Friday, March 2nd, 2012 at 1.15 pm,, the rain has flushed Malang
city, finally my friends and I decided to wait the rain to let up .. Precisely at 4 pm we went to the
truss bridge using the car with my father, Mr. Suhartoyo. Arriving at the
bridge site, Sitirejo Village, Wagir District, Malang Regency, we carried out
the survey so that we know the truss bridge construction, especially in
Kebonagung. Beside that, we understand the details of the truss bridge and
understand the stability of the bridge and positioned..
Kebonagung
Truss Bridge
Truss bridge is a bridge that
constructed by two main frame which is connected by several horizontal angle
elements thus forming a box-shaped
structure. Two of the main frame is tied together with transverse beams and
longitudinal beams. Truss structure
is generally used as a stiffener for
a conventional suspension bridge,
because it has a good ability to pass wind (aerodynamically).
Relatively light weight is an advantage in construction,
where the bridge can
be assembled section by section.
History of Kebonagung Truss Bridge
At first there was ordinary
concrete bridge, but the bridge collapsed due to flooding so that the truss
bridge was built which is made of
steel.
Ex
concrete Bridge beside Truss Bridge
The advantages of the Truss Bridge
• The style of the main stem is axial force
• The agency truss system is open (open web) that is
possible to use maximum height as compared with the beam bridge without a
cavity.
Both
factors lead to a reduction in weight over its own structure. In addition, a
high measure also reduces the deflection so that the structure is more rigid.
This advantage is obtained in lieu of manufacturing costs and higher
maintenance. Conventional truss bridge is the most economical to moderate
spans.
The Weaknessof truss bridge
Efficiency
depends on the length of the truss spans, meaning that if the truss bridge is
made longer, then the size of the own truss must be enlarged or made higher
with a larger angle to maintain rigidity, until it reaches the point of the
truss where the weight of own bridge too
large so that the trusses could no longer support the load.
Details of Kebonagung Truss Bridge in one side :
• Model :
V pattern truss
• Number of trunks :
31
• Number of nodes :
17
• The number of clamps :
64
• Length of bridge :
40 m
• Width of road :
8 m
• Width of pavement :
0.94 m
• The distance between nodes :
5 m
V pattern truss bridge
Type of Bridge
The type of Kebonagung bridge is Warren type. This bridge type
was patented by James Warren and Willoughby Theobald Monzani in 1848 in the
United Kingdom. Warren truss bridge type has no vertical rod-shaped frame in
the form of an isosceles triangle or an equilateral triangle. Most of the
diagonal rods having a compressive force (compression) and others are subjected
to stress (tension).
Warren Type Bridge
Truss Bridge Analysis
Form of the truss structure is chosen because it is capable to
receiving relatively large loads structures and can serve the needs of
long-span structures. Form of this structure is intended to avoid bending the
rod structures like occur on the beam.
On the truss rod structure is intended only accept either the pull of the
normal load or compressive load. The simplest form of this structure is a
series of rods which is strung together to form a triangular wake. This
structure can be found on the roof frame and the bridge.
The point of the chain is referred to nodes / knots or
contact points. Static frame structure generally has two holder that has the
same principle with block structure holder. Truss structure composed by a
series of triangles which has stable nature basic form.
nodes / knots or contact points
The truss structure consists of 31
rods (member) and 17 contact points or nodes. Kebonagung bridge placement is
elestomer. The first holder can receive 2 reaction components way (vertical
reaction and horizontal reaction). Likewise the other holder can receive 2
components (vertical and horizontal reaction). So there are 4 components of the
reaction holder. Under the terms of the stability of the truss can be written:
b + r ≥ 2t
where:
b = number of stems
r = number of reactions to the placement
t = number of nodes
Thus, 31 + 4 ≥ 2 (17)
35 >
34 (ok)
Hence the stability of the truss construction is fulfilled.
Other details of Kebonagung Bridge
1. Bronjong /
anchor
Bronjong / anchor
The main function of
Bronjong anchor is a ground reinforcement system, because the tile (anchor) is
designed to be able to cut the collapse
line so that the land become stable, qualified as road and bridge construction
materials.
The others function of anchor
as
1.
Output protective culvert,
2.
Protective buffer bridge,
3.
Protective shoreline, and
4.
A variety of other uses in controlling soil erosion
and stability.
2. Liaison
Plate
•
Kebonagung
truss bridge have connector plate to connect the rod ones to another
rod. These bars are connected using nuts bolts.
•
At the top of the bridge nodes using double U
channel.
Liaison Plate
3. Placement
The type of Kebonagung bridge placement is elastomer. Using
rubber as thick as 10cm that mounted on
the head of the bridge that serves as flexibility.
A = elastomer and B = head of the bridge
4. Rods's
Transverse profile
• Bridge Rod Profile = "I" profile
• Profile
High = 0.4 m
• Profile Width = 0.28 m
•
Thickness 1 = 10 mm
•
Thickness 2 = 20 mm
“I” Profile
Cross Section
5. Clamps
and Riling
• Clamps serves as a connector of riling and rods
bridge.
• Rilling serves as a backrest as well as safety
for pedestrians on the sidewalk to keep from falling.
1 = Clamps and 2 = Riling
6. Drainage
System
•
There are 9 drainage holes on one side, which is
located parallel to the location of a node. Between the drainage holes within 5
feet at the edge of the pavement.
•
Functions that water does not puddle on the road
/ pavement.
Drainage System
7. Pavement
•
On either side of the bridge there is a sidewalk
along the 40m with a width of 94cm as pedestrian facilities.
•
At the end of the sidewalk, there are 3 holes
that serve to reduce the volume of concrete, so it does not increase the burden
of own construction.
Pavement
That is my explanation
about survey in Kebonagung Truss Bridge with my friends..
This is a little video footage of the
survey that was conducted with my father..
Let's check this out.. ^_~
Thanks to my father as a
survey companion..
U know the meaning of Father is :
F= Forever With His Family
A= Always There For You No Matter What
T= The Only One Who's There
H= He's My Hero Till The End
E= Encouraging In Everything I Do
R= Really The Only One...No One Can Beat Him He's The Best!!!
Hopefully the assignment
of the truss structure can be applied better than before and may we will be
great engineer.. Aamiin..
See you.. Bye-bye ^_^
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