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Building Structures (ARC 2523)
Project
Fettuccine Truss Bridge
ChngXing Yue 0310425
Fam Li Kian 0310639
Goh Chin Zhi 0314562
Wesley Hew Xin Han 0307585
Sharifah Diyana Syed Hussain 1006AH78373
Lim Wei Ze
Tutor: Ms. Ann See Peng
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Table of Content
Introduction
Methodology
Precedent study
Analysis
i) strength of materials
ii) truss analysis
- Mock up 1
- Mock up 2
Final model testing
Conclusion
Appendix exercise
References
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1.1 Study Objective
The objective of this particular study is to explore and thus evaluate and improve onknowledge of skeletal construction. In the event of constructing a truss bridge with
fettuccine, exploration on truss members in different arrangement was carried out while
applying the understanding of load distribution in truss systems. Besides that,
understanding and the application of the knowledge on calculating the reaction force and
internal force within the truss design. Lastly, gaining the ability to identify the tension and
compression members in a truss structure to fully utilize the potential of the material -
Fettuccine.
1.2 Project Overview
In a group of 6, a truss bridge was produced by using fettuccine as the construction
material. Before starting with the model making, students were required to carry out
precedent study of a truss bridge.
With a clear span of 750 mm and a maximum weight of 200 g, the truss bridge is then
subjected to a point load which determines the efficiency of the structure. The efficiency
of the bridge is calculated with the formula:
, = ( )
For this project, only glue is allowed for the connection of the bridge members.
1.3 Report Overview
This report includes the precedent study of the bridge our group referred to while
designing the truss systems of the fettuccine bridge. Besides that, the report also
includes the development process of the fettuccine truss bridge including the analysis
and calculation of the particular design.
Introduction
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Methodology
Working Schedule:
DESCRIPTION
Precedent Study A study on different types of bridge
trusses will be conducted. We will study
the connections and arrangements ofmembers. This will be then applied to
our model bridge.
Material Testing The strength of different types of
fettuccine and glue will be tested out.
Model Making Based on the AutoCAD drawings done,
the sides of the bridge will beconstructed before joining them together
using members.
Structural Analysis The analysis of both mockup and final
model will be carried out after each
testing.
DATE TASKS
21 September 2014 Material strength testing of different
fettuccine.
24 September 2014 1stMockup model making and testing.
28 September 2014 2ndMockup model making and testing.
30 September 2014 Final model making.
1 October 2014 Final model submission and testing.
3 October 2014 Final report submission.
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MATERIALS DESCRIPTION
Butter Paper Design of chosen truss bridge is drawn
on the butter paper as a reference for
placement of each member.
Fettuccine Fettuccine is used to construct the entire
truss bridge.
Masking Tape Masking tape is used to keep thealignment of each member in place
before gluing.
Super Glue This glue instantly holds the fettuccine
together due to the strong bonding.
Plastic Bag Tied around center point of bottom chord
of the bridge for testing purposes.
Water Bottle Used to measure the amount of water
as weight during testing process.
Camera Recording of all work progress.
Electronic weighing scale To obtain accurate weight measurement
of the Fettuccine bridge.
For the final bridge model, we weighed
the members before assembling ittogether to ensure its within 200g.
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Precedent Study -Railway Bridge Tulle
Railway Bridge Tulle is a railway bridge which built at 104 years ago. The
railway bridge across the Danube at Tulle has been completely reconstructed. The
new bridge is based on warren truss construction. The construction period only took
15 months. The total length of the bridge is approximately 440m, each span width
around 13m.
Image 1 : Railway Bridge Tulle
Joint connection
Image 2 & 3 : Rigid Joints. Gusset Plate and Bolts Joint Connection
In order to have a stable and strong truss bridge, the concept of force
equilibrium should be apply. Assuming the point load is at the centre of the bridge,
and both side of truss bridge are fixed points.
Load
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Arrangement of Members
The base of Tulle Bridge is connected by horizontal members.
Image 4 : Bottom view of Tulle Bridge
Image 5 : Tulle Bridge side view
Point of Horizontal Member Connect to
Truss
Top view of Tulle Bridge
Points of Horizontal Members at lower
chord connected to the truss
For the upper chords, horizontal members are welded to the intersection point of
the truss to hold both sides of the truss members in shape and ensure the distance is the
same along the bridge. The bracings hold the horizontal in position to prevent deformation
of the bridge when load is applied.
As the report mentioned previously, the top chord of warren truss are greatly
affected by compression while the bottom chord of warren truss is experiencing tension
force. The bracings as shown on diagram above act as a member to distribute the
compression force and hold the members in position. The bottom chord of Tullen Bridge
does not required as much bracings as the members (steel beams) are great in tension
force.
.
Pin Joints
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Types of glue Time taken to dry
out
Strength Weakness
UHU glue Takes relative long
time to dry.
Large surface
contact area with
material
Flexible when
force is applied
Superglue
(Dolphin)
Solidifies fast. Could bear relative
heavy load.
Becomes
fragile after it
dried off a few
days later.
Low surface
contact area
with materials
Hot glue gun Solidifies very fast. Large surface
contact area with
material
The glue peels
off easily.
Messy and bulky
in size.
Rubber glue
(Dunlop)
Takes relative long
time to dry.
Large surface
contact area with
material
Stronger than
UHU
Needs 24 hours
to gain maximum
strength
Flexible when
force is applied
Analysis
Materials analysis
The diagram above shows different orientations of fettuccine and the load being applied
from the top.
When the fettuccine is placed horizontally, the thickness of the fettuccine is thinner,therefore the load it can withstand is small. The area of breaking point of the fettuccine
also increases with the horizontal placement.
The vertical fettuccine is stronger in this case as it has a smaller breaking point surface.
But when the fettuccine is 4 members thick, the length of the fettuccine for both sides
are the same (5mm).
Load Analysis of Fettuccine
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Types of design
Number of members 3 6 6
Load withstand (kg) 2.5 6.1 5.4
Types of Fettuccine Shape Strength
Standard San Remo Flat
(Easier to glue)
Weak
San Remo Spinach Slightly rounded
(smaller surface area
in contact with the glue)
Stronger than standard San
Remo Fettuccine
Standard Divella Relative rounded
and larger in size
Strongest
Standard San Remo San Remo Spinach Standard Divella
Types of designs for middle support of the bridge
We decided to use the 2nd design instead of triangles after the test due to the realization
that we could not create a perfect triangle to efficiently transfer the load.
1 2 3
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Truss AnalysisTruss analysis
Pratt truss has been chosen as the mock up bridge to test the load bearing of the
truss. The load will be hang at the center of the bridge to act as point load. There
are several factor to be considered to ensure that it can withstand 50N.
Factors affecting strength of bridge:1. Types of bracing used
2. Span to depth ratio
3. Joint connection and displacement of fettuccine
4. Design of middle member supporting load
5. Number of fettuccine used in one member
Side Elevation of Mock up Fettuccine Bridge
Mock Up Fettuccine Bridge 1
Top elevation of Fettuccine Bridge
Total weight :236g
Height : 10cm
Length : 90cm
Load : 4.1kg
Pratt truss has high efficiency due to the vertical member and horizontal member. Thediagonal member act as tension member and vertical member act as compression
member. The purpose of this orientation of the members is to achieve force of
equilibrium. Imagine it as a simple triangle, 3 forces acting at a point can be represented
in size or direction by the sides of a closed triangle, then the forces are in equilibrium,
provided their directions can form a closed triangle.
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As to prove the assumption is correct, calculations has been done to determine the
efficiency of fettuccine bridge.
+ = 0 + 5 0 = 0 + = 50 + 2 5 = 5 0
= 25N
Clockwise = positive
= 050 9 5 90 = 0
2250 - 90 = 02250 = 90
=2 5 1
25N 25NSection equation is used to interpret the internal tension force or compression force.
25Nt a n = 105 c o s = 5125
s i n = 10
125
10
5
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= 0 c o s = 0
()
= 0 (10) (cos)(10) ( sin)(40)=0 10
5
12510 10
12540 = 0
= 4.472 35.77710 = 3 . 1 3 1
+ = 0 sin + 25 = 0 s i n = 2 5
= 25sin =
25( 10125)
= 27.95 () 2
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Joint Connection
A gusset plate like fettuccine is used to improve the load distribution. It acts as a
connection to increase the contact surface area between horizontal member and
the diagonal member.
At the other side, the horizontal member and diagonal member does not
connected by gusset plate. These arrangements are to test the difference of
having gusset plate, hence to reduce the unnecessary weight.
Joint with gusset plate Joint without gusset plate
Number of fettuccine for one member
Position Number of fettuccine
Top horizontal 4Top diagonal 1
Top vertical 2
The number of fettuccines for each members has been done according to our
truss analysis. The compression members should use the most fettuccine to
reduce the compression force. As fettuccine is good in tension force, the tension
member required 2 fettuccine to stack together to support the fettuccine bridge.The diagonal member act as a member to distribute the force and to avoid
torsion force act on the bridge, hence it requires 1 fettuccine only.
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Position Number of fettuccine
Bottom horizontal 4
Bottom diagonal 1
Bottom vertical 2
Bottom vertical
(triangular column)
3
The number of fettuccine stacking for one member is similar to top of the
fettuccine. There are only one changes as to allow the member withstand the
point load. A triangular column-liked fettuccine is used for the bridge. The
strength of triangular column has been tested and shown in fettuccine-testing
(methodology).
Position Number of fettuccine
Side Vertical 2
Side Diagonal 2
As the weight of top structure is heavier than the bottom structures, we worriedthat the side structures cannot withstand the weight itself, causes bending and
reduce the strength of fettuccine bridge. Hence, we decided to stack 2 fettuccine
for each member to reduce possibility of bending.
After testing
The bridge breaks when the total point load weight 4.1kg. The triangular columnitself does not broke, but the horizontal members. We concludes that it is
possibility of 3 second glue affects the strength of fettuccine bridge as the
horizontal has been done before 2 days we test the bridge. The placement of
broken member should be changed to improve efficiency of fettuccine bridge.
The whole structures are still rigid after testing. Hence, we decided to change the
number of fettuccine stacks for each members to reduce the total weight.
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Final Model Testing
1stbottle
4th bottle
7thbottle
11th bottle
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Side Elevation of Mock up Fettuccine Bridge
Mock Up Fettuccine Bridge 3
Total weight :196g
Height : 100mm
Length : 850mm
Load : 5.744kg
A Pratt truss similar to the previous test models was used due to the high efficiency
of the vertical and horizontal member. The diagonal member act as tension
member and vertical member act as compression member. The purpose of
orientation of the members is to achieve force of equilibrium. Although the spinach
fettuccine has smaller contact surface, but it is stronger than the normal fettuccine.
Hence, we have chosen the spinach fettuccine in building our final bridge model.
Top Elevation of Mock up Fettuccine Bridge
The efficiency for the final bridge is:
E =(.)
6
0.1683
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Joint Connection
Position Number of fettuccine
Top horizontal 4
Top diagonal 1
Top vertical 1
Through the first and second model testing, we realized that the top vertical
members could be reduce to just one layer since it is not in direct contact with
load applied. This is also one of the approaches taken in order to reduce the total
weight of the bridge. Besides, there are only one layer of diagonal members
because they act as bracing to prevent torsion force. Hence, one layer will be
sufficient to support the trusses.
At both sides, the vertical and diagonal members are laid on the outer surface of
the horizontal members by using super glue. After tested the first and second
bridge, we decided to use the first joint connection by removing the gussets. This
is to maximize the surface area in contact so that every members can hold still in
place and perform well in acting with the forces applied.
At the top and bottom part, the vertical members was stacked on the horizontal
member and following by the diagonal bracing on top of the vertical members.
While force is applied, the vertical members can transfer load down directly since
they are sitting on top of the horizontal member.
Number of fettuccine for one member
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Position Number of fettuccine
Bottom chord 4
Bottom diagonal bracing 1
Bottom bracing 1
Bottom bracing
(middle)
8 (divided into two, four on
each side)
The number of fettuccine supporting the horizontal chord for both top and bottom
have been reduced to one as it didntrequire to withstand much force but rather
to prevent torsion of the bridge. The middle bottom bracing which holds the load
applied are required to be stronger since it has direct contact with the load.
Hence 8 fettuccines are used to strengthen the member. The fettuccines are
divided into half, where four layers of fettuccine are stacked together to form a
member. The two members were placed side by side to provide a wider surface
area for the hook to hold the load and to prevent it from breaking easily.
Position Number of fettuccine
Side Vertical 2Side Diagonal 1
In order to withstand the force of the weight, the number of fettuccine in the side
bracings remain unchanged. The amount of fettuccine in the diagonal bracing
was reduced to one as it helps prevent sliding of the vertical and horizontal
members under pressure.
The middle bottom bracing
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After testing
The final bridge managed to support a maximum of 5.744kg before breaking.
The middle bottom bracing remains unbroken as the bottom chord had snapped
first causing the entire bridge to cave in downwards. This is partly due to the
difference in height of tables used during the testing of the bridge, the impropertransfer of force causes the chord to split on both sides.
Middle beam didntbreak during testing The bottom chord after splitting
The bridge had broken on opposite ends at the moment of breakage. The torsion
caused all the horizontal bracings to twist and snap although several portions of
the side bracings remains in one piece a side from point breaks.
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The final bridge has the highest efficiency out of all the model testing we did and was
considered a success to us. Throughout the whole project, different materials,
arrangement of members and joint connections are used to explore and improve thebridges.
We came out with systematic ways to do the model in order to reduce the time taken for
the construction and to increase the precision of the Fettuccine bridge. We also realized
the importance of workmanship during the model making. Inaccurate or twisted
fettuccine will contribute to the deformation of the bridge and thus causing lower
efficiency.
We did identify the tension, compression members and weak points as to determine onwhich parts to strengthen and which to reduce the layers of Fettuccine used. This
method allows us to reduce the weight of the bridge to meet the requirement of the brief.
Lastly, this project allows us to understand the importance of structure and construction
method in design and the load distribution in truss to enable us to create a better
structure for our designs in the future.
Conclusion
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Reference List :
Analysis of Structures. (n.d.). Retrieved from
http://ocw.nthu.edu.tw/ocw/upload/43/733/static_ch6.pdf
Calvert, J. (2000, January 1). Truss Design. Retrieved from
https://mysite.du.edu/~jcalvert/tech/machines/bridges.htm
Trusses Introduction. (n.d.). Retrieved from
http://www.ce.memphis.edu/3121/notes/notes_03a.pdf
Image Reference :
Image 1 : Retrieved by http://structurae.net/photos/144783-tulln-danube-river-railroad-
bridge
Image 2 : Retrieved by http://structurae.net/photos/144765-tulln-danube-river-railroad-
bridge
Image 3 : Retrieved byhttp://structurae.net/photos/144763-tulln-danube-river-railroad-
bridge
Image 4 : Retrieved by http://structurae.net/photos/144760-tulln-danube-river-railroad-
bridge
Image 5 : Retrieved by http://structurae.net/photos/144783-tulln-danube-river-railroad-
bridge
Reference