e-mosty June 2017: Osman Gazi B. US Suspension. Hålogaland B. e-mosty June 2017: Suspension Bridges | Page 42

INSPECTION, PRESERVATION AND
REHABILITATION OF US SUSPENSION BRIDGES
Barry R. Colford, Vice President, AECOM
Shane R. Beabes, Associate Vice President, AECOM
Delaware Memorial Bridge
1. INTRODUCTION
The preservation of bridges provides different
challenges to the bridge engineer than those faced
when designing a new structure. These challenges are
likely to be more numerous and increase in scale and
complexity when dealing with long span cable
supported bridges.
several decades, twelve countries share over 90% of
the inventory, with China and the U.S. having the most,
followed by Japan, Norway and Canada (Figure 1).
In the USA, as is the case in most countries, these long
span bridges are almost always vital links in the
nation’s infrastructure and any failure, either at the
serviceability or ultimate limit state level is likely to
cause significant disruption to the public.
There are approximately 147 major cable suspension
bridges across the globe with a main span length
greater than 300m and over 50% of these major
suspension bridges were built after 1988. As a result
of the suspension bridge construction over the last
Figure 1: Global Cable Suspension Bridge Inventory (Spans > 300m);
Country by Number of Bridges
2/2017