BUILDING STRUCTURES [ARC 2213] FETTUCCINE TRUSS BRIDGE ANALYSIS REPORT
Azrin Bin Fauzi 0317770 Bibi Ameerah peerun 0313939 E Jy Huey 0313332 Julia shenjaya 0317774 Liau Wen Bin 0319062 Lim Ming Chek 0317743
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TABLE OF CONTENT: 1- Introduction 2- Methodology 2.1 Precedent Studies 2.2 Making of Fettucini Bridge 2.3 Requirements 3- Precedent Studies 3.1 130th Street Railroad Bridge, Chicago: Cook County, Illinois. 3.2 Stone Levee Bridge 3.3 San Joaquin Bridge 4- Materials and Equipment 4.1 Equipments. 4.2 Strength of materials. 4.2.1 Properties of fettuccine. 4.2.2 Testing of fettuccine. 4.2.3 Experiments. 4.2.4 Adhesive analysis 4.3 Conclusion 5- Bridges Testing and Load analysis 5.1- Timeline 5.2- Bridge 1 5.3- Bridge 3 5.4- Bridge 4 5.5- Bridge 5 5.6- Bridge 6 6- Final Bridge 6.1 Amendments 6.2 Final Model Making 6.3 Joints Analysis 6.4 Final Bridge testing and Load Analysis 6.5 Calculation 7- Conclusion 8- Appendix (Individual part) 9- References 2
Introduction In Building Structure (ARC 2523) Project 1: Fettuccine Truss Bridge is to design and build a bridge to achieve the effective truss bridge. Truss is a structure of the bridge that built up of three or more members. Ways of placing and designing the truss will affect the strength and weight of the bridge. Some precedent studies , material testing, model making and analysis of design has been done to conduct more understanding about distribution of tension and compression between each member of truss, at the same time practice the knowledge from lecture about moment force, reaction force, and internal force. Knowing the strength of fettuccine also one of the key to achieve higher effectiveness. The effectiveness of the bridge was depend on the load that can be taken by the bridge before it break and weight of the bridge itself. Heavier bridge intent to carry more load but not efficient. Higher efficiency rate mean the light bridge that can stand heavier load. To effectiveness can be calculate using the formula bellow: đ??¸đ?‘“đ?‘“đ?‘’đ?‘?đ?‘–đ?‘’đ?‘›đ?‘?đ?‘Ś, đ??¸ =
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The main material in this project is using fettuccine as main construction materials and glue or other joint’s materials for connection. Some initial failure through some bridge trial was expected in the process to explore, analyze and further improve the arrangement of truss members, height and width as part of strength and weakness. The requirement of this project is to build a bridge with clear span of 350mm and no more than 80gr.The Bridge was expected to carry more weight in expended period time. The aim of this project is to understand compression, tension and strength construction material to achieve a perfect bridge design without sacrificing the aesthetic and using minimal construction materials.
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2.0 Methodology 2.1 Precedent Studies Before start to built the bridge, some precedent studies has been done as a base design through researching and analysing the existing design of bridge to understand better the distribution of its compression and tension that allow us to make adjustment of the bridge or even make some combination from each advantage of the placement of the truss.
2.2 Making of Fettucini Bridge • Phase 01: Strength of Fettuccini as materials. Understanding of properties of fettuccini taken an important part to decide the placement of truss and the height, length and size of each gap of truss member with another member.. Fettucine was low on the compression compare to properties of other construction material such as steel. From this knowledge, it can implement to design of effective bridge that can carry maximum loads. • Phase 02: Connection There are variant types of adhesive or other method that can be used as connection. Each type of adhesive has its own advantage and disadvantage and give a different result after attach it to fettucine. Some of them may start make it flexible and slowly harden or bond faster and slowly become fragile. Different brand also has it own strength which should be tried before decide which one to use. Other than using adhesive, students also allowed to use other method such as using rope, finger joint or slot in. • Phase 03: Model Making To ensure the right measurement of the bridge, the drawing was drawn in auto cad with 1:1 scale and mm as a units. Trace each length of fettuccine from the drawing make it easier to cut, measure and glue it. A part from that advantage, having a 3d drawing of the bridge will help us to have a picture of the final outcome of the bridge that is desired. Each piece of fettuccine that have been cut was placed according to different height without marking it on it surface as a part of aesthetic. • Phase 04: Model Testing Some trial bridge models was test before accomplish the final model to ensure the development of first model was keep improving to achieve a maximum load. The weight was placed on both side of base I-beam to transfer the load not only in the middle but whole bridge.
2.3 Requirements -
Clear span of the bridge is 350mm The maximum weight of the bridge is 80gr. The main material allowed in this project only Fettuccine Connection of each member can use specific adhesive or another joint such as rope. 4
3.0 Precedent Studies 3.1 130th Street Railroad Bridge, Chicago: Cook County, Illinois. Overview
Figure 3.1.1 Views of 130th Street Railroad Bridge.
Built by Structure type : Material Structure Length : Main Span Length :
: [Unknown] 8 Panels Rivet-Connected Polygonal Warren Through Truss : Metal 131.6 Meters 83.4 Meters
Components of the bridge
Figure 3.1.2 : Components of the bridge from elevation Figure 3.1.3: Components of the bridge from bottom view
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Construction details
Figure 3.1.4 : Top chord connection of the bridge.
Figure 3.1.5 : Bottom chord connection of the bridge.
Figure 3.1.6 : View of the truss web of the bridge.
3.2 Stone Levee Bridge Overview
Figure 3.2.1 : Views of Stone Levee Bridge.
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Built by Structure type Material
: Interstate Building Company : 12 Panel Rivet-Connected Baltimore Through Truss, Fixed : Metal
Structure Length : 36.9 Meters Main Span Length : 34.8 Meters
Components of the Bridge
Figure 3.2.1Components of the bridge from elevation. Figure 3.2.2 Components of the bridge from bottom view.
Construction Details
Figure 3.2.3 : View of the truss web.
Figure 3.2.4 : Top chord connection of the bridge.
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Figure 3.2.8 : Sway bracing.
Figure 3.2.9 : V-laced end post.
3.3 San Joaquin Bridge Overview
Figure 3.3.1: Views of San Joaquin Bridge.
Built by Structure type Material
: E. H. Riley : Rivet-Connected Howe Through Truss : Metal
Structure Length : 92 Meters Main Span Length : 39.3 Meters
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Components of the Bridges
Figure 3.3.2 : Components of the bridge from perspective. Figure 3.3.3 : Components of the bridge from bottom view.
Construction Details
Figure 3.3.6 : View of the truss web.
Figure 3.3.8: Bottom chord connection of the bridge.
Figure 3.3.7 : Top chord connection of the bridge.
Figure 3.3.9: Portal bracing.
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Figure 3.3.10: Sway bracing.
Figure 3.3.11: Main span railing.
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4.0 Materials and Equipements 4.1 Equipments Equipments Pen Knife
•
Used to cut the fettuccine in model making
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Used to cut the fettuccine in model making
•
Used to sand the edges of the components of the bridge
•
Adhesive material in model making
•
Used as load
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Used as a standard weight of the load poured into the bucket
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Used to measure the load and models
Scissors
Glass Paper
Super Glue
Mineral Water
Plastic Cups
Weighing Machine
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Pail
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Used to carry the load
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Used to hook the bucket on the bridge
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Used to tie the bucket to a specific height
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Used to photograph and record the process
S-Hook
Strings
Camera
4.2 Strength of materials. As per stated in the project brief, fettuccine was the only material approved in this project. Thus, research and analysis of Fettuccine was conducted before model making session.
Figure 4.2.1 Fettuccine used in model making.
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4.2.1 Properties of Fettuccine.
The fettuccines used in making the truss bridge have the average thickness of 1mm and width of 4mm. It is brittle and thus is stronger under tension. Before use, fettuccine need to be checked and filter out those that are twisted to ensure that the load is able to distribute evenly and effectively through the flat surface of the fettuccine. 1. Tensile Strength : 2000psi 2. Stiffness (Young’s Modulus)E : 10,000,000psi (E=stress/strain) We have tried 3 types of fettuccine to test its strength and weakness: Types of Fettuccine
Kimball Fettuccine
Prego Fettuccine
Characteristics
• • •
Thin Light yellow Shorter in width
• • •
Thicker Light yellow Shorter in width
• • • San Remo Fettuccine
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Thickest Golden Yellow Longer in width
4.2.2 Testing of Fettuccine.
Before testing the fettuccine, we made sure that the fettuccine are glued with the proper gluing technique to prevent uneven surface, so that the load can be distributed evenly. We also made sure that the fettuccine are cut with the proper technique to prevent broken edges.
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Figure 4.2.2.1 Gluing Technique.
Figure 4.2.2.2 Cutting technique using penknife.
Figure 4.2.2.3 Cutting technique using scissors.
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4.2.3 Experiments.
As the length of the bridge is longer than the length of the fettuccine, we made the beams using the staggered arrangement to ensure that the breaking points are not aligned and thus minimizing the number of weak spots.
Figure 4.2.3.1 Staggered arrangement of fettuccine in beams.
To understand the efficiency and the maximum load of the fettuccine, we had tested several types of beam with different orientations to determine which is the best to be implemented into our bridge.
Layers of Members
Length of fettuccine (cm)
Clear Span (cm)
Load Sustained (Vertical facing) (g)
Load Sustained (Horizontal Facing) (g)
1 Layers
25
15
287
100
2 Layers
25
15
386
189
3 Layers
25
15
630
487
4 Layers
25
15
1000
960
4 Layers (I-beam)
25
15
-
1375
Table 4.2.3.1 Test results of Kimball Fettuccine.
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Layers of Members
Length of fettuccine (cm)
Clear Span (cm)
Load Sustained (Vertical facing) (g)
Load Sustained (Horizontal Facing) (g)
1 Layers
25
15
300
120
2 Layers
25
15
402
204
3 Layers
25
15
697
503
4 Layers
25
15
1189
970
4 Layers (I-beam)
25
15
-
1460
Table 4.2.3.2 Test results of Prego Fettuccine.
Layers of Members
Length of fettuccine (cm)
Clear Span (cm)
Load Sustained (Vertical facing) (g)
Load Sustained (Horizontal Facing) (g)
1 Layers
25
15
415
198
2 Layers
25
15
487
300
3 Layers
25
15
754
600
4 Layers
25
15
1286
1103
4 Layers (I-beam)
25
15
-
1632
Table 4.2.3.3 Test results of San Remo Fettuccine.
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4.2.4 Adhesive analysis.
We had tested three different kind of glue in order to ensure the joints are strongly attached to each other and thus strengthen the bridge. Type of Adhesive
Advantage
• UHU Super Glue (Gel) • •
Disadvantage
• High efficiency • Easy to use Fast solidifying time
UHU Super Glue (Liquid)
• • •
Kwik-Fix Super Glue
• • •
High efficiency • Easy to use • Fast solidifying time • Easy to use Fast solidifying time • Cheap
• •
• • •
UHU Glue
Easy to use Hard when dry
Expensive Leave gaps when solidify when it is not connected properly Expensive Makes fettuccine brittle Low efficiency when dry Makes fettuccine brittle Low Efficiency Slow solidifying time Makes fettuccine pliant
Rank 1
2
3
4
Table 4.2.3.4 Comparison of different types of adhesive. UHU Super Glue (Gel) was the best adhesive among all as the gel enables the joints to be connected easily when compared to liquid super glue. It holds the connections stronger than liquid and it dried very fast although it is expensive. So, we used UHU Super Glue (Gel) mostly for the connections and joints. We also used UHU Super Glue (Liquid) to stick the layers of the fettuccine. It is high in efficiency and dried very fast. When compared to UHU Super Glue (Gel), it ensures that the fettuccine is glued evenly without having gaps in between. This prevents uneven surface and allows load to distribute equally. UHU Glue was not used in the bridge because it dried very slowly and it made the fettuccine pliant. Hence, the bridge is at its optimum condition after at least 4 hours of drying using super glue.
4.3 Conclusion After testing the different types of fettuccine and adhesives, we had decided to use San Remo Fettuccine as out material because it is the strongest fettuccine when compared to the others. Then, we had decided to use I-beam as the base and 2 layers of fettuccine for the trusses to control the weight of the bridge. Others than that, we had also decided to use both UHU Super Glue gel and liquid to glue the components together as both of them have the highest efficiency among all the others adhesive and they dried very fast. 16
5.0 Bridge Testing and Load Analysis 5.1- Timeline 9th September 2015
16th September 2015 19th September 2015
20th September 2015
21ST September 2015
23rd September 2015
26th September 2015
27th September 2015
Work progress -Testing the strength of fettuccine by using 1 to 5 layers - Discussion and research on suitable truss for precedent study - Testing of I-beam design -Testing different ways of fettuccine joints by using different types of adhesive to test the strength and suitable adhesive Brainstorming on truss design that can be used and proceed with the study model of 3 bridge Negative outcome -Based on tutorial comments that day, further brainstorming has been made -Study model: Bridge 1, 2 and 3 from different trusses -Load testing -Decide on the final truss to be used Encouraging outcome - Model making of the chosen truss based on required dimension. (Bridge 4) -Discussion based on the results -Amendments to be done Negative outcome -Model Making based on previous meeting (Bridge 5) - Load testing -Discussion on minor amendment Encouraging outcome -Proceed to the final test model of the final Bridge (Bridge 6) -Model making of the Final bridge for submission (bridge 7) Positive outcome
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For the first three bridges (Bridge 1, 2 and 3), we made three basic bridge designs based on the three precedent studies. This was to test and study which truss design is the best to withstand heavy load, and thus, has the highest efficiency.
5.2 Bridge 1(mini bridge) We used the precedent study, the 130th Street Railroad Bridge, as a reference for our first bridge. In this study model trial, we did not restrain ourselves too much on the weight of the bridge, but more on reinforcement, adhesive, joints and orientation of the trusses.
Figure 5.2.1: The design of our first bridge.
Figure 5. 2.2: Bridge before
Figure 5.2.3: Horizontal member failed.
The failure only occur at the horizontal member (Figure 5.2.2), because the member is bearing the highest load and are too thin (2 layers of fettuccine) and weak to carry the load by itself without distributing the load around (Figure 5.2.3). Total length: 25cm Clear span: 17cm Bridge weight: 33g Maximum load: 3030g Efficiency: (3.03)2 = 278.2% 0.033 Failed Components
Horizontal member.
Failing Reasons
Member is too thin, poor load distribution.
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5.3 Bridge 2 (mini bridge) We used the precedent study, the Stones Levee Bridge, as a reference for our second bridge. In this study model trial, we did not restrain ourselves too much on the weight of the bridge, but more on reinforcement, adhesive, joints and orientation of the trusses.
Figure 5.3.1: The design of our second bridge.
Figure 5.3.2: Bridge during
Figure 5.3.3: Horizontal members and truss failed.
The failures occur at the horizontal members and the truss (Figure 5.3.3), because they are too thin (2 layers of fettuccine) and were not able to withstand the compression force, causing them to buckle. Hence, adding more fettuccine should thicken the truss under compression. Other than that, some parts of the truss were not properly constructed and have caused uneven members, joining and force distribution. Total length: 25cm Clear span: 17cm Bridge weight: 44g Maximum load: 6070g Efficiency: (6.07)2 = 837.4% 0.044 Failed Components
Horizontal members and truss.
Failing Reasons
Member is too thin, uneven load distribution caused by rough workmanship. 19
5.4 Bridge 3 (Mini bridge) We used the precedent study, San Joaquin River Bridge, as a reference for our third bridge. In this study model trial, we did not restrain ourselves too much on the weight of the bridge, but more on reinforcement, adhesive, joints and orientation of the trusses.
Figure 5.4.1: The design of our third bridge and the failed component.
Total length: 25cm Clear span: 17cm Bridge weight: 33g Maximum load: 4630g Efficiency: (4.63)2 = 649.6% 0.033 Failed Components
Horizontal members and truss.
Failing Reasons
Member is too thin, uneven load distribution caused by rough workmanship.
5.5 Bridge 4 Bridge 4 is a continuation from Bridge 3 that is constructed to the required length with a clear span of 350mm. We had a discussion whether to use the superstructure from Bridge 2 as from the tests it could withstand the highest load. However, we came to the conclusion that when it is constructed to the required length, the weight of the bridge will be very much over the allowed weight of 80g because the weight of Bridge 2 is already more than half of the allowed weight even at such a short length. Therefore, the design of Bridge 2 is ruled out and Bridge 3 is then taken. In this study model trial, we had a little more consideration to the weight of the bridge.
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Figure 5.5.1: The design of our fourth bridge.
Figure 5.5.2: Failed component of our fourth bridge.
The failure occurred on the horizontal member at the centre of the bridge where the pencil was placed (Figure 5.5.2). The failure occurred because of the truss design where is does not support sufficiently support the centre of the bridge. Hence, the truss design should be improved and adding more fettuccine should thicken some parts of the trusses. Total length: 25 Clear span: 17 Bridge weight: 33g Maximum load: 5000 Efficiency: (5.0 )2 = 756% 0.033 Failed Components
Horizontal members and truss.
Failing Reasons
Truss design does not sufficiently support the centre of the bridge and some of the members are too thin.
5.6 Bridge5 Bridge 5 is an improved design from Bridge 4. The length of each member is changed and cross braces to the base are added. In this study model trial, we kept the weight of the bridge within the allowed limit of 80g and tried to construct the bridge as precise as possible.
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Figure 5.6.1: Design of our fifth bridge.
Figure 5.6.2: Failed component of our fifth bridge.
The failure occurred at the centre of the bridge once more but this time it's more due to the cut location of the base I-Beam (Figure 5.6.2). This is because the I-Beam cuts are located at the same location, which makes that point weak. The cross bracing of base also did not help as it is made up of 1 long component and 2 shorter components where the shorter components have the tendency to slide off. Hence, the I-Beam design should be thought about further to determine the best cut locations and the base cross bracing should be removed. Total length: 25 Clear span: 17 Bridge weight: 82g Maximum load: 2000g Efficiency: ( 2)2 =48 % 0.082 Failed Components
I-Beam and base cross bracing.
Failing Reasons
Cut locations of the I-Beam are located at the same point and the cross bracings have a tendency to slide.
5.7 Bridge 6 Bridge 6 is further improved from Bridge 5 and is also our final bridge design. The base cross bracings are removed and the base design is tweaked slightly. The truss design on the superstructure of the bridge is also changed to provide more support. Furthermore, cross bracings are also added to the top chords of the bridge. In this study model trial, the weight of the bridge is kept within the allowed limit of 80g and the bridge is also constructed very precisely to obtain the best results.
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Figure 5.7.1: The design of our sixth bridge.
Figure 5.7.2: Failed component of our sixth bridge
Total length: 25 Clear span: 17 Bridge weight: 82g Maximum load: 7600g Efficiency: (7,6)2 = 704% 0.082 Failed Components
Top and bottom chord
Failing Reasons
Uneven forces distribution and workmenship
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6.0-Final Bridge 6.1 Amendments The design and construction method of our final fettuccine bridge is shown in the figure below (Figure 7.1.1). After thorough analysis of our previous bridge design tests, this is the bridge design we concluded that has the highest efficiency. We compared the results of each tests as well as the total weight of different truss designs as well as base designs in order to achieve this.
Figure 7.1.1: Final Bridge Design.
• Amendments made: a. Base Cut Locations And Additional Members Dimensions of each of the components that make up the I-beam, which forms the base of our bridge, are adjusted in order to balance the bridge. From the previous bridge design test, we found out that the bridge breaks at a certain point because that point has a lot of cut connections which makes the I-beam weak at that particular point which causes the bridge to break as can be seen in the figure (Figure 7.1.2). The change in length of the components spreads the cut locations out to different parts of the I-beam and therefore making it stronger and not break easily at a certain point. Additional members of 5cm each are also added to the connection points to further strengthen them. The changes made are shown in the following figures (Figure 7.1.3 and Figure 7.1.4).
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Figure 6.1.2: Previous test breaking points.
Figure 6.1.3: Previous bridge I-beam design.
Figure 6.1.4: Final bridge I-beam design.
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b. Base Bracing The design of the base bracing that holds the I-beams together is changed. This is because the cross brace is made up of 1 full length component that connects to both the I-beams and 2 smaller components that connect to one side of the I-beam and the aforementioned longer component. The cross bracing as we found out from the previous bridge design test is that it does not really help as the shorter components have a tendency to slide at the point it connects to the longer component as can be seen in the figure (Figure 7.1.5). Therefore, the cross brace for the base is removed to lighten the total weight of our bridge and the design of the base bracing is tweaked slightly as shown in the following figures (Figure 7.1.6 ad Figure 7.1.7).
Figure 6.1.5: Sliding of the base cross-brace components.
Figure 6.1.6: Previous base bracing design.
Figure 6.1.7: Final base bracing design.
c. Addition Of Cross Brace On Top Chords The addition of cross brace holds the top chords in place by resisting torsion caused by the load. This is because the cross braces pushes the top components against one another and therefore increasing the stability of the bridge. The cross brace for the top chords however has a different design compared to the cross brace used previously for the base. It is designed with 2 full-length components that connect to both sides of the top chords in order to prevent the components from sliding at the centre. The following figure (Figure 7.1.8) shows the addition of the cross brace on top. 26
Figure 6.1.8: Addition of cross brace on the top chords.
6.2 Final Model Making Calculations to the dimensions of the final model are made and the bridge is drawn in AutoCAD for easy reference. According to the drawing and the dimensions, all the components of the bridge are first measured and cut as shown in the figure (Figure 6.2.1). The pieces are then sanded using sandpaper to its exact shape and dimensions required.
Figure 6.2.1: Components of the fettucine bridge.
After the pieces are cut, the construction work of the bridge is split into 2 groups. A group for the base of the bridge and another for the side superstructures of the bridge. For the first group, the 2 Ibeams are the first to be connected together accoding to the figure below (Figure 6.2.2) and the completed I-beam is also shown (Figure 6.2.3). Braces are then added to the I-beams which forms the base of the bridge (Figure 6.2.4).
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Figure 6.2.2: I-beam construction.
Figure 6.2.3: Completed I-beam.
Figure 6.2.4: Base bracing.
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While that is going on, the other group starts on the construction on the side superstructures according to the following figure (Figure 6.2.5). The base of it which is the longest component are glued and left aside for it to dry completely as the point of connection between the components of this piece is very small and it breaks very easily if the glue is not completely dry. The trusses of of the bridge superstructure are then connected to the top component which is the top cord of the bridge. The top cord and the trusses are then connected to the base and the whole process is then repeated for the other side of the bridge.These trusses are made to resist forces and maintain the stability of the bridge. Figure 6.2.6 shows the completed bridge superstruture.
Figure 6.2.5: Bridge superstructure construction.
Figure 6.2.6: Fettucine Bridge Superstructure.
After the base of the bridge and the side superstructures of the bridge are completed, they are then connected as shown in the figure below (Figure 7.2.7). Lastly, the top chords are braced with a cross brace design as shown in the figure below (Figure 7.2.8).
Figure 6.2.7: Connection of the base and the superstructure.
Figure 6.2.8: Bracing of the top chords.
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6.3 Joint Analysis
JOINT A The long diagonal members are joined between the base of beam and the top. The edges were sanded to achieve stronger bond between the components.
JOINT B The ends of the diagonal bracing members of the beam are cut at an angle to fit into the space between vertical members. The direct contact of the end of the beam surfaces allows the adhesive to bond them stronger, thus creating a stiffer joint.
JOINT C The horizontal members are simply laid on the top of the bridge, strengthening the connection between two parallel members. Only one layer of fettuccine is used for the cross bracing to help keep the top chords of the bridge from bending or deforming in or out.
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JOINT D The diagonal members act as the bracing of the bridge. The edges of these members were sanded at an angle to make sure they fit perfectly in the space between the vertical members and beam. Efficiency can be increased by delicate craftsmanship as redundant parts of members are removed.
JOINT E Two diagonal members are joined at the same point on the top of the bridge to the base of the beam. Similarly, The edges of these members fit perfectly in the space by sanding.
JOINT F The vertical member is joined directly onto the surface of the horizontal beam using super glue as adhesive.
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6.4 Final Bridge testing and Load analysis The picture below shows the design of our final Bridge and the load distribution.
Figure 6.4.1: Diagram showing members in compression and tension
In our Final bridge the main amendment done was the cross bracing on top chord to prevent better downward bending resistance and stable force resistance.
Figure 6.4.2 photo showing the 2nd last bridge Test Without cross bracing
Figure 6.4.3 photo showing the last bridge test with cross bracing on top
Figure 6.4.4: Final bridge for testing
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Figure 6.4.5: Results after testing
Total length: 25 Clear span: 17 Bridge weight: 82g Maximum load: 9500g Efficiency: (9.5)2 = 1100% 0.082 Failed Components
Top and bottom chord
Failing Reasons
Uneven distribution of forces
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6.5 Calculation
9.00kg = 90N 1) Determine perfect truss J = number of joints = 15 m = number of structural members = 27 2J = 2(15) = 30 m + 3 = 27 + 3 = 30 Therefore, 2J = m + 3, it is a perfect truss. 2) Determine reaction force ∑MA = 0 (90 x 0.2) – (RA x 0.4) = 0 18 – 0.4RA = 0 RA = 45N ∑Fy = 0 90N - 45N – RA = 0 RA = 45N
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3) Determine internal forces of main structural members
*Assuming all structural members is in tension. At joint A, tan α = 2.5 5 α = 26.6°
cos 26.6° = FABx FAB FABx = FAB cos 26.6° sin 26.6° = FABy FAB FABy = FAB sin 26.6° ∑Fy = 0 45 + FABy = 0 45 + FAB sin 26.6° = 0 FAB = -45 sin 26.6° = -100.5N ∑Fx = 0 FABx + FAC = 0 (FABx cos 26.6° ) + FAC = 0 FABx cos 26.6° = FAC FAC = (-100.5) cos 26.6° = 89.9N ≈ -90N
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At joint C, ∑Fx = 0 FAC + FCD = 0 90 + FCD = 0 FCD = -90N
At joint B, α = 26.6° θ = 180° – 90° - 26.6° = 63.4° FBEx = FBE cos 63.4° FBEy = FBE sin 63.4°
∑Fx = 0 FBEx + FABx + FBDx = 0 FBE cos 63.4° + 90 + 90 = 0 FBE cos 63.4° = -180 FBE = -180 cos 63.4° = -80.6N ∑Fy = 0 FABy + FBEy + FBC + FBDy = 0 45 + FBE sin 63.4° + FBC + (-45) = 0 (-80.6) sin 63.4° + FBC = 0 FBC = 72.1N
At joint E, tan θ = 0.05 0.05 FBEx = FBE cos 45° = 80.6 cos 45° = 57N FBEy = FBE sin 45° = 80.6 sin 45° = 57N 36
∑Fx = 0 FEF + 57N = 0 FEF = -57N ∑Fy = 0 57N - FED = 0 FED = 57N At joint D,
FBDx = 45N FBDy = 90N
FDFx = FDF cos 45° FDFy = FDF sin 45°
∑Fy = 0 90 + 57 + FDFy = 0 90 + 57 + FDF sin 45° = 0 FDF = 207.69N ≈ 207.7N ∑Fx = 0 FCD - FBDx + FDG + FDFx = 0 90 - 45 + FDG + FDF cos 45° = 0 45 + FDG + FDF cos 45° = 0 FDG + FDF cos 45° = -45 FDG = -45 – (-207.69 cos 45°) = 101.86N ≈ 101.9N
At point F,
FDFx = 207.69 cos 45° = 146.86N FDFy = 207.69 sin 45° = 146.86N ∑Fx = 0 57 + 146.86 – FFH = 0 FFH = -203.86N ≈ -203.9N 37
∑Fy = 0 146.89 + FFG = 0 FFG = 146.86N ≈ 146.9N At point G, tan θ = 0.05 0.025 θ = 63.4° FGHx = FGH cos 63.4° FGHy = FGH sin 63.4° ∑Fx = 0 -101.86 + FGI + FGHx = 0 -101.86 + FGI + FGH cos 63.4° = 0 -101.86 + FGI + (-164.2 cos 63.4°) = 0 FGI = 175.3N ∑Fy = 0 146.86 + FGHy = 0 146.86 + FGH sin 63.4° = 0 FGH = -164.2N At point I, FHIx = FHI cos 45° FHIy = FHI sin 45°
∑Fx = 0 -175.3 + FHIx = 0 FHI cos 45° = -175.3 FHI = -247.9N ∑Fy = 0 FJI + FHIy – 90 = 0 FJI + FHI cos 45° - 90 = 0 FJI = 90 + 247.9 sin 45° FJI = 265.3N
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At point H,
FGHx = FGH cos 63.4° = 164.2 cos 63.4° = 73.45N FGHy = FGH sin 63.4° = 164.2 sin 63.4° = 146.86N FHIx = FHI cos 63.4° = 247.9 cos 63.4° = 110.89N FHIy = FHI sin 63.4° = 247.9 sin 63.4° = 221.73N ∑Fx = 0 203.86 + FHJ + 73.45 – 110.89 = 0 FHJ = -166.4N
Figure 6.4.6: Diagram showing members in torsion and compression with forces
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From what we observe in figure 6.4.6, internal tension in C, D, G, and I gradually increase. There’s no big gap between each value. Se we conclude that out bridge did not break because of torsion or compression but snap because of load tension forces in the middle of the highest point, as it keep pulling the fettuccine until it breaks. Since the load was distributed at both elevation and plan, as a results the bridge was broken into 2. If refer to picture 6.4.5 there’s no major deformation of the bridge.
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7-Conclusion Our group have construct total of 6 Fettuccine Bridge to experiment different design and which can withstand the maximum load. The existing bridge that we use as a precedent studies for this project is 130th street railroad bridge which represent a wooden through trust structure with I-beam that consist both horizontal and vertical elements, Stone leeve bridge represent Baltimore Through Truss and san Joaquin Bridge represent howe through truss. Three of this bridges are having a brace both overhead structure and base structure which our group implement it to the trial bridge and final bridge. Each type of bridge has it own advantage and disadvantage on its structural member to resist compression and tension and combine the structure after analyzing it to improve the strength of the bridge. For our final model, it has a lighter weight but can withstand the heavier load compare to another 5 trial bridge. It is the result of the bridge that have keep improving since the first bridge. It has 80 gr weight and can carry 9000gr load. This project had been conduct for us to understand the distribution of load, tension and compression in a truss structure directly. We evaluate, explore and improve the properties of construction materials of every each bridge to determine which member should be strengthen, and which member is a critical member. We also realize the important of connection. It not only the material properties that we will use to connect each members, but also the way we connect it. There is different strength between attaching it or slot in which have some surface to support it. Time also a main consideration for fettuccine, as it may become fragile in longer time thus it necessary to build it on certain time. As an architecture students, the outcome of this project that we had gain a knowledge how to design an effective bridge with a small amount of materials hence create an environmental sustainability without sacrificing the design and aesthetic of it.
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7-Appendix • CASE 1- AZRIN BIN FAUZI
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• CASE 2- JULIA SHENJAYA
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Case Study Summary - Highest tension internal force Is 250kn at CH member. - Highest compression internal force is 239,62kn at BG member - 10 over 19 internal members are compression - 9 over 19 internal members are tension
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- CASE 3- BIBI AMEERAH PEERUN
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• CASE 4- LIAU WEN BING
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• CASE 5- LIM MING CHECK
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• CASE 6- E JY HUEY
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CONCLUSION FOR THE 6 CASES Case 1: Highest internal tension forces: 219KN Highest internal compression forces:193 KN Number of members in torsion: 8 Number of members in compression:11 Case 2: Highest internal tension forces: 250 KN Highest internal compression forces:239.62 KN Number of members in torsion: 9 Number of members in compression: 10
Case 3: Highest internal tension forces: 193.75 KN Highest internal compression forces:193KN Number of members in torsion: 7 Number of members in compression:12
Case 4 Highest internal tension forces: 495 Highest internal compression forces: 192 Number of members in torsion: 7 Number of members in compression: 12
Case 5: Highest internal tension forces: 838.93 Highest internal compression forces: 530 Number of members in torsion :11 Number of members in compression: 8
Case 6: Highest internal tension forces: 250 Highest internal compression forces: 219.20 Number of members in torsion: 9 Number of members in compression: 10
In conclusion of the 6 cases, we have come to determine that case 5 is the most efficient truss, because of the total resultant forces of this truss system has the highest number of internal forces in tension which will result to big pulling forces within the truss. 84
9.0 References Historicbridges.org,. (2015). CA-4 San Joaquin River Bridge - HistoricBridges.org. Retrieved 8 October 2015, from http://historicbridges.org/bridges/browser/?bridgebrowser=california/ca4sanjoaquinriv er/ Historicbridges.org,. (2015). Stones Levee Bridge - HistoricBridges.org. Retrieved 8 October 2015, from http://historicbridges.org/bridges/browser/?bridgebrowser=ohio/stoneslevee/ Historicbridges.org,. (2015). 130th Street Railroad Bridge - HistoricBridges.org. Retrieved 8 October 2015, from http://historicbridges.org/bridges/browser/?bridgebrowser=illinois/130rr/
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