Experimental and Analytical Investigation of Bridge Piers Having Structural Fuses and Bi-steel Columns

Bridges are built in a variety of locations, many of which are susceptible to earthquakes. These bridges must be built to achieve the objectives of both accelerated bridge construction (ABC) and rapid return to service following a disaster. 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. The structural fuse concept considered here for seismic resistance was developed and experimentally validated for implementation in a composite multi-column pier using double composite rectangular columns of Bi-Steel panels. The concept is applied to an innovative multicolumn accelerated bridge construction (ABC) pier concept. Different types of structural fuses are investigated to compare the effect of each on ABC bridge bents. Two corresponding 2/3 scale models were developed and were tested at the Structural Engineering and Earthquake Simulation Laboratory (SEESL) at the University at Buffalo. The two specimens were designed for a maximum horizontal force of 400kips. Three quasi-static tests were performed. For the 1st 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 to investigate the effectiveness of adding the fuses in dissipating the seismic energy, then testing continued till column failure. Then, the other specimen was installed and tested utilizing Buckling Restrained Braces (BRBs) as a series of structural fuses. The BRBs were then removed and bare frame cyclic test was performed until reaching failure of the columns.