Determination of probabilistic models for resistance of Missouri bridges

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] As part of an overall project sponsored by MoDOT to calibrate the live load factor considering the typical bridge configurations in Missouri and state-specific traffic environment for the Strength I Limit State in AASHTO LRFD Bridge Design Specification, this thesis determines the distribution of resistance using the most up to date material parameters. The ratio actual to required (design) resistances of 100 selected representative bridges were determined. The analysis showed that almost all representative bridges were generally over designed according to current AASHTO standards. The resistance distribution was determined using material parameters updated with the latest research available. The resistance distribution calculation was achieved through process which used a Monte Carlo simulation. The results of the calibration show an increase in bias and decrease in coefficient in variation (COV) for all types of bridges evaluated with the most drastic changes being for the concrete and steel bridges. With these new bias and COV's, it is expected that the calibration will lead to a new lower live load factor for bridges, thereby possibly reducing the material cost of the bridge.