The research into fatigue fracture formulations for the Theory of Critical Distances (TCD) in concrete is advancing, with a focus on reducing the occurrence of fatigue failures in concrete structures. Despite design safety factors, concrete fatigue failures persist, and the associated fatigue tests are resource intensive. While TCD is known for its accuracy, it exhibits instability concerning variations in water-cement ratios in concrete mixes. The absence of standardized procedures further complicates fatigue testing, hindering research progress. This paper proposes a unified relationship between static and fatigue properties, streamlining fatigue characterizations through less laborious static tests. This research paves the way for Part B, which explores mathematical enhancements to this formulation. Together, Parts A and B aim to bridge knowledge gaps, offering a foundation for safer and more efficient concrete structures.