|Name||Hungerford Bridge, London|
|Owner||Westminster City Council - with funding from various sources.|
|Cost Consultant||Davis Langdon & Everest|
|Contractor||Costain Norwest Holst Joint Venture|
|Contractor's advisor||Gifford and Partners|
|Latitude||N 51 30' 22"|
|Longitude||W 00 07' 13"|
|When||2002||Why||Footbridge over the Thames on same alignment as Charing Cross Railway Bridge|
|Links Charing Cross and South Bank Centre.||Site of I K Brunel's footbridge opened in 1846 then demolished in 1864 to make way for Charing Cross Railway.|
|The new bridge is in two parts.||One part is upstream and one downstream of the Charing Cross Bridge|
|How to read the bridge||Read more about the book metaphor.....|
|Overall type||Hanging - cable stayed.|
|Spans||5 main spans all approximately 50 to 53 m. with side spans of 36.9 m. and 20.2 m.|
|Towers/pylons||There is one A-frame 35m. tall and 5 masts at 25 m. They are tapered steel cylinders held at an angle by the stays. At the south end of the bridge each deck is suspended from a pair of pylons, one upstream and one downstream, supported on a new island. Because of concern about possible inundation of the London Underground tunnels the mast at the north end is out of the river and the foundations for the next mast are a hand dug shaft rather than piles.|
|Cables||28 Macalloy bar stays per pylon.
They were fabricated to preset lengths and the induced tensions checked by measuring their natural frequencies.
The multi-span cable-stay arrangement makes the structure multiply redundant. The tops of the pylons are complex because there are so many cables joining. Special spherical bearings were designed for both top and bottom of the masts for two reasons. Firstly they relieved any bending effects from temperature changes as well as creep and shrinkage. Secondly the masts could be designed as pin-ended struts. The pylon top fabrications are called 'angel wings' because of their shape.
Reinforced concrete 650 mm. deep. There is a simple stainless steel dowelled expansion joint at the south end of the A-frame
to allow londitudinal movement and rotation of the deck but resist lateral and vertical movement.
There is a fixed support at the north end. The bridge is fixed to the pier next to the south bank
with a second expansion joint at the bank.
The new bridge and the old railway bridge are apart so there is no additional load on the old structure but if here is a ship impact the two will act together to resist it through new precast concrete beams.
The bridge deck was launched incrementally in 50 m. lengths
Deck: Reinforced concrete slab
|Foundations||The bridge is on a busy waterway, next to a mainline railway and above several London Underground tube tunnels.
As a consequence the foundations were designed to withstand the impact of a ship using advice from the Port of London Authority.
Concern about a possible unexploded world war 2 bomb and the risk of inundation of the London Underground tunnels resulted in the foundations at the north end being 5 m. hand dug shafts. The piles for the other masts are 1.5 m. diameter.
|Grammar||Technically the bridge is a way of taking forces from up in the air down to the ground.
So imagine the flow of those forces through the structure.
Think of a truck standing on the brdge and how its weight is transmitted through the bridge to the ground.
Read more about hanging bridges.....
The dynamic behaviour of the bridge was studied in detail using computer modesl, wind tunnels tests and measurements on site. The deck is relatively wide, restrained at reasonably closed centres and made of concrete so the frequencies are out of the range of pedestrian footfalls.
Parker J S, Hardwick G, Carroll M, Nicholls N P, Sandercock D, Hungerford Bridge millennium project- London, Proc Inst, Civ. Engs.,
Civil Engineering, 156, May 2003, 70-77
Fletcher M S, Parker J S, Dynamics of the Hungerford Millennium footbridges, UK, Proc Inst, Civ. Engrs., Bridge Engineering, 156, June 2003 Issue BE2, 57-62