Fettuccine truss bridge report
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Transcript of Fettuccine truss bridge report
1
FETTUCCINE
TRUSS BRIDGE
PROJECT I ARC 2523 BUILDING STRUCTURES SCHOOL OF SCIENCE, ARCHITECTURE AND BUILDING DESIGN TUTOR:MR. ADIB FUNG HO YENG 0319473 IVY VOO VUI YEE 0319534 LEONG VUI YUNG 0320362 LIONG SHUN QI 0315942 LO JIA WOEI 0318585
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TABLE OF CONTENT PAGE NUMBER 1. Introduction
1.0 General purpose of study 3 1.0 Report preview 3 1.1 Learning Outcomes 3
2. Methodology
2.0 Precedent Study 4 2.1 Materials and Equipment Testing 4 2.2 Model Making 4 2.3 Structural Analysis 4-5 2.4 Model Testing 5 2.5 Bridge Efficiency Calculation 5 2.6 Working Schedule 6
3. Introduction of truss 3.0 Introduction of Warren Truss 7-9 3.1 Precedent Studies 10-12
4. Materials & Equipment 4.0 Equipment 13-14 4.1 Materials Strength Study 15-21
5. Bridge Testing 5.0 Test Bridge 1 Analysis 22-23 5.1 Test Bridge 2 Analysis 24-25 5.2 Test Bridge 3 Analysis 26 5.3 Test Bridge 4 Analysis 27 5.4 Test Bridge 5 Analysis 28 5.5 Test Bridge 6 Analysis 29 5.6 Test Bridge 7 Analysis 30-31 5.7 Test Bridge 8 Analysis 32 5.8 Test Bridge 9 Analysis 33 5.9 Test Bridge 10 Analysis 34
6. Final Bridge 35-44
7. Conclusion 45
8. Case Study 46-66
9. References 67
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CHAPTER 1
INTRODUCTION 1.0 Introduction
In a group of 5, 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 analyze 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 are to not exceed a maximum weight of 70g and must have a clear span of 350mm. The bridge must carry at least 10 kg of load and we are required to analyze the reason of its failure and calculate the efficiency of the bridge using the formula:
bridge of Weight
Load MaximumE,Efficiency
1.1 Report preview
The report started off with a precedent study carried out on a truss bridge. Analyze the load distribution and how it affects its member. The report also recorded down the several designs we had tried out before the deciding on the final design. These test bridges were improved and developed further based on previous test results and analysis to increase its efficiency. A set of analysis regarding the strength of the bridge structure and its reason of failure had been done. Individual case studies calculations are attached at the end of the report.
1.2 Learning Outcomes At the end of this project, we are able to:
Evaluate, explore and improve attributes of construction materials.
Explore and apply understanding of load distribution in a truss.
Evaluate and identify tension and compression members in a truss structure
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CHAPTER 2
METHODOLOGY 2.0 Methodology
To complete this project, we have carried out following methods in the process of researching and building a suitable truss bridge:
2.1 Precedent Study
By looking through precedent studies, we will have a better understanding on the types of trusses available. We had chosen Warren Clem Lowell Road Bridge as our case study to refer to and help us along the analysis of our model bridge. We focused on the connection of joints and the arrangement of members, as well as whether it was aesthetically pleasing. This bridge has inspired us for our final fettuccine bridge in terms of design and truss member arrangement. Further exploration and findings will be elaborated in the Precedent Study section later.
2.2 Materials and Equipment Testing
Phase 1: Physical properties of material
We first understand how forces act on the fettuccine. We tested the tension and compression strength of the fettuccine. Physical properties of fettuccine are important to build the bridge so that it can carry the maximum load. We stick several pieces of fettuccine and put a load at the centre to test it, starting to test from the horizontal faces then vertical faces. From the experiment, we found that fettuccine is weak in compression and strong in tension.
Phase 2: Brands and types of material
After we had tested the physical properties, we continued testing different brands of fettuccine, which are San Remo and Kimball. We also did experiment on the types of fettuccine, whether original fettuccine or spinach fettuccine has the stronger strength. It is important to test different brands and types of fettuccine to observe their strength when subjected to loads. After the experiment, San Remo spinach fettuccine is the finalized brand and type of fettuccine that we have chosen as it is the strongest compared to others. Our analysis will be recorded under the chapter “Material Strength Study”.
Phase 3: Adhesive
The adhesive also plays a huge role in building the bridge, as what we used to bond the fettuccine together would affect the overall strength of the structure. There are various choices of glue with different characteristics available, so it is obviously crucial to choose the appropriate adhesive. We had experimented and observe how various types of adhesive are being used and how they affect the joints. We settled on super glue at the end.
2.3 Model making
Upon understanding from our precedent study, we started to sketch out a possible design for an efficient perfect truss bridge. We had to be sure to design for a clear span of 350mm bridge (leaving 40mm on the sides to hoist up on the table. Once we agree on the design, we drafted it out on AutoCad and the drawings were plotted and printed in 1:1 scale to ensure precision in
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the model making process. Then, we also did quality check on the packets of fettuccines and sorted out the straight one and the twisted one.
2.4 Structural Analysis
Structural Analysis is the determination on the effects of load on the bridge and its members by calculation. The truss’s strength was analyzed by understanding which members were used for tension purposes and which for compression. Based on the methods practiced by truss analysis exercises, the structural analysis of the bridge will be done by the same way.
2.5 Model Testing
Completed models are being placed aside to allow the glue dry properly (at least 5 minutes) before testing. To test the bridge, we set two tables (of equal height) exactly 350mm apart, and put the bridge in the middle. Before testing, we must first weigh the bridge to see how far above or below the 70g limit given. After documenting the weight, the S hook and bucket are weighed to calculate the total weight of the load that will be hung on the bridge. The S hook is placed in the middle of intermediate member to ensure the load distribution is even. The bucket handle is then hook on the S hook. The bucket does not elevate too far above from the ground to avoid the bucket break when falling down. We had also prepared 100g load, 200g load and 500g load before the testing. We started to record video as we started to test the bridge. This is our way to check more accurately where the problem is after testing. As load is being added, the bridge is checked for any deformities. As the bridge starts to deform, the points where the bridge are the weakest will be noted down. We then continue adding load until the bridge broke. The results and problems are being recorded for further improvement. Based on the records, the strength of the bridge is studied and the design is modified accordingly by enhancing its weak points. We strengthen the parts that deformed quickly and parts that snapped upon heavy loads are applied to the bridge. Every time a draft model could not hold the required weight, we analyzed the reason behind it and improved upon it with the next one until the bridge can hold a desirable loads as well as the mass is lesser than 70g.
Fig. 2.1, 2.2 and 2.3: Process of the crafting of the bridges.
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2.6 Bridge 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
2.7 Working Schedule
Date Task
11th April 2016 Case study research
18th April 2016 Testing of the strength of the materials (brands and types of fettuccine) and different adhesives
25th April 2016 Initial designing of truss
25th April 2016 Confirmation of design and crafting of bridge #1a
25th April 2016 Testing of bridge #1a
25th April 2016 Modifying bridge #1 and construction of bridge #1
25th April 2016 Testing of bridge #1
30th April 2016 Construction of bridge #2
30th April 2016 Testing of bridge #2
30th April 2016 Construction of bridge #3
30th April 2016 Testing of bridge #3
6th May 2016 Modifying bridge #3 and construction of bridge #4
6th May 2016 Testing of bridge #4
7th May 2016 Construction of bridge #5
7th May 2016 Testing of bridge #5
7th May 2016 Modifying bridge #5 and construction of bridge #6
7th May 2016 Testing of bridge #6
8th May 2016 Construction of bridge #7
8th May 2016 Testing of bridge #7
8th May 2016 Modifying bridge #7 and construction of bridge #8
8th May 2016 Testing of bridge #8
8th May 2016 Construction of bridge #9
8th May 2016 Testing of bridge #9
8th May 2016 Construction of bridge #10
8th May 2016 Testing of bridge #10
8th May 2016 Construction of final bridge
9th May 2016 Submission and testing of final fettuccine bridge
Table 2.7.1: Working Schedule
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CHAPTER 3
INTRODUCTION OF TRUSS 3.0 Introduction of Warren Truss
A truss is an assembly of linear members connected together to form a triangle or triangles that
convert all external forces into axial compression or tension in its members.
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.
Figure 3.1: Components in a truss bridge
Tension and compression force is a happening in a truss bridge. Tension is a force that acts to
stretch or pull the structure. Meanwhile, compression is a force that acts to squeeze or push the
structure. They affect and damage the structure of the bridge varying from different weight of
loads. Lateral wind forces is also a force which acts on the bridge.
Figure 3.2: Tension force and compression force act on truss
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Figure 3.3: Direction of compression and tension force act on a structure
A truss designed for uses must safe and stable. If the force that applies on the truss has
exceeded its load bearing capability, it goes buckling or snapping.
Figure 3.4: Buckling
Buckling happens when the compression force has exceeded its load bearing capability.
Figure 3.5: Snapping
Snapping happens when tension force exceeds.
Different members in the truss bridge experiences different kind of forces, therefore the
designer and engineer have to determine the structural strength and solve it by using different
truss design.
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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 greater area, so that
no one spot bears the concentrated brunt of it.
WARREN TRUSS
Figure 3.6: Warren truss
The history of warren truss can be traced back to Italy because there are no exact records on
what time the first warren truss was used. The first truss bridge was built in the mid 1800s by
Alfred Neville in France. His design used isosceles triangles vs the equilateral triangles that were
used by James Warren in 1848.
The warren truss uses equilateral triangles to spread out the loads of the bridge. This is different
from Neville truss, which uses the isosceles triangles. The equilateral triangles minimize the
forces to only compression and tension. Let say, if an object moves across the bridge, the forces
for a member change from compression to tension. This would occur mostly for the members
near the car or train.
When the load is focused on the middle of the bridge, just like our fettuccine bridge with a point
load, pretty much all the forces are larger. The top and bottom chord are under large forces,
even though the total load is the same. Meaning to say, if a fettuccine bridge need to hold more
weight, then spreading out the forces across the top of the bridge is mandatory and for a real
life warren truss bridge, the forces should be much localized and should not be spread out along
the bridge. The designer and engineer should decide and calculate the strength of each member
of the bridge and build accordingly.
Figure 3.7: Force act on warren truss
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3.1 Precedent Study
Clem Lowell Road Bridge
Figure 3.1: Clem Lowell Bridge
The Clem Lowell Bridge served the citizens of Carroll County, Georgia for more than 70 years
but, over time and from increased use, the steel truss was in need of repair in order to bring it
up to today’s standards. Carroll County officials closed the bridge for four months in 2008 to
perform the much needed maintenance and repair. Additionally, the County lowered the load
limit on the bridge to below 3 tons. The completed repair work lasted for approximately one
year until a heavy truck crossed the bridge, breaking the seal on the concrete slab. The county
wanted the new structure to resemble the original structure and contacted Health & Lineback
Engineers to design the new abutments. They worked with U.S.Bridge on the new bridge design.
As a result, a 130’ x 28’ U.S.Bridge Cambridge Flat model was selected as the structure that best
replicated the old Clem Lowell Road Bridge while also providing the current load rating
standards and structural integrity. This is a warren bridge with a sufficient rating 18 out of 100.
Length of largest span 61.7ft
Total length 101.7ft
Style Warren Truss
Finish Weathering steel
Decking Concrete
Decking width 16.1ft.
Average daily traffic 510
Table 3.2.1: Information of Clem Lowell Bridge
11
Installation of Clem Lowell Bridge (Figure 3.2, 3.3, 3.4, 3.5)
Figure 3.6, 3.7: Completed Clem Lowell Bridge
Figure 3.8: Clem Lowell Bridge is a warren truss with vertical
12
The Clem Lowell Bridge makes use of a number of connecting joints.
1. Connections of portal bracing members
2. Gusset plate connections
3. Connection of multiple diagonal members
13
CHAPTER 4
EQUIPMENT AND MATERIAL ANALYSIS 4.0 Equipment
Table 4.1: These were the tools we used during the model making
1. Pen knife and Scissors :
Pen knife and scissors used in the model
making process to cut the fettuccine into
specific dimension needed.
2. Rulers
Used to measure the fettuccine members,
clear span of the bridge and the total length of
fettuccine accurately.
3. Kitchen Balance
Measuring equipment for weighing the
fettuccine to ensure it did not exceed the
restricted weight by following the brief given.
(70gm)
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4. S-Hook
Used as connection between fettuccine bridge
and the load (weights) at the center part of the
bridge.
5. Bucket
Equipment used to hold the loads (water)
during the load testing.
6. Phone Camera and Tripod Stand
Used to document and record the working
process and the testing of bridges.
7. Calculator
Equipment used to solve all the calculations
accurately during the model making.
15
4.1 Material Strength Study
4.1.1 Adhesive Types
Experiment of different types of glue were carried out before starting design the fettuccine
bridge in order to obtain the best result for our connections :
Table 4.2. : Comparison between different types of adhesive.
(Ascending order from strongest adhesive properties to weakest)
Types of Adhesive Analysis
Super Glue
(Elephant brand)
Fast bonding time about 10 seconds (slower than 3-second glue)
High bonding strength High efficiency Strength of bonding strong and lasting for
few days after built Clean connection of joints Easy to apply
502 (3-Second Glue)
Fastest bonding time (about 3 seconds) High connection bond strength High tendency of cracking after few days.
(Fettuccine brittle faster than other glue) High efficiency Clean connection of joints Easy to apply
UHU Glue
Slow bonding time (about 40 seconds) Easy to apply Average connection bond strength Average efficiency
16
Hot Glue Gun Troublesome to use (easy to get hurt) High connection bond strength Finishing are bulky and messy Heavy compared to other glue (increase
bridge weight)
White Glue Long bonding time taken Low connection bond strength Low efficiency
17
4.1.2 Adhesive Strength Test
Table 4.3: Comparison adhesive strength of different types of glue by using same type of
fettuccine (San Demo regular type fettuccine) and applied on whole fettuccine within one day.
According to the data recorded in the table above, it shows that 502 (3-second glue) have the
highest efficiency of adhesive strength among all of the other glue. Besides, the result showed
that UHU glue have same adhesive strength efficiency with Super glue (Elephant glue).
Type of
Glue:
Clear
Span
(mm):
Length
(mm):
Layer
of
pasta:
Weight
Sustained (g):
Weight of
fettuccine (g):
Efficiency
Super
glue
(Elephant
glue)
15 25 5 1016 9 112.89
502 (3-
second
glue)
15 25 5 1016 8 127
UHU glue 15 25 5 Cannot sustain 416 9 0
Hot glue 15 25 5 1016 9 112.89
White
glue
15 25 5 416 9 46.22
18
Table 4.4: Comparison adhesive strength of different types of glue by using same type of
fettuccine (San Demo regular type fettuccine) and applied on whole fettuccine more than one
day.
After fettuccine layers left to settle for more than one day, we carried out another test to
examine whether the fettuccine layer can sustain more or less load than what it could be that
shown in table 4.4. From the test result, it shows that Super glue( Elephant glue) could sustain
even more weight, while the 502 (3-second glue) and UHU glue sustain less.
In conclusion, this two experiments prove that 502 (3-second glue) is the most suitable adhesive
media for our fettuccine bridge. It is due to the 502 (3-second glue) takes fastest bonding time
with just about 3 seconds compared to Super glue( Elephant glue). And it has high connection
bond strength and high efficiency that very close to Super glue( Elephant glue). While Hot glue
was not being accepted due to it is heavy than other types of glue , bulky and messy finishing
and troublesome to use. Moreover, the issue of 502 (3-second glue) with high tendency of
cracking and brittle faster than other glue after few days being overcome by our planning on
making the fettuccine bridge within a day before submission to ensure the best performance of
the fettuccine bridge.
Type of
Glue:
Clear
Span
(mm):
Length
(mm):
Layer
of
pasta:
Weight
Sustained (g):
Weight of
fettuccine
(g):
Efficiency
Super
glue
(Elephant
glue)
15 25 5 1040 9 115.56
502 (3-
second
glue)
15 25 5 1000 8 125.00
UHU glue 15 25 5 Cannot sustain 416 9 0
Hot glue 15 25 5 1000 9 111.11
White
glue
15 25 5 350 9 38.89
19
4.1.3 Fettuccine Types & Strength Study
Strength test on fettuccine used for the bridge also being carried out to determine which brand
and type of fettuccine was the strongest to carry loads since it is our main construction material.
This is an important part to test our main construction material before we start making the
physical model.
Table 4.5: Fettuccine brands and the weight they could sustain under same type of glue and
layers of pasta.
Fettucci
ne
brands
and
types
Type of
Glue:
Clear
Span
(mm):
Length
(mm):
Layer
of
pasta:
Weight
Sustained
(g):
Weight of
fettuccine
(g):
Efficiency
San Demo
regular
type
502 (3-
second
glue)
15 25 5 1016 8 127.00
Kimball
regular
type
516 6 86.00
San Demo
spinach
type
1150 9 127.78
San Demo
regular
type
Super
glue
(Elepha
nt glue)
15 25 5 1016 9 112.89
Kimball
regular
type
516 7 73.71
San Demo
spinach
type
1150 9 127.78
20
Image
Brand Types Max.Weight
Sustained (g)
within 5 layers
San Demo Regular type 1016
Kimball Regular type 516
San Demo Spinach type 1150
As table 4.5 illustrates, we can conclude that San Remo was our choice of fettuccine brands for
the final bridge. While the type of fettuccine chose for the final bridge was Spinach type of
fettuccine. It is because Spinach fettuccine has slightly higher efficiency than San Demo original
type fettuccine with just 1 gram heavier than original type.
After decided San Demo Spinach type fettuccine as our main constructed material, a test in the
way we layered the fettuccine was carried out to find out the strongest type of layering which
can sustained highest load.
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Table 4.6: The test results of different layers of fettuccine and the load each could sustain.
Structural
members
Length
of
fettucci
ne (cm)
Clear
span
(cm)
Load
sustained,
horizontal
facing (g)
Weight
of
fettucci
ne (g):
Efficiency
5 layers 25 15 1300 9 144.44
4 layers 25 15 750 6 125.00
3 Layers 25 15 516 4 129.00
C-beam 25 15 416 4 104.00
L-beam 25 15 Cannot sustain
416
2 0
3 Layer I-beam 25 15 516 5 103.20
4 layer I-beam 25 15 1000 6 166.67
5 Layer I-beam 25 15 1000 8 125.00
6 Layer I-beam 25 15 1250 11 113.64
8 Layer I-beam 25 15 1616 22 73.45
Based on the table above, it is clear that four layer I-beam has the highest efficiency and follow
by five layer structure then is three layer structure. After evaluation, we decided to use four
layer I-beam and three layers structure as three layer structure has slightly lower efficiency than
five layer structure but with just half of the weight of five layer structure.
22
CHAPTER 5
BRIDGE TESTING 5.0 Test Bridge 1 Analysis
Date: 25 April 2016
Figure 5.1, 5.2
Efficiency
= Load / Weight of the bridge
=1800g / 115g
=15.65
Warren Truss
Bridges Clear Span:35cm
Weight: 115g
Total length: 45cm
Test Load 10-Second Test
1 500g Ok
2 1000g Ok
3 1200g Ok
4 1400g Ok
5 1600g Ok
6 1800g Ok
7 2000g Not ok
23
Failure
Figure 5.3, 5.4, 5.5, 5.5 (from left)
Using Sam Remo Spinash Fettucini with super glue for the bridge after we have done our all
experiments. In the other way, we are going to chose to do a warren truss for our first bridge.
After figuring and testing up different types of member and their strenght, we decided to use 4
layer I-beam as our base and the columns, 3 layers for our top and secondary members as we
found that although the efficiency for both of them are not the higher one but we used these
members is because it can carry a certain weight and achieve a standard effiecency level. We
designed a ‘X’ at the middle bottom part of the bridge to hangthe S hook. At last, the bridge
failed at some of the connection parts and the base part due to imperfect connections and too
thin to carry the loads.
24
5.1 Test Bridge 2 Analysis
Date: 30 April 2016
Efficiency
= Load / Weight of the bridge
=170g/100g
=17
Figure 5.6
Figure5.7
Figure 5.8
Failure
Warren Truss
Bridges Clear Span:35cm
Weight: 100g
Total length: 45cm
Test Load 10-Second Test
1 500g Ok
2 1000g Ok
3 1200g Ok
4 1400g Ok
5 1600g Ok
6 1800g 7s
25
Figure 5.9
Figure 5.10
For the second testing, we still remained the 4 layer I-beam at the bottom, but the bottom was then
rest on the end of the beams at the end of the column and the beams will rest on the table, means
that the bottom was lifted from the table and didn’t touch the table directly. We believed that this
way can helped the forces transferred in a more proper way. We had rearranged all the orientation
of the fettuccini which are lying in vertical orientation because we found that placed the fettuccini
vertical orientation could effort more forces than normal. Furthermore, we also picked out some
necessary vertical members to reduce the weight. For the failure, the bottom part, beside the “X”
part broken first then following by the rest of the members.
26
5.2 Test Bridge 3 Analysis Date: 30 April 2016
Efficiency
= Load / Weight of the bridge
=1500g/79g
=18.99
Figure 5.11
Figure 5.12, 5.13, 5.14
This time we changed our hooked place from bottom to the top. We wanted to figure out was the
bottom or the top will be more suitable to hook. We also enlarged the “X” part and rested on the
top part. Design became simpler due to the weight. Lastly, the big X broken as it is too big and just
rested on the top bream, it may disturbed the forces transmition.
Warren Truss
Bridges Clear Span:35cm
Weight: 79g
Total length: 45cm
Test Load 10-Second Test
1 500g Ok
2 1000g Ok
3 1200g Ok
4 1400g Ok
5 1500g Ok
6 1600g Not ok
27
5.3 Test Bridge 4 Analysis Date: 6 May 2016
Figure 5.15
Figure 5.16, 5.17
Efficiency
= Load / Weight of the bridge
=2200g/70g
=31.43
Because we will hooked from the bottom, so our bottom should be thicker than the previous failure
bridge. So, we changed the bottom structure members from 4 layers I-Beam to 8 layers I-Beam so
that it could enough to effort the load. We also changed the ‘X’ hooked part become “H” in 8 layers
I-Beam and they are rested on the base column so that they can transferred the load to the base and
let the base transferred to the other members or directly to the surface. We cut all the extra
fettuccini from 2 or 3 layer to 1 layer as they just act as a support or secondary member due to the
overweight problems.
Test Load 10-Second Test
1 1000g Ok
2 1500g Ok
3 2000g Ok
4 2200g Ok
5 2400g Not ok
Warren Truss
Bridges Clear Span:35cm
Weight: 70g
Total length: 45cm
28
5.4 Test Bridge 5 Analysis
Date: 7 May 2016
Figure 5.18, 5.19, 5.20
Efficiency
= Load / Weight of the bridge
=3400g/88g
=38.64
Compare to the others, our bridge only can carried 2 kg (highest record) until this stage. So, we
decided to deduce the width and the height of the bridge. We knew that, height and width might
affect the streghten of the bridge just like we use 2 slices of fettuccini to tested out will the shorter
or longer piece more sustainable and we come out will the shorter will better when placed in vertical
orientation but longer will better when placed lying horizontally. The ‘V’ shape members we add
more so that it can helps to divide the forces.
Warren Truss
Bridges Clear Span:35cm
Weight: 88g
Total length: 45cm
Test Load 10-Second Test
1 1000g Ok
2 1500g Ok
3 2000g Ok
4 2200g Ok
5 2400g Ok
6 2600g Ok
7 2800g Ok
8 3000g Ok
9 3200g Ok
10 3400g Ok
11 3600g Not ok
29
5.5 Test Bridge 6 Analysis
Date: 7 May 2016
Figure 5.21, 5.22, 5.23 Efficiency
= Load / Weight of the bridge
=4500g/83g
=54.22
Still remaining the 8 layers I-Beam and the ‘H’ hooked at the middle. This time, we added the “V”
structure to 8. We realized that, the “V”s were really worked well to distribute the forces properly.
The most important part to let the “V” performed well was the connections. The connections has to
rest and connect between the base beam and the columns, so that the forces will only passed to the
columns and the beams. For this failure, only the “H” hooked broken, the whole structure is still
remained perfectly. From this point, we tried to asking ourselves, was the structure too strong or we
didn’t design all the structure members to distribute the forces properly.
Warren Truss
Bridges Clear Span:35cm
Weight: 83g
Total length: 45cm
Test Load 10-Second Test
1 1000g Ok
2 1500g Ok
3 2000g Ok
4 2500g Ok
5 3000g Ok
6 3500g Ok
7 4000g Ok
8 4500g Ok
9 5000g Not ok
30
5.6 Test Bridge 7 Analysis Date: 8 May 2016
Figure 5.24, 5.25, 5.26
Warren Truss
Bridges Clear Span:35cm
Weight: 91g
Total length: 40cm
Test Load 10-Second Test
1 1000g Ok
2 1500g Ok
3 2000g Ok
4 2500g Ok
5 3000g Ok
6 3500g Ok
7 4000g Ok
8 4500g Ok
9 5000g Ok
10 5500g Ok
11 6000g Ok
12 6500g Ok
13 7000g Ok
14 7500g Ok
15 8000g Ok
16 8500g Not ok
31
Efficiency
= Load / Weight of the bridge
=8000g/90g
=88.89
Failure
Figure 5.27, 5,28, 5.29
This bridge failed due to the incorrect position of s hook located and week top beam used.
After experiments many of the bridges, we found that the more the warren truss members, more weight can be carried. So, we decided to add structural truss members from 10 into 13 on our next design. We also realized the problems of balancing the forces throughout the overall structure. The trusses need to be upright and symmetrical to another side. Hence, equilateral triangle was used in the design to distribute force equally. Moreover, proper design of fettuccine use is important to solve overweight problem.
32
5.7 Test Bridge 8 Analysis Date: 8 May 2016
Figure 5.30, 5.31, 5.32
Efficiency
= Load / Weight of the bridge
=11200g/87g
=128.74
13 trusses members of warren Truss show the best efficiency among all the test bridges. The main
failure of this bridge is the main supportive core. The separated 8 layer I beam that carry s hook
failed after 11 kg but the whole structure is still remain strong and steady. Moreover, over weight
was one of the main problems.
Warren Truss
Bridges Clear Span:35cm
Weight: 87g
Total length: 40cm
Test Load
1 1119g
33
5.8 Test Bridge 9 Analysis Date: 8 May 2016
Figure 5.33, 5.34, 5.35
Efficiency
= Load / Weight of the bridge
=11883g/81g
=146.7
Using the same structural and material as 10th test bridge, but only shorten the main core and also
re-position to center part. As a result, the shorter the core, the stronger it is.
Improvement:
Decreasing all the necessarily structure and thinner the main structure from 8 layer I beam to 6
Layer I beam. Beside that, replace the bracing and connecting members from Sam Remo Spinash
Fettucini to the Original Sam Remo Fettucini.
Warren Truss
Bridges Clear Span:35cm
Weight: 81g
Total length: 39cm
Test Load
1 11883g
34
5.9 Test Bridge 10 Analysis
Date: 8 May 2016
Figure 5.36, 5.37, 5.38
Efficiency
= Load / Weight of the bridge
=9374/81g
=115.73
First of all, we have successfully design a 70g warren bridge. Due to the limited weight,by mixing of
fettuccine and decrease the core members into 4 layer stack beam and re-position of center core
have improved the efficiency of the truss bridge. Whereas, this bridges sustain until it maximum
weight and fail at the top and bottom main beam.
Warren Truss
Bridges Clear Span:35cm
Weight: 70g
Total length: 39cm
Test Load
1 9374g
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CHAPTER 6
FINAL BRIDGE
6.1 Amendments
The final bridge design is same as the 9th fettuccini bridge we made previously as its efficiency is the
highest among the bridges we made that withstand 10kg. However, the previous bridge can only
withstand 9.3kg. This might caused by the decreased weight compared to the best bridge. We are
using the same dimension for the final bridge but different enhancement on particular members,
which do not carry much weight to control the total weight of the bridge within 70g.
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6.2 Top Chord
Fettuccini is weak in compression but good in tension. Therefore, several layers are added to
enhance the ability to withstand compression force. After comparing the 6th (8-layers I-Beam as the
top main diagonal member and double layer members as horizontal member), 7th bridge (4-layers
member as the top main diagonal member and single layer member as horizontal member), we
found out that the main supporting members that withstand the highest weight among other
members is the top main diagonal member, but it is not necessary to use the 8 layers I-Beam as it is
quite heavy for diagonal members. However, the horizontal member is a must to add in but single
layer member is enough to support both side of members.
Figure 6.1 6th bridge (using 8-layers I-Beam as main diagonal member)
Figure 6.2 7th bridge (using 4-
layers member as main
Figure 6.3 Top chord of final design diagonal member)
Figure 6.4 Top view of final design
Therefore, amendments are made, where we remove the I-Beam for the main diagonal member to
reduce the weight of the whole bridge. After several tests on the types of beam, we concluded that
3-layers member is enough to withstand the force. For the horizontal, we decided to use single layer
member to reduce the weight of the bridge.
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6.3 Bottom Chord
Base is the most important among the whole structure as it carries most of the load and transfers
the load to the top. After all experiment for the base structure, we concluded that heavier base
support more load. We did try 8-layers I-Beam as our base, it did withstand the highest load but it is
quite heavy and exceed our limitations. So, we decided to change it to 6-layers I-Beam. For the
horizontal element, we use single layer member to support both side of the beam.
Figure 6.5
Figure 6.6
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6.4 Core Horizontal Element
Figure 6.7 Perspective view of core horizontal Figure 6.8 Elevation of core horizontal element
The core horizontal member must be as strong as possible because it is where the load directly
asserted on it. The core element must have great tension force to overcome the direct compression
force from the load. Therefore, the core horizontal element is amended into 6-layers member as it
provides more stiffness for the load to fix in its direction. The core elements sit on the bottom chord
as it direct transfer the load to the nearest and strongest member (Bottom Chord). The two
members have been put near each other so that the core horizontal can fit the S hook accurately.
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6.5 Vertical & Diagonal Truss
The diagonal and vertical members form the truss web, and carry the shear force. Individually, they
are also in tension and compression, the exact arrangement of forces is depending on the type of
truss and again on the direction of bending. In our truss bridge, the vertical members are in tension
and the diagonals are in compression. After comparing the 7th bridge (without vertical) & 8th bridge
(with vertical), we found that the vertical members did helped to carry the tension force from the
top and bottom. Besides that, the diagonals should be placed inside both top and bottom members
so that they can help to carry the compression force instead of putting outside.
Figure 6.9 7th bridge , 6.10 8th
bridge
Figure 6.11 vertical member,
6.12 diagonal member
Amendments are made in the
trusses as well. Adding more
diagonals and verticals help in
withstand more loads. These
members do not need to have
lots of layer as they act as
aiding members.
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6.6 Joint
A :
Both side of the bottom part of diagonal bracing cut precisely and lay on the base structure of
Fettuccine bridge with butt joint. And, both diagonal bracing attach to each other in order to
distribute the force equally.
B :
Both left and right top part of diagonal bracing cut precisely and joined with butt joint to the top
part of vertical member. It formed a equilateral triangle structure between the top and base of
fettuccine bridge. The rigidity of equilateral triangle structure provide stability and strength to the
force acting on the bridge.
C :
The bottom part of diagonal bracing cut precisely and lay on the end part of the base structure of
the Fettuccine bridge with butt joint.
A
B
C
41
The top and bottom joists are placed between its perspective beams to prevent the bridge from
shearing and twisting from external forces. The edges of the joist are inserted into the beam beside
so that they can distribute the force evenly.
Horizontal hooked member of the fettuccine bridge is simply laid perpendicularly on the base 6 layer
I-beam structure. This horizontal hooked member (6 layer I-beam) function as the load distribution
member to channel and balance the downward loads along the whole fettuccine bridge.
42
6.7 Final Bridge Test
Figure 6.13
Bridge weight : 70g
Load carried : 10.5kgDuring the final bridge test, our bridge can withstand 10.5kg and reach
efficiency of 150, which is about 5 times compared to the 7th bridge we made. This is due to the
presence of more tension force than compression force especially the part where the load being
located. Tension force is used to resist the compression force of the load. The middle part of the
bridge encounters a lot of tension force that is good in preventing the bridge from breaking. The
compression force of the upper part is evenly distributed among the vertical and diagonal truss.
Green line : Tension
Red line : Compression
43
6.8 Failure Analysis
In our final bridge model testing, the centre of the base where the S hook put on is the first part to
break. It caused the base breaks afterwards. We concluded that our structure is quite useful to
withstand the force. We realized that the parts that broke on the bridge were completely on the left
side and also the centre of the long span of the base that distributed the entire load to the base. The
bridge started to buckle after 4 minutes and as we added more weight to it, we could see the bridge
slowly bending and falling apart.
Test Result:
Effectiveness of = Load /Weight of bridge
= 10500g /70g
= 150
Figure 6.14
Figure 6.15
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6.9 Final Drawing Calculation
45
CHAPTER 7
CONCLUSION Throughout this project, we had constructed a total number of 11 fettuccine bridges includes the final test model. We had experimented all of them with many factors such as types of beams, orientation of members, design of trusses and ways to limit the weight of the bridge. We then chose the best result to build our bridge to make it stronger to withstand more loads. Other than understanding how those members work, we also learnt how important is tension force and compression force were in making the bridge more effective. On top of that, we understood the importance of the diagonal bracing member. These members are strengthen using double layered beams. The precision of each connecting joints were achieved as we had built the bridge based on the computer aided drawing we had prepare. Each connecting point is milled evenly using sand paper to prevent imperfect connecting joints. Upon understanding, our final model achieved the highest efficiency among the previous bridges model which we have done. An efficiency of 150E is achieved withstanding a total load of 1050g and its weight 70g. In conclusion, it has been a great experience to construct a bridge that can withstand heaviest load with the minimum weight using fettuccine. We are lucky to study the strength of the pasta and how can it join to get the best results. Although the process was long and tedious, requiring lots of patience putting the whole thing together, but it never fail to amaze us how fettuccine is able to withstand load. We really enjoyed the whole process.
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CHAPTER 8
CASE STUDY
47
CASE 1 BY FUNG HO YENG 0319473 page 1
48
CASE 1 BY FUNG HO YENG 0319473 page 2
49
CASE 1 BY FUNG HO YENG 0319473 page 3
50
CASE 1 BY FUNG HO YENG 0319473 page 4
51
CASE 2 BY LIONG SHUN QI 0315942 (page 1)
52
CASE 2 BY LIONG SHUN QI 0315942 (page 2)
53
CASE 2 BY LIONG SHUN QI 0315942 (page 3)
54
CASE 2 BY LIONG SHUN QI 0315942 (page 4)
55
CASE 3 BY LEONG VUI YUNG 0320362 (page 1)
56
CASE 3 BY LEONG VUI YUNG 0320362 (page 2)
57
CASE 3 BY LEONG VUI YUNG 0320362 (page 3)
58
CASE 3 BY LEONG VUI YUNG 0320362 (page 4)
59
CASE 4 BY LO JIA WOEI 0318585 (page 1)
60
CASE 4 BY LO JIA WOEI 0318585 (page 2)
61
CASE 4 BY LO JIA WOEI 0318585 (page 3)
62
CASE 4 BY LO JIA WOEI 0318585 (page 4)
63
CASE 5 BY IVY VOO VUI YEE 0319534 (page 1)
64
CASE 5 BY IVY VOO VUI YEE 0319534 (page 2)
65
CASE 5 BY IVY VOO VUI YEE 0319534 (page 3)
66
CASE 5 BY IVY VOO VUI YEE 0319534 (page 4)
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CHAPTER 9
REFERENCES 1. Clem Lowell Road Bridge. (n.d.). Retrieved May 5, 2016, from
http://bridgehunter.com/ga/carroll/clem-lowell/
2. SRT251 Group 2. (n.d.). Retrieved May 5, 2016, from http://srt251group2-blog.tumblr.com/
3. SiteSolutions News. (n.d.). Retrieved May 5, 2016, from http://www.conteches.com/our-
company/news/ctl/viewitem/mid/2784/itemid/135
4. What is Warren Truss? (n.d.). Retrieved May 5, 2016, from
http://www.innovateus.net/transportation/what-warren-truss
5. Warren Truss. (n.d.). Retrieved May 5, 2016, from
http://www.garrettsbridges.com/design/warren-truss/