David Collings BSc CEng FICEMaking the complex simple

LONG SPAN BRIDGES

Making the complex simple.

Summary Presentation by

David Collings BSc CEng FICE

University of Surrey, UK; Feb 2015.

David Collings BSc CEng FICEMaking the complex simple

Figure 1

Long Span Bridges

Arches, trusses and box girder bridges have

reached the economic limits to span, the

maximum spans in figure 1 (previous slide)

are fairly flat with time. The span of cable

stay and suspension bridges is still

increasing and technology still developing.

And so, the main focus of the long span

bridge (LSB) course is on SuspensionBridges and Cable Stay Bridges.

David Collings BSc CEng FICEMaking the complex simple

Chaotian Bridge over the Yangtze

River, Its 520m trussed span is the

longest arch span in the world.

However its form is similar to those

built almost a century ago.From 5

Long Span Bridges

Summary presentation of the MSc Module for 2015.

Full details of the course can be found at:

http://www.surrey.ac.uk/postgraduate/bridge-engineering

Tutors

David Collings BSc CEng FICEIndependent Consultant

Professor Gerry Parke BSc MSc

PhD CEng FICE FIStructE EurIngHead of Civil & Environmental Engineering University

of Surrey

The Course

The course consists of 6 Units:

• Introduction to LSB

• Suspension and Stay Systems

• Box Girders

• Aerodynamics

• Stays and Hangers

• Towers and Pylons

Introduction to LSB

This outlines the history and development,initial design and construction of Cable-stayand Suspension bridges. The initial designexamples use a simple method based on adata-base of past structures (figure 2) toallow the student to work within currentnorms. Some failures [ref 4] are alsodiscussed. The construction of LSB isillustrated with historical and currentstructures (figure 3).

David Collings BSc CEng FICEMaking the complex simple

Figure 2 Note: 11.8 is taken from Collings [ref 2] which outlines the behaviour of cable stay and extradosed bridges in the context of steel-concrete composite construction.

David Collings BSc CEng FICEMaking the complex simple

Figure 3

Suspension and Stay Systems

This outlines the classic theory of the

Catenary, Cable Deformations, the

Rankine Theory and the Elastic Theory of

Suspension Bridges. Preliminary Analysis of

Cable Stayed Bridges. The initial design

examples are revisited to determine cable

and stay forces by analysis (figure 4).

David Collings BSc CEng FICEMaking the complex simple

Figure 4

Box Girders

Steel box girders are used on all LSB above500m span (fig 5) The the behaviour ofplates, plates in compression, plates inshear , plates under in-plane bending,panels under lateral loading, plates undercombined in-plane stresses are all importantfor the design of Box Girders (fig 6), thedesign of web stiffeners and diaphragmdesign.

David Collings BSc CEng FICEMaking the complex simple

Figure 5

David Collings BSc CEng FICEMaking the complex simple

Figure 6

Aerodynamics

Throughout the history of LSB wind hasbeen a major consideration (fig 7) andcaused many failures [ref 4]. This Unitoutlines the Basic Wind Loads, theDynamics of LSB, Basic Aerodynamics,Wind Tunnel Testing, the use of BD 49-01and an Example of the design decisionsneeded to avoid instability and limitmovements are discussed.

David Collings BSc CEng FICEMaking the complex simple

Figure 7

Stays & Hangers

Cables, Stays and hangers can beprefabricated or built on site, Installation,Maintenance, Strengthening and replacementare important considerations. Cabledehumidification is reviewed. Cables, Staysand Hanger Analysis and design issues suchas fatigue, progressive collapse, etc. arereviewed.

The special issues associated with multi-spanLSB and footbridges are discussed (fig 8).

David Collings BSc CEng FICEMaking the complex simple

Figure 8

Figure 9

Towers & Pylons

Types of Pylons and Towers, Loading andConceptual Design, Cable Connections toPylons and Towers, Pylon and TowerConstruction.

Towers and Pylons are a key visual feature,the aesthetics of LSB are discussed (fig 10).

.

Figure 10

David Collings BSc CEng FICEMaking the complex simple

References

1. Parke & Hewson (2009) Manual of Bridge Engineering,

second Edition, ICE Publishing..

2. Collings D, (2011) Steel-concrete composite bridges,

second Edition, Thomas Telford, London.

3. Collings D, Santiago A S, (2013) Extradosed and cable

stayed Bridges: Exploring the boundaries, Proc ICE BE 166,

Dec 2013, pp 231-239.

4. Collings D (2008) Lessons from historical bridge failures,

ICE Proceedings, Learning from Failures - a Civil

Engineering special issue, Thomas Telford Ltd.

Summary

Long Span Bridgeshttp://www.surrey.ac.uk/postgraduate/bridge-engineering

Other Summary presentations on Slideshare:http://www.slideshare.net/DavidCollings/cable-stay-bridges-presentation-summary-

of-a-lecture-delivered-at-uni-of-surrey

http://www.slideshare.net/DavidCollings/extradosed-bridges-exploring-the-

boundaries

http://www.slideshare.net/DavidCollings/chinese-arch-bridges-timber-stone-

concrete-steel

…making the

complex simple…

http://www.slideshare.net/DavidCollings/david-collings-bsc-

ceng-fice-personal-careerdc-summary

David

Collings

大衛

Presentation by CRD and Wolf productions.

The full lectures are available on Surreylearn.