BUILDING STRUCTURE [ARC 2523] PROJECT 1

FETTUCCINE TRUSS BRIDGE

LEE RUN SEN

LIM FOU SING
WONG JIAN KAI
TAN KWOK SEONG
TSAI WAN CHING

0398266
0314997
0314794
0314700
0315185

TABLE OF CONTENT
1.0 Introduction
1.1 Summary
1.2 Report Preview
1.3 Aims and Obective

2.0 Methodology
2.1 Precedent Study
2.2. Material and Adhesive Strength Testing
2.3 Model Making
2.4 Structure Analysis

3.0 Precedent Study

3.1 History
3.2 Analysis

4.0 Equipments and Materials

4.1 Equipments
4.2 Adhesive Types
4.3 Guing Method
4.4 Fettuccine Testing

5.0 Model Making

5.1 Joint
5.2 Method of Construction

6.0 Design Progress & Analysis

6.1 1st Bridge Desigm
6.2 2nd Bridge Design
6.3 3rd Bridge Design

7.0 Final Design

7.1 Final Bridge Design
7.2 Result
7.3 Failure Analysis
7.4 Solutions

8.0 Conclusion

1.0 Introduction
1.1 Summary
Trusses are typically comprised of five or more triangular units constructed with straight members
whose ends are connected at joints or referred to as nodes. The connected elements, which are
typically vertical may be stressed from tension, compression, or sometimes both in response to
dynamic loads.

1.2 Project Preview

In a group of 5, we were assigned to construct a fettuccine bridge witth clear span of 750mm and
200g of weight limitation. The fettuccine bridge will be tested on the efficiency by load testing.
Different types of truss typologies and arrangement, jointing methods between each member,
load distribution analysis and efficiency of Fettuccine bridge will be discussed for in-depth study of
truss bridge structure. To aid the analysis of truss bridge structural study, a set of testing result
will be provided alongside with analysis diagrams and calculations.

1.3 Aims and Objective

This project aims to understand the physical theory of tension and compressive strength of
construction method and construction materials. In this project, a perfect truss bridge is designed
in order to develop understanding of force distribution in a truss. The truss bridge has fulfilled a
high level of aesthetic value and the use of minimal construction materials, which is fettuccine.
Throughout this project, evaluation, exploration and improvisation have attributed on the
construction materials to achieve higher effeciency and at the same time, decreasing the load of
the truss. By the end of this project, all of the group members are able to evaluate and identify
tension and compression members in the truss structure and exploration on different
arrangement members are made.

2.0 Methodology
2.1 Precedent Study
Precedent studies are done to serve as examples of different types of truss designed. By the use of
precedent studies, it helps in understanding on the arrangement and joint connections of different
types of trusses. Based on our findings, we then developed a perfect truss bridge and add on desired
joint connections to strengthen the entire structure.

2.2 Material and Adhesive Strength Testing

Fettuccine is the only material that builds up the entire truss bridge. We have tested the physical
strength of fettuccine by load testing on mockup models. By then, we proceed to the number of
fettuccine needed for top chords, bottom chords and webs. UHU Glue, Hot Gun Glue and 3 Seconds
Glue were tested on its adhesive strength. However, 3 Second Glue is used throughout the model
making process as we found out that it is the strongest and most stable material to adhere
fettuccine.

2.3 Model Making

A set of AutoCAD drawing is drawn for model making purpose so that the dimensions of cut
fettuccine are all accurate. This is to minimize the error in joining each member and to ensure that
all of the members are in its correct position.

2.4 Structural Analysis

Upon completion of the truss bridge, water is filled into a pail that is connected with S hook at the
middle point of the truss bridge. Load testing is done for several times to evaluate the effeciency of
the truss bridge and improvement is made after that. Improvement is then brought to the next
model making session to achieve higher effieciency. However, a thorough analysis of the truss
bridges are made to examine the reason of failure on the truss bridge.

3.0 PRECEDENT STUDY:

Hurley Railroad Overpass West

Official Name:
Hurley Railroad Overpass West
Facility Carried / Feature Intersected:
Railroad (Abandoned Soo Line)
Over Railroad (Abandoned Chicago and Northwestern)
Location:
Near Hurley: Iron County, Wisconsin
Structure Type:
Metal 8 Panel Rivet-Connected Baltimore Through
Truss, Fixed
Structural Dimensions:
Main Spans: 1
Construction Date and Builder/Engineer:
Unknown

3.1 HISTORY
This bridge is a gorgeous four panel truss bridge that
once separated two railroad grades. Today both
lines are abandoned, but remain in use for
snowmobiles. The bridge's structural steel is built-up,
and V-lacing is present on all members, and also
under the top chord and end post, and the bottom
chord. The portal bracing and one set of sway
bracing features a lattice design. The bridge is
seated on concrete abutments.
This bridge is technologically significant as an
example of a Baltimore truss, which is less common
than the mainstream truss configurations, the Pratt
and the Warren. It is also locally significant as one of
the last remaining metal truss bridges of any kind in
northern Wisconsin.

3.2 ANALYSIS
By studying and understanding the Hurley Railroad Overpass West, we have gathered a good
amount of knowledge on the nature of truss bridges. Being one of the the less mainstream truss
configurations, Hurley Railroad Overpass West remains a technologically significant until today, and
the reason we have chosen it as our case study subject. Hurley Railroad Overpass, a Baltimore truss,
possesses a very simple and yet very strong design structure. The Baltimore truss is a subclass of the
Pratt truss. It has additional bracing in the lower section of the truss to prevent buckling in the
compression members and to control deflection. After understanding how a Baltimore truss works,
we then proceed to analysis its flaws. With numerous counter braces attached, the Baltimore truss
relies a lot on the joints, thus further emphasis must be put on to the joints.

Compression
Tension
Reaction

Diagram 3.2 Baltimore Truss

From the diagram above, we can see how the forces react when load is applied. With the right
height to width ratio, Hurley Railroad Overpass West manages to obtain a respectable result, thus its
mainly being used for snowmobiles.

In terms of the joinings, The Baltimore truss bridge uses the bolted joint. This is to ensure every
joint is in its optimum state as the Hurley Railroad Overpass West is one of the last remaining
metal truss bridges of any kind in northern Wisconsin.

4.0 Equipments and Materials

4.1 EQUIPMENTS
Fettuccine
Fettuccine is the main material that builds up the entire
truss bridge.

3 Seconds Glue
This is chosen to adhere fettuccine as it is the strongest
among other glues and fettuccine turns into stable
structure within seconds.

Plastic Bag
The use of plastic bag is to test the physical properties
of fettuccine before model making.

S Hook
S hook is used to connect the centre of the truss bridge
and carry water pail for load testing.

Water Pail
Water pail is used for load testing and the efficiency of
truss bridge is calculated based on the load carried.

Kitchen Balance and Electronic Balance

Measuring equipment used for weighing
the truss bridge to ensure that the
weight does not exceed 200g. Kitchen
balance is used initially, but electronic
balance is after that as the readings
from electronic balance is more
accurate.

4.2 ADHESIVE TYPES

Several types of glue are tested out to determine which is the best to bond fettuccine.

Type of Glue

Observation

Analysis

- Adjustable for a short period

- Lowest efficiency for joinings
- Non-rigid joint
- Require more time to be
solidified

- Provides flexibility to joints

- Removable glue stain
- Glue stain can be
troublesome

- Rigid joint
- Adjustable within 2 seconds
- Quick solidifying

- Possibility of bending and

expanding
- Cracking after couples of days

- Rigid joint
- Non-adjustable
- Significate increased on
weight

- Bulky finishing
- Affect the quality of
fettuccine
- Not effective in bonding

UHU Glue

3 Seconds Glue

Hot Glue
Table 4.2 Types of Glue & Analsis

4.3 GLUING METHOD

Several gluing methods had been carried out in order to determine the most efficient method which
doesn't lower down the strength of the fettuccine.

Diagram 4.3.1 Applying glue at the end points of the fettuccine stick

Diagram 4.3.2, Applying glue at the end points and middle point of the fettuccine stick

Diagram 4.3.3 Applying glue at the whole surface of the fettuccine stick

Type of
Glue

Glue
Applied

Clear Span
(mm)

Length
(mm)

2 Points
3 Second
Glue

3 Points

20

24

Whole

No. of
Layers

Weight
Sustained
(grams)

149

251

297

Table 4.3 Effectiveness of Gluing Method

The table above shows the result of different gluing method by using 3 seconds glue. All having
the same weight, same length, same properties, but different gluing spot. The one which got
glue applied all over the fettuccine have the highest efficiency, followed by 3 interval points
and 2 interval points. Though the fettuccine will occur to bend more a day after.

4.4 FETTUCCINE TESTING

Fettuccine is the only material that was approved to be used throughout the project. Hence, as
efficiency is the main consideration for the project, testing methods to joint layers of fettuccine was
executed in order to determine the best method to withstand maximum loads. Different
arrangement, number and orientation of Fettuccine were made to be tested by applying point load
(volume of water) at the centre point of Fettuccine.

Throughout the testing of the fettuccine, in depth analsis was conducted for further development in
order to achieve higher effiency.

Physical Strength
All of the physical strength of fettuccine is tested by horizontal surface facing on the table
that has a length of 15cm and clear span of 10cm for both stacking and
I-beam method.

Stacking
Quantitiy of
Fettuccine

Weight Sustained
(gram)

48

82

100

125

148

Figure 4.4.Testing of Fettuccine Properties

Observation:
A horizontal facing of five layers of fettuccine withstand higher load and all of the fettuccine
tested started to bend at the centre and break after that.
Conclusion:
All of the fettuccine started to bend at the centre and breaks after that although the quantity of
fettuccine increases. This proves that the fettuccine will break easily even though the layer
increases, therefore this arrangement of fettuccine is still under consideration in producing the
truss bridge.
Load
Compression
Tension
Diagram 4.4.1 Horizontal Facing Fettuccine

I-Beam
Quantitiy of fettuccine

Weight Sustained (gram)

163

160

Observation:
The I-beam arrangement of fettuccine is in horizontal facing on the table where the
vertical members resist shear force and the horizontal members prevent the beam from
rotating. Although the quantity of fettuccine increases until 6, but the weight sustained is
slightly lower only compared to I-beam that formed of 4. The flanges stop the beam from
rotating in the both planes of the web which is caused by bending moments.
Conclusion:
I-Beam is a very efficient form for carrying both bending and shears loads in the plane of
the web. This is an effective way in joining fettuccine rather than the stacking method.
Moreover, with consideration of properties of fettuccine, members under tension do not
need to be fabricated as trusses because their strength is only depends on sectional area.
The quantity used for model making is 4 fettuccine as there was only a slight difference of
weight sustained compared to the quantity of 6 fettuccine.

Load
Quantitiy of fettuccine: 4

Compression

Shear

Tension
Diagram 4.4.2 I-Beam

Diagram 4.4.3 Internal Force

Load
Quantitiy of fettuccine: 6

Compression

Shear

Tension
Diagram 4.4.4 'Solid' Cube I-Beam

Diagram 4.4.5 Internal Force

5.0 Model Making

5.1 JOINT

As fettuccine is used as the material for this truss making project, joint is the main concern as it can
only be slot and stack, unlike the actual material, steel, which can be bolt or weld, Therefore
method of slotting and stacking has been tested via our design progress.

Efficiency = (Maximum load) / Weight of bridge

Based on the formula, the efficiency of the bridge is determine as square of maximum load applied
on the bridge divide by the weight of the bridge. To achieve high efficiency, the bridge must be able
to carry as much load as possible whereas the weight of the bridge itself have to be as light as
possible. After obtaining result from the final load test, the efficiency of our final bridge is then
calculated.

Slotting Method

Figure 5.1.2 Slotting Mathod Truss

Three layer stackings

Three layers will ensure the joint
become stronger since the forces will
be balance at each sides.

Figure 5.1.2.1 Layerings

Sloting method
Vertical members are being slotted to the
main beam to enhance the whole structure.

Figure 5.1.2.2 Slotting

Cut and fill

One placed in front of another member to
hold it and one placed behind it to support
and it can solve the stacking problem.

Figure 5.1.2.3 Joint

Stacking Method

Figure 5.1.2 Stacking Mathod Truss

Flat joint
Flat joint at the bottom part of
the bridge ensure the stability
and will increase the efficiency.

Figure 5.2.2.1 Joint

Members focus lay on main

beam
It's better to concentrate the
load on the main beam since it's
the strongest part of the bridge.

Figure 5.2.2.2 Layerings

Complex joint
Complex joint form compact joint and structure
that combine all joints more effectively.

Figure 5.1.2.3 Joint

5.2 METHOD OF CONSTRUCTION

Step 1: Draw out the truss through AutoCad drawing to help in accuracy dimensions of each
member and the distance between each joint, followed by printing it in one to one scale.

Figure 5.2.1 AutoCad Drawing Printout

Step 2: Cutting fettuccine carefully according to the printed drawing to ensure every members are
perfect enough to fit in so the truss bridge will be balance.

Figure 5.2.2 Cutting Fettuccine

Step 3: Stick the fettuccine according to the printed drawing to ensure each are on the exact
position so the force transfer will be balance.

Figure 5.2.3 Stacking and Sticking Fettuccine

Step 4: Each members are placed carefully as some will be stick at the external and some will be
stick in the internal of the straight member at joints, this step is to ensure it's perfectly balance so
none of the member is slanted.

Figure 5.2.4 Pasting and Trimming for Joints

Step 5: Erecting two facade vertically with internal distance of 9cm.

Figure 5.2.5 Erecting the Two Facade of the Truss Bridge

Step 6: Making horizontal connectors which helps in supporting and connecting both facades, to
form a complete truss bridge.

Figure 5.2.5 Connectors Making

Step 7: Stick the connectors and form I-beam to enchance the middle connector which holds the
load, cause that particular spot will be receiving direct downwards force while testing.

Figure 5.2.7 'Solid' I-Beam Making

Step 8: Complete set is done after joining the top part.

Figure 5.2.8 Complete Truss Bridge

Step 9: Weighing the truss bridge before testing to check if it has exceeded the requirement weight
and to be recorded for efficiency calculation later.

Figure 5.2.9 Weighing

6.0 Design Process

6.1 1st Bridge
Structural Design:
We first started with Pratt Truss. A Pratt truss includes vertical members and diagonals that slope
down towards the center, the opposite of the Howe truss. The interior diagonals are under
tension under balanced loading and vertical elements under compression.

Diagram 6.1 Pratt Truss

Analysis:
If pure tension elements are used in the diagonals (such as eyebars) then crossing elements may
be needed near the center to accept concentrated live loads as they traverse the span. It can be
subdivided, creating Y- and K-shaped patterns.
By understanding how the Pratt Truss was formed, we closely analyse the forces acting on the
truss. We realise that the Pratt Truss has a good balance in both compression and tension force.
With the knowledge of the nature of fettuccine, we understand that the fettuccines are only good
in tension and weaker in compression, thus the reason we started with the Pratt Truss as it
possesses only of the best balance in the forces.

1st Model Load Testing

Figure 6.1.1 Pratt Truss Testing

Failure:
After the testing, we proceed by analysing the breaking point and try to justify the failure. After
close inspection, we noticed the breaking area are all near the centre of the braces; the
slanted bracing especially. With more in depth researching, we realised its due to the weak
point of the fettuccine, which is in the centre of the it.

Suggestions:
-

Add support around the centre of the slanted bracing

Double the amount of fettuccine with slotting joint
Baltimore Truss

6.2 2nd Bridge

Structural Design:
To address this issue faced in test 1, we started looking at subclasses of pratt truss; we then
stumbled upon the Baltimore Truss. A Baltimore truss has additional bracing in the lower section
of the truss to prevent buckling in the compression members and to control deflection.

Diagram 6.2 Baltimore Truss

Analysis:
The Baltimore truss is a sub-type of the Pratt truss, but differs by the addition of half-length struts
or ties in the top, bottom, or both parts of the panels. It was first used on the railroads in the
1870's.
By analysing how the pratt truss failed, the baltimore truss seems to address our issue as it
provides extra support around the centre of the slanted braces and will prevent buckling in the
compression member. Besides it introduces more tension members into the bridge, which is an
advantage to our model as fettuccine is stronger in tension. Slotting joint is being used.

2nd Model Load Testing

Figure 6.2.1 Baltimore Truss Testing

Failure:
After the testing, the breaking point changed from centre to the side of the bridge. By further
analysing the broken part, it seems to have snapped due to wrong force displacement.
Besides, the bottom part of the truss gave way too soon before the bracing could reached its
maximum potential. The bracings on the other hand did not break at all.

Suggestions:
-

Change width to height ratio

Change base to I-beams
Change to stacking joint
Widen the bracings gradually along the sides

6.3 3rd Bridge

Structural Design:
Since the issue faced from test 2 was due to wrong displacement of forces, we started making
changes of the baltimore truss. We increased the height to obtain a more stable height to width
ratio, increase the distance of each bracing gradually and lastly removed the short vertical
bracings.

Diagram 6.3 Modified Baltimore Truss

Analysis:
The Baltimore Truss we tested had proven that it has better reinforcement and compression
strength due to the additional diagonal braces. However, we wanted to reach higher efficiency
thus we studied about the ratio between the horizontal and vertical length. We discovered that
the best and optimum ratio of horizontal over vertical length is 1/6 for the fettuccine bridge to
withstand the compression force. Hence, we decided to extend the length of the vertical braces to
12.5cm over 750cm horizontal length.
Besides, to further strengthen the bridge, we decided to add on more fettuccini layers on the
horizontal span which is in a form of an I-beam. Two crossover hanging points were also made to
enhance the force spreading to the rest of the bridge.
We have also discovered that in the case of fettuccine bridges, the strenght of a slotting joint and
a stacking joint are on par. Thus in the favour of time saving, we have decided to go with the
stacking method.

3rd Model Load Testing

Figure 6.3.1 Baltimore Truss Testing

Failure:
Once again, the bridge broke at the side. The fettuccine bridge managed to hold up to 4.8kg load
which became our highest result compared to the previous models. However, after the
measurement of the weight of the bridge, it exceeded 200g which reached up to 264g. Due to
strict weight restriction, this model is still considered a failure. But we thought that this design
structure lived up to our expectations.

Suggestions:
-Remove number of fettuccine layers at unnecessary areas
-Make sure the side triangle base sits perfectly on the edges of the table

7.0 Final Bridge Design

7.1 Final Bridge Design
Structural Design:
In the end, we have decided to maintain its structural design and only tweak the weight by
reducing number of layers of fettuccine in unnecessary areas. Width to height ratio, usage of Ibeams for the base, stacking joint and gradual widening of the bracings are all kept the same.

Diagram 6.4 Modified Baltimore Truss

Analysis:
With numerous attempts and testings, we have finally come to such a modified baltimore truss (as
seen above). We believe that is design structure is one of the most stable and best suits the nature
of fettuccine. Most of the fettuccines are in tension rather thn compression. Besides, the diagonal
bracings are all angled prefectly to correctly redirect the forces to the supported joints.
And when forces are all redirected correctly, the braces actually carry much lesser weight. Thus
we decided to decrease the weight of the bridge by reducing layers of fettuccine down to 1 for the
short diagonal bracings.
With the discovery that in the case of fettuccine bridges, the strenght of a slotting joint and a
stacking joint are on par. Therefore, we proceed the final model with stacking method as it's much
quicker and less workmanship error.

Final Load Testing

7.2 Result
Result of all models are gathered and calculated, shown in Table 7.2.

Model

Weight (Grams)

168

185

234

192

Load Withstand
(KG)

2.3

3.2

4.8

2.8

Efficiency

31.42

55.35

98.46

40.83

Talbe 7.2 Efficiency Calculation

As the result shown in the table above, we had actually improved significantly from model 1 to
model 3. As for the final model, the result has been a disappointment as the efficiency dropped,
which is out of expected, it's most likely due to the wrong analysis as we changed the number of
layers at last. Details of failure analysis will be explain in failure analysis later.

7.3 Failure Analysis

Neglection on Webs
The final load testing of the truss bridge has once again broken at the side of the structure
instead of centre. The reason of this failure is due to the neglection towards the omittance of
the short dimension of webs as we have changed the number of fettuccine of webs from double
sticks to single. Although this helps in reducing the weight of the truss bridge, the low strength
of the short webs has caused instability tensile and compressive strength on the entire structure.
Due to this reason, the structure has then reached its own strength capacity and it broke.

Digram 7.3.1 Web failure analysis

Slanted Truss Bridge

Workmanship is one of the reasons that caused the failure of the structure. The truss bridge has
already slanted even before load testing. Therefore, the tension and compression of the bridge
did not distribute well and there is a possibility that one side of the truss bridge has carried
more forces than the other side. We have analysed that the design of the truss bridge is not the
main problem but on the other hand, the structure has not reached its maximum physical
strength due to workmanship failure.

Diagram 7.3.2 Structure failure analysis

7.3 Solutions
Double Sticks of Short Webs
The use of webs should not be neglected. Although the webs are in short dimensions, the
webs did help to support the longer web and make the structure to be more rigid. Therefore,
we should have maintained the webs to double sticks to secure the structure form.

Diagram 7.4.1 Solution 1

Use of Set Square

As we found out that printed AutoCAD drawings has helped in accuracy dimensions of each
member, but then the structure has slanted when we joined two sides of the truss to form a
bridge. Prevention of slant truss bridge can be done during the joining of both trusses by the
help of set square to ensure that the base and the top of the truss bridge are of equal length
in between.

Diagram 7.4.2 Solution 2

7.4 Truss Analysis

Compression

Tension

Reaction

Diagram 7.4 Final Truss Design Load Transfer Analysis

The diagram above shows the internal force transfer, compression and tension. It can be seen
that this structure design depends more on the tension members, which shows that manwork
ship is very important. The height should be 1/6 through our research, which works the best for
this truss structure. Therefore, it has shown that this truss can be very effective, but it relies on
materials, steel will work very well for this truss, but as we are using fettuccine for this project,
the properties itself and workmanship cannot stimulate the actual potential of this truss.

8.0 Conclusion
We have deeper understanding for load distribution through this project, as well as in
identifying the differences between tension and compression members in a truss bridge.
According to the efficiency equation, a high efficient bridge is defined as a bridge that can
withstand high load with minimal weight. Although the result of our final bridge was not up to
expectation, but we learnt that properties of fettuccine has to be up to a certain thickness in
order to present the true potential of the truss which we designed on.
Throughout the project, we have explored different arrangement of structural members and
realized it is important to identify the force (tension/compression/zero/critical) in structural
members in order to achieve a high efficient bridge design. We have tried to strengthened
the weaker part of the bridges in order to have a higher efficiency.
In this project, quality of craftsmanship is a crucial key for the truss as well. To ensure a better
workmanship, proper planning should be made before model making. Proper way of adhesive
and consistency of jointing the members are vital to ensure the connections are strong too.
Lastly, we learnt to apply the theory into partical, using lesser weight to sustain more loads,
this is beneficial to the community as we uses less resources when we really designing a real
bridge.