lugs, subjecting the lugs to bending forces as well as shear forces. With the diagonals not carrying the load they were intended to carry, extra stress was placed on the chords. Unequal loading of the angle blocks worsened the metal fatigue. The construction of the upper chord of the bridge was also poor. This chord consisted of five I-beams running in parallel. Having all five members end at panel joints actually weakened a bridge, so Howe trusses were built so that three ended at one panel connection and the other two at the next panel connection. As with the connection between diagonals and angle blocks, it was critical that there be no space between the I-beams and the lugs on top of the angle block because these lugs transferred axial forces to the next member. Space between the member and lug would reduce the effectiveness of this transfer and introduce shear stress to the lug. The problems with camber led to members of the chords being shortened and the lugs being shaved down, actions which introduced space between the lugs and the chord members. Construction workers used metal shims to fill the space between the lug and the chord members until a tight fit was achieved. Friction alone, rather than an active connection such as a yoke or bolt, kept the shims in place. For some years prior to the disaster, locomotive engineers reported hearing "snapping sounds" as their trains crossed the Ashtabula Bridge. This indicates that some shims had come loose and fallen off, reintroducing space between the chord members and angle block vertical lugs. This allowed members of the chord to thrust suddenly against the lugs, inducing even more metal fatigue. There is also an indication in the construction record that several chord members were misaligned. Even if their bearings had been flat, they would not have met the lugs completely. This, too, would have created uneven loading and worsened metal fatigue. Gasparini and Fields conclude that the bridge might have survived the loss of the lug had the chords and diagonals been made stronger through active continuous connection. Active continuous connection was not used on the bridge: The members of the chords were connected to angle blocks at only every other panel, the five beams making up each chord did not have a continuous interconnection between them, and the none of the parallel I-beams making up the