Bridges are essential infrastructure components and perform an important role by allowing for uniform traffic flow. Bridges experience a decrease in efficiency and sustain damage from various factors over time, which can result in severe threats to the integrity of infrastructure, particularly fatigue damage that leads to unexpected failure. Periodic inspection is crucial for detecting early indications of damage and prolonging the structural integrity. Orthotropic steel decks (OSDs) consist of a steel deck plate that is welded to ribs and stiffeners, creating a strong and lightweight structure. The orthotropic design enables the deck to carry loads efficiently while reducing overall weight. OSDs are prone to fatigue damage, especially at deck-to-rib (DTR) joints caused by dynamic loadings. In this paper, fatigue damage in the early stage has been evaluated through an experimental investigation. All the experimental protocols adhere to the Australian Standards. Fatigue evaluation of OSDs under realistic traffic conditions revealed varying fatigue life across critical locations. Strain-cycle graphs revealed that areas subjected to higher loads experienced accelerated strain accumulation, indicating fatigue-prone locations. Additionally, linear potentiometers (LPs) analysis highlighted varying fatigue life across critical locations, pinpointing specific design strategies for improved durability and performance.