Building Structure Project 1 Fettuccine Bridge

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 (ARC2213)
____________________________________________________________________
Project 1
Fettuccine Truss Bridge
Loo Giap Sheng 0310390 Gan Chin Bong 0313738 Teo Kean Hui 0310165
Ng You Sheng 0309997 Kong Chee Seng 0308360

Table of Content
1.0 Introduction
1.1 Aims & Objectives
1.2 Project Scope
2.0 Precedent Study
2.1 Overview
2.2 History
2.3 Structure Details
3.0 Materials Study
3.1 Fettuccine
3.2 Materials & Equipment
4.0 Design & Structure Analysis
4.1 Design 1
4.2 Design 2
4.3 Design 3 & 4
4.4 Design 5 & Final Design
5.0 Conclusion
6.0 Appendix
7.0 References

1.0 Introduction
1.1 Aim & Objectives
The objectives of this project are as follows:
 To develop student’s understanding of tension and compressive strength of
construction materials
 To develop student’s understanding of force distribution in a truss
 To design a perfect truss bridge which fulfils the following criteria:
 High level of aesthetic value
 Minimal construction material
1.2 Project Scope
As a group, we are required to carry out precedent study of a truss bridge. Then, we have to
design and construct a truss bridge using fettuccine and adhesive materials such as glue. The
bridge must be at least 750 millimetres of clear span and weight not more than 200 grams.
The structure is then tested to carry load until it breaks.
Efficiency of the bridge can be calculated as follow:
Efficiency, E = (Maximum Load)² / Weight of Bridge
In order to achieve higher efficiency, structure analysis have to be carried out to study and
determine members of tension and compression. Several times of load testing have to be
carried out to identify structure failure point and weaker truss members.

2.0 Precedent Study
To have better understanding of truss bridges, appropriate precedent study should be carried
out. The following is our study of truss bridge:
Image 2.1: Perspective view of the bridge. Source: Sun Current
Name: Long Meadow Lake Bridge
Location: Old Cedar Avenue at Minnesota River, Bloomington, Hennepin.
Largest spam: 170.0 feet
Total length: 864.5 feet
Deck width: 21.0 feet (2 lanes)
Materials: Steel and Iron
Type of truss: Camelback truss
Diagram 2.1 above shows camelback truss. Source: Wikipedia

2.1 History
The Long Meadow Lake Bridge is a five-span through truss camelback bridge that was built in
1920. Before the highway 77 overpass opened in 1981, it was one of the few bridges that
connects traffic from Old Cedar Avenue to Dokata County. This bridge was given to the City
of Bloomington by the State of Minnesota in 1981, and was still open to automobile traffic as
late as 1993. It remained open to pedestrian and bicycle traffic after it was closed to vehicle
traffic. In the early 2000s, the bridge deck was declared to be unsafe. The bridge was deemed
unsafe again in 2002, and had to be barricaded at each end. It was scheduled to be
rehabilitated beginning in 2014. The builder of this bridge was Illinois Steel Bridge Co. Of
Jacksonville. The bridge today called Old Cedar Avenue Bridge and had average daily traffic of
400 vehicles.
Image 2.2 showing the bridge was closed down in 2002. Source: Johnweeks
Image 2.3 showing the spring flood in 2010. The water level is just under the bridge deck.
Source: Johnweeks

2.2 Structural Details
Image 2.4 showing the beams and decking of the bridge. Part of the decking had already
teared off. Source: Johnweeks
Image 2.5 shows the connection between girders and a stringer at the abutment. Note that
you can see daylight through holes at several spots on this beam, and that the stringer is rotted
through on the right side of the image. Source: Johnweeks

Image 2.6 showing the bridge bearing at the end of the structure. The bridge structure is
pushed fully back up against the concrete abutment. This is most likely caused by the bridge
sagging due to a weakened structure. The pressure is causing the concrete to crack. Source:
Johnweeks
Diagram 2.2 showing the joints at the corner end of the bridge. Source: Past-inc.
org

3.0 Material Study
3.1 Fettuccine
Fettuccine is used as the main material for the bridge construction. Before use, fettuccine
need to be check and filter out those that are twisted; it is to ensure that the load is able to
distribute evenly and effectively through the flat surface of the fettuccine.
Dimension: 250mm x 5mm (average)
Tensile strength: ~2000psi
Stiffness (E=stress/strain): ~10,000,000psi
We have tried 2 types of fettuccine to test its strength and weakness:
San Remo Spinach fettuccine
San Remo fettuccine
Strength of material is analyzed:
 Greenish yellow
 Slightly harder than normal fettuccine
 Surface a bit round
 Gold Yellow
 Softer than the spinach fettuccine
 Flat surface
 Ratio of usable fettuccine is higher
Shear force Shear force
When the fettuccine is laid flat and the force is only applied on the middle, bending will occurs
due to tension and compression.

Shear force Shear force
When the fettuccine is put upright, the thickness of the fettuccine provide more tensile
strength then laying it flat. However the narrow surface’s load distribution is much lesser than
flat surface, this increases pressure on the structure.
Solution:
Image 3.1 shows force acting on ‘I’ beam structure.
‘I’ beam structure is use; both advantages of horizontal and vertical position are able to be
put in use. When the vertical member is placed in between two horizontal members, the
horizontal members will enhance the load distributions and the load will transfer to the
vertical member which can withstand more loads.
Image 3.2 shows force acting on one side of solid structure
By adding more vertical members, it enhances the load transfer from horizontal member to
the vertical members.

3.2 Materials & Equipment:
PVA UHU Super Glue (Selleys)
 Water based glue
causes fettuccine to
soften
 Take long time to dry
 Weak joints
 Take long time to dry
 Joint not rigid
 Shifting occurs when
load apply on it
There are other equipment to aid this project:
 Luggage scale (max. 5kg)
- Act as a hook between bridge model and water pail, at the same time determine the
weight of the load.
 Water pail
-Act as a container to carry loads.
 Camera
-Record down the procedure of load testing, to determine which part of the structure
causes failure.
 Mineral bottles (500ml)
-Use as the standard addition of weight during load testing.
 Dry within 10-20
seconds
 Produce strong and
rigid joints
 Surface that was
applied once can’t be
apply on again

4.0 Design & Structure Analysis
We did six bridges in total, in five different designs, to test out whether different designs will
have different outcome.
4.1 Design 1
Image 4.1.1 shows the first design of our truss bridge
For the 1st design, we decided to start off with a Truss bridge with curved top chord. So, we
searched of type of truss which is bowstring arch truss where the top chord is a true arc and
has diagonal load-bearing members. Then, we decided to add in hinged arch which is located
at the bottom sides of the truss bridge that is supposed to transfer load to the edge of tables.
At the middle of the bridge where force is being act on is like a 'H' letter where 1 beam is laid
perpendicularly on top of 2 other beam to transfer load more equally rather than just acting
in the middle. The distances between the trusses are the same throughout the bridge design.

Structure Analysis
Diagram 4.1.1 shows the force analysis of our first design
Bridge Details:
Weight of the bridge: 246 g
Clear Span: 750mm
Width of the base: 120mm
Height: 130mm
Maximum Load Capacity 3.3 kg
Efficiency: 44.3
The load is from the middle part of the bridge, we place the truss in this arrangement so that
the load can be transferred to other parts of the bridge. The top part we design it to be curved
because curve is a pre-bend structure, and when it receive load from the bottom, it will be
pulled down and trying to get back to its original form, so it will be more flexible when
compared to straight structure.

Model Test
Image 4.1.2 shows the fettuccine bridge has been set up for testing and use water as load.
Image 4.1.3 shows the water has been pour into the bucket, the fettuccine bridge started
bending downwards slowly as the load is getting more.

Image 4.1.4 shows the bridge’s members started to fall apart when it reached 2.5 kg.
Image 4.1.5 shows the bridge broke at 3.3kg.

Cause of failure
Image 4.1.6 shows the weak and breaking members of our bridge
As this the first fettuccine bridge that we have ever built, we still unable to understand the
properties of fettuccine and how it work. Besides lack of understanding, we also lack of
workmanship that cause the bridge came up with unbalance structure from both sides and
some members are not attached to the structure properly.

4.2 Design 2
Image 4.2.1 shows the second design of our truss bridge
From the 1st process, we understand that the hinged arch at the bottom does not provide as
much load-transfer but only stabilize the bridge. Therefore, for the 2nd design approach we
reduced the size of it. Not only that, we tried to curve the horizontal member of the bridge
hoping it achieves the potential to pre-bend to sustain more load before it breaks. Also, we
changed the design of the truss where instead of a truss design, we connect vertical load-bearing
member tangent to the top chord. The reason we did this is because we were trying
to predict the direction of the force so that it is parallel to the vertical members. By doing so,
the whole bridge actually serve more as a cable bridge than a truss bridge where most of the
forces are tension beside top chord and the horizontal members. The distances between
trusses are also modified where it slowly expands exponentially from the middle to both sides.
This is to support the heavy force acting to the middle of the bridge and reducing the
members at the sides because they usually receive the least force.

Structure Analysis
Diagram 4.2.1 shows the force analysis of our second design
Bridge Details:
Clear Span: 850mm
Height: 130mm
Efficiency: 81.8
For this design, we place the truss in this way is to predict the direction of magnitude of tensile
force in different position of the total bridge span. Using the same theory from the previous
bridge, now we made both top and bottom part of the bridge structure to be curved. After
testing, the problem is the curve is not strong enough and fails to transfer the load to two
sides of the structure.

Model Analysis
Image 4.2.2 shows the fettuccine bridge has been set up for testing and water as load.
Image 4.2.3 shows the bridge is tested with 2 kg initial weight.

Image 4.2.4 shows when the load is getting more, the pre-bend fettuccine bridge started to
bend downwards. The base of the bridge started to turn into an ‘M’ shape.
Image 4.2.5 shows the bridge failed at 3.9 kg.

Cause of failure:
In this structure, we’ve used pre-bend structure method to build it. Due to it’s a pre-bend
structure, during the constructing process the pre-bend component keep breaking as the
fettuccine fragile properties. Although it’s hard but we’re still able to complete with the
bending and came out with a pre-bend fettuccine bridge. Along the testing session, the
bridge’s base that bended upward has been pulled by the load from the middle and cause the
bridge to form ‘M’ shape.
4.3 Design 3 & 4
Image 4.3.1 shows the third and fourth design of our truss bridge
In our 3rd design and 4th design, we decided to repeat using bowstring truss bridge design
where only the top chords are different. For 3rd design, the top chords are a series a shorter
members connected by vertical members to form a curve shape whereas the 4th design is a
triangular top chord to experiment different possibilities with fettuccine as well as the
difference between the effectiveness of the different length of fettuccine when it is used as
top chord. The distances between trusses are as the 2nd design where they increase steadily
by each truss from the middle.

Structure Analysis
Diagram 4.3.1 shows the force analysis of our third design
Bridge Details:
Clear Span: 850mm
Height: 130mm
Efficiency: 67.5
In design 3, we remove the bottom part of two sides, to try out whether the structure will
help out supporting the bridge, and the truss is following our first design. For the bottom
chord of the bridge, we are using straight structure for this design as we found out that using
curve structure for the bottom chord is not effective. Unfortunately, the bridge failure is again
caused by the bottom chord.

Model Test
Image 4.3.2 shows the fettuccine bridge has been set up for testing and bottle with water as
load.
Image 4.3.3 shows the bridge seems rigid after load has been added.

Image 4.3.4 shows the bridge started to bend to one side when the load reach 3.3kg.
Image 4.3.5 shows the bridge had collapsed at 3.6kg due to twisting and breaking apart.

Cause of failure:
This bridge goes well along the constructing process, the structure only have bending on the
top beam and flat base. In the process of testing, the bridge doesn’t show any sign of bending
and due to the load has been placed unevenly and cause the hock to move towards one side
and cause twisting then broke. After identify and verification, we’ve found out that the
problem is with the base we’ve made was not strong enough.

Structure Analysis
Diagram 4.3.2 shows the force analysis of our fourth design
Bridge Details:
Clear Span: 850mm
Height: 200mm
Efficiency: 64.8
In design 4, we changed the bridge design into triangular structure; the truss arrangement is
still the same as previous bridges. We used the triangular top chord to test if the structure
will help supporting the load more efficiently than curved top chord structure. We are unable
to get the result we want as the same problem still occurs, the midpoint of the bottom chord
broke faster than other members.

Image 4.3.7 shows the bridge has been set up for testing and water as load.
Image 4.3.8 shows the bridge seems rigid and doesn’t show any sign of bending after load has
been added.

Image 4.3.9 shows the bridge broke at the middle suddenly when the load reached 3.6kg.
Cause of failure:
We’ve building this bridge without using any pre-bend structure, the overall form of the
bridge was a triangle. In the testing process, bridge is slightly similar to the previous one which
doesn’t show any sign of bending and due to the load has been placed unevenly and cause
the hock to move towards one side and cause twisting then broke. The problem also with the
base of the bridge was still not strong enough.

4.4 Design 5 & 6
Image 4.4.1 shows the fifth and final design of our truss bridge
For our last design approach, using all the data and analysis that we have gathered, we
understand that the height of the whole bridge should be reduced to increase effectiveness.
The whole bridge is designed to be more flat-out than all the previous ones. Also the middle
part where load is being hung must serve the function to distribute force as equally
throughout the entire bridge span rather than just depending on the trusses.
Structure Analysis
Diagram 4.4.1 shows the force analysis of our fifth and final design
Bridge Details:
Weight of the bridge: 155g / 165 g
Clear Span: 850mm
Height: 200mm
Maximum Load Capacity: 5.9kg / 5.0 kg
Efficiency: 224.6 / 151.5

In this design, we reduced the height of the bridge, reducing the weight to increase the
efficiency. Due to the same failures from our previous experience, we found out that the top
chords did not actually help much in carrying the loads, as the bottom chords are the main
load carries, so we enhance the bottom chord by using I-beam structure, three layers of
fettuccine in the middle and one layer in both ends.
Model Test
Image 4.4.2 shows the fettuccine bridge has been set up for testing. Water poured into bucket.
Image 4.4.3 shows the bridge is stable during the test.

Image 4.4.4 shows the bridge doesn’t affect by the load but the part that supporting the load
started to bend.
Image 4.4.5 shows the part that hold the load broke but the whole structure remain unharmed.
The load is 4.9 kg. Second test after replacing the supporting part and it reach 5.5kg.

Cause of failure:
This bridge has been constructed without using any pre-bend just, an evolve product of mock-up
4. At first we lack of confident toward this bridge which is supposed to be the final, so we
came out with an idea of testing it as mock-up no.5. Everything goes well in the whole process
of testing, the structure is very rigid but only the part that act to hold the load broke. After
replace with a better one we went for 2nd test, we’re all satisfied with the outcome.

Model Test (Final Design)
Image 4.4.6 shows the bridge was evolve of design 5 has been set up for the final load test.
Image 4.4.7 shows the bridge remain stable throughout the test.

Image 4.4.8 shows the bridge fail due to twist at the end of bridge. The load is 5kg.
Cause of failure:
This bridge was actually a rebuild of the mock-up no.5, we spent then whole night construct
it. Due to all the classes and work in the afternoon we’re all tired. The bridge is slightly bended
due to lack of workmanship. During the final load testing, the table surface were slightly
unbalance. The testing process go well and the bridge end up fail by twisting, but we’re still
contented with the outcome.

The following table concludes each design efficiency:
WEIGHT LOAD EFFECIENCY
Design 1
246 g 3.3 kg 44.3
Design 2
186 g 3.9 kg 81.8
Design 3
192 g 3.6 kg 67.5
Design 4
200 g 3.6 kg 64.8
Design 5
155 g 5.9 kg 224.6
Design 6
165 g 5.0 kg 151.5
Table 4.4.1 shows the efficiency of each bridge.

5.0 Conclusion
In this project, we managed to understand tension and compressive strength that is highly
depending on the materials. On the other hand, we are also able to understand how loads
are distributed through trusses. Through trials and errors, we were able to test out new
structure by playing around with different design of trusses. Unfortunately, load distributions
of the model were not performing well due to random errors from workmanship issues and
etc. In our opinion, the usage of fettuccine as material is not a good choice because every
pack of fettuccine contain random amount of fettuccine that are suitable for use and the
quality of it varies from each other. After this project, we also felt that a lot food is wasted
especially when there are 100 over students doing this project. We believe there are model
making materials that are more suitable for this project especially when fettuccine is
manufactured as food not as modelling material.
Source: Chatelaine

Building Structure Project 1 Fettuccine Bridge

7.0 References
Hanks, M. (2013, September 19). SunThisweek | Bike-pedestrian bridge to be rehabilitated
to link Bloomington to Dakota County. Retrieved from
http://sunthisweek.com/2013/09/19/bike-pedestrian-bridge-rehabilitated-link
bloomington-dakota-county/
James, B. (n.d.). Bridgehunter.com | Long Meadow Bridge. Retrieved from
http://bridgehunter.com/mn/hennepin/3145/
John A. (2011). Long Meadow Bridge, Eagan, MN. Retrieved from
http://www.johnweeks.com/bridges/pages/b09.html
Mike H. (2014, July 3). Sun Current | A glimpse into the future of the Old Cedar
Avenue Bridge. Retrieved from http://current.mnsun.com/2014/07/a-glimpse-into
the-future-of-the-old-cedar-avenue-bridge/
Long Meadow Bridge. (n.d.). Retrieved from
http://www.nps.gov/nr/feature/places/13000324.htm

Building Structure Project 1 Fettuccine Bridge

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