Collapse of U.S. 35 Highway Bridge, Point Pleasant, West Virginia, December 15, 1967 (HAR-71/01)

Read from the scan by GLM-OCR; expect the odd misread word.

its north edge. The top of the north leg of the Ohio tower was about eight feet east of its normal position. The north truss was generally disintegrated between panel points 21 and 30. The portion of the north truss between panel points 15 and 20 had begun to tear loose from the chain due to the loss of support at the toggle link at panel point 15. The portion of the truss east of panel point 30 was momentarily restrained by its cantilever action from the West Virginia tower and was deflected downward at its west end by perhaps five or six feet.

The top of the south leg of the Ohio tower was now about 30 feet north of its normal position. The south chain was still intact and was exerting strong northward components on the south Ohio chain bent post, the south truss in the Ohio side span and the main span, and the south leg of the West Virginia tower. The effect of this latter component produced a permanent bend in the upper portion of the south leg of the West Virginia tower, the axis of the bending moment observed in the permanent distortion above the portal bracing being approximately along a northeast/southwest line. The northward component exerted at the upper chord level of the central portion of the south truss in the main span caused further rotation of the deck system in this portion in a counterclockwise direction (viewed from the west).

The northerly edge of the West Virginia side span was still being pulled upward by the increase in cantilever moment exerted by the north truss in the main span. The south edge was beginning to fall due to the reduction in eastwest tension in the south chain.

In the Ohio side span, the vertical deflection at panel point 7 of the north truss had reached about 16 fcet. The combination of the eastward motion of the west half of the span and the rotation about L0 due to the vertical deflection has again tightened the portion of the north chain between the north chain bent post and the anchorage. It is believed that very little cantilever moment was achieved, due to the fact that the chain bent post was already nearly completely separated at point L0. It is likely that the resultant shock, combined with the northerly components of lateral force being exerted on the north truss through the floor system and the northward twist of the span, resulted in the final separation of the post with sufficient westward velocity to account for its final resting place. Since there is evidence (Reference 35, installment 1, p. 36) that the bottom of joint L0 struck something during the collapse, and the northeast corner of the coping on the chain bent pier is damaged, it is speculated that L0-L2 caught and pivoted at this point, throwing joint L2 farther to the north. It is believed that the rupture of the gusset plate at panel point U7N also took place at this time due to this shock, which also completed some of the partial fractures at L2, L4 and L6N.