey

Principal Investigator: Michel Bruneau

Project Completion Date: 07-01-2009

The concept of designing sacrificial elements to dissipate seismic energy while preserving the integrity of the structure’s other main components is known as the structural fuse concept. Few implementations of the structural fuse concept have been rigorous in emphasizing easy and complete replaceability of the sacrificial elements and absence of damage to the primary load-resisting structural system. Here, the concept is applied to an innovative multi-column accelerated bridge construction (ABC) pier concept. Different types of structural fuses are investigated to compare the effect of each on ABC bridge bents.

A three span continuous bridge prototype having two twin-column pier bents with fixed base spaced at 36m (120 ft) and 9m (30 ft ) tall, was designed according to the AASHTO LRFD bridge design specifications. Its piers were designed using double composite rectangular columns using Bi-Steel panels and structural fuses. Two corresponding scale models were developed and were tested at the SEESL at the University at Buffalo. The two specimens were designed for a maximum horizontal force of 400kips. Four quasi-static tests were performed (two per specimen). For the 1^st specimen, Steel Plate Shear Links (SPSLs) were installed between the columns as a series of structural fuses. Testing was performed up to a drift corresponding to the onset of column yielding, then the SPSLs were then removed and replaced by a continuous web plate (similar in concept to the infill of a Steel Plate Shear Wall) and the specimen was re-tested. Then, the other specimen was installed and tested utilizing Buckling Restrained Braces (BRB) as a series of structural fuses. The BRB’s were then removed and bare frame cyclic test was performed until reaching failure of the columns.

This project was supported by the Bonneville Power Administration (BPA).