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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]
Project 1: Fettuccine Truss Bridge
Tutor: Mr. Mohd. Adib Ramli
Group member:
Tan Wei How 0310707
Teh Xue Kai 0317021
How Pei Ngoh 0316929
Ang Jia Pin 0315506
Lucas Wong Kok Hoe 0309421
Wong Kah Voon 0317510
Content
1. Introduction
1.1 Objective of project
1.2 Project requirement
1.3 Project schedule
2. Precedent studies
2.1 Navajo 1995 Bridge
2.2 Pratt Truss Bridge
3. Equipment and material study
3.1 Types of fettuccine
3.2 Adhesive test
3.3 Layering test
3.4 Clear span test
3.5 Joint test
4. Design process
4.1 Design 1
4.2 Design 2
4.2.1 Initial design
4.2.2 Modified design
4.2.3 Final design
5. Structural analysis of final design
5.1 Comparison between final design and modified design
5.2 Internal forces
5.3 Reflection
6. Reference
7. Appendix
7.1 Structural analysis of Final Design
7.2 Case Study 1
7.3 Case Study 2
7.4 Case study 3
7.5 Case study 4
7.6 Case study 5
7.7 Case study 6
1.0 Introduction
1.1 Objective of Project:
To design a fettuccine truss bridge using understanding on tension, compression and force distribution in a truss.
1.2 Project Requirements:
Design and construct a fettuccine bridge with 750mm clear span, maximum weight of 200g and
high efficiency.
bridge ofWeight
Load Maximum,
2
EEfficiency
1.3 Project Schedule
Date Task 23/03/2015 Precedent studies on truss bridge
26/03/2015 Discussion on precedent studies 31/04/2015 Preparing materials
04/04/2015 Equipment and material study, eg. adhesive test 08/04/2015 Building of Prototype Bridge 1
10/04/2015 Testing of Prototype Bridge 1
15/04/2015 Building of Prototype Bridge 2 17/04/2015 Testing of Prototype Bridge 2
20/04/2015 Building of Prototype Bridge 3 and 4 24/04/2015 Testing of Prototype Bridge 3 and 4
25/04/2015 Building of Parts for Final Bridge Design 26/04/2015 Assembling of Final Bridge Model
27/04/2015 Final testing of Final Bridge Model
2.0 Precedent Studies
2.1 Navajo 1995 Bridge
Figure 1 shows Navajo 1995 Bridge perspective view.
Navajo Bridge crosses the Colorado River's Marble Canyon near Lee's Ferry in the
US state of Arizona. It carries U.S. Route 89A. Spanning Marble Canyon, the bridge
carries northbound travellers to southern Utah and to the Arizona Strip, the otherwise
inaccessible portion of Arizona north of the Colorado River.
The Navajo 1995 bridge is 143 meters height above the Colorado River. It has 11 spandrel
panels within the main span, which is 221 meters span. Each panel is 10 meter from each other. (Godaddy software, 2010)
Figure 2 illustrates Navajo 1995 Bridge Elevation (Deck Arch Bridge).
Figure 3 illustrates reaction force in Navajo Bridge.
LOAD
Compression
Tension
4 5
6 7
Figure 4 shows how bracings are connected to curved-base chord.
Figure 5, 6 show joints of Navajo Bridge.
Figure 7 shows connection point of the bridge to the ground.
4 5
6 7
Figure 8, 9, 10 & 11 show arrangement of diagonal members, truss and connection parts.
8 9
10 11
2.2 Little Walnut River Pratt Truss Bridge
Figure 12 shows Little River Pratt Truss Bridge elevation.
The Little Walnut River Pratt Truss Bridge is a Pratt truss bridge. It was constructed
shortly after 1885, in Bois d'Arc, Kansas. The bridge was constructed by the Kansas City
Bridge and Iron Company as a carriage, horse and pedestrian bridge over the Little
Hickory Creek. The bridge connects the Walnut River in southern Butler County. It was
added to the National Register of Historic Places in the year 2003.
The height limitation of the bridge is 6 feet and 6 inches. Consisting of two distinct spans, one span of 102 feet and the other 75 feet in length, using the Pratt Truss bridge design. The bridge is iron manufactured by the Carnegie Steel Company. The road surface is made of heavy timber. The total length of the bridge is 196.8 feet and the width of the deck is 13.4 feet.
Figure 13 illustrates elevation of Little Walnut River Pratt Truss Bridge, 1885.
Figure 14 illustrates reaction force.
LOAD
Tension
Compression
Figure 15, 16, 17 & 18 show connection parts and truss members of Little Walnut River Pratt Truss Bridge.
15 16
17 18
3.0 Equipment and Material Study
Figure 19 shows average thickness of a single fettuccine is 10 mm.
Figure 20 shows fettuccine comes in different length with an average of 250 mm.
3.1 Types of Fettuccine
Constant Length = 60mm, clear span = 40mm, no. of layers = 2, adhesive
Manipulated Brand Responding Ability to withstand load for 10 seconds.
Brand Load withstand/g Cross-section of fettuccine
Kimball
200
San Remo
165
Barilla
105
Average length: 250 mm
Average thickness: 10 mm
Conclusion: Barilla fettuccine is the strongest, but San Remo is the most
suitable for bridge making as it has flatter surface which enables larger contact adhesive surface.
Figure 21 illustrates how surface condition influences strength of fettuccine.
3.2 Adhesive Test
Figure 22 shows how test is being carried out.
Constant Length = 60mm, clear span = 40mm, no. of layers = 2 Manipulated Adhesive
Responding Ability to withstand the load for 10 seconds *Remark: V=vertical, H=horizontal, load [= water + 150g (container + hook + thread)]
Adhesive
Water /g 300 800 1300
V H V H V H
3-seconds √ √ √ √ √ √ Bossils √ √ √ √ √ x
Dunlop √ √ √ x x x
PVC √ √ √ x x x
Super glue √ √ √ √ √ x
UHU √ √ √ x √ x
White glue √ √ √ x x x
3s+Dunlop √ √ √ √ √ x
3s+PVC √ √ √ √ √ x
3s+UHU √ √ √ √ √ x
Bossils+Dunlop √ √ √ √ √ x
Bossils+PVC √ √ √ √ x x
Bossils+UHU √ √ √ √ √ x
Conclusion: 3-seconds glue is the most effective glue. White glue is water-based glue so it actually softens fettuccine by a certain degree and makes its joints weak.
Constant Length = 255mm, clear span = 110mm, no. of layers = 4, water = 500g Manipulated Adhesive
*Remark: V= vertical, H= horizontal
Adhesive V H 3s √ √ 3s+Dunlop √ x
3s+UHU x x
Conclusion: 3-seconds glue performs well even in longer clear span.
3.3 Layering Test
Constant Adhesive= 3-seconds, load (water= 500g), length = 255mm
Manipulated No. of layers *Remark: V=vertical, H=horizontal
No. of layers
Clear span /mm 110 130 150 170 190 210 230
V H V H V H V H V H V H V H
2 x x x x x x x x x x x x x x 3 √ √ √ √ √ x x x x x x x x x
4 √ √ √ √ x x √ √ √ √ √ x x x
5 √ √ √ √ x x √ √ √ √ √ √ √ √ Conclusion: Number of layers needed increases as clear span increases.
3.4 Clear Span Test
Constant Adhesive= 3-seconds, load (water= 500g), length= 255mm, no. of layers= 4
Manipulated Clear span *Remark: V=vertical, H=horizontal
Clear Span /mm V H
70 √ √ 90 √ √ 110 √ √ 130 √ √ 150 √ √ 170 √ √ 190 √ √ 210 √ x
230 x x
3.5 Joint test
Figure 23 shows three different types of joint. They are commonly used
in timber construction and fettuccine comes in shape similar to timber. No fixture is required for these joint thus damage to fettuccine is avoided.
Figure 24 shows how test is being carried out using frame, strap with
chain and plastic bag filled with water. Water is weighed using electric balance.
Constant Dimension of frame = 50 x 50 mm, no. of layers = 3, adhesive = 3-seconds Manipulated load [= water + 80g (plastic bag + strap)]
Responding Ability to withstand the load for 10 seconds *Remark: fettuccine frame is tested vertically, load [= water + 80g (plastic bag + strap)]
Joint
Load /g
500 1100 1500 2000 2400 Butt
√
X (2.60s)
X
X
X
Lap
√
√
√
√
X (1.00s)
Mortise and tenon
√
√
√
X (3.93s)
X
Conclusion: Lap joint has less contact adhesive surface than mortise and tenon but it is the strongest.
Butt Joint Lap Joint Mortise and Tenon
4.0 Design Process
4.1 Design 1
Figure 25 shows the reaction force diagram of the bridge. Inspiration of this design is taken from Navajo Truss Bridge.
Force
750
100 100
60
Front View
Top View
Tension
Compression
100 750 100
40
140
Figure 26, 27 & 28
show testing of
Design 1.
Total Length = 950mm Clear Span = 700m
Weight of Bridge = 260g Load Sustained = 1600g
Efficiency = 0.0098
Design 1 is inspired by the Navajo 1995 Bridge (Precedent Study), which is the deck arch truss. This design has high aesthetic value but it exceed the 200 grams to 260 grams.
Problem Identification:
1. The bridge is over-weight, 260 grams. 2. The bridge experienced twisting when load applied.
3. The end of the bridge was not strong enough and it broke. 4. The forces are not fully distributed to some of the members of the bridge as the
joints are not connected properly. 5. Efficiency of bridge is not satisfied yet for us although there is improvement.
4.2 Design 2
`
Figure 29 illustrates the reaction force of the bridge.
42
58
950
60
75
60
100
100
950
Forces
Tension
Compression
Figure 30 shows testing of Design 2.
Total Length = 950mm Clear Span = 700m
Weight of Bridge = 200g Load Sustained = 6180g
Efficiency = 0.1910
Design 2 used back the same design as Design 1, which is the deck arch truss with some
improvement. Thus, its efficiency is getting higher compared to Design 1. However, its
aesthetic value is still remained the same
Improvement:
1. Decrease numbers of panel and layers of the tension members in order to decrease the weight of the bridge. (The weakness of design 1)
2. Add bracing of the top. (The weakness of design 1) 3. Strengthen the both the ends of the bridges, adding more layers to make it
thinker. (The weakness of design 1)
4. Add three triangular members to the centre of the bridge to strengthen it. 5. Improve the way of connecting the joint by using mortise and tenon joint. (The
weakness of design 1)
Problem Identification:
1. The middle part of the bridge is still not strong enough to withstand the load. 2. Efficiency of bridge is not satisfied yet for us although there is improvement.
4.3 Design 3 - Space Truss
Figure 30 illustrates reaction force in Space Truss.
Total length = 800mm
Weight of bridge = 140g
Efficiency = 0.0926
Clear span = 750mm
Load sustained = 3.6kg
Efficiency = 3.62/140 = 0.0926
Figure 31 shows testing of Design 3 – Truss Bridge.
800
80
800
50
50
Tension
Compassion
Figure 32 shows failure of Truss Bridge.
Problem identified:
1. The joint of the bridge is not strong enough to withstand the load.
2. Mortise and Tenon joint method used is good for fixing the members together however the strength of the joint is low.
3. The members turned brittle and weak after 2 days
4. The height of the bridge is too high in relation to the width.
5. Uneven load distribution due to the top point of truss did not meet with another side and form a pyramid.
4.4 Final Design 1
Figure 33 illustrates reaction force of the bridge.
Problem Identified:
The top chord was not properly glued to the members of the truss.
Improvement suggested:
1. The height of the bridge is decreased.
2. Butt joint is used.
3. More layers are added to truss members and chord.
Top View
Front View
Cross-section
60
60
55
55
980
55
980
55
Compression
Tension
Forces
Final Design 2
Figure 34 illustrates reaction force of the bridge.
Model Testing
Two lanyards were used at two points of the top horizontal interconnecting member in the center
between the two planar trusses of the bridge. Then the lanyards were tied to a pail. Starting at 530g
(the weight of the pail) we poured in water to the pail our bridge re
Figure 35 shows
testing of Final Model.
Top View
Front View
Cross-section
60
60
55
55
980
55
980
55
Compression
Tension
Forces
Modified Design 2 Final Design 2 Total length /mm
900 980
Clear span /mm
750 750
Total weight /g
160.0 216.0
Load withstand /kg
8.100 5.750
Efficiency/kg2g-1
8.12 / 160 = 0.4101 5.752 / 216 = 0.1531
Time between completion and testing / hr
48 3
Cross-section
Elevation
Adhesive medium added on top of
base chord to increase contact adhesive surface.
Failure Analysis
1. Time between completion and testing of final bridge is too short. Fettuccine truss
has lower load bearing when adhesive is still wet.
2. Base chord should be perpendicular to desk surface to ensure maximum surface
area is used for load transfer. Diagonal base chord is due to poor workmanship.
3. Weight of 20cm fettuccine is 1.30g. 17 pieces of 5cm doubled-layer hanging
member contribute to redundant members of approximately 11g.
4. Adhesive medium added to enable greater contact adhesive surface is not glued
tightly to base chord. This is the paramount reason for lower truss efficiency.
Structural Analysis
Our final fettuccine bridge model is designed based on a warren (with verticals) truss
design. The reaction forces of the bridge were calculated and identified. The bridge was
tested with multiple types of adhesive and joining methods. We obtained different levels
of strength in different types of design. The result of the testings showed that fettuccine
is strong against tension and weak against compression forces as fettuccine is higher in
elasticity. The strength is also determined by the amount of fettuccine used per part. The
top and bottom chords of the bridge were using more layers than the posts and the
braces. After testing the final model of the fettuccine bridge, we obtained calculations of
forces and reaction forces acting upon the bridge. (Garrett, B., 2011)
Aspect ratio or lower span to longer span ratio for truss frame is 1-1.5, 1.5-2.0 will affect
effective load transfer in space frame member. In final design, ratio of 1.1 (5.5/5) is
within the range. (Tian, T.Lan, 2005)
Figure 36 illustrates how Final Model is was bent during final testing.
Figure 37 shows labelling of Final Model in Structural Analysis (refer calculation in Appendix: Final Structural Analysis).
Conclusion
After all it was a good experience to construct a truss bridge by using fettuccine because
it is a totally new material for us to explore. We carried out tests to study the material’s
tensile and compressive strength. By understanding the nature of the material, we can
utilize it to its full potential in making a stronger bridge. Not to mention the type of
adhesive, we also learn that workmanship plays an important role in increasing the
bridge’s strength and efficiency. This reflects in reality, the stability and strength of a
construction is massively affected by the adhesive too. Furthermore, we learned that the
procedures in a construction need to be well-planned and organized. It is very important to have a well-thought construction sequence throughout the process.
As a conclusion, I think that our group did a good job although the final testing is a failure
compared to the previous one. We explored 4 prototypes by developing and improvising
them based on two main designs from precedent studies. Analysis was done on the load
distribution and at the same time, we successfully determined the critical members and
enforced them by adding layers and pushing the weight of the bridge to 200gram which is
the limit because our previous design weighed only 180gram. This is responding to the
efficiency formula which has square for the maximum load, so by increasing the weight in
order to strengthen it, the bridge can support heavier load, then the efficiency can be
increased by higher rate.
As a designer, it is not a big deal if once in a while our design does not work well or even
fail, it is just that we have to absorb the lessons and learn from it so that in upcoming
projects we can address it. This is because after all designing is a life-long process and we
should always enjoy it by living it to the fullest.
7.0 Reference
Godaddy software. (2010). Highestbridges. Retrieved 6 April, 2015, from http://www.highestbridges.com/wiki/index.php?title=Navajo_1995_Bridge
Garrett, B. (2011). Garrett's Bridges. Retrieved 3 May, 2015, from
http://www.garrettsbridges.com/design/pratt-truss/
Tian, T.Lan. (2005). Space Frame Structure. Retrieved 3 May, 2015, from http://www.gfsmaths.com/uploads/1/0/0/4/10044815/ch24spaceframestructure.pdf
8.0 Appendix (Attachment)
Fin
al S
tru
ctu
ral A
nal
ysis