At our February 2017 Dinner Meeting, Lawrence Keenan of Hoffman Architects presented an analysis of fatigue failure of precast double-tee connections due to high cycle vehicular loading to a packed house. The presentation included an in depth look at why welded tee-to-tee flange connections are poorly configured to withstand high-cycle vehicular loading and violate Building Code requirements for fatigue resilient design. Attendees learned how to identify fatigue failures and examine Building Code requirements and industry standards as they apply to high-cycle fatigue performance of commonly used details. Parameters discussed included connection configuration, cycle analysis, weld type, effective weld size, Allowable Stress Range, Stress Category, crack initiation point, and allowable design capacity. The most commonly used connection detail, consisting of fillet welds on a flat erection bar, was analyzed to demonstrate application and implications of AWS and AISC Code provisions. Scanning electron micrograph images of fractured welds were analyzed to demonstrate fatigue failure mechanism. Consequential effects of fatigue failure and considerations for optimized fatigue-resistant connection design were also discussed.