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SCHOOL OF ARCHITECTURE, BUILDING & DESIGN
Research Unit for Modern Architecture Studies in Southeast Asia
Bachelor of Science (Honours) (Architecture)
Building Structures (ARC 2523)
Prerequisite: Building Construction 2 (ARC 2213)
Project 1
Fettuccine Truss Bridge
Cheah Teck Wei 0315215
Chew Ung Heng 0315397
Low Yong Ging 0313679
Tan Kai Chong 0314223
Tsang Hao Ren 0315753
Yap Kar Juen 0313737
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Table of Content Page Number
1. Introduction 3
2. Methodology 4
3. Introduction of Truss 6
4. Materials & Equipment 10
5. Bridge Testing 15
6. Final Bridge 23
7. Conclusion 32
8. Case Study 33
9. References 65
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1.0 Introduction
In a group of 6, we are required to design a roof truss using fettuccini as construction
material, then tested for how many loads it can carry. The aim of this project is to
develop an understanding of how forces are going on in a building structure, such as
the tension and compression force. To achieve that, we are required to conduct a
precedent study of a bridge to learn and analyse about how the connections,
arrangements, and orientation of its truss members affects the strength of the bridge.
With the research and understanding, we are required to apply them on the design the
truss of our bridge.
The requirements of the bridge is to not exceed a maximum weight of 80g and must
have a clear span of 350mm. The bridge strength as how much kg of load it can carry
will be tested and we are required to analyse the reason of its failure and calculate the
efficiency of the bridge using the formula:
1.1 Objectives
The objective of this project is to develop our understanding of tension and
compressive strength of construction material as well as an understanding of force
distribution in a truss.
We are also required to learn and able to calculate the efficiency of the bridge and the
forces going on in each member so that we could make changes to the design of the
truss. By all the objectives achieved we are produce an outcome of a bridge with high
level of aesthetic value using minimal construction material.
1.2 Learning Outcomes
At the end of project, we will be equipped with the ability to evaluate, explore and
improve the attributes of construction materials. Besides that, we are able to explore
and apply understanding of load distribution in a truss such as the identifying the
tension and compression members in a truss structure. Lastly, with the understandings
we could explore different arrangement of members in a truss structure.
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2.0 Methodology
2.1 Materials Testing & Equipment Preparation
Phase 1 : Strength of material
Properties of fettuccine is important in building a bridge so that it can carry the
maximum load. Properties of the fettuccine must be analysed before construction
because the tensile strength in the fettuccine is considered low.
Phase 2 : Adhesive
Adhesive plays a huge role in building the bridge as it connects the fettuccine to form
a structure. Therefore the adhesive must be chosen wisely as there are many types of
adhesive with different function and characteristics. There are certain types of
adhesive, which are suitable for constructing the brigde.
Phase 3 : Model Making
Drawings are plotted and printed in 1:1 scale to ensure precision in the model making
process. The dimension of the fettuccine must be accurate so that the bridge can be
strengthenned as much as possible.
Phase 4 : Experiment
Completed models are being placed aside to allow the adhesive to sit on the model
before testing. Weight is placed in the middle of intermetidate member to ensure the
load distribution is even. The results and problems are being recorded for further
improvement.
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2.2 Model Making & Design Development
The model is plotted according to scale and printed out, so the model making of the
fettuccine bridge is based on the printed dimension.
Requirements
• To have a clear span of 350mm
• Not exceeding the weight of 80g
• Only fettuccine and adhesive allowed in the construction of model
• The bridge will be tested to fail
• Workmanship is important as part of aesthetic value
2.3 Bridge’s Efficiency Calculation
Efficiency of the bridge is calculated after it is tested to fail by using the formula
below
Efficiency, E = (Maximum load)
Mass of bridge
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3.0 INTRODUCTION OF TRUSS
A bridge is generally a structure that connects two places that is unreachable by
walking, driving and etc., such as river, cliffs and etc. As people and object pass
through a bridge, it has to be structurally load bearing and strong enough to withstand
their weight. In order to increase its structural strength, bridge truss is designed.
A bridge with truss is called a truss bridge, which is a load bearing superstructure that
is composed of a structure of connected elements forming triangular units. The
elements may be stressed from tension, compression forces or sometimes both in
response to dynamic loads.
Diagram 2.1 Components in a truss bridge.
Tension and compression force is a happening everywhere in our daily life. The
tension is a force that acts to stretch or pull an object whereas the compression is a
force that acts to squeeze or push an object.
These forces are applied to bridges as well, and they highly affects and damages the
structure of the bridge varying from different weight of loads. Besides these forces,
there are also different forces such as lateral wind force.
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It is the designer or engineer’s responsibility to design a structure that is safe for
public uses, when the forces that applies on the bridge has exceed its load bearing
capability, it goes buckling or snapping.
Buckling happens when the compression force has exceed its load bearing capability
whereas snapping happens when tension force exceeds. Different members in the
truss bridge experiences different kind of forces, and they will have to determine their
structural strength and solve it by using different truss design.
Figure 1 Picture of a bridge buckling.
Figure 2 Picture of a bridge snapping.
The best way to deal with these powerful forces is to either dissipate them or transfer
them. With dissipation, the design allows the force to be spread out evenly over a
greater area, so that no one spot bears the concentrated brunt of it.
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3.1 INTRODUCTION OF HOWE TRUSS
Howe of Massachusetts licensed the Howe truss design in 1840. It is truly an
elaboration on the different kingpost design where by two substantial metal poles are
substituted for the vertical timbers.
There are likewise minor departure from this example that add a second corner to
corner timber to the first single slanting of the different kingpost and/or another
inclining timber running the other way between the vertical poles. A few records
show that the Howe outline gave an extension that was more grounded than the all-
wood structure; thus, it turned into the harbinger of iron scaffolds
The design of Howe truss is the opposite to that of Pratt truss in which the diagonal
members are slanted in the direction opposite to that of Pratt truss (i.e. slanting away
from the middle of bridge span) and as such compressive forces are generated in
diagonal members. Hence, it is not economical to use steel members to handle
compressive force.
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3.2 INTRODUCTION OF WARREN TRUSS
The Warren Truss was patented by James Warren in 1848. It has been around a while.
It is a standout amongst the most famous bridge design. The Warren Truss uses
equilateral triangles to spread out the loads on the bridge. This is against the Neville
Truss which utilized isosceles triangles.
The equilateral triangles design is recognized by equal sized members and the ability
of some of the diagonals to act in both tension and compression. Interestingly, as a
load (such as a car or train) moves across the bridge infrequently the strengths for a
part change from compression to tension. This happens particularly to the individuals
close to the focal point of the bridge.
A Warren truss is a support structure used as a part of distinctive developments, for
supporting a load. These are used extensively in bridges as well as, residential and
public works designs. The contiguous triangles that are a characteristic part of the
Warren truss, also gives them the name, Triangular Truss. These are not common now
since modern bridges are made of be steel box girder, post stressed concrete or cable
Warren
Truss
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4.0 MATERIALS AND EQUIPMENT
4.1 Main Material - Fettuccine
Investigation has been made to 2 diverse kinds of fettuccine to determine their
strength and suitability for model making.
Type of Fettuccine Observation & Description Efficiency
1.Arbell • Flat Profile
• Heavy
• Thin
• Fragile
1
2. San Remo • Concave Profile
• Light
• Thick
• Strong
2
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Glue- Adhesive Materials
Investigation on a few sorts of super glue to tried on fettuccine to figure out which
one is the most suitable as the glue as far as efficiency for model making
Type of glue Observation & Description Efficiency
1 Dolphin Super Glue • Fettuccine unstiffen
by the glue
• Creates rigid joints
• Messy Outcomes
• Glue joints take long
times to dry
• Joints are not strong
once it dry
2
2 V-Tech 3 seconds glue • Dry very fast
• Easy to use
• High efficiency
• Joints are very strong
after it dry
3
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4.2 EQUIPMENT
Cutter Sand Paper
The cutter used to cut the fettuccine in model making and the sand paper use to sand
the edges of the components of the bridge to fit perfectly.
S-Hook Bucket
S hook used to hang the load with the guide of bucket on Fettuccine Bridge
consequently all the force connected on one purpose of the bridge.
Weight Water
Weight and water bottle act as the load to test the strength of Fettuccine Bridge
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Weighing Machine
Weighing machine use to weight the mass of Fettuccine Bridge to ensure that is not
overweight or exceed the maximum weight over 80g
Strength of Material
Fettuccine was the main materials that only can be used for the final submission of
model making. For better result, we had done the research and analysis before the
model making session.
Properties of Fettuccine
The fettuccine that we used during the making of the truss bridge model has the
thickness of 1mm and the width of 4mm. It is brittle and thus is stronger under the
tension. However, fettuccine has a low compression strength
• Ultimate tensile strength: 2000 psi
• Stiffness (young’s Module) E: 10,000,000 ( E= stress/strain )
Glue Technique
In order to get better efficiency, we ensured that the fettuccine glued with the proper
technique to prevent uneven surface and also the ease of building with modular units.
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4.3 Strength Testing
Strength testing on 2 types of fettuccine that we choose according to the efficiency.
Fettuccine also were tested by having 5 layers
+ + + +
Brand Type of glue 100g 200g 250g 300g 350g 400g 450g 500g
Kimball Super glue ü ü ü
X
X
X X X
Kimball 3 seconds
glue
ü ü ü ü
X X X X
San
Remo
Super Glue ü ü ü ü ü ü
X X
San
Remo
3 seconds
glue
ü ü ü ü ü ü ü
X
Model Making & Design Development
Requirement for Fettuccini Bridge:
1. Maximum bridge weight of 80g
2. Only fettuccini can be used
3. 350mm clear span bridge
4. Bridge will be tested until break
San
Remo
Kimball
San
Remo
Kimball
3
seconds
glue
3
seconds
glue
Super
glue
Super
glue
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Problem
1. Connection between frame and structural components applied stacking method.
2. Structural components too weak due to amount of layer.
3. Frame is intact, problem due to poor craftsmanship.
The Warren Truss is one of the most popular bridge designs and examples of it can be
found everywhere in the world. The Warren Truss uses equilateral triangles to spread
out the loads on the bridge. This is opposed to the Neville Truss which used isosceles
triangles.
The equilateral triangles minimize the forces to only compression and tension.
Interestingly, as a load (such as a car or train) moves across the bridge sometimes the
forces for a member switch from compression to tension. In our first design we just
used 1 layer of fettuccini to connect all joints and we didn't use the super glue
properly for sticking all joints so the bridge broke off with just 1kg of water.
Solution
1. Connection between frame and structural components thickened.
2. Sandwich joining method applied.
3. Length of structure calculated & increased.
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(4)!
0.07
= 228%
Problem
1. Mixture of different brand of fettuccine.
2. Structural components in between frames not added.
3. Left gap between frames, causing frame to collapse.
From the exhortation from the first design of our fettuccini bridge, we found out that
Warren Truss Design makes a lot of troubles in the support and joints. So we look for
another design (Double Howe Truss), a truss having upper and lower horizontal
members, between which are vertical and diagonal members; the vertical members of
the web take tension, and the diagonal members are under compression. After the
weight test, we found out that the support from on the triangular joints member are
stronger than warren truss and the efficiency as well.
The main problem of this design is the gap between the frames, makes the bridge has
a lot of week points. And we also strengthen up the middle part with adding more
layers of fettuccini beam to give better support but it doesn’t have good result in the
end which can only take about 4kg weight. Based on our research, we found out that
I-beam helped a lot in supporting weight so we decided to change I-beam as our main
support.
Solution
1. Mixture of different brand of fettuccine.
2. Structural components in between frames not added.
3. Left gap between frames, causing frame to collapse.
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Efficiency:
(8)!
0.107
= 598%
Problem
1. Minimum gap between frames.
2. Slanted structural components were not strong enough.
3. Weight exceeded.
4. Weak connecting point of fettuccine.
After the previous failure, we had found out that the orientation of diagonal member
of the bridge are arranged in a way that does not contribute much in helping to sustain
the load as the main load pressure is exerted in the middle of the bottom cord. We had
changed its orientation into the opposite orientation from / to where the bottom tip of
the diagonal member is attached to the middle of the bottom cord which we think it
may help in increasing its structural strength.
In this design, the efficiency of bridge had a huge increase but it is because of the
exceeded weight of bridge so it couldn’t be used.
Solution
1. Weight reduced.
2. Changes in joining material.
3. Reduced thickness of frames and structural components.
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Total Length: 420mm
Clear Span: 350mm
Bridge Weight: 78g
Load Sustained: 5kg
Efficiency:
(5)!
0.078
= 320%
Load Sustained: 5kg
Problem
1. Middle structure not strong enough to withstand the weight.
Based on our observation and analysis, we had found that the design of our previous
bridge has a high potential of load carrying ability and the main problem is having too
much of weight. In order for us to maintain or increase its strength when we reduce
the weight of bridge, we had decided to redesign it which having a lower pitched end
post, shorter vertical and diagonal members.
It has successfully came out with a lower weight which is appropriate according to
our requirement but unfortunately having a lower efficiency and load carrying ability.
The only reason of failure at 5kg is because of the breaking of middle I-beam for the
hook, and all other structural members were remained stable. So we can assume that it
can possibly weight more than 5kg when it has a stronger middle I-beam.
Solution
1. I-beam amount reduced
2. Increased strength of middle I-beam.
Summary
Lastly, the efficiency of our final bridge boost up to 680%. Affected by the good
craftsmanship, joints and weight to achieve high efficiency of fettuccini bridge. In the
final test of our fettuccini bridge, it’s not fully cracked in the end, only the middle part
broken off, we found out that the glue which stick the I-beam to the truss in the
middle is not strong enough and became the main breaking point. In addition, we
finished our final model 3 hours before the final testing to reduce the chemical side
effect of superglue.
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6.0 FINAL BRIDGE
FINAL MODEL
After a few attempts in designing our bridge, we had chosen the fettuccini bridge
design 5 as our final model to be tested as it has the highest load carrying efficiency.
The same design and construction method was used and being constructed in a more
aesthetic way such as the joints were perfectly made without roughness.
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6.1 FINAL MODEL MAKING STEPS
In order to construct our bridge in a more effective way, we had planned steps to
construct our bridge.
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Step 1. Both of the base I-beam which is the bottom cord will be constructed.
Step 2. Both of the bottom cord will be connected together by using floor beams. The
vertical members will be constructed and glued according to its position with the edge
cut bevelled.
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Step 3. The end post will be constructed creating a triangular form.
Step 4. Top lateral bracing is then added.
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Step 5. The diagonal members will be added in between the vertical members. Struts
will be added connecting both of the end post.
Step 6. Extra I-beam will be added to the middle member to create a platform for
hanging of hook.
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6.2 Joint Analysis (side view)
Joint 1
The top part of the bridge is connected to the bottom cord by using a vertical member
that is cut and shaved until it is perfectly fits. This is to ensure a larger contact surface
that sticks and connects both posts to create a stronger bond. It is tested that perfect fit
joints holds more weight compared to just joining the fettuccine by sticking by the
side using super glue. Perfect fits makes the entire structure more solid.
Joint 2
The diagonal members are also cut into perfect fit to join in the structure, filling in the
blank space and helps to maintain weight. It acts as a member that makes the whole
trangular structure rigid. However, it is tested that the diagonal members are not so
effective in the structure. It adds more weight into the structure rather than efficiency.
1
2
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6.2.1 Joint Analysis (top view)
Joint 3
The fettuccine block is fit into the I-beam perfectly to ensure the solidity of the
structure. The structure is a lot more stronger while the joints are perfectly cut and fit.
Joint 4
Stacking method is used on the I-beams at the center of the entire structure. This is to
ensure balance load distribution of the structure. It is the most important part of the
structure because it acts as the haging spot for the weight testing. It has to be strong
enough to sustain as much weight as possible.
3
4
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Final Bridge Testing and Load Analysis
Figure 3The bridge when it is testing.
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Final test analysis and conclusion
In our final model for submission, we managed to carry a 7kg weight by using our
bridge which is 72g producing 680% efficiency. It was a great success as it has a
higher efficiency value with a lower weight that our last bridge.
However, the broken part is still the middle I-beam which we found out it was
because that the super glue that we used to stick it was not strong enough cause by the
rain water while we bring it to final testing area. It also caused the drying glue to
reduce its adhesive strength and it became the weak point of the whole structure.
FINAL BRIDGE DATA
Total Length: 420mm
Clear Span: 350mm
Bridge Weight: 72g
Load Sustained: 7kg
Efficiency:
(7)!
0.072
= 680%
The final result has not met our expectations as it should probably carry more load
that 7kg if the structure was not being exposed to rain.
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7. CONCLUSION
Throughout the project, we had constructed a total number of 6 fettuccine bridges
including the final test model. All of them were being experimented for its efficiency
in the maximum load it can hold and from each of the breaking and failure, we learnt
something and make changes gradually.
This project made us more comprehend load distribution in a structure more profound
as we are able to calculate the type of force applying in each structure member.
Before we had our final test model, we investigated diverse course of action of basic
individuals and acknowledged it is key to recognize the power
(Tension/Compression/Zero/Critical ) in basic individuals so as to accomplish a high
productive scaffold outline.
In the conclusion, we learnt how significance of legitimate arranging, as far as work
designation and the time interim between culmination of scaffold and load testing. It
is because of the proficiency of finishing the scaffold on time and giving a
satisfactory time for the glue to dry out and keep up its quality until burden testing.
Final
testing
model
bridge
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8.0 Case Study
Case Study 1 (Tsang Hao Ren 0315753)
