Bstructure report

ARC2213 Building Structures Project 1: Fettuccine Truss Bridge Analysis Report

BUILDING STRUCTURES (ARC 2523)
PROJECT 1
FETTUCCINE TRUSS BRIDGE
ANALYSIS REPORT
GARNETTE DAYANG ROBERT
0315491
OOI ZHI QIAN
0313999
CHUNG WEI JIN
0313789
LEONG HUI YI
0319280
ABDUL MAHI MUHSIN
0314421
DANAR JOVIAN ADITIYA VADYA PUTRA
0314575


CONTENTS
1. INTRODUCTION
1.1 AIMS & OBJECTIVES
2. METHODOLOGY
2.1 MAKING OF FETTUCCINE BRIDGE
2.2 REQUIREMENT
3. PRECEDENT STUDY
4. MATERIALS & EQUIPMENTS
4.1 STRENGTH OF MATERIAL
4.1.1 PROPERTIES OF FETTUCCINE
4.1.2 TESTING OF FETTUCCINE
4.1.3 EXPERIMENTS
4.1.4 CONCLUSION
4.2 ADHESIVE ANALYSIS
5. BRIDGE TESTING AND LOAD ANALYSIS
5.1 TIMELINE
5.2 FIRST BRIDGE
5.3 SECOND BRIDGE
5.4 THIRD BRIDGE
5.5 FOURTH BRIDGE
6. FINAL BRIDGE
6.1 AMENDMENTS
6.2 FINAL MODEL MAKING
6.3 JOINT ANALYSIS
6.4 FINAL BRIDGE TESTING AND LOAD ANALYSIS
6.5 CALCULATIONS
7. CONCLUSION
8. APPENDIX
8.1 CASE STUDY 1
8.2 CASE STUDY 2
8.3 CASE STUDY 3
8.4 CASE STUDY 4
8.5 CASE STUDY 5
8.6 CASE STUDY 6
9. REFERENCES


1.0 INTRODUCTION
Truss is a structure built up of three or more members that are normally
considered being pinned and hinged at the joints. The following figure shows
different types of trusses. Load applied to the truss is transmitted to joint so
that each individual member is in either pure tension or compression.
1.1 AIMS & OBJECTIVES
This project aims to develop our understanding of tensile and compressive
strength of construction materials by understanding the distribution of force in
a truss and to design a perfect truss bridge of high level of aesthetic value and
minimal construction material.
In order to achieve that, in a group of 6 we were required to carry out a
precedent study on a truss bridge of our choice, analyzing the connections,
arrangements, design and orientations of the members. After that, we were
required to design and construct a fettuccine bridge of 350mm clear span and
maximum weight of 80g. These requirements are to be met, and the bridge
will be then tested to fail. After that, we then need to analyze the reason of its
failure and calculate its efficiency.


2.0 METHODOLOGY
2.1 MAKING OF FETTUCCINE BRIDGE
STRENGTH OF MATERIAL
Understanding the strength of the fettuccine is important in order to build one
bridge that can carry a maximum load. For the tensile strength in the
fettuccine is considerably low when comparing to aluminum, which has the
same amount of stiffness to the fettuccine.
ADHESIVE
Choosing the best type of adhesive is important as it plays a huge role in this
assignment. As there are many types of adhesive, that each has their own
function and characteristic. Not only the type of it, but the brand itself is
important as it has different quality and choosing one that suits constructing
fettuccine bridge is primary.
MODEL MAKING
To ensure precision in our model making, we drafted the drawings in AutoCad
and it was drawn in 1:1 scale, and we plotted out to ensure precision and to
ease our process. Each pasta was marked individually and placed at their
own location and length and were glued accordingly to strengthen our bridge.
MODEL TESTING
Models were then being tested by placing a hook and a pail hanging under
the bridge. Water was being poured into the pail slowly and all these were
being recorded to allow us to fix and amend and analyze our bridge.
2.2 REQUIREMENTS
-‐ A clear span of 350mm
-‐ Maximum weight of 80g
-‐ Bridge must be made out of fettuccine
-‐ Allowed to use any type of adhesive
-‐ Design and workmanship is put to consideration as part of aesthetic


3.0 PRECEDENT STUDY
The precedence study below is used as reference knowledge for our
understanding of forces, real truss bridge connections, arrangement and
orientation of both horizontal and vertical members. The analyzed information
is applied in constructing our final model through a series of trial and error.
Information is obtained from different internet sources as well as books.
HISTORIC NAME: WADELL ‘A’ TRUSS BRIDGE
LOCATION: ENGLISH LANDING PARK, PARKVILLE, MISSOURI
ENGINEER: JOHN ALEXANDER LOW WADDELL (1854-1938)

A BRIEF HISTORY
Originally built as a railroad bridge across Linn Branch Creek, in the
vicinity of Trimble, Clinton County, Missouri, it now crosses Rush Creek
carrying a pedestrian path between a day-use recreational area and two
isolated ball fields. It is a triangular shaped, steel, through-truss, bridge
approximately 100 feet long and 40 feet high. It rests on two concrete
abutments and is composed of pin-connected riveted units. In 1980, the
bridge was disassembled and stored for seven years by the U. S. Army Corps
of Engineers, while awaiting a suitable location and a responsible owner.
Despite its relocation, the Waddell "A" Truss Bridge retains its integrity of
design as drawn by its creator, John Alexander Low.


PHYSICAL DESCRIPTION
The bridge is a single-span, four-panel, pin-connected, steel truss bridge.
The triangular trusses, known as "A" trusses because of their shape,
resemble king-post roof trusses, except that the king "post" is in tension. The
span is 100 feet (30m), and the trusses, 17 feet (5.2m) apart, are nearly 40
feet (12m) high. Near the apex, well above the height of a railroad locomotive,
X-bracing between the two trusses provides lateral stability. This top bracing
and the designed reduction in the quantity of steel needed to construct the
bridge, are the principal reasons for the bridge's shape.
FORCE DISTRIBUTION DIAGRAM

The compression members of the trusses are shop-riveted built-up sections,
made of channels, angles, and plates, while most tension members are made
of pairs of eye-bars. The bottom chord is in four sections, 25 feet by 17 feet,
sway-braced by angle braces and supporting a pair of girder stringers which
are, in turn, angle braced. The floor system consists of cross-braced, built-up
wooden floor beams and stringers.


TRUSS CONNECTIONS and MEMBERS


COMPARISON OF THE BRIDGE BEFORE
RELOCATION

Railroad bridge across Linn Branch Creek, 1989 ( Before dissembling )


DETAIL IMAGES
A) B) C)
A) Detail View Of Circa 1952 Steel Approach Beams Taken From
Underneath Bridge
B) Detail Of Support Column Looking At Right Angle To Truss
C) Detail View Of Bracing Around Support Column
DETAILED TRUSS CONNECTION REFERENCE OF
MEMBERS


4.0 MATERIALS AND EQUIPMENTS

FETTUCCINE
3 SECOND GLUE
PEN KNIFES
S HOOK
PAIL
WATER BOTTLE
SAND PAPER
WEIGHING
MACHINE
CAMERA
To
build
the
bridge

Adhesive
for
model
making

Used
to
cut
fettuccine

Used
to
hook
on
the
bridge
and

to
carry
the
pail

Used
to
carry
the
water
load

Used
to
calculate
how
much

load

To
sand
the
edges
of
any

members
to
have
a
perfect

angle
or
fit

To
weigh
the
right
amount
of

the
bridge
and
the
load

Take
pictures
of
progress
and

the
final
bridge


4.1 STRENGTH OF MATERIAL
Fettuccine was the only material approved to be used for the bridge for this
project. Thus, research and analysis of Fettuccine was conducted before the
model making session.
4.1.1 PROPERTIES OF FETTUCCINE
Before using the fettuccine, it needs to be checked and filtered out, those that
are twisted cannot be used; 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
Tensile strength: 2 000 psi
Stiffness (E= stress/strain): 10 000 000 psi
4.1.2 TESTING OF FETTUCCINE
Before testing, we made sure the fettuccine were glued with the proper
technique to prevent uneven surface and to ensure the ease of building.
FIgure 4.1.2.1 Wrong way
of gluing fettuccine

FIgure 4.1.2.2 Correct
gluing technique for the
members

FIgure 4.1.2.3 Correct
gluing technique for the
beam


4.1.3 EXPERIMENTS
The fettuccine was arranged in so many ways, and we’ve found the best way,
which was the staggered arrangement, it helps us to ensure that the breaking
points were not aligned, hence its stronger.
Also to understand its efficiency and the maximum load each can carry, we’ve
tested several types of beams with different placements and ways to
understand which is the best to be implemented in our bridge.
Layers of
Members
Length of
Fettuccine
(cm)
Clear Span
(m)
Load
Sustained
(Vertical
Facing) (g)
Load
Sustained
(Horizontal
Facing) (g)
1 Layer 26 15 420 205
2 Layers 26 15 500 320
3 Layers 26 15 770 630
4 Layers (I-
beam)
26 15 1300 1110
4.1.4 CONCLUSION
Based on the testing, the I-beam (4 layers of members) is the strongest, both
horizontal and vertical positions can 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
that can withstand more loads. The 3 layers was not used as it was just
carrying extra weight but not effective enough to hold any load. For the 2
layers, it was strong enough and light weight to carry the loads. As for the first
one, it was not used, as it couldn’t hold any load.


4.2 ADHESIVE ANALYSIS
Four different kinds of glue used to ensure the joints were strong and thus
strengthen the bridge.
Types of
Adhesive
Advantages Disadvantages Rank
V-Tech Super Glue -High efficiency
-Fast setting
-Low viscosity
-Burns skin
-Makes fettuccine
brittle
-Leaves marks on
fettuccine
1
UHU Glue -Easy to use
-Neat
-Low efficiency
-Slow setting time
3
YAMAYO Super
Glue
-High efficiency
-Strong and neat
-Fast setting time
-Expensive 2
V-Tech Super Glue was used the most while constructing the fettuccine
bridge. It has high efficiency and it dried faster than other adhesives, as it is
more concentrated when compared to the rest. The glue was allowed to dry
out for a minute or two in order to ensure the glue to dry out and let the
bridges to perform at its best capabilities.
Yamayo Super Glue was also used a lot as it was very easy and also strong
and neater, but because it was expensive and not much in one bottle we
decided to stick with V-Tech. Furthermore it provides the same strength as V-
Tech.
UHU glue was tried once and it was not as good as the rest. It required longer
time to dry and making it very flexible. Not strong enough to hold loads.
In conclusion, the V-tech Super Glue were much more effective when
combining the joints as well as stacking the layers of the fettuccine as it was
much more efficient, easier to use and it dries out very quickly. In order for the
bridge to reach its maximum potential strength, the bridge was left to dry out
for hours before being tested.


5.0 BRIDGE TESTING & LOAD ANALYSIS
5.1 PROGRESS TIMELINE


5.2 FIRST BRIDGE

FIRST BRIDGE
The first bridge model that we tested was based on the precedent studies of
the ‘Howe Truss’. In this first experiment, we did two different kinds of ways of
hooking the load onto the bridge as can be seen in figure 1.1 and figure 1.2.

Figure 1.1 First bridge model

Figure 1.2 Single S-hook was attached to the middle part of the horizontal member


Figure 1.3 Failed horizontal member (Single s-hook)
The structural failure in figure 1.2 occurs at the horizontal member because
the member that bears the most load was too thin and it bears the load all by
itself without distributing it equally through the structure.
Bridge Weight: 64g
Maximum load capacity: 1.6kg
Efficiency: (1600)^2 = 40%
0.064


5.2.1 Calculations


new doc 7_1.jpg


5.3 SECOND BRIDGE

The second bridge model was based on the ‘Baltimore Truss’ precedence
study. Some amendments were made for this bridge, by adding more cross
bracings in order to distribute the tension force more equally along the
structure, reducing the possibilities of it breaking. We also improved the top
and bottom chords by replacing them with I-beams.
The I-beams were constructed with 3 layers of fettuccines.

Figure 2 Cross bracings were made when constructing the second bridge

Figure 2.1 Top and bottom chords were improved with I-beams


Figure 2.1 and Figure 2.3 Failed horizontal members

Figure 2.1 and 2.3 shows structural failure that occurred at the horizontal
member. The failure was similar to the first bridge test, where it occurred in
the horizontal member. This is due to the fact that the S-hook was placed in
the middle of the horizontal member and too much load was concentrated on
that particular spot. Moreover, the fettuccine were not thick enough to
withstand the force, causing it to break apart.
Much improvement was made from the previous test, as this bridge could
withstand loads of up to 5.4kg, 3.8kg more than the previous bridge. This is
due to the I-beams that were constructed along the top and bottom chords.
Bridge Weight: 62g
Efficiency: (5400)^2 = 47.03%
0.062


5.4 THIRD BRIDGE
After the first two tests, we decided to change our truss design into the Wadell
‘A’ truss bridge. This is because we want to explore more on the possibilities
of a stronger structure than the previous models.
I-beams design was constructed lighter than the previous model, with only 2
layers of fettuccines. This is to make the whole structure lighter and to fulfill
the requirements of the project.
Figure 3 Third bridge model
Figure 3.1 Load distribution diagram
Amendments were made whereby positions of the S-hook were changed from
the center of the bridge towards the both sides of the trusses as can be seen
in figure 3.2 in order to distribute the compression and tension load equally on
both trusses.


Figure 3.4 Failed members of the bridge

Figure 3.3 and 3.4 shows structural failure, which occurred on many members
of the bridge (Cross bracings, bottom chords and one side of the top chord).
The placement of the S-hooks in this experiment plays a huge role on the
structural failures. The cross bracings were too small to withstand the tension
and compression force, causing both bottom chords to break apart. Poor
workmanship on constructing the diagonal members has an effect too as they
are not connected properly, hence the poor load distribution along the
members.
Bridge Weight: 50g
Efficiency: (2300)^2 = 105.8%
0.050

Figure 3.2 Placements of S-hooks on
both sides of the trusses

Figure 3.3 X bracings were
constructed


5.5 FOURTH BRIDGE

We decided to stick with the same truss design for the fourth bridge, with
amendments made with the cross bracings as well as improved workmanship
the joints of the diagonal members. Cross bracings were made longer than
the previous experiment in order for it to withstand the tension forces.

Figure 4 fourth experimental models with improved cross bracings


Figure 4.1 Double S-hook attached to both trusses

Figure 4.2 Breakage of the bridge during test

Figure 4.13 Occurrence of structural failures


Figure 4.3 shows structural failures, where it occurred on the diagonal
members as well as the bottom chord. This occurred due to the compression
and tension forces. With poor workmanship of the joints of the diagonal
members, joints were weak and were easy to break apart. The I-beam on the
bottom chord was constructed in two separate pieces, where joints of it were
weak and caused it to break apart.
Bridge Weight: 73g
Efficiency: (7790)^2 = 83.13%
0.073


6.0 FINAL BRIDGE
6.1 AMENDMENTS

Final Bridge
6.2 FINAL MODEL MAKING
After going through a few times of trial experiments on the draft
bridges, we managed to finalize the structure and joints of our bridge. Also,
we made sure that the efficiency of the final structure was on point to its
maximum by increasing its strength in terms of the constant weight. So, here
is how our final bridge, that weighted 69kg with its ability to hold a bucket of
water that had a weight of 9.1kg in total, was made.
We started off with the individual bridge parts that will be used to build
up the whole bridge model. Using the strongest 3 seconds super glue, we
placed two layers of fettuccini sticks together for each part until it is enough
for the whole structure. The two-layered part was then left ready to be cut
accordingly to the desired measurements based on the outline of the bridge.
For each frame of the bridge structure, we placed one layer of fettuccini stick
on the top and bottom side of the uncut two-layered structure to create an I-
beam-like structure.
We printed out the outline of our bridge structure that was drawn on the
AutoCAD software. In order to achieve the maximum accuracy of the
structure, we placed the two-layered sticks and the I-beams on the outline
sheet and cut the sticks according to the lengths of each structural parts of the
bridge. Then, we placed the readied parts back on the outline sheet to stick
up the edges to create the form of the bridge. We started off from the sides of
the bridge followed by its top and bottom.


6.3 JOINT ANALYSIS
The joint methods that are used in the construction of the bridge is very
important as it affects the efficiency and failure of the final fettuccine bridge.
The joints are thoroughly tested and studied in order to achieve the maximum
strength in each connection of members. Below are the final joint methods
that were used in our bridge, according to the requirement of each part.


JOINT A
DIAGONAL/VERTICAL LOAD DISTRIBUTING MEMBERS
From analyzing the forces, we found out that the top of the structural frame
experiences compression forces upon application of load. The vertical
member helps to balance out the force as it has an internal tension force and
transfers the load to the adjacent diagonal member and to the bottom of the
structural frame. This reduces the stress on the I beam as the vertical
member now functions as a supporting column for the I-beam.
JOINT B
MIDDLE MEMBER AS ‘SUPPORT’ COLUMN
The central
vertical member of
the bridge is
joined very
carefully so that it
stands perfectly in
the centre of the
mitre joint of the I-
beam, acting as a
mean of support
and prevents the
top member from
collapsing. We
found of that, when the vertical member is even slightly off balance from the
centre, it causes stress to the structure above


JOINT C
TOP CONNECTION OF I-BEAM (STRUCTURAL FRAME)
The diagonal members of the structural frame ( I-beams ), are joined with a
mitre joint. A mitre joint is joint made by beveling each of two parts to be
joined, usually at a 45° angle, to form a corner, usually a 90° angle. The
rigidity of the structural frame is strengthened due to this design, and provides
stability and strength to the loads acting on it from the structures below, and
helps to evenly distribute the forces.
JOINT D
TOP DIAGONAL TO BASE, FRAME CONNECTION OF I-BEAM
Since the top part of the structural frame is in full compression, and the
bottom part is in tension, the force needs to have a proper path to flow along
the structure. To accommodate this huge compression force, the top structure
needs to be carefully shaped and connected to the base without any
faulty/disconnected edges. In order to do that, the I-beam member is cut at a
45’ angle as it adheres perfectly to the bottom member. This provides better
resistance to the structure against compressive stress.


JOINT E
The vertical connecting members are very critical in the bridge design as
means of supporting as well as distributing the load along the entire structure.
The improvement is made from a very first design where we placed the
horizontal member merely against a single vertical member. The horizontal
member did not aid in transferring the load to the other members however
was only dependent on the adhesive (three second glue) that was used. This
resulted in an instant breakage of the horizontal member.
The second design was improved by placing the horizontal members on top of
the structural base frame, on either sides of the vertical member. This gave
support to the vertical member as well as increasing the surface distance
horizontally. However it did not transfer the load vertically.
The final design was improvised by using two diagonal members touching the
center vertical member. This helped to divert the load stress evenly to the
other parts of the bridge.


JOINT F
In order to further strengthen the base members, a
horizontal member was placed on either side of the
diagonal members that were supporting the vertical
members. This helped to reduce the stress on the
diagonal members and prevented it from sliding or
breaking off (distortion) from the vertical member.
These members also helped to distribute the loads
horizontally from one side to the other. The edges of the
connection are carefully shaped so as to fit perfectly into the slots between
the base structural frame and diagonal members, to provide extra strength
and rigidity.
BASE JOINTS
JOINT G
HORIZONTAL ‘X’ BRACING ( JOINT TO THE STRUCTURAL FRAME )
Joint H is using the concept of how I-beams are coped inside each other with
one member’s flange resting on the other. This provides a ‘lock ‘mechanism
for the horizontal beam and gives it some strength. Two diagonal bracings are
placed below the two-parallel members, in order to strengthen the beam


JOINT G & I
HORIZONTAL ‘X’ BRACING ( JOINT TO THE HORIZONTAL BRACING )


6.4 Final Bridge Testing and Load Analysis
The picture below shows the final design of our fettuccine bridge and its load
distribution. In this bridge, the final amendments made are the number of
diagonal members in the structure and an addition of a cross bracing in the
base to strengthen the bridge from torsion.
Figure () Final bridge design showing the distribution of compression and
tension force in the bridge.

Figure () Top view of the bridge

Figure () Base Design


Figure() Bridge while testing.

Figure () Top chords of bridge broke and caused the bridge to fall
After observing, calculating and analyzing our final bridge, we came to a
conclusion that the failure of this bridge is due to the breakage of the top
chords which had to withstand a huge amount of compression forces. Longer
members tend to have a weaker resistance to compression force which might
also be one of the reasons to the failure to our bridge as the top chords are
both 215mm each. Moreover, Joint BE and Joint IJ, which are diagonal
members are also under large compression forces which are 133.41N each,
further weakening the support of the bridge.In addition to that, the middle
member is also under large compression force, which is 202.91N, causing a
large upward force acting on the top and bottom chords, resulting in torsion in
both of these members.


Figure () Highlighted are the failed members.
Bridge weight: 74g
Load: 8670g
Efficiency: (8.67)
=1015.80%
The efficiency of the final bridge was over our expectations as the maximum
load that our final testing bridge withstood was 7790g which was 880g lighter
than the final load withstood. If the large amount of compression force could
be lessen down to a smaller amount, the bridge could have resulted in a
higher efficiency than this. Moreover, if the middle member was acted on by a
tension force instead of compression force, The top chords and bottom chords
would have lesser force acting on them in the middle, resulting in higher
efficiency.

Failed Components Top chords and bottom chords.
Failed Reasons Large compression force acting on
top chords and bottome chords
exerted from middle member of the
fettuccine bridge.

2
0.07
4


6.5 Calculations


7.0 CONCLUSION

In a group of 6, we have carried out experiment and tested 5 bridges in
total. Each of them has different truss and different efficiency is tested out.
The precedent study that we have taken inspiration and modified from is the
“Waddell A Truss Bridge”.
After rounds of testing and calculating the efficiency, we have decided
to make our bridge triangular shape because the equivalent triangle is the
strongest form in withstanding pressure. In the process of changing the truss
and pattern, we realize that the angle too, plays a crucial part in sharing the
load and having clear state of how tension and compression work in different
methods.
In the last few rounds of finalizing the bridge shape, we decided to
keep it simple because the more truss added in, the weaker it actually gets
because these trusses act as additional and useless weight that serve no
purpose except adding the total loads. Thus, we make it to the easiest and
obvious triangle shape with the same length and same angle on inverted side.
At the end, it’s efficiency increases way more than our first try.
As a team, we learnt that time management is very important as we
need time to carried out countless experiments and also calculating the
efficiency and highest possibilities of either which bridge can withstand the
most weight. We also learnt that the unity of all team members can make the
workload lesser and also make the progress faster when all of us corporate
well together as a team.


8.0 APPENDIX
CASE STUDY NO. 1
JANE OOI ZHI QIAN
0313999


CASE STUDY NO. 2
MEGAN CHUNG WEI JIN
03


CASE STUDY NO. 3
ABDUL MAHI MUHSIN
0314421


CASE STUDY NO. 4
GARNETTE DAYANG
ROBERT
0315491


CASE STUDY NO. 25
LEONG HUIYI
0319280


CASE STUDY NO. 6
DANAR JOVIAN ADITIYA PUTRA
0314575


9.0 REFERENCES
Vitaltechnical.com,. 'Sealant Manufacturer In Malaysia | Adhesive | Vital
Technical'. N.p., 2015. Web. 8 Oct. 2015.
Ching, Francis D.K (2008) Building Construction Illustrated Fourth Edition.
New Jersey: John Wiley & Sons, Inc.

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