Bridge Collapse Cases/Falls View Bridge

From MatDL: Failure Cases Wiki
Jump to: navigation, search

Contents

Falls View Bridge, 1938

Introduction

Construction of the Falls View Bridge started in 1895 and was completed in 1898. The structure was a two-ribbed steel arch of 256 m (840 ft) span. Each rib was a two-hinged truss arch with a uniform depth of 7.9 m (26 ft) and a rise of 45.7 m (150 ft). The chord members were plate and angle box sections. Most of the other members were steel sections with lattice connections. The original wooden deck of 14 m (46 ft) width carried two-track street railway and was supported by unbraced single spandrels. The four concrete and stone foundations rested in solid rock about 12 m (40 ft) above the normal water level.

The arch bridge replaced a suspension bridge which was built in 1868 with wooden towers and floor system. Later the wooden elements of the structure were changed to steel, and on January 10, 1889 the entire deck was carried away by a windstorm. The structure was repaired and opened to traffic, but was judged to be inadequate and it was decided to build an arch bridge.

Falls View Bridge at Niagara Falls (adapted from Wikipedia Commons)

Collapse

On January 27, 1938 the Falls View arch bridge, just below the Niagara Falls, was torn from its foundation as a result of the worst ice jam on record. The bridge was a tourist attraction, known as the Honeymoon Bridge.

The ice jam was formed during the night of January 25, 1938 and by the following afternoon it had piled up to a height of 15 m (50 ft) above normal river level, or 3 m (10 ft) above the pins supporting the arch. The ice pack moved downstream like a glacier for about 122 m (400 ft) covering at least 9 m (30 ft) of the upstream truss, causing the failure of many of the bracing members. Shortly thereafter the structure was closed to traffic. The movement of the ice pack was halted, but the upstream truss continued to move very slowly downstream accompanied by further buckling and failure of secondary members. On the afternoon of January 27, the buckled section of the lower chord broke with loud report and the bridge collapsed. The bridge was replaced by the Rainbow Arch, a fixed arch rib of 290 m (950 ft) span.

Lessons

This is a very unusual case where the principal cause of the failure was the proximity of the ice mass to the structure and the flexibility of the structure. Although it is not always possible to design for unusual natural phenomena, the foundation of bridges should be protected where possible.

Other Falls View Bridge Websites

Photos of the Honeymoon Bridge Collapse

Falls View Bridge at Wikipedia

Honeymoon Steel Arch Bridge Article at Niagara Falls info.com

Honeymoon Bridge at Structurae


References


Return to List of Case Studies (chronological)
Return to List of Courses
Return to Case Studies Project Main Page
Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox