an alternative proposal for the design of balanced cantilever bridges ...

8 Proceedings IBSBI 2011
construction method is employed. The dead load of the bridge deck, which
typically constitutes the largest portion of the bridge’s vertical loading, is
decreased due to the reduction in the height of the deck cross section.
However, the variation of the deck cross section along the bridge deck
obstructs the falsework as the scaffolding is more demanding in terms of
geometry, compared to the conventional segmental bridge construction.
• The bridge aesthetics are significantly improved compared to the
conventional segmental bridge construction. This is due to the refined archtype
view of the bridge constructed by the proposed method and the reduced
deck cross section height.
• As far as it concerns the cracking of the deck, the proposed construction
method can be utilized for the construction of bridges with short to medium
spans up to 35 m. The check against cracking due to the short term vertical
loading of the deck, namely against the infrequent loading, showed that the
deck does not exhibit cracking. In case of bridges with longer spans up to
50m the use of partial prestress shall be used.
• The deflections of the deck were significantly reduced due to the objective
set during the design of the prestressing force, which ensured that the
cantilevers had a pre-cambering upwards, at least when the scaffolding was
removed.
• Possible differential settlements of the piers can be received by the resulting
bridge system without developing high bending loading to the deck, due to
flexibility of the arch-type superstructure.
REFERENCES
[1] CALTRANS, “Bridge Design Aids Manual”, California Department of Transportation,
Sacramento, 1994.
[2] Chen WF and Duan L, Bridge Engineering Handbook, CRC Press Boca Raton London, New
York Washington, D. C., 1999, Chapter 1.
[3] Trost H., Lastverteilung bei Plattenbalkenbrucken, Werner Verlag, Dusseldorf, West
Germany, 1961.
[4] Kwak H-G and Son J-K, “Determination of design moments in bridges constructed with a
movable scaffolding system (MSS)”, Computers and Structures, Vol. 84, Issue 31-32, pp.
2141-2150, 2006.
[5] EN 1992-1-1:2004 Eurocode 2: Design of concrete structures, Part 1-1: General rules and
rules for buildings, 2004.
[6] DIN-Fachbericht 102, Betonbrücken, DIN Deutsches Institut fuer Normung e.V, 2003.
[7] EN 1991-2:2003 Eurocode 1: Actions on structures - Part 2: Traffic loads on bridges, 2003.
[8] EN 1992-2:2004 Eurocode 2: Design of concrete structures-Part 2: Bridges, 2004.
[9] EN 1998-2:2005 Eurocode 8: Design of structures for earthquake resistance, Part 2: Bridges,
2005.