|
|
|
|
| FORTH ROAD BRIDGE UPGRADING OF MAIN TOWERS |
| CLIENT General Manager & Bridgemaster, Forth Road Bridge Joint Board C OST£10.3M The Forth Road Bridge with its 1,000m main span, was opened in 1964. The weight of the bridge is carried by main cables to the tops of 150m high towers. By 1985, the potential weight of traffic was over double the design load criteria and the towers were becoming overstressed. Permanent traffic restriction was not an option. After detailed analysis, the solution adopted entailed strengthening each tower leg by transferring part of the load at the tower tops and part at deck level. To strengthen each 5-cell tower leg, a new independent rectangular steel column was constructed in the leg’s central cell which measures just 3.6m by 1.5m. This was carried out by forming new access openings, feeding in each 3.2m long column section in turn at pierhead level, bolting it to its predecessor and then lifting the entire column assembly to allow the next section to be inserted below. When the full 150m height was reached, jacking was used to transfer part of the load by jacking it onto the new column, thus eliminating the overstressing to the leg’s original box structure. Jacking was done at night to minimise temperature and traffic effects. The entire project was successfully carried out without compromising the bridge’s safety or operation. |
|
| SERVICES RENDEREDPrincipal Designer - Civil and Structural
Engineering.
A WARDS1998 Winner - BCIA Award for Civil Engineering 1998 Saltire Society Design Award for a project advancing the art of Civil Engineering in Scotland 1998 Saltire Society Award for Construction Commendation |
|
|
