suspension bridges detailed study

1. HARP TYPE CABLE STAYED BRIDGE

2. HISTORY & DEVELOPMENT
The harp is a stringed musical
instrument that has a number of
individual strings running at an
angle to its soundboard; the strings
are plucked with the fingers. Harps
have been known since antiquity in
Asia, Africa and Europe, dating
back at least as early as 3500 BC.
The instrument had great
popularity in Europe during the
Middle Ages and Renaissance,
where it evolved into a wide range
of variants with new technologies,

3.  and was disseminated to Europe's
colonies, finding particular
popularity in Latin America.
Although some ancient members of
the harp family died out in the Near
East and South Asia, descendants of
early harps are still played in Burma
and parts of Africa, and other
defunct variants in Europe and Asia
have been utilized by musicians in
the modern era.

4. CABLE STAYED BRIDGES
 FOLLOWING ARE THE MAIN TYPE OF CABLE
BRIDGE

5. DESIGN
 In the harp or parallel design, the cables are nearly
parallel so that the height of their attachment to the
tower is proportional to the distance from the tower to
their mounting on the deck

6. STRUCTURE SYSTEM OF BRIDGE
 The main structural elements of a cable stayed bridges
are the bridge deck, piers, towers and the stays. The
deck supports the loads and transfers them to the stays
and to the piers through bending and compression.
The stays transfer the forces to the towers, which
transmit them by compression to the foundations

7.  The static system of a cable-stayed bridge can vary due
to the conditions of support of the deck at the
abutments and the whether there are piers in the side
spans. The connection between the deck and the tower
is also of great importance. This system primarily
affects how effectively the structure carries live loads.

8.  The longitudinal system is characterized by the ratio
of the height of the towers to the central span, the
relationship between the central span with the side
spans, the connection of the deck to the approach
viaduct, and the ratio of stiffness of the deck and the
towers. The geometry of the tower depends on the type
of suspension system (Fan, Semi-Fan, or Harp), the
form of suspension at the deck (with center or side
anchors), whether the deck rests directly on the tower,
and the available space for anchoring and tensioning
of the stays inside the tower.

9. BRIDGE SUPPORTS DESIGN
 There are also four
arrangements for support
columns: single, double, p
ortal and A-shaped.
 The double arrangement
places pairs of columns
on both sides of the deck.

10. BRIDGE SUPPORTS DESIGN
 The portal is similar to the double arrangement but
has a third member connecting the tops of the two
columns to form a door-like shape or portal. This offers
additional strength, especially against traverse loads.

11.  The A-shaped design is similar in concept to the portal
but achieves the same goal by angling the two columns
towards each other to meet at the top, eliminating the
need for the third member. The inverted Y design
combines the A-shaped on the bottom with
the single on top.

12. Y- SHAPED BRIDGE SUPPORTS

13. Extradosed bridge(HARP TYPE)
 The Twinkle-Kisogawa is an extradosed design, with
long gaps between the cable supported sections.

14. Extradosed bridge(HARP TYPE)

15. Extradosed bridge(HARP TYPE)
 The extradosed bridge is a cable-stayed bridge but
with a more substantial bridge deck that, being stiffer
and stronger, allows the cables to be omitted close to
the tower and for the towers to be lower in proportion
to the span. The first extradosed bridges were
the Ganter Bridge and Sunniberg Bridge in
Switzerland. A new extradosed bridge is also being
planned to cross the St. Croix River between Bayport,
Minnesota and Houlton, Wisconsin in the Twin Cities.

16. CANTILIVER (HARP BRIDGE)

21. 3. Case Study
 The case study is a cable-stayed bridge with a
composite deck having a total length of 829 m (the
central span is 420 m, and the side spans are 204.7 m)
supported by two H-shaped towers that are 95 m
above the deck (having a 150 m total height). The stays
are spaced at 13.125 m along the sides of the bridge
deck and are composed of two sets of sixteen stays. 4

22.  The composite deck consists of two longitudinal 2.5 m
high side girders (suspended only by stays) and a slab
of uniform thickness of 0.25 m. The slab is supported
by the longitudinal girders and the floor beams (the
floor beams are transverse girders spaced at 4.375 m).