MacDonald River bridge, St Albans facts for kids
Quick facts for kids MacDonald River Bridge |
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MacDonald River Bridge in St Albans, in 2009
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| Coordinates | 33°17′39″S 150°58′21″E / 33.2942°S 150.9726°E |
| Carries | Main Road |
| Crosses | MacDonald River |
| Locale | St Albans, City of Hawkesbury, New South Wales, Australia |
| Other name(s) | Norton Bridge |
| Owner | Roads and Maritime Services |
| Characteristics | |
| Design | Truss bridge |
| Material | Timber |
| Pier construction | Tapered cylindrical iron, with metal cross bracing |
| Total length | 116.1 metres (381 ft) |
| Width | 4.6 metres (15 ft) |
| Longest span | 36 metres (118 ft) |
| Number of spans | Two |
| Piers in water | Two |
| History | |
| Engineering design by | Ernest de Burgh |
| Constructed by | John Ahearn & Son, Burwood |
| Construction begin | 1901 |
| Construction end | 1903 |
| Construction cost | A£7290 6s 11d |
| Official name: St. Albans Bridge over MacDonald River; St Albans Bridge; deBurgh Truss Bridge | |
| Type: | State heritage (built) |
| Designated: | 20 June 2000 |
| Reference #: | 1480 |
| Type: | Road Bridge |
| Category: | Transport - Land |
| Builders: | John Ahearn & Son, Burwood |
The MacDonald River Bridge is a special road bridge in St Albans, Australia. It carries St Albans Road over the beautiful MacDonald River. This bridge is also sometimes called Norton Bridge. It was designed by a famous engineer named Ernest de Burgh and built by John Ahearn and Son. Because of its history and design, it's listed on the New South Wales State Heritage Register, meaning it's an important part of the state's history. The bridge is owned by Roads and Maritime Services, a government agency in New South Wales.
Contents
A Bridge Through Time
Timber bridges were super important for roads in New South Wales a long time ago. Before these bridges, crossing rivers was often tricky and dangerous, especially when it rained. This made it very hard and expensive to move goods like farm produce or mining materials. Only really valuable items, like wool, could afford the high costs of transport.
The NSW Public Works Department loved using timber for bridges from the mid-1800s to the early 1900s. This was because timber was cheap and found locally. The government at the time didn't have much money. They wanted to build as many roads and bridges as possible for the lowest cost. This meant they couldn't use iron or steel, which had to be brought in from England.
Ernest DeBurgh's Design
Ernest de Burgh was a leading engineer for the Public Works Department. He was a very important person in New South Wales in the early 1900s. He designed many bridges, including the special "DeBurgh truss" type.
Building the MacDonald River Bridge
The MacDonald River Bridge in St Albans was built between 1901 and 1903. It replaced an older bridge that was no longer safe. The builders were John Ahearn and Sons from Burwood. It cost about A£7290, which was a lot of money back then!
The bridge opened in February 1903. People said it was "the largest composite truss span without overhead bracing yet erected in the state." This means it was a very impressive and advanced bridge for its time. It was named "Norton Bridge" to honor John Norton, a local politician who strongly pushed for the bridge to be built. However, most people today call it the MacDonald River Bridge.
Bridge Features
The St Albans bridge is a special type of timber truss bridge called a DeBurgh truss. A truss is like a strong framework of triangles that makes the bridge very sturdy.
How the Bridge is Built
The bridge has two main timber truss spans. Each of these spans is about 36 meters (118 feet) long. A "span" is the distance between two supports. There are also three shorter sections at one end and one at the other, leading up to the main part of the bridge.
The total length of the bridge is about 116.1 meters (381 feet). The main spans are held up by two strong, round iron piers (supports) in the water. These piers have metal bars crossing between them for extra strength.
Driving Across the Bridge
The bridge has one lane for cars. It's about 4.6 meters (15 feet) wide. Most of the bridge has a metal guard rail called an Armco rail. Some of the shorter sections at the ends have a timber post and rail guard rail.
Why This Bridge is Special
The St Albans Bridge was finished in 1902. It's an early example of a DeBurgh timber truss road bridge. In 1998, it was still in great condition!
Historical Importance
This bridge is important because it shows how the road network in New South Wales grew. It also shows how people in NSW started to accept American bridge designs. And, of course, it's linked to Ernest de Burgh, the brilliant engineer who designed this type of truss.
DeBurgh trusses were a big step forward in bridge design. They were the fourth type in a series of five different timber truss designs used in NSW. Ernest M. DeBurgh adapted the American Pratt truss design. His DeBurgh truss was one of the first to use a lot of steel and iron. This was a big deal because steel and iron were expensive, and the government usually preferred cheaper timber.
Design and Beauty
The bridge shows off the amazing technical skill of its design. You can clearly see all the parts that make it strong. It also looks beautiful in its natural setting. With its fancy iron piers, the bridge has a lot of aesthetic (visual) significance.
Community Connection
The people who live in St Albans really value this bridge. It's near a popular pub and a common stop for tourists visiting from nearby Sydney. So, many visitors also appreciate the bridge. Timber truss bridges are very noticeable to people traveling by road. New South Wales was even called the "timber truss bridge state" in the past. This means these bridges are important to many travelers in NSW.
Technical Significance
The bridge is technically important because it's a DeBurgh truss. It represents many major technical improvements in timber bridge design made by the Public Works Department. The St Albans bridge has the largest DeBurgh truss spans ever built, which makes it even more technically significant.
Rarity
This bridge is quite rare in the Sydney area. It also has some unique technical features that make it uncommon.
A Great Example
The MacDonald River Bridge is an excellent example of a DeBurgh truss bridge. It shows all the main features of this type of bridge.
