Structure and Analysis Bridge Design brief
Moh-993
WhatisaBridgeRevA.pptx
What is a Bridge? You need inspiration…perhaps!
A bridge is just a Beam!
Functional! Timber sleeper bridge Pembrokeshire coast path
Rock and timber pole bridge Orgiva - Spain
Clapper Bridge Dartmoor
Queen’s College Mathematical Bridge
West Quay Footbridge, Southampton
The ‘Horn’ Bridge Bristol
Girder and Frame Bridges
The Plate Girder
Tenby - rail bridge Plate girder - a deep beam
Tenby - rail bridge Plate girder - a deep beam
Two flanges
One web
4 Fillet welds
The Plate Girder
Composite Plate Girder
Bearing stiffener
Composite Precast Planks
Composite Beam Innovation…
The PreCoBeam (Prefabricated CompositeBeam) solution is a new bridge construction method. It is an example of an economic bridge solution using
hot-rolled beam sections and a high degree of prefabrication.
The method employs a hot-rolled steel beam section, oxycut longitudinally into two
T-sections with a special shape. This shape of the web works as a continuous shear connector, allowing shear connection between steel profile and the concrete slab without the use of welded shear studs, and therefore without any site welding.
Composite Beam Innovation…
DLR London Continuous - haunched plate girder
Note: Bearing stiffener
DLR London Plate girder
Girder cross bracing
Finite Element Modelling – Bridge Structure
Predicted deflections under load (exaggerated scale)
Finite element modelling is being used to analyse the behaviour of this complex structure under static, dynamic and accidental loading.
The Box Girder
Box Girder Forms
Open top - ‘bathtub’
- used with composite
concrete deck
Trapezoidal box - all steel
Rectangular box - all steel
Avonmouth - continuous - haunched - twin steel box
Avonmouth Site visit ‘98
Inside the Box
‘Bathtub’ Box
Inside another Box
Inside another Box!
The Steel Box Portal
Luxembourg
- steel box portal
Luxembourg
- steel box portal
Twin steel box construction
The Lattice Girder
(or Truss)
Hotwells Footbridge Bristol
SFD
BMD
Deventer - rail bridge Warren truss
Amberley Footbridge Virendeel girder
The Arch
Calatrava - ‘sickle arch’
Salobreña – Sunny Spain!
Salobreña – Sunny Spain!
Compression rib
Tension hangers
Deck Tension Tie
Slough Footbridge - tied arch
Enschede road bridge - tied arch
Wales - River Usk - lattice arch
Bristol
- lattice arch
Garabit viaduct
Garabit viaduct
Garabit viaduct
Birchenough Bridge
Zimbabwe 1935 329 m
Victoria Falls Bridge – Zambezi River 1905
Cable-stay
Calatrava - Alamillo cable-stay
Puente de Alamillo
Calatrava
Calatrava - ‘Trinity’ - Salford
The Oresund ridge
Denmark
Rotherhithe Bridge, London – Concept Design Proposals
Second Severn Crossing
Dual-plane ‘Harp’ system
Deck can be more flexible than in a suspension bridge.
The load path is shorter and stiffer.
Plate girder or lattice girder
Plate girder or lattice girder
Concrete deck slab
Cable – stay deck construction:
A simple ladder arrangement of beams…
Edge stringer
Cross girders
Deck span
Cable-stay at cross girder locations
- Not necessarily at each cross girder
- Deck erected in pre-fabricated sections
Cable stays!
Rhine - Cable stay
Cambridge Cycleway Cable-stay and warren truss ‘tube’
Bathurst Basin Footbridge Bristol
The Wye Bridge
The Wye Bridge…...
Single plane - ‘Harp’ system
Quite uncommon - requires a deck similar to a suspension bridge
to provide adequate torsional stiffness.
The Wye Bridge…...
Cable-stay = ‘Stiff’ Load Path
The Wye Bridge…...
Internal Forces
Tension
Compression
Compression
Compression
In contrast to the suspension bridge, significant compressive
forces develop in the deck.
These are greatest at the pylon locations.
The deck is relatively flat.
Salobreña – Sunny Spain!
Single plane hanger
system – requires a
torsionally stiff deck
Temple Meads Footbridge
Temple Meads Footbridge
Temple Meads Footbridge
Lateral bracing
Temple Meads Footbridge
Temple Meads Footbridge
London – somewhere….
Czech Republic – somewhere…
Portland Atrium
- fink truss
The Fink Truss
- a type of cable stay system
Suspension
The Severn Bridge
...under the Severn Bridge
Suspension = ‘Flexible’ Load Path
The deck of a suspension bridge is
curved in elevation and acts in
bending, shear and torsion.
Compression is not
significant compared to
cable-stay bridges.
Tension
Tension
Compression
Internal Forces
Modern Suspension bridges
- typically use steel box girder
deck construction
Box Girder - torsionally stiff
The Chirundu Bridge - Zambezi River between Zambia and Zimbabwe