Building Structure Analysis Report

BUILDING STRUCTURES

[ARC 2213 ]

FETTUCCINE TRUSS

BRIDGE ANALYSIS

REPORT

C H O O A I L I N

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BUILDING STRUCTURES [ ARC 2213 ]

TA B L E O F C O N T E N T S

1 I N T R O D U C T I O N

2 M E T H O D L O G Y

2 . 1 P R E C E D E N T S T U D Y

2 . 2 M A K I N G O F F E T T U C C I N E B R I D G E

2 . 3 R E Q U I R E M E N T

3 P R E C E D E N T S T U D Y

4 A N A LY S I S

4 . 1 S T R E N G T H O F M A T E R I A L

4 . 2 A D H E S I V E A N A LY S I S

5 M O D E L M A K I N G

5 . 1 M E T H O D O F C O N S T R U C T I O N

5 . 2 J O I N T

6 T E S T I N G

6 . 1 F I R S T B R I D G E

6 . 2 S E C O N D B R I D G E

6 . 3 T H I R D B R I D G E

6 . 4 F I N A L B R I D G E

7 D E S I G N M O D I F I C AT I O N

7 . 1 F A I L U R E R E A S O N I N G

7 . 2 S O L U T I O N

8 C O N C L U S I O N

9 A P P E N D I X

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BUILDING STRUCTURES [ ARC 2213 ] 01

1 I N T R O D U C T I O N

This project aims to develop our understanding of tensile and compressive strength of

construction materials by understanding the distribution of force in a truss.

In order to do achieve that, we were required carry out a precedent study on a truss

bridge of our choice, analyzing the connections, arrangements and orientations of the

members. Once that was completed, we were required to design and construct a truss

bridge made out of fettuccine.

The requirements for this bridge include it having a 750mm clear span and a maximum

weight of 200g. This bridge will then be tested to fail and we were required to analyze

the reasons of its failure and calculate its efficiency.


2 M E T H O D O L O G Y

2.1 PRECEDENT STUDY

By looking through precedent studies to have a better understanding of the types of trusses

available. Next, understanding the forces that would be exerted to the trusses;

compression and tension, would allow us to make adjustment to our bridge, that would best

suit the given material; fettuccine.

2.2 MAKING OF FETTUCCINE BRIDGE

PHASE 01: STRENGTH OF MATERIAL

Understanding the properties of the fettuccine is important in order to build one bridge that

can carry maximum load. For the tensile strength in the fettuccine is considerable low when

compare to aluminium which has the same amount of stiffness to the fettuccine.

PHASE 02 : ADHESIVE

Choosing the right type of adhesive is important as it plays a huge role in this assignment.

As there are many types of adhesive in the market that each has their own function and

characteristics. Not only the type of adhesive is important but the brand of adhesive is

important as well, for different brand has different quality and choosing one that suits

constructing the fettuccine bridge is primary.

PHASE 03: MODEL MAKING

To ensure precision in our model making, Autocad drawings are drawn in 1:1 scale and

plotted out to ensure precision and ease our process. And in order to strengthen our bridge

as much as possible, each pasta is marked individually as each has their own location of

placement and length, and are glued accordance.

02


2 M E T H O D O L O G Y

PHASE 04 : MODEL TESTING

Finished models are being tested after placing aside to allow the adhesive to sit on the model.

By placing weight on the middle of intermediate member to ensure that load is evenly

distributed. All these are being recorded to allow us to fix and analysis our bridge.

2.3 REQUIREMENTS

• To have a clear span of 750mm

• Not exceeding the weight of 200g

• Only material allowed is fettuccine pasta and adhesive

• Allowed to use any type of adhesive possible

• Workmanship is put to consideration as part of aesthetic value



The Heshbon Bridge, located at Indiana, Pennsylvania state in the United State of America,

is one of the last state-standard truss bridges built. Many bridge were constructed across

the Pennsylvania state from the late 1920's through 1941. This bridge was constructed in

1941 by Paul Construction Company and Pennsylvania State Highway Department which

has a main span of 153ft(46.6m) with a total length of 158 ft(48.2m) and 26ft(7.9m)

r o a d w a y w i d t h o v e r t h e B l a c k L i c k C r e e k .

HESHBON BRIDGE, INDIANA (1941)

04


This bridge is a relatively small example of Pennsylvania's very attractive standard plan of

1930s to 1940s truss bridge design. As such, it features a shallower portal bracing design

that other bridges built to this standard. In 2009, the government wanted to replaced the

bridge but fortunately they decided to rehabilitate it instead of replacing it. This will include a

deck replacement as well as structural steel repairs. So, the Heshbon bridge represents a

good preservation project and it became one of the tourist attraction in Pennsylvania.


Heshbon Bridge from 1941-2009

Old railroad bridge with wooden

pathway.

Heshbon Bridge 2009 until today

After rehabilitate, the bridge

became a bike path

Heshbon Bridge Before Restore Heshbon Bridge After Restore

The map above shows the bridge is located over Black Lick Creek In Heshbon,

Indiana County, Pennsylvania.

05



The 1941, skewed, 158ft long, riveted Parker truss bridge is supported on ashlar

abutments with concrete caps. The trusses are traditionally composed with the upper

and lower chords being built up box sections, and the verticals and diagonals rolled I

sections. Lateral and sway bracing are laced channels. The deck is reinforced

concre te , and the s teel ra i l ings inside the t russ l ines are or i g inal .

TRUSS CONNECTIONS AND MEMBERS

Portal view on bridge Top chord connections

Bottom chord connections. Connections of truss web

06


Vertical member detail End Post


Railing detail Railing

Abutments Ashlar abutment

07


4 A N A LY S I S 4 . 1 S T R E N G T H O F M A T E R I A L

WEIGHT

With the requirement of only 200G, we had to creative solution, to reinforce our bridge

while making sure that the weight of bridge does not exceed the requirement. Thus we

came our with solution by selecting parts that holds load and reinforce it by adding layers

to it. But bearing in mind that the more layers added, the more weight it holds.

Before we started our model making, we did a little experiment of the maximum weight the

fettuccine can carry. We tried out with 4 different layers to carry out this experiment.

Experiment (left to right):

I. One Layer

II. Two Layers

III. Three Layers

IV. Four Layers

Experiment 03: Three Layers

When load is applied, members could be seen slightly sturdier

when compare to Experiment 2. But a slight bend in the middle

could be seen. Total weight being 1.8G

Experiment 02: Two Layers

In the two layer of fettuccine, a slight bend could be seen in the

fettuccine, although it is not as extreme as Experiment 1. Total

weight being 1.17G

Experiment 01: One Layer

Members starts to bend after load is applied with just one layer of

fettuccine. Total weight being 0.56G.

Experiment 4: Four Layers

With four layers, it has proven to be the most stable option

among all experiments. Total weight being 2.05G.

Properties of spaghetti (dry)

1. Ultimate tensile strength ~2000 psi

2. Stiffness (Young’s modulus)

E ~10,000,000 psi

(E=stress/strain)


4 A N A LY S I S 4 . 1 S T R E N G T H O F M A T E R I A L

ORIENTATION

Horizontal members were placed between

trusses, to hold both pieces of the bridge

together. They held no force besides balancing

the whole truss bridge. Hence, we reduced the

horizontal members to one layer in our second

and third bridge, for our bridge to fit the

requirement in terms of the bridge’s weight.

V

S

Method 01 was used in our case

because the members were fitted

between the arch and the bottom

chord. This can ensure that the

load was distributed evenly to the

arch. Comparing to Method 02,

which the bracings were glued on

the outside truss. Thus, Method 01

was a better choice of orientation.

Where Method 02 is still able to

distribute the load but the bracings

were not secured onto arch and

bottom chord, relying on the glue Method 01 Method 02

The intermediate member is where

the hook that held on load is

placed. Making its role important.

Where the orientation and its

layers are vital. We found out the

load can be transferred more

efficiently when it was placed

exactly in the middle in upright

position, where the load can be

distributed evenly to the sides.

09


4 A N A LY S I S 4 . 2 A D H E S I V E A N A L Y S I S

Type of Adhesive Advantages Disadvantages

X’traseal’s Super Glue • High efficiency

• Fast solidify time

• Easy to use

• Easy to bend fettuccine

when applied

• Cracked joint after

dried for few days

Selleys’ Supa Glue • High efficiency

• Fastest solidify time

• Easy to use

• Cracked joint after

dried for few days

UHU Glue • Easy to use • Low efficiency

• Causes flexible joints

• Longer solidify time

• Causes bridge to

weigh more

Three different kinds of glue used to ensure the joints are strong and thus strengthen

the bridge.

Selleys’ Supa Glue was used the most while constructing our fettuccine bridge. It has

high efficiency and it dried faster compared to the other adhesives, as it is more

concentrated when compare to X’traseal’s Super Glue. To make sure the glue worked

at its best, allow the glue to settle in the bridge to make sure it is dry before the

t e s t i n g i t . T h i s i s t o e n s u r e t h e b r i d g e p e r f o r m a t i t s b e s t .

The X’traseal super glue is only used on the arch where slower solidify of glue is

needed in order to buy some time while constructing the arch, for better precision.

UHU Glue is avoided if possible, as it causes the joints to be flexible. It also requires

longer time to dry. Making it the worst option, for joints should be rigid.

10


5 M O D E L M A K I N G 5 . 1 M E T H O D O F C O N S T R U C T I O N

02. We started off by doing the

bottom chord of the bridge by

dividing the base of the bridge into 4

layers with different length.

03. Then we glued the it together

using the method above to distribute

the breaking point of the base

evenly.

04. For the arc of the bridge, we

also divided it into 4 layers. In order

the get the shape of the arc, gluing

it layer by layer and bend it

accordingly.

01. First, we printed out a copy of

the design of our bridge so that it will

be easier for us to bend the

fettuccine to get the shape of the

arc.

05. We cut and glued the vertical

truss and the bracing of the bridge.

After completing one side of bridge,

we used the same method for the

other side

06. Finally, we connected the 2 sides

of the bridge by placing horizontal

fettuccine in between.

Joint

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5 M O D E L M A K I N G

7. The middle piece of the

horizontal truss is reinforced as it

was the piece that holds the

weight.

9. The completed final model.

8. The top parts of the bridge are

joined with double layers of

fattucine.

5 . 1 M E T H O D O F C O N S T R U C T I O N


5 M O D E L M A K I N G 5 . 2 J O I N T

PLAIN BUTT JOINT

1. Two fettuccine

doubled-layer to make it

stronger

3: Repeat this procedure.

2. Join one fettuccine to

other the end of another

fettuccine.

Final Product

OVERLAID JOINT

1. Randomly choose 2

fettuccine.

2. Place a fettuccine

horizontally in between of

the 2 fettucine.

3. Trim the excess and

repeat the procedure.

Final Product

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6 T E S T I N G 6 . 1 F I R S T B R I D G E

For our first bridge we used the

precedent study as a guideline for our

first bridge. By changing it to an arch to

allow the bridge to increase the

compression member. On our first trial

we did not focus much on the weight of

our bridge but more our reinforcing it and

understanding the adhesive and the orientation of the trusses. Although our required clear

span is just 750MM we added an additional 74MM on each sides of our bridge to allow it to

rest on the table, in order to spread the load applied on bridge. Each segments having a

total length of 80MM allowing us to produce total of an odd 11segments where we produce

just one ‘X’ truss on the middle segments. This is part of our technique in order to produce

as little weight than producing an even number of segments where we would be force to produce two ‘X’ truss in order to be centralized.

Model Testing

Middle of intermediate member broke off after 6KG


6 T E S T I N G 6 . 1 F I R S T B R I D G E

Length:

Width:

Height:

Weight:

Max. Load

Efficiency

After a few trials, only the intermediate member would

broke after applying force. Proving that our truss is

stable. Thus, the only problem with our bridge is the

weight of it. Resulting in the second bridge.

L

O

A

D

Compression

Tension

209MM

908MM

90MM

FAILURE

Two layers

Four layers

908MM

90MM

209MM

225G

6KG

0.16

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6 T E S T I N G 6 . 2 S E C O N D B R I D G E

The second bridge also

followed the design of the

precedent study - Heshbon

Bridge similar to the first bridge.

The first bridge was too heavy

as we have a weight limit stated

by the brief which was 200g.

We decided to maintain the

height and the bottom chord chord because these two were the most important members in a truss. So we reduced the

layers of the zero force members which were the horizontal members holding both truss

together. Two intermediate members were place in the middle where the load would be

hung. One, which had four layers, was placed in the centre of the whole truss to hold the

both trusses together. The other, which had eight layers, was placed diagonally on the

bottom chord intersecting with the middle member.

Intermediate member bending just before it breaks.

Broken intermediate members

16

209MM

900MM

90MM

L

O

A

D

Compression

Tension

FAILURE

Two layers

Four layers One layer


6 T E S T I N G 6 . 2 S E C O N D B R I D G E

Length:

Height:

Width:

Weight:

Max. Load:

Efficiency:

Only the intermediate members of the second bridge

broke off without damaging the truss which means that

it had not achieved its maximum efficiency yet with the

load of 5KG.

908MM

90MM

209MM

225G

5KG

0.12

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6 T E S T I N G 6 . 3 T H I R D B R I D G E

besides increasing stability, we also reduced 0.7G of weight which contributes into higher

efficiency. Total height of the third bridge is 178MM. Proven that our proposal of reducing

the height was a success. Conversely, when the height decreased, the center of gravity

become lower hence the bridge become more stable., standing up straight raises the

center of gravity above the base of support and decreases stability. The amount of layer

used in each location of the member is the same because we couldn’t afford to lessen the layers of the bottom chord or the arch, thus we choose to shorten the height instead.

After considering from

failure of the second

br idge design, we

intended to reduce the he igh t o f the a rch

Perspective view of third bridge. Placement of horizontal member is the

same with previous bridge

Model testing.

18

Two layers



6 T E S T I N G 6 . 3 T H I R D B R I D G E

L

O

A

D

Compression

Tension

178MM

908MM

90MM

FAILURE

The reason third bridge failed is because the horizontal

member was just one layer causing the joint not to be

strong enough to withstand the load exerted onto the

bridge. And the intermediate member broke fall off,

i s s u i n g a p r o b l e m w i t h w o r k m a n s h i p .

908MM

90MM

178MM

200G

3.8KG

0.0.722

FAILURE

Length

Width

Height

Weight

Max. Load: Efficiency:

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6 T E S T I N G 6 . 4 F I N A L B R I D G E

were broken. We decided to rearrange our horizontal bracing. Instead of using one strip of

fettuccine we decided to have two layers but reduce the number of horizontal bracing, thus

we managed not to exceed much weight as stated in requirement. We mainly placed these

bracings where the forces would act most upon.

By rearranging and adding the additional layer of to the horizontal fettuccine members, it

managed to increased the efficiency of our bridge. During the final testing of our bridge, the

middle of the immediate member of our bridge broke under the force exerted by the load.

After the testing of our third bridge,

our arch and trusses were still in

tact and only the horizontal braces connecting the trusses



L

O

A

D

Compression

Tension

178MM

908MM

90MM

FAILURE

Two layers




MODEL TESTING

Weight: ~ 500g Weight: ~ 1000g







Length:

Width:

Height:

Weight:

Max. Load:

Efficiency:

908mm

90mm

178mm

202g

4.7kg

0.109


7 D E S I G N M O D I F I C AT I O N 7 . 1 F A I L U R E R E A S O N I N G

Reason 01:

The bottom chord of our bridges aren’t completely touching the base at both sides, as it is

only partially touching the base. This is due to the lack of precision in our workmanship.

This cause our bridge to be unbalance and not stable. Our models could have slipped off

when load is being exerted towards bridge. Causing our bridge to be twisted.

Reason 02:

As some of the is slanted and not 180˚ flat, for nothing is perfect. As it is crucial to use a flat

fettuccine pasta for when layering the width of layered fettuccine would be uneven at

slanted area. And with the slanted part the load distribution would be disturb and unstable


7 D E S I G N M O D I F I C AT I O N 7 . 2 S O L U T I O N

Solution 01:

Using masking tape on the members onto the printed drawing, to ensure that members

does not slipped off. Thus member would remain constant and provide precision. But one

would need to make take into consideration that masking tape is not as strong as we want

t h e m t o , so me mb e r s wo u l d sh i f t wh e n wo r k i n g on o t h e r me mb e r s .

Solution 02:

Using UHU Glue to fill the gaps in between joints would help Reason 01, but bearing in

mind that weight of bridge would increase and aesthetic value of the bridge would fall. By

reinforcing both Super Glue and UHU Glue, structure seems to work just fine with it.


8 C O N C L U S I O N

From this assignment we were able to have a better grasp of understanding

the load and compressive strength of construction material. Teaching us

methods as to constructing a building structurally stable. As forces and loads

plays an important role in this assignment, aiding us to understand how it is

distributed in truss. Not forgetting that we were to be creative and maintain

high level of aesthetic value while putting the minimizing the amount of

m a te r i a l s used . Hence p rom ot i ng sus ta i nab le a rch i t ec tu re .

Group photo along with final bridge


9 A P P E N D I X

As for our individual part, we were assigned to further analyse total of 5 trusses. Each

were distributed to following :

First Case:

Second Case:

Third Case:

Fourth Case:

Fifth Case:

The analysis and calculations of trusses are attached after this page.

Elaine Bong Poh Hui

Lau Ee Tian

Surayyn Selvan

Choo Ai Lin

Soh You Shing


1 0 R E F E R E N C E S

Historic Bridges.org.(2012,January 11)..Retrived September

20,2014,from http://www.historicbridges.org/info/about.htm

http://www.historicbridges.org/info/about.htm

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