03_how to design timber bridges

7/28/2019 03_How to Design Timber Bridges

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holzbaulehrstuhl Univ.-Prof. Michael Flach

Michael Flach Ole Einar Bjoerndalen

Lillehammer, Norway 12-15 September 2010


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ICTB 2010 Lillehammer

how to design bridges

a methodical approach

Univ. Prof. DDI Michael Flach


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cooperation between

architect and engineer

bridge of Leonardo da Vinci 1452 - 1519


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holzbaulehrstuhl Univ.-Prof. Michael FlachBridge in As, Norway

Following the plans of Leonardo da Vinci


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holzbaulehrstuhl Univ.-Prof. Michael Flacharchitectural sketches


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Drau, A

Crest, F

collaboration architect -

engineer


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design procedure (example 1)

ground profile

clearance profile under the

bridge

supports

type of exploitationclearance profile above the

construction

width of construction

span

constructioncosts

statical

height

placement of the

structure

loads


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design process example 1

pedestrian bridge in Grenoble, F


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holzbaulehrstuhl Univ.-Prof. Michael Flachpedestrian bridge in Grenoble, F

competition project


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design procedure (example 2)

span

statical

height

position of the structure

clearance profile

type of use

construction

costs


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holzbaulehrstuhl Univ.-Prof. Michael Flachdesign procedure (example 2)

pedestrian bridge in Grenoble, F


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protection of the structure against weather use of adequate assembly systems adaptedfor timber bridge constructions reduce moment bending effects in members avoid perpendicular to grain tension

Basic design rules for timber bridges

structural systems


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wrong choice of type programmed failures

non-linear stresses, torsion, no protection, no maintenance


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in addition: for arched gluelam structures

concentrated loads perpendicular to grain tension

tension


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However there is a trick !

To compensate perpendicular to grain tension by ..

forced displacement to introduce compensating bending moments


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Structural systems for bridges

bending structures with full sections:-

beams, girders and slabs

bending structures with composed sections:- trusses, lower chord structures

structures with intermediate support:

- strut and cabled stayed systems funicular structures:

-

arches, suspension structures, shells

structural systems


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Bending structures with full cross sections

rib systems I- and T-beams et box girders

structural systems


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shoulder to shoulder

structural systems


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nailed laminated -, gluelam-and CLT- decks

structural systems


B di t t ith f ll ti


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Bending structures with full cross sections:

connected wood-concrete decks

structural systems


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bending structures with composed sections:

trusses, lower chord structures

triangular truss lower chord structure

structural systems


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holzbaulehrstuhl Univ.-Prof. Michael Flachlower chord structures

Pedestrian bridge in Orvault, F

Pedestrian bridge in Fliess

/ A


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trusses

structural systems


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge across the Sanne, F

triangular truss with suspensions and a connected wood-concrete deck


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge of Fayettes, F

framework with suspensions and a wood-concrete deck


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holzbaulehrstuhl Univ.-Prof. Michael Flachpont pour circulation lourde sur la Dore, F

framework with strutsand a wood deck


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truss with variable height

heavy traffic bridge in Kssen, A


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge in Walpole / USA

truss with variable height with a connected steel concrete deck


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systems with intermediate supports

strut system

cable stayed system

t t t


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strut systems

structural systems


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holzbaulehrstuhl Univ.-Prof. Michael Flachpedestrian bridges in Ajoux, F and in Pians , A

polygonal arch in

Ajoux, F

strut bridge in

Pians, A


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge in Steinerbach / A

strut structure with a connected wood-concrete deck


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge on the highway A 89, F

strut structure with a disconnected wood-concrete slab


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holzbaulehrstuhl Univ.-Prof. Michael Flachheavy traffic bridge on the highway A 89, F

branched structure with a cross laminated timber panels, Crest, F

cable stayed structures


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cable stayed structures

structural systems


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cable stayed pedestrian bridge

in Orvault, F

cable stayed pedestrian bridge on the lake of Saint Point, F

cable stayed bridges


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holzbaulehrstuhl Univ.-Prof. Michael Flachbridge in the valley of Lech, Acable stayed bridges


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cable stayed bridge

heavy traffic bridge in Avoudray, F


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funicular structures

arch bridge

bowstring

suspension

structural systems


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Covered bowstring bridge

Bridge in Blagnac, F


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holzbaulehrstuhl Univ.-Prof. Michael Flachtimber bridges of the future

200 m heavy traffic bridge

Saint Gervais, F

1000 m pedestrian bridge

Ziegelwies,A

Fssen,D

03_how to design timber bridges

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