REIDsteel - Design and construction of standard steel stayed bridges for highways and roads

REIDsteel - DESIGN AND CONSTRUCTION OF STANDARD STEEL STAYED BRIDGES FOR HIGHWAYS AND ROADS

The construction and design of REIDsteel stayed bridges means that the effective span is 35-100m with one tower and 70-200 m with 2 towers.

The Carriageways are 2-lane. They are 7.3m wide between crash barriers.

Our stay bridges will have local Reinforced Concrete decks 0.25m thick, placed on our lost formwork decking with no propping needed. They can have 0.05m of surfacing.

They have three levels of steel crash barrier on both sides of the carriageways so that neither trucks nor their payloads can hit or damage the steel stays.

The stayed bridge decks are carried by a series of sloping stays from a tower at the 'home' end of the bridge; or from towers at both ends. Several stays at different angles go from the top of the tower down to the deck. These towers are stabilised with a bracing system between them above 6m clear of the carriageways. The bridge stay loads are resisted by stays on the land side of each tower going down to substantial anchor blocks.

The stay bridge decks are cambered from side to side using pre-cambered steel transoms; and slightly cambered from end to end using the adjustment of the stays.

There are two walkways, both outside the main trusses, 1.2m wide, with handrails outside. The pedestrian, handcart and cycle traffic using them is protected from the vehicle traffic by the crash rails and main trusses.

The decks of the walkways are local reinforced concrete 0.125m thick placed on our lost formwork decking.

The bridge steel is entirely bolted together using regular high strength tension and shear bolts. There are no friction grip bolts. Most of the main connections are end-plated. Adjustment is by means of steel packs which can be inserted between end plates.

The bridge steel is all in pieces which can easily be transported in 20ft or 40ft containers, or on regular road vehicles to the construction site.

We design our stayed bridge to British Standard BS 5400 for 2 lanes of full highway loading, and for 30 units of HB loading, equivalent to an occasional 120 tonne truck. All the structural design is in house by REIDsteel.

All the stay bridge steel work is hot dip galvanised 85microns, 610gm/m2, for long low maintenance life.

There are two arrangements possible: either the towers and the anchor block are on one side only, with a stayed bridge stayed only from one side of the gap and with a short simply supported link at one end: or there can be towers and anchor blocks at both ends, with a simply supported link at the centre of the span. The first step is the erection of the abutments, anchor blocks, towers and back-stays. Then the first segment of deck is erected, and the first transoms bolted between them. A railway is built on these transoms, and on the railway an erection gantry. The erection gantry permits the addition of the steel stays and then further extensions of the bridge deck, and further stays. For a bridge with towers at both sides, an erection 2 erection gantries may be used at the same time.

The bridge will sit on our steel bearings on your abutments. Expansion joints for the roadway are provided at both ends of the simply supported link section.

The erection gantries are re-usable on other bridges of the same span.

If you choose to use REIDsteel for the design and construction of your bridge our work carries a ten year warranty.

UTILISATION:

A Stayed Bridge is more expensive than a through truss bridge. But if it is not possible to get into the gap, (because of a deep canyon, or a fast flowing river); and if it is not possible to cantilever launch the bridge, (because there is not enough straight approach) (but we still need about 35% of the main span behind the one tower, (or 18% of the span for a 2 tower bridge); or if the span is too big (greater than about 100m); or if it is not possible to access the far side with heavy loads and equipment); or even if there is a requirement for a big, visible structure: then a Stay Bridge may be the right choice. Of course stayed bridges cannot be widened, other than building another one next to the first.

To find out more about your Stayed Bridge specific requirements, please complete our Highway Bridge Enquiry Form.