Building Structure Project 1 - Fettucine Truss Bridge

1. Bachelor of Science (Honours) (Architecture)
Project 1:
Fettuccine Test
Module:
Building Structures (ARC 2523)
Group Members:
Farah Farhanah Kassim (0317534)
Felicia Novera (0316206)
Johan Syahriz bin Muhaiyar (0316115)
Muhammad Faridzul Fikri bin Jeffry (0311836)
Renee Lim Wei Fen (0311016)

2. Table of Contents
1.0 Introduction
1.1 Aims and Objectives
1.2 Project Scope
2.0 Methodology
3.0 Precedent Study
3.1 History
3.2 Structural Details
4.0 Materials and Equipment
4.1 Materials
4.2 Equipment
5.0 Design and Structure Analysis
5.1 Bridge Design 1
5.2 Bridge Design 2
5.3 Bridge Design 3
5.4 Bridge Design 4
5.5 Bridge Design 5
6.0 Conclusion
7.0 Appendix
8.0 References

3. 1.0 INTRODUCTION
1.1 Aims and 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
In a group, you are required to design and construct a fettucine bridge of 750mm clear
span and maximum weight of 200g. These requirements are to be met, or else it may result in
reduction of grade. The bridge will be then tested to fail.
Other than aesthetic value, the design of the bridge must be of high efficiency, i.e. using the
least material to sustain the higher load. The efficiency of the bridge is given as following;
In order to achieve higher efficiency, you need to analyse and evaluate each of the following
items.
 Material strength
 By adopting appropriate method, determine the strength of fettucine, i.e.
tension and compression strength
 By knowing the strength of fettucine, you will be able to determine
which members to be strengthened
 Structural analysis of the truss
 Perform detailed structural analysis of the truss
 Identify critical members
 Strengthened the critical members if necessary

4. 2.0 METHODOLOGY
In a group of five, we were assigned to build and design a truss bridge with fettuccine as sole
material of the bridge.
Before designing and building the bridge, first we were required to have a sample of existing
truss bridge. The Deep River Camelback Truss Bridge has been chosen as the precedent
study object for this project. The purpose of conducting a precedent study is to gain an
understanding on how a truss design might affect the stability and the strength of the bridge.
As fettuccine is never a material for construction, we had to test its strength beforehand.
Different types of glue were also being tested for its adhesive strength.
Second, we started on building our fettucine bridge.
The first bridge we build referred to Waddell “A” Truss and it was able to withstand load as
heavy as 3 kg. The bridge itself weighs around 150 grams with 750mm bridge span and
54mm gap span.
The second bridge referred to Arch Bridge and was able to withstand load just until 1.5kg.
The third test-bridge too referred to Waddell “A” Truss, but we added some supports on some
part of the bridge and it was able to withstand load until 5kg.
The fourth test-bridge was similar to the third bridge. We added support on the parts that
seemed to be broken in the third bridge and it was able to withstand load as heavy as 4.8kg.
After obtaining and consolidating the data we received from the testing of the previous
bridges, we settled on a centre reinforced Waddell “A” Truss design with reinforced bracing
supports for our final bridge.

5. 3.0 PRECEDENT STUDY
In order to achieve a proper understanding of the truss bridge system, we carried out a
precedent study on a currently existing truss bridge; The Deep River Bridge in North
Carolina,USA.
Image 2.1: Deep River Camelback Truss Bridge. Source: Google
Name: Deep River Camelback Truss Bridge.
Location: North Carolina, United States of America.
Largest Span: 160.1 ft.
Total length: 365.2 ft.
Inside width: 14.8 ft., one lane
Design: Eight-panel, pin-connected Camelback truss with steel stringer/timber approaches.
Year Built: 1901
Materials: Steel
Type of Truss: Camelback truss

6. 3.1 History
Figure 1 Main span of the Deep River Camelback Truss Bridge
The Deep River Camelback Truss Bridge spans the Deep River in North Carolina, allowing
the access between the community of Cumnock in northern Lee County and The community
of Gulf in southern Chatham County. The bridge was originally constructed in 1901 as part of
a multi-span bridge over the Cape Fear River at Lillington. The bridge was dissembled after a
span of the bridged collapsed in December 1930 in order for a new bridge to be erected. In
1932, one of the spans was rebuilt at the site over the Deep River to replace another wooden
bridge that was burned in 1929. Ever since 1833, bridges had always been used as connecting
access above the Deep River.
In 1979, the bridge was marked as one among thirty-five bridges that are eligible for the
National Register as significant examples of metal truss engineering technology in the state
starting from 1880 to 1935, as well as for associations with transportation improvements in
the beginning of the twentieth century. The Deep River Camelback Truss Bridge which was
also named Truss Bridge #155, is one of four surviving camelback truss bridges in North
Carolina. On east of Truss Bridge #155, a new concrete bridge spanning the Deep River was
completed in 1992 by the Department of Transportation. The older bridge then had its
ownership transferred to the Deep River Park Association and will be preserved as part of the
group’s Rails-Trails route under development.
The camelback configuration originated from the Pratt truss which explains the similarity
between the two designs. With the exception of two extra panels, the arrangement of the
diagonal structural members of the Camelback is identical to that of the Pratt truss. Two
center panels of the Camelback have double diagonals that cross to form an “X”. The most
significant and distinguishing feature of a Camelback is the top chord, the Deep River Truss
Bridge’s top chord for example has three sections to it. The center section is straight while
the left and right sections angle down to the frontal posts. This gives Camelback truss’s top
chords four angles while the semi-curve of the top chord allows the bridge to span greater
distances using fewer materials.

7. 3.2 Structural Details
The Deep River Camelback Truss Bridge is a pin-connected
bridge, all the connections between members are made using
large steel pins which are held in place by like-size nuts. The
bottom chord comprises of a series of eyebars which are more
similar to a diagonal member as opposed to a single beam. The
vertical members use “built-up” beams, which are two lengths
of steel “stitched” together to form one single beam. This is
accomplished by riveting together short pieces of steel across
the beam in a “zigzag” pattern. The top chord and front posts
are also “built-up” but employ steel plates called batons
instead.
The extent of the rehabilitation of this remains unclear but
modifications throughout the years include paving over with
asphalt the wooden deck. Modern guardrails supported by
their own beams as opposed to being bolted onto the bridge’s
structural members were added. A few of the diagonals have
also been reinforced with parallel cables.
Truss Analysis
A comparative study using a Pratt truss which Camelback truss
is a derivative of.
Conclusion: In both cases,the total load = 100. The camelback truss emulates the exact same formula
however it’s top chord does not stay parallel with the bottom chord. This creates a lighter structure
without losing strength, less dead loads at ends and more concentrated strength at center.
Figure 2 Portal shot of the Deep River
Camelback Truss Bridge.
Figure 3 The decking below the bridge.
Figure 4 Pratt Truss.
Figure 4 Pratt Truss with centered load. Figure 6 Pratt Truss with spread load.

8. Figure 5 A pinned connection between the lower chord and a vertical member.
Figure 6 The same connection as viewed from above. Note the added steel cable.
Figure 7 An upper chord/front post connection.

9. 4.0 MATERIALS AND EQUIPMENT
4.1 Materials
SAN REMO FETTUCCINE No. of
layers
Length
(cm)
Span
(cm)
Vertical
(g)
Horizontal
(g)
1 20 10 130 80
2 20 10 890 520
3 20 10 1000 900
4 20 10 1700 1550
SUPER GLUE DESCRIPTION
Mostly used as it sticks just right and does not
deteriorate the fettuccine as fast as 3 second glue.
3 SECOND GLUE DESCRIPTION
It sticks right away and strong, but it also
deteriorates the material fast.
DUNLOP GLUE DESCRIPTION
Was used to increase the flexibility of the bridge
so it doesn’t break straight away, but crack slowly
instead.

10. 4.2 Equipment
PEN KNIFE / CUTTER DESCRIPTION
Was used to cut the pasta / fettuccine
S HOOK DESCRIPTION
Was used as connector between the bridge
and the pail
PAIL DESCRIPTION
Was used to hold loads
WATER DESCRIPTION
Was used as loads
KITCHEN BALANCE DESCRIPTION
Was used to weigh the bridge and loads

11. 5.0 DESIGN AND STRUCTURE
ANALYSIS
5.1 Bridge Design 1
In the firstdesign,we designed our bridge in accordingto the Pratt truss
manner. In which the bridgeis made of trusses that have vertical web
members to take tension forces and with angled braces to take
compression.As a startwe made the bridge exactly at 750mm which
gave us a span of less than 750mm. The weight of the bridge only took up
150 grams. At the end of the bridge testing, the bridge could only hold a
load of 3.3 kilograms.Theefficiency of the bridge was 72% the bridge
broke on most of the members instead of the joints.Which concludes
that the members were not strong enough as torsion occurred.
Solution:
1. The members of the bridge should be strengthened by
multiplyingthe number of fettuccine in each member.
2. Besides that, the bridge should havehorizontal members
at the top of the structure to prevent torsion fromoccurring.
Load (g) Checked Remarks
100 / -
200 / -
300 / -
600 / -
900 / -
1200 / -
1500 / -
1800 / -
2100 / -
2400 / -
2700 / -
3000 / -
3300 x *broken*
Weightof bridge:150g
Clearspanof bridge:650mm
Load sustained:3.3
Efficiency: 72%
Tension
Compression
Breakage point

12. 5.2 Bridge Design 2
As for the second bridge, we tried designinga new form
(ref. photo) by making the lower beam in an arch and
curved shape. Whatwe analysed from Bridge CaseI, the
lower beam of the bridge is bend downwards.We tried
to improve the bending problem by makingthe lower
beam in a curved/arch shape; with this we expected the
lower beam to straighten when load is carried.
Unfortunately,the Fettucine doesnothave elasticcapabilityorcharacteristics.Inadditiontothat,
the (3 secondsglue/superglue) usedinthe processmade the fettucine bondsinafix position.There
are no movementswithinthe jointsorthe membersof the trusses.Whenloadiscarried,everytruss
distributestheirforces;compressionandtensiontoothertrussmembers.
Bridge Case II managedtocarry weightupto1.5kg, comparedtoBridge Case I whichcarriedup to
3.3kg withdifference of 1.8kg.
Solution:
1. Lowerbeamsshouldbe remainedstraightened.
2. Truss membersshoulddistributeweightevenly.
Load (g) Checked Remarks
300 / -
500 / -
700 / *bends
900 / *bends
1100 / *bends
1300 / *bends
1500 X *broke*
Weightof bridge:200g
Clearspanof bridge:700mm
Load sustained:1.5kg
Efficiency:11%
Breakage point
Tension
Compression

13. 5.3 Bridge Design 3
Design has not reached the required 750mm span but is
well within the weight limitat144gm out of the 200gm. The
center member supportingthe hook for load testing broke
in the middle of testing due to insufficientlamination,
however itdid not affect other members of the bridgeand
we quickly and simply replaced itwith a doublelaminated
member to continue testing. Aesthetic valueis less than
bridge 2 but efficiency rate improved significantly with this
change in design.
Solution:
1. Reinforce area around the concentrated point load by addingmore layers of lamination as well as
addingmore horizontal and cross bracingto center.
2. Divertingload to spread away from center and reducingthe concentration of applied load by
changingthe direction of center diagonal bracingson both sides.
Load (g) Checked Remarks
300 / *no changes
1200 / *no changes
2100 / *no changes
2700 / *bends
3700 / *bends
4700 / *bends
5300 X *Broke*
Weightof bridge:144gm
Clearspanof bridge:650mm
Load Sustained:5.3kg
Efficiency:35.4%
Breakage point Tension
Compression
Figure 9 Center support on one side completely broke off along with
the horizontal center member.
Figure 8
Horizontal
member
broke off due
to insufficient
lamination

14. 5.4 Bridge Design 4
As for the Bridge Case4, the bridge engaged in the samedesign as the third which is the Howe truss.The
Howe truss is identical to the Pratt truss but the angled braces aremirrored in a different direction,therefore
the load is distributed in a different direction.However the difference that was made on this bridge was the
height of the vertical members and the length of the bridge. We wanted make a study on how the height of
the bridge will affectits efficiency to hold the load.The bridge was 850mm in length with a span of 750mm.
The weight of the bridge was 190 grams.At the end of the bridge testing, the bridgecould hold up to 4.8
kilograms beforepart of the truss at the center broke. It can be identified that the center joints were not
strong enough to withhold the load ata certain point and it then gave way. As a conclusion,theheight did play
a role in the structure as itcould carry more loads then the one before.
Solution:
1. The joints atthe center should be improved by making surethe fettuccine
does not detach easily fromits joints.
Load (g) Checked Remarks
300 / -
600 / -
900 / -
1200 / -
1500 / -
1800 / -
2100 / -
2400 / -
2700 / -
3000 / -
3300 / -
3600 / -
3900 / -
4200 / -
4500 / -
4800 x *broke*
Weightof bridge:190g
Clearspanof bridge:750mm
Load sustained:4.8kg
Efficiency:121%
Tension
Compression
Breakage point

15. FINAL MODEL
5.5 Bridge Design 5
With all the casestudies conducted, we can concludethat casestudy 3 and 4 were the most efficient. With
that being proven we have adapted the designs from both the cases and settled with the Howe truss.We
made amendments to the height and the number of vertical members in the bridge. The reason for reducing
the number of members is so that we could lighten the weight of the bridgeas we were emphasizingon
strengthening the joints through bracing.The bridge was 850mm in length with a given span of 750mm. The
weight of the entire bridgeadded up to 199 grams which did not exceed the requirement of the project.
Unfortunately, the bridge could only carry a load of 1.2 kilograms.Itwas observed that the unexpected end of
the bridge broke because the load was not transferred equally due to the center vertical member that was not
placed at a 90 degree. As a conclusion fromthis final test,angles of members in trusses placean important
rolein the whole truss system.
Solution:
1. To placemembers of fettuccine at 90 degrees to ensure an equal load transfer throughout the whole bridge.
2. Reinforce area around the concentrated point load by addingmore layers of lamination as well as adding
more horizontal and cross bracingin between members.
Weightof bridge:0.199kg
Clearspanof bridge:750mm
Load sustained:1.2kg
Efficiency:10%
Tension
Compression
Breakage point

16. 6.0 CONCLUSION
Analyzing all the cases in general, it is visible which is the most efficient amongst the 5.
Firstly, we should assume all these cases act simultaneously. Secondly, if the member carries
more force, it tends to break easily.
For example in case 5, one of the diagonal members exerts about 926.3 kN of force. It will
break easily and will be less sufficient.
In case 3, columns supporting 150kN or less will break first due to the top members
transferring 734 kN force and it is not distributed evenly.
In case 2, column carrying 210kN will break first but if compared with case 4, case 4 will
collapse before case 2 and case 1 due to heavy loads being supported by small horizontal
members.
If the compression is big, the members will be prove to buckling while high tension will
cause the members to snap. From all the 5 cases, case 2 will be the most efficient in our
opinion because it has better load distribution among the members.

17. 7.0 APPENDIX

18. 8.0 REFERENCES
Boon,G. (2015). Garrett's Bridges » Pratt Truss. Garrettsbridges.com.Retrieved6May 2015, from
http://www.garrettsbridges.com/design/pratt-truss
Sites.google.com,.(2015). Deep River CamelbackTrussBridge - Matthew B Ridpath.Retrieved6May
2015, fromhttps://sites.google.com/site/matthewbridpath/bridges-and-highways-1/truss-
bridges/deep-river-camelback-truss-bridge
Pghbridges.com,.(2015). Bridge Basics - A Spotter'sGuide to BridgeDesign. Retrieved7May 2015,
fromhttp://pghbridges.com/basics.htm