fettucini bridge
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BUILDING STRUCTURES [ARC 2522] PROJECT 1
LEE YIANG SIANG (DEAN) WONG SOON FOOK LING TECK ONG PRO WEI KEAT CHUNG KA SENG WONG KIEN HOU 0312104 LECTURER MR. ADIB
0302966 0302953 0303127 0303646 0316922
FETTUCCINE TRUSS BRIDGE
TAYLOR’S UNIVERSITY SCHOOL OF ARCHITECTURE, BUILDING & DESIGN
PRECEDENT STUDY: WADDELL “A” TRUSS BRIDGE, PARKVILLE, MISSOURI.
CONTENT
1. Introduction
1.1 General purpose of study
1.2 Report preview
1.3 Restriction
1.4 Working schedule
2. Methodology
2.1 Precedent study
2.2 Making of fettuccine truss
bridge
2.3 Structural analysis
3. Precedent Studies
4. Equipment & Material
Study
4.1 Adhesive types
4.2 Material strength study
4.2.1 Fettuccine types
and strength
test
4.2.2 Gluing method
4.2.3 Orientation
5. Model Making
5.1 Method of construction
5.2 Joint
6. Design Process
6.1 1st Bridge
6.2 2nd Bridge
6.3 3rd Bridge
6.4 Final Bridge
7. Testing
7.1 Material and protocol test
7.2 Final model test
7.2.1 Observation
7.2.2 Efficiency
8. Design Modification
8.1 Failure reasoning
8.2 Solution
8.3 Result
9. Conclusion
10. References
11. Appendix
11.1 Detail of Missouri Bridge
11.2 Truss analysis exercise
1. INTRODUCTION
1.1 GENERAL PURPOSE OF STUDY
This project purposely aims to develop the understanding of tension and compressive strength of construction materials and thus be able to evaluate, explore and improve attributes of construction materials. Besides, this study also purpose to develop understanding of force distribution in a truss by exploring and apply understanding of load distribution in a truss. In this project, the ability of designing a truss bridge with high level of aesthetic value but minimal construction material is to be learnt. Moreover, through the process of designing fettuccine truss bridge, exploration will be taken on different arrangement of members in a truss structure thus able to evaluate and identify tension and compression members in a truss structure.
1.2 REPORT PREVIEW
In a group of 6, a precedent study of a truss bridge are required to carry out. Next, a fettuccine truss bridge of 600mm clear span and with maximum of 150g based on the gathered info from the precedent study. In this report, the precedent study, Waddell “A” truss bridge located in Parkville, Missouri is studied and analysis on strength of the material used load transfer system and truss system of this precedent study is stated in this report. Before building the fettuccine bridge, a method of researching the strength of the material in different brands and experiment on creating joints is taken. Besides, a set of testing result of our truss bridge model is carried out and the designated bridge is showed. Calculation regarding the given questions in exercise 1 is also included in the last few page.
1.3 RESTRICTION
Fettuccine is the only material that can be used to build the model bridge and we are required to construct it with 600mm clear span and maximum weight of 150g.
1.4 WORKING SCHEDULE
Date Tasks
2 April 2014 Buy material and prepare equipment
3 April 2014 Fettuccine strength test
8 April 2014 Case study and fettuccine strength test
9 April 2014 Construct 1st bridge
13 April 2014 Testing 1st bridge
16 April 2014 Construct 2nd bridge
17 April 2014 Testing 2nd bridge
20 April 2014 Construct 3rd bridge
21 April 2014 Testing 3rd bridge
24 April 2014 Construct final bridge
25 April 2014 Final bridge testing
Table 1.4.1: Working schedule
2. METHODOLOGY
2.1 PRECEDENT STUDY
To study on the precedent study, Waddell “A” truss bridge, research is taken from the source of internet and books. Looking at the detail of the precedent study, a real truss bridge connections, arrangement of members and orientation of each member is to be studied and put into the truss model structure design. Thus, the truss model’s structure will be depended on the information obtained from the precedent studies.
2.2 MAKING OF FETTUCCINE TRUSS BRIDGE
PHASE 1: MATERIAL STRENGTH TESTING Main material of doing the model bridge is fettuccine and the secondary, adhesive to stick the fettuccine together as a whole structure. It is important to test different brands of fettuccine to see their strength of taking load before skipping to the next phase ,model making. Data showing the fettuccine strength results in different circumstances is recorded in the subtopic of material under the topic, Analysis.
PHASE 2: CHOOSING ADHESIVE Adhesive that is used to bond the fettuccine together might affect the strength of whole structure .There are various choices of glue with different characteristics that could have change the physical strength of fettuccine. As so it is crucial to choose the right adhesive.
PHASE 3: MODEL MAKING Based on the obtained information, we tried to apply some improvement on the truss bridge model. To build a perfect model, it is first to produce an Autocad drawing of the design model to be printed out into 1:1 scale and build it based on the cad drawing. Jointing of the model bridge will be further discussed under the topic of truss analysis.
PHASE 4: MODEL TESTING Finished model is tested by applying load with string attached to the middle of the intermediate member of the model with the restriction of 60 cm clear span. Model are tested and improved into the final designated model.
2.3 STRUCTURAL ANALYSIS
Structure model Is analyze to show the understanding of the truss and its load transfer system. Failure models are analyzed to discover the problem and the analysis is the reference to the next model bridge. In structural analysis, calculation and load transfer diagrams are show.
3. PRECEDENT STUDY
2.1 PRECEDENT STUDY
To study on the precedent study, Waddell “A” truss bridge, research is taken from the source of internet and books. Looking at the detail of the precedent study, a real truss bridge connections, arrangement of members and orientation of each member is to be studied and put into the truss model structure design. Thus, the truss model’s structure will be depended on the information obtained from the precedent studies.
Missouri Bridge Waddell A Truss
History Background Built 1898 for the Quincy, Omaha and Kansas City Railway. Abandoned in 1939, but converted into a highway bridge on MO 4 in 1953. Dismantled in 1980 to make room for Smithville Reservoir, but relocated to English Landing Park in Parkville in 1987. Through truss bridge originally spanning Linn Branch Creek in Clinton County near Trimble, but relocated to English Landing Park in Parkville spanning Rush Creek open to pedestrians only.
Bottom Chord
Cross Brace Diagonal
Hip Vertical
Top Brace
End Post
Middle Chord
Design Strategies The waddell‘A’truss bridge is identified by the Historic American Engineering Record. Designed and patented by the famous American Engineer John Alexander Low Waddell, the ‘A’truss is a significant type of late 19th century, short-span railroad bridge that used pin-connections to join its major structural members. Because of its great height the ‘A’truss of this type of Bridge are great rigidity in all directions, ease and cheapness of erection and economy of metal when it is compared with structures of other types having equal strength and rigidity.
Compression
Tension Force Distribution
Truss Connection
Diagram 4.2.7: Identification of members in Waddell “A” truss bridge.
View From through Bridge Southwestern Portal
Bridge Dateplate Overview Looking North
Comparison between Previous and Present site Built 1898 for the Quincy, Omaha and Kansas City Railway. Abandoned in 1939, but converted into a highway bridge on MO 4 in 1953. Dismantled in 1980 to make room for Smithville Reservoir, but relocated to English Landing Park in Parkville in 1987.
Present Site Parkville 1987 - present
Barrel Shot With Dateplate In Right Foreground
Steel Approach Beams View From Underneath Bridge
Approach View
Previous Site Kansas 1898 - 1939
Missouri Bridge Engineering Elevation Drawing by John Alexander Waddell
General View Of 'A' Truss From Side Showing Abutments
Detail View Of Lateral Cross Bracing
Detail of Top chord Connection by John Alexander Waddell
General View From Side Showing Guard Rail In Foreground
Detail View Of Support Column Looking Down Axis Of Truss
Detail of Truss Connection and Members by John Alexander Waddell
Detail View Of Bridge Underside Showing Original Floor Beams And Bottom Chord Lateral Bracing
Detail View Of Circa 1952 Steel Approach Beams Taken From Underneath Bridge
4. EQUIPMENT AND MATERIAL STUDY
4.1 ADHESIVE TYPES
Three different glue kinds are tested to get the best result on connection.
3 second ok glue - Highest effieciency. - Fastest solidify time
between connection - Easy to use - Clean joint
Epoxy glue - High effieciency. - Rigid joint
Uhu glue - Easy to use
Hot glue - Easy to use.
- Expand and bending
might occurs - Cracked joint after store
for a few days.
- Long solidify time - Messy
- Messy if not control
well
- Joints slightly flexible when dry
- Longer solidify time than 3 seconds glue
- Longer solidify time. - Easily create bulky finishing
- Weight increase significantly - Joints flexible when dry
Table 4.1.1: Comparison of advantages and disadvantages of different types adhesives
Type of Glue
Glue applied (on fe0uccine)
Clear Span (mm)
Length (mm)
Layer of S;cks
No. of 50$ coins
No. of 20$ coins
Weight Sustained (g)
UHU Whole 20 24 2 16 38 364.70
3 Sec Glue
Whole 20 24 2 16 24 285.12
From the table above, Uhu glue is obviously better than 3 seconds glue even though Uhu needs more time to solidify the connection. This is because Uhu does not solidify the connection thoroughly and causes to preserve the elasticity of the fettuccine thus can sustained more stress form the load.
Type of Glue
Glue applied (Point)
Clear Span (mm)
Length (mm)
Layer of S;cks
No. of 50$ coins
No. of 20$ coins
Weight Sustained (g)
UHU Whole 20 24 2 16 38 112.79
3 Sec Glue
Whole 20 24 2 16 24 285.12
The results of the second test seems totally different from the first test, which on the first test: Uhu is better than 3 second glue , whereas on the second test where the fettuccines are to let dry for more than one day: 3 seconds glue has the better quality. Besides, in terms of workmanships, 3 second glue leave no tracks which made it the best choice among all the glue types.
Table 4.1.2: strength of fettuccine after applied with UHU and 3 seconds glue and tested within a day.
Table 4.1.3: The second test on glued fettuccine let to dry for more than one day.
In addition, we discovered that the stick that using Uhu glue to connect are separated when second test is carrying out. This proves that Uhu glue does not bond the fettuccine well as it separate into two after it was left dry for two days.
Days to left dry
Type of Glue
Glue applied (Point)
Clear Span (mm)
Length (mm)
Layer of S;cks
Weight Sustained (g)
1 3 Sec Glue
Whole 20 24 2 285.12
3 3 Sec Glue
Whole 20 24 2 101.37
The table shows that the strength of fettuccine falls sharply after three days left to dry. This is because the 3 second glue make the fettuccine oxidized and brittle. As a conclusion, the truss bridge has to be done freshly one day or two before the model test as to prevent the oxidization happened on the bridge.
Table 4.1.3: Third test shows comparison of the fettuccine’s strength after let dry for different amount of days.
4.2 MATERIAL STRENGTH STUDY
4.2.1 FETTUCCINE TYPES AND STRENGTH TEST
Several tests on material strength is carried out to identify which brands or which type of material does the best to be the members of the bridge.
Since fettuccine is the only material that can be used to construct the bridge, its attribute is required to be studied and tested before making the model. The way of putting or joining fettuccine could affect the whole structure bridge. To build a strong bridge, it is crucial to know which fettuccine’s brand can be used and has the strongest strength to withstand load. Below are three different brands of fettuccine and each brand is tested with load hanging on one stick of fettuccine.
Image Name Weight sustained
Shape/ Section of fettuccine
Barilla 187g
San Remo 156g
Kimball
112g
From the diagram above, it is obviously stated that the strongest fettuccine is Barilla, followed by San Remo and Kimball. Barilla brand’s fettuccine has the utmost strength mostly because of the expanded shape of the fettuccine. Yet, the unique shape of the fettuccine has bring the disadvantage on making bond with another fettuccine and its strength may fall when stack with two or more straps.
Table 4.2.1: Fettuccine types with description.
The capacity of the bonding is too small which may cause the the fettuccine to fall apart when light force is applied.
Barilla fettuccine (2 stacks)
Light Force
The fettuccine is flatter thus the capacity of the bonding is big enough which make the fettuccine hard to break apart when light force is applied. As a conclusion, we eliminates Barilla as the bridge material and choose San Remo because of its higher physical strength and bigger capacity to stack on to create stronger bond. In addition, the flatter shape of San Remo fettuccine will easy our work on building the truss bridge.
San Remo fettuccine (2 stacks)
Light Force
Diagram 4.2.4: Result of two layer San Remo fettuccine after light force is applied.
Diagram 4.2.3: Result of two layer Barilla fettuccine after light force is applied.
4.2.2 GLUING METHOD
Several gluing method are tested to determine which method does the best by not destruct or affect the strength of fettuccine.
3 Sec Glue
2 Points 20 24 2 16 10 149.28
3 Points 20 24 2 16 18 250.90
Whole 20 24 2 16 24 285.12
Diagram 4.2.5: 3 seconds glue is applied at the end point of a fettuccine stick.
Diagram 4.2.6: 3 seconds glue is applied at the end point and the middle point of a fettuccine stick.
Diagram 4.2.7: 3 seconds glue is applied wholly on a fettuccine stick.
Table 4.2.2: 3 different gluing method to show comparison.
Table above shows that the gluing method of 3 seconds glue apply wholly on fettuccine works the best, followed by 3 interval points and then 2 interval points. In addition, 2 points and 3 points method which does not glue the whole fettuccine had left some unglue space to be flexible. In this case after the glued fettuccine is let to dried for one day, observation shows expanding and bending occurs.
Type of Glue Layer of S;cks
Glue Applied Weight Sustained (Horizontal)(g)
Weight Sustained (Ver;cal)(g)
3 Sec Glue 2 Whole 285.12 355.45
3 Whole 395.13 450.28
4 Whole 453.72 533.34
5 Whole 589.33 522.56
4.2.3 ORIENTATION
Testing on the orientation of fettuccine (horizontally or vertically) helps to determine which placing position would have more strength to be put into our model design.
Horizontal orientation Vertical orientation
Diagram 4.2.8: Horizontal and vertical orientation of fettuccine.
Table 4.2.3: Comparison of horizontal and vertical orientation with the increasing amount of layer.
Outcome of the test shows when fettuccine members are to stack to 4 layers, it is best to use vertical orientation, whereas horizontal orientation is suitable for 5 layers of fettuccine.
5. MODEL MAKING
5.1 METHOD OF CONSTRUCTION
1)
Cut 3 pieces of 24cm length fettuccine to form the base.
2)
Use a 5cm piece to glue the main base together. Place a 15cm piece in the middle and connect the triangle with two other 40cm pieces.
Put straight trusses after every 9cm interval on t h e m a i n base.
3)
4)
Then, connect pieces from the middle towards each vertical truss,
5) Thicken the truss a f te rwards . The bottom base with 5 pieces, upper two parts with 4 pieces and the trusses by 2. Replicate another one after finishing.
6) Start connec;ng the two parts at the bo0om end.
7)
The leftmost picture shows how it looks like after joining them. The middle piece is reinforced as it will be the piece holding the weight.
The top parts are joined with two singular fettuccine pieces.
8)
The completed final model.
9)
5.2 JOINT
Step 1: Randomly choose two Fe0uccine
Step 2: Glue them together
Step 3: Repeat the procedure
Final Product
OVERLAID JOINT
BRIDLE JOINT
Step 1: Label the area that need to be cut
Step 2: Glue them together
Step 3: Measure and label the cut area
Step 4: S;ck them together to fill the gap
Step 5: Cover it by a new Fe0uccine
Step 6: Repeat the procedure
Final Product
Overlaid joint is used in the first bridge design. We are then discovered that bridle joint is better as it makes the surface clear and having more aesthetic value. Yet, bridle joint required careful t r imming and the trimming need to be planned cautiously too.
6. DESIGN PROCESS
6.1 1st BRIDGE
First bridge referring the design from precedent study — Waddell 'A' Truss Bridge. From the observation of Waddell “A” truss bridge, The truss members are a few as its span length is shorter and the material using metal which meant to be stronger. In this project, fettuccine, the only material is quite weak to be a construction material. As so, more truss members and bracing are added into the bridge as supports.
Design 2
Design 2
BOTTOM LAYER
TOP VIEW
SIDES LAYER CROSS SECTION
740
50
300
Diagram 6.1.1: Tension and compression member (1st bridge)
Length : 74cm Max Height : 30cm Max Width : 5cm Mass : 182 g Max Load : 5KG Efficiency : 137.36
6.2 2nd BRIDGE
The second bridge also resemble the design from precedent study —Waddell 'A' Truss Bridge, relying support from the triangle shape beam. As the load is meant to hang at the bottom, there are 5 hanging members on each side connected to the beam to support the whole the structure. The hanging members are designed in tens ion to favour the characteristic of fettucine.
Besides that, the bottom layer on each side connected with 20 fettucine with lenght of 7cm. There are 4 members on each side connected to the point that load applied to strenghthen the whole structure. The arrangement of bracing members and number of layers of fettucine are tested from this design.
Length : 72cm Max Height : 30cm Max Width : 7cm Mass : 170 g Max Load : 5KG Efficiency : 147.06
Model testing of 2nd bridge
2nd bridge fall at max load of 5kg.
BOTTOM LAYER
TOP VIEW
SIDES LAYER CROSS SECTION
Diagram 6.2.1: Tension and compression member (2nd bridge)
300
6.3 3rd BRIDGE
After considering the failure of previous designs, we intended to reduce some braces in the structure, the horizontal members was removed to reduce the weight of the structure and it didn’t really support the whole structure as well. Besides that, we also adding two more hanging members on each side of the structure that connected to the triangle beam to strengthen the br idge. Gather ing information from precedent study and some other existing bridge, we reduce the height of the bridge from 380mm to 330mm to increase the overall stability of the structure, . At the thesss same time, it also reduce the weight of the structure which in turn contributing to higher
efficiency.
Length : 74cm Max Height : 20cm Max Width : 7cm Mass : 169 g Max Load : 8KG Efficiency : 378.7
MODEL TESTING OF 3RD BRIDGE
3RD BRIDGE FAILURE
The whole structure remain the same accept the horizontal interconnec;ng member at the center break when the load is 8kg.
3RD BRIDGE FAILURE
740
70
BOTTOM LAYER
TOP VIEW
SIDES LAYER
200
CROSS SECTION
Diagram 6.3.1: Tension and compression member (3rd bridge)
Final Bridge Design
Length : 72cm Height : 15cm Width : 7cm Mass : 0.142kg
After considering the failure of previous designs, the horizontal interconnecting member at the center have been strengthened by 7 layered of fettuccine.
The picture above shows the 4th design which is the final bridge. The bridge height changed
from 20cm to 15cm to re d u c e t h e o v e r a l l weight and thus increase
6.3 FINAL BRIDGE
in efficiency. Moreover, by understanding that fettuccini has a weak compression strength, the bottom horizontal member which intersects the center were added more layer of fettuccini to strengthen the bridge structure. The previous bridge were weight 169gram which already overweight. Therefore we also reduce the layers of the vertical
members, from each 5 layers to ratio of 4:3:2:1 which the 4 is the nearest to the center load and 1 is at the end. Furthermore, every surface at joints were worn flat to maximize area of bonding. Lastly, the layers between layers of fettuccini were properly glued to increase the tightness and make it more durable.
TOP VIEW (FINAL DESIGN)
BOTTOM LAYER
SIDES LAYER
720
150
70
5 LAYERED
3 LAYERED 4 LAYERED
2 LAYERED
1 LAYERED
CROSS SECTION
TENSION COMPRESSION
LOAD
Model testing Final model falls
Diagram 6.4.1: Tension and compression member (3rd bridge)
7. TESTING
7.1 MATERIAL AND PROTOCOL TEST
Material and protocol design model are tested using the equipment that we had in our dedicated working area. The equipment included a pail, “S” hook, 50 cents, 20 cents, two tables, water, 6 liters bottle, measuring ruler and a long plastic bag.
Load for fettuccine strength test are using 50 cents and 20 cents coins which per 50 cents weighted 9g and per 20 cents weighted 6g. The reason is we have enough coin supply and it is easy for us to clean the place once the load is fallen.
Diagram 7.1.1: Equipment
First, different layers of fettuccine which are to test are labeled for ease of recording.
Second, fettuccine is placed in between of two tables with a clear span of 20cm and two full water bottles are served as weight placed at the end of the table holding and stable the fettuccine.
Third, an ‘S’ hook with the pail carried is hanged on the middle part of fettuccine and is ready to carry coin. Coin is putting in one by one slowly until the fettuccine breaks.
Once the fettuccine finally break, collected coins are recounted to assure the amount and to be recorded.
In protocol test, we demand a more accurate result, so we use water as load instead of coins. As under normal condition and specific gravity of water, 1 litre is equal to 1 kg. The method of weighing is almost the same as the different is only replacing the pail into bigger one and the coin into water.
First thing to do before testing is to weight the bridge.
Water is then poured into the pail. Weight of the pail is added into the record along with the water weight.
Failure: the bridge is not fu l l y tes ted fo r not knowing the breaking point. This is because the pail is too small that even when the water is full, the bridge is still not break. Solution: the small pail is replaced by a bigger pail.
7.2 FINAL MODEL TEST
Final model is tested in a classroom on 25th April 2014. During the model testing, the horizontal interconnecting member in the center was placed with a ‘S’ hook and empty bag was hung into it. Then we slowly put the loads starting with 2kg into the bag with interval of 10 seconds time until it reached 6kg. At this point, we changed the 2kg load to 1kg load until the bridge reached its breaking point at 8kg.
7.2.1 OBSERVATION:
Weight: 142g Maximum Load: 8kg Efficiency, E= (Maximum Load) Weight of Bridge = 64 0.142 = 450.7
When more load is added into the bag, the bridge becomes heavier and we observe that there is a slight bending to the right together with a crack sound but later when we add another load to it at the point of 7kgs, we were surprised that it bend back to original position. The bridge collapse when it reached its maximum point at 8kg.
7.2.2 EFFICIENCY:
Diagram 7.2.1: Final model test
2
8. DESIGN MODIFICATION
8.1 FAILURE REASONING
Reason 01: Uneven sizes of the two main triangular truss
Throughout the process of analyzing the failure of the truss bridge, we found out that the two triangular trusses we made were not even, one is slightly higher and another is lower making them unbalance when combined together. The fettuccini bridge were tilt a little to a side and when the load added to it, causes uneven distribution of force acting on the bridge. By failing to have even distribution force acting on all members, the part that is slightly lower to ground will withstand more force and will break eventually.
Reason 02: Lesser fettuccini layers used in the slanted part.
The breaking failure of the fettuccini bridge include the lesser fettuccini layers in the slanted part to support the bridge. Because of the intention to minimize the load of the bridge, we have minus out the layers used in the slanted part from 4 layers to 3 layers making it less durable. The more fettuccini layers stick together as a member of truss bridge, the stronger the bridge but it will also cause a heavier mass.
Reason 03: No support from the sides of the bridge at the edge of table
At the two sides of the bridge, there were no truss members to support the lower part of the bridge to make it still. There might be chances that it slide and cause the structure to tilt off because of compression force. When the exertion forces were added, the members will start to bend. By adding extra members to strengthen the sides, the force will be distributed more and thus increase the overall efficiency of bridge.
Solution 01: Adding supporting members at both ends of the truss bridge
By adding two diagonal bracing at the both sides of the bridge and triangular structure at the bottom of the bridge, the bridge will be strengthen and make it more balance to withstand more loads. Adding extra members is a good way to distribute the compression force. But because of adding the extra members, the bridge will be overweight. Therefore we analyzed that the bridge only have weakness in supporting compression force therefore, horizontal members of the structure which support the tension force can be reduced in terms of layers of fettuccini to reduce weight.
Solution 02: Always check that the truss members in the lower part are all flat and lies in a straight line
We have to carefully calculate correctly making sure that the trusses bridge were even and the two triangular truss were symmetrical. This will make the bridge more stable and able to withstand more external forces. The highlighted part in the figure above should lies in a straight line so that the force will distribute evenly and deflection will not occur in one even part.
8.2 SOLUTION
Diagram 8.2.1: Final bridge with supporting members added
Diagram 7.2.2: Final bridge with flat straight base
8.3 RESULT
After analyzing the solutions, we modified our bridge again and tested once again by applying the solutions. As expected, it was a success design as it able to withstand a load of 12kg, resulting efficiency as below: Weight of bridge: 138gram Load withstand: 12kg Efficiency= (12) 0.138kg =1043.48
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