❞ كتاب Design and Construction of Cable-Stayed Bridges in the Czech Republic ❝

Design and Construction of Cable-Stayed Bridges in the Czech Republic

Design and Construction
of Cable-Stayed Bridges in
the Czech Republic
Jiri Strasky, Ph.D.
Consultant
T.Y. Lin International
San Francisco, California
For 22 years, Jiri Strasky worked as
chief design engineer with Dopravni
Stavby, Olomouc-a leading state
company for the construction of bridges
in Czechoslovakia. In this position,
Dr. Strasky was responsible for the
development and design of precast
segmental, stress-ribbon and cablestayed
bridges. After political changes in
1989, he opened his own design office
and was appointed professor of concrete
structures at the Technical University of
Brno. In the United States, he served as
a special consultant in the design of the
first stress-ribbon bridge built in North
America and for the recently completed
Wisconsin Avenue viaduct. For his
design work, he received the FritzSchumacher
Prize from the University of
Hannover, Germany, and an Award of
Excellence from the Portland Cement
Association. Currently, Dr. Strasky is a
consultant with T.Y. Lin International in
San Francisco.
24
The author discusses the design, analysis and construction of
two innovative precast, prestressed concrete cable-stayed
bridges recently built in the Czech Republic. The first bridge
was built across the Elbe River near Podebrady and the
second bridge was built over a major railroad junction in
Prague- Vrsovice. The decks of these bridges comprise a
spine box girder assembled of precast, match-cast segments
and cast-in-place overhangs supported by precast concrete
struts. External prestressing was used to strengthen the deck.
To confirm the validity of the design, a static and dynamic
analysis of the structural system was conducted together with
model testing. The author shows how this system, with some
modification, can be applied to other cable-stayed and
segmental concrete bridges.
T wo cable-stayed bridges using precast, prestressed concrete segmental
construction (see Figs. 1, 2 and 8) were recently erected for a freeway in
the Czech Republic. One bridge was built across the Elbe River near
Podebrady while the other bridge was built over a major railroad junction in
Prague-Vrsovice.
The bridges combine the high quality and speed of construction of precast segmental
structures with the structural continuity of cast-in-place concrete (see
Figs. 3 and 4). The deck of the main span and approach spans of these bridges
consists of a spine box girder assembled of precast, match-cast segments and
cast-in-place overhangs supported by precast concrete struts.
Both bridges are suspended in the bridge axis on composite steel pylons that
are fixed into the deck (see Fig. Sa). The stays are arranged in a semi-fan shape
and are formed by strands grouted in steel tubes. The approach spans are posttensioned
(suspended) on draped external tendons placed in the bridge axis (see
Fig. Sb). The precast concrete segments were erected in progressive cantilevers
by a special crane moving on the deck.
PCI JOURNAL






. المزيد..