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