In this paper the results of SC Solutions’ performance-based evaluation of the as-built Unit 10 frame of the SR5 Lake Washington Ship Canal Bridge are presented. This unit is a three-span frame, located between bridge piers 24
and 27 on the north approach to the bridge and extends approximately 329 ft between expansion joints. A three dimensional model of the Unit 10 frame was developed using the computer program ADINA (ADINA User Interface Command Reference Manual, Volume 1: ADINA Model Definition, ADINA R&D, Inc., September 1997) and ADINA’s moment-curvature beam element. This paper discusses the method of evaluation of this frame, the material and member properties used for the ‘pushover’ analysis, properties of the as-built structure, and the results of capacity analysis of the as-built Unit 10 assembly. Several pushover analyses were performed, consisting of mass proportional and mode shape lateral load profiles. One of the mass proportional lateral load analyses was selected for presentation in this paper. This load pattern resulted in maximum shear forces in the frame columns. Following the pushover analysis, a nonlinear dynamic time-history ADINA analysis was conducted to estimate maximum displacements and to evaluate the performance of the bridge during a simulated earthquake ground motion.
