Civil Engineering Reference
In-Depth Information
Whatever the design criteria, it is essential to have an effective regime of inspection
of the stays and of their anchors to avoid the possibility that a series of stays may be
weakened by undetected corrosion or fatigue damage.
Consideration of progressive collapse may also apply to other deck components,
such as cross-beams or stringers. However, one cannot be specifi c about the design
strategies to be taken to prevent disproportionate damage in the event of an accident;
the risks need to be assessed case by case.
18.4.11 The Ah Kai Sha Bridge
The Ah Kai Sha Bridge constitutes a useful case history that illustrates many of the
design features described above. Benaim were commissioned to design this bridge to
carry the dual four lanes of the East-South-West Guangzhou Ring Road and the dual
three lanes of a local road across the Pearl River in Guangdong Province in Southern
China, Figure 18.18. The bridge was fully designed in detail and the construction
of the main foundation piles for the towers had commenced before the project was
abandoned as the highway project was modifi ed. The design was carried out with the
assistance of Leo Leung of the client organisation, Hopec Engineering Design Ltd, a
subsidiary of Hopewell Holdings [9, 10].
The main span was 360 m and the side spans 170 m, and as the bridge provided
34 m navigation clearance over the river, it required approach viaducts. The towers
rose 78 m above the deck, Figure 18.19. The bridge was situated in a zone subject to
both seismic activity and typhoons.
The Ring Road was equipped with wide hard shoulders giving rise to 10 loaded
lanes. Together with the local road there were thus 16 traffi c lanes to carry. Various
combinations of single and twin bridges with one or two decks were considered before
it was concluded that the cheapest scheme would be to carry all 16 lanes on one
Figure 18.18
Project for Ah Kai Sha Bridge (Image: David Benaim)
