Bridges in the wind

Mock-up ot the cable-stayed bridge of Mourom (Russia)

India, Vietnam, Turkey, Russia, etc.:  climatologists and aerodynamics experts at CSTB Nantes have played their part to assure that bridges being built in many parts of the world resist extreme climatic conditions.  They are specialized in studying the behaviour of bridges under the effects of wind, and design and engineering offices, architects and public works contractors are calling upon large numbers of CSTB experts to check the stability of bridges under wind loads.  "In general, requests apply to an examination of the different times in the life cycle of the bridge, from the "construction" phase until the “service with and without traffic" phase, says Gérard Grillaud, controller of the Wind and Structures domain and more particularly simulation of highly critical construction steps, for example when launching a deck."

CSTB’s methodology for typical projects includes a sequence of well-defined steps.  The first and absolutely essential step is to compile, analyse and validate climatic and geographic data (topography) on the projected bridge site.  The next step is to define wind tunnel tests to be carried out.  These are determined as a function of the configuration and specific features of the bridge to be studied.  Once the customer has accepted the proposal, Wind and Structures technicians will take over:  a mock-up of the central part of the deck is made – this is usually the part of large suspension bridges or cable-stayed bridges most sensitive to wind - and then installed in the wind tunnel.  It is suspended in the wind tunnel using a spring system which simulates the bridge stiffness and is then instrumented.  All types of sensors and cameras are used to observe the behaviour of the mock-up (vertical bending, torsion) as a function of the wind velocity in the wind tunnel test section.

Predict bridge behaviours

"After this first set of tests, we can predict the wind force at which the bridge no longer satisfies the specific requirements set down in the specifications, says Gerard Grillaud.  If these velocities are not sufficiently higher than the velocities that could be observed on the bridge site, we will then have to suggest possible actions for improvement to our client, either to the geometric form of the deck or the mechanical properties of the bridge.  Once these problems (if any) have been solved, we carry out a second series of tests to measure aerodynamic loads applied to the deck."  In general, a month of work is necessary before the bridge is declared "good for service".  Tested methods that should eventually give way to digital simulations.

Deck of Chambal bridge (India) right for trials in the CSTB tunnel test air stream

Four prestigious bridges

During the past few months, the CSTB’s Wind and Structures team has been asked to carry out several studies on currently planned bridges.  Four of these bridges (the Chambal bridge (India), the Golden Horn (Turkey), Phu My (Vietnam) and Mourom (Russia) ) are particularly remarkable.

Bridge name


Golden horn

Phu My










Ho Chi Minh Ville


Traffic type


railway (metro)



Bridge type




Cable-stayed, multi-span


700 m

405 m

705 m

806 m

Central span

350 m

180 m

380 m

2*231 m


30,2 m

27 m

27,5 m


Hight above  water

46 m

17 m

51 m

25 m

Nature of deck





Design office (CSTB client)(client CSTB)


Systra – Hakan Kiran