Title: Bridge Engineering (9-1) Suspension Bridges
1Bridge Engineering (9-1) Suspension
Bridges
- Components
- Anchorage (blocks or tunnel type),
towers, main cables, hangers, stiffened (box)
girder and deck, substructure and foundation - II. Form an arch upside down or the shape of a
catenary - 1 Thursday, December 04, 2014
2Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.1 The anchorage, constructed as a concrete
block or by tunneling the ground, forms a giant
weight to anchor the bridge and transmit the
tension generated through the cables firmly to
ground. - 3.2 The anchorage type is determined by the
terrain where the anchorage points are
constructed. - 2 Thursday, December 04, 2014
3Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.3 A general type anchorage that supports
unidirectional forces transmitting through
cables. (One block for one bridge). - 3 Thursday, December 04, 2014
4Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.4 An anchorage of a type that supports
bi-directional forces transmitting through
cables. (One block for two bridges) - __located between two bridges and serving as
two anchorage points. - __cable strands crossing each other in the
air before entering the anchorage. - 4 Thursday, December 04, 2014
5Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.4 Bi-directional forces transmitting type
__The Kurushima Kaikyo Bridge use four
anchorages for which three types of forms are
employed. - 5 Thursday, December 04, 2014
6Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.5 .1 A tunnel type anchorage which allows
minimum alterations to be made to the existing
landform. - 6 Thursday, December 04, 2014
7Bridge Engineering (9-1) Suspension
Bridges
- III. Anchorage
- 3.5.2 Cable anchor frames securing the cables to
the tunnels. - 7 Thursday, December 04, 2014
8Bridge Engineering (9-1) Suspension
Bridges
- IV. Tower
- 4.1 The main tower functions to transmit forces
through the cables and into the main tower
foundation. - 8 Thursday, December 04, 2014
9Bridge Engineering (9-1) Suspension
Bridges
- IV. Tower
- 4.1 The towers can be prefabricated in the
plants or cast in situ.The blocks for the main
tower were fabricated at the shop in blocks 6 m
in length. The blocks are erected in the field
using a climbing type of tower crane in
building-block fashion to form the main tower. 9
Thursday, December 04, 2014
10Bridge Engineering (9-1) Suspension
Bridges
- IV. Tower
- 4.1
- Towers of Kurushima Kaikyo Bridge The blocks
for the main tower were fabricated at the shop in
blocks 6 m in length. The blocks are erected in
the field using a climbing type of tower crane in
building-block fashion to form the main tower. - 10 Thursday, December 04, 2014
11Bridge Engineering (9-1) Suspension
Bridges
- V. Cables
- 5.1 Cables usu. of high tensile steel wires
support bridge girders and other loads, including
vehicle loads, and transmit these dead and live
loads into the anchorage points. - 5.2 Wires, strands, and ropes
- 11 Thursday, December 04, 2014
12Bridge Engineering (9-1) Suspension
Bridges
- V. Cables
- 5.2 Wires, strands, and ropes
- 5.2.1Galvanized bridge wire for parallel wire
bridge cables. Recommended diameter .196 inch. - 5.2.2 Galvanized bridge strand--consists of
several bridge wires, of various
diameterstwisted together. - 5.2.3Galvanized bridge rope--consists of six
strands twisted around a strand core. - 12 Thursday, December 04, 2014
13Bridge Engineering (9-1) Suspension
Bridges
- 5.3 Types of Cables
- 5.3.1 Parallel wire cables This type of
cable is made up of a large number of individual
wires parallel to one another. Neither the cables
nor the wires are twisted in any manner. The wire
is shipped to the site of the bridge on reels and
the individual wires are installed or' "spun" on
the bridge and later compacted together to form a
round crosssection. Cables of this type are used
on monumental structures, such as the Golden Gate
Bridge and the George Washington Bridge. - 13 Thursday, December 04, 2014
14Bridge Engineering (9-1) Suspension
Bridges
- 5.3.2 Parallel Strand Cables, Closed
Construction--These consist of several
prefabricated Galvanized Bridge Strands, all laid
parallel and in contact with one another. Wood or
aluminum fillers are used to bring the cable to a
circular cross-section, after which the whole
cable is wrapped with wire for protection. The
cable may contain 7, 19 37, 61, 91 or 127
strands. - 14 Thursday, December 04, 2014
15Bridge Engineering (9-1) Suspension
Bridges
- 5.3.3 Parallel Strand Cables, Open
Construction--This type of cable consists of
several prefabricated galvanized bridge Strands
which are all laid parallel to one another and
not in contact. The strands are usually arranged
in the form of a rectangle and the cable may
contain 2, 4, 6, 9, 12, 16, 20, 24 or 30 strands. - 15 Thursday, December 04, 2014
16Bridge Engineering (9-1) Suspension
Bridges
- 5.3.4 Parallel Rope Cables, Open
Construction--These are the same as Parallel
Strand Cables except that Galvanized Bridge Rope
is used in place of Bridge Strand. - 16 Thursday, December 04, 2014
17Bridge Engineering (9-1) Suspension
Bridges
- 5.3.5 Single Rope or Single Strand Cables--These
are used for small structures. -
- 17 Thursday, December 04, 2014
18Bridge Engineering (9-1) Suspension
Bridges
- 5.4 A single-stranded cable with a hexagonal in
cross section is formed by tying together 127
high-tension galvanized steel wires each about 5
mm in diameter. (as used for Kurushima Kaikyo
Bridge) - 18 Thursday, December 04, 2014
19Bridge Engineering (9-1) Suspension
Bridges
20Bridge Engineering (9-1) Suspension
Bridges
- V. Cables
- 5.5 Erecting cables
- 20 Thursday, December 04, 2014
21Bridge Engineering (9-1) Suspension
Bridges
- 5.6 Squeezing the cables
- __After all the strands are laid, they are
squeezed to form one single cable with a circular
cross section. - __The strands are first tapped manually
using a wooden maul to form a cable roughly
circular and then squeezed using a hydraulic
squeezing machine to form a circular cross
section. - 21 Thursday, December 04, 2014
22Bridge Engineering (9-1) Suspension
Bridges
- 5.7 Cable strength
- 5.7.1 Strength of cables One single steel
wire (about 5 mm in diameter) is strong enough to
hoist three passenger cars (1.2 tons each), and
one stranded cable (consisting of 127 steel
strands) is strong enough to hoist six space
shuttles (74 tons each). 5.7.2 Length of cables
The main cables for the Kurushima Kaikyo
Bridges weigh 16,000 tons, and the strands are
long enough to run round the earth two and one
half times. - 22 Thursday, December 04, 2014
23Bridge Engineering (9-1) Suspension
Bridges
- VI. Stiffening Girder
- 6.1 The stiffening girder functions as a driveway
for vehicles. The girder was designed with a
cross section in the shape of a slim box to
reduce vibrations in strong winds to a
minimum. 23 Thursday, December 04,
2014
24Bridge Engineering (9-1) Suspension
Bridges
- VI. Stiffening Girder
- 6.2 Erecting box girder with barge
- Stiffening girder sections, each 36m in
length, are prefabricated in the plant and loaded
on a self-propelled barge for transport to a site
directly below each erection points. There they
are lifted into position by a lifting beam and
secured to hanger ropes. - 24 Thursday, December 04, 2014
25Bridge Engineering (9-1) Suspension
Bridges
- VII. Features of suspension bridges
- 7.1. Aesthetic, light, and strong
- 7.2 Span range 2,000 to 7,000 feet -- far longer
than any other kind of bridge - 7.3 Most expensive to build
- 7.4 Complicated in force bearing and
distribution - 25 Thursday, December 04, 2014