  This study introduces a simplified model for bridge-vehicle interaction for
medium- to long-span bridges subject to random traffic loads. Previous studies
have focused on calculating the exact response of the vehicle or the bridge
based on an interaction force derived from the compatibility between two
systems. This process requires multiple iterations per time step per vehicle
until the compatibility is reached. When a network of vehicles is considered,
the compatibility equation turns to a system of coupled equations which
dramatically increases the complexity of the convergence process. In this
study, we simplify the problem into two sub-problems that are decoupled: (a) a
bridge subject to random Gaussian excitation, and (b) individual sensing agents
that are subject to a linear superposition of the bridge response and the road
profile roughness. The study provides sufficient evidence to confirm the
simulation approach is valid with a minimal error when the bridge span is
medium to long, and the spatio-temporal load pattern can be modeled as random
Gaussian. Quantitatively, the proposed approach is over 1,000 times more
computationally efficient when compared to the conventional approach for a 500
m long bridge, with response prediction errors below $0.1\%$.
