SCHOOL OF ARCHITECTURE, BUILDING & DESIGN Research Unit for Modern Architecture Studies in Southeast Asia Bachelors of Science (Honours) (Architecture) Building Structures (ARC 2523) Prerequisite: Building Construction 2 (ARC2213)
Project 1
Fettuccine Truss Bridge
Tutor: Mr. Adib Astari Razak 1101P11983 Celine Tan Jean Inn 0303669 Feiven Chee 0312004 Tang Hui Ying 0312089 Hong Si Mun 0312643 Wong Jia Xin 1101G13277
Table of Content 1. Introduction 1.1. Aim of Objectives 1.2. Perfect Truss 1.3. Scope of Study 1.4. Limitation 2. Methodology 3. Precedent Study 3.1 History and Background 3.2 Structure 3.3 Construction 4. Equipment and Material Study 4.1 Material Strength Study 4.1.1 Types of Fettuccine 4.1.2 Orientation 4.2 Equipment Study 4.2.1 Glue Types 4.2.2 Gluing Method 4.3 Model Making 4.4 Working Schedule 5. Design Process 5.1. Proposed Design - Part 1 5.2. Truss Analysis - Part 1 5.3. Proposed Design - Part 2 5.4. Truss Analysis - Part 2 5.5. Proposed Design - Part 3 5.6. Truss Analysis - Part 3 5.7. Final Design 6. Model Testing 6.1. Observation 6.2. Efficiency 7. Analysis 7.1. Structural Analysis 7.2. Failure Analysis 7.3. Design Modification 8. Conclusion 9. Appendix 10. References
1.0 Introduction 1.1 Aim & Objectives Aim For this project, we were to design a fettuccini bridge with the requirements of a clear span of 600mm length and a maximum of 150g in weight. Our aim was to construct a bridge with high efficiency with minimal material weight and high load.
Objectives
To develop and be able to apply our understanding of tension and compressive strength of construction materials
To develop our understanding of force distribution in a truss
To design a high efficiency perfect truss bridge with high level of aesthetic value
1.2 The Perfect Truss Truss: A structural member that is usually found in a framework used to support a structure. By definition, a truss can be various structural frames based on the geometric rigidity of the triangle and composed of straight members subject only to longitudinal compression, tension, or both.
Perfect Truss: A truss is considered perfect if the condition 2J = m + 3 is fulfilled, whereas J is the number of joints, m is the number of members. A perfect truss can be analysed to get the internal and external member forces by using the three conditions of static equilibrium.
1.3 Project Scope This project has the requirements of building a fettuccini bridge of a clear span of 600mm length and a maximum of 150g in weight. Precedent studies were carried out to study a truss bridge of our choice. The studies were then used to apply our understanding to the design of our bridge. Structural analysis were carried out through the observation of load test to design several bridges and then selecting the best bridge.
1.4 Limitations
This project limit us to design a perfect truss bridge with the use of fettuccini as our only material, with any adhesive of our choice. The properties and method of construction of the fettuccini bridge vary from our precedent study due to the size and nature of our material. Therefore, the relationship of the fettuccini bridge and a life-size bridge of another material dissimilar.
In reality, a well constructed bridge is subjected to lateral loads, mobile loads and other factors compared to a single point load which is used in our fettuccini bridge. As a result, the design of our fettuccini bridge cannot be assumed to be functionally adequate for life size bridges.
2.0 Methodology Precedent Study Research on truss bridge design is carried out from books and internet to demonstrate existing bridge styles and construction. Information of bridge’s connection, arrangement and orientation of truss member is collected and applied to the bridge design.
Material Strength Testing Material properties of fettuccine is tested with its tensile strength, compressive strength and bending strength before model making in order to provide the material its highest performance.
Model Making Only fettuccini may be used for construction of bridge and any adhesive may be used in jointing. A 2-D AutoCad drawing of all the elevations, including top layer, bottom layer, sides layer and cross section is done before executing bridge model making. The drawing are printed out and used as a pattern for the bridge design. This helps in cutting the fettuccine precisely tot the right size by laying it down on the drawing and cutting it.
Model Testing The bridge is centered on support and a “s� hook is hanged at the center of the bridge where load is applied. Failure of the bridge is defined as the inability of the bridge to carry additional load and the bridge is tested to fail.
Structural Analysis Other than efficiency evaluation, it includes design drawing and calculations of internal force for each member at every joint to further evaluate compression and tension members of the bridge design. It also
3.0 Precedent study – The Sydney Harbour Bridge 3.1. History and background
Figure 1: The Sydney Harbour Bridge, Australia
The Sydney Harbour Bridge is a steel through bridge that spans across Sydney harbour which consists of two railway lanes, eight vehicular, a bicycle lane and a pedestrian lane. It is the world’s largest steel arch bridge with a total span of 1149 metres and an arch span of 503 metres, with the top of the arch 134 meters above the harbour.
It was not originally thought of as an arch bridge. Dr Bradfield initially had a cantilever bridge in mind to span the harbour. However, on a trip to New York he was inspired by the Hell Gate Bridge and he realised the cantilever design was inferior to an arch for his proposed bridge.
3.1. Structure The Sydney Harbour Bridge is a two-pin arch construction, made up of two arches side by side, joined by horizontal cross-members. The arch is composed of two 28-panel arch trusses; their heights vary from 18 m at the center of the arch to 57 m at the ends next to the pylons. The arch has a span of 504 m and its summit is 134 m above mean sea level. An arch bridge functions quite differently from a cantilever bridge (or beam bridge). In an arch bridge, the vertical loads (live and dead loads) tend to flatten the arch and push out against the abutments, creating both vertical and horizontal reaction forces. A beam bridge, by comparison, exerts only vertical forces at its supports. This means that an arch must have significantly stronger abutments than a beam bridge.
RHA = Horizontal reaction force at point A
RVA = Vertical reaction force at point A
RHB = Horizontal reaction force at point B
RVB = Vertical reaction force at point B
The Sydney Harbour Bridge
The Pratt truss bridge design
The truss of the arch of the bridge resembles the Pratt truss bridge design. The road deck is placed underneath the arch, supported by tension members, and the deck ties the two ends of the arch together, forming a tied arch. The tension tie takes the horizontal thrust, therefore, the foundations need only to support the gravity loads on the bridge, which allow arches to be used where there may not be otherwise suitable subsoil conditions.
Diagram 1: Showing the compression and tension forces acting in the bridge
The bridge structure is supported on four horizontal, cylindrical forged steel pins in the main bearings, one at each end of the two arches. This allows the movement in the arch caused by temperature variations and dynamic loading to be accounted for. The arch may rise up to 180 mm due to heating during the day.
Abutments at the base of the pylons are essential to hold its span firmly in place and most importantly, support the loads from the arch by taking the lateral thrust. However, the pylons themselves have no structural purpose.
Figure 2: The massive hinges against the abutment, supporting the load from the arch.
The bridge structure rests on four large concrete skewbacks, two on each side of the shore. The excavation made was directly into the solid sandstone. Each skewback is 40 feet wide (12.192 m), 90 feet long (27.432 m) and up to 30 feet (9.144 m) deep. The upper surface of these, for the main bearings, is at an angle of 45째 to take the main bearing casting.
Diagram 3: The thrust of the main arch below the main bearings is at an angle of 45Ëš.
Figure 3: Construction of Sydney Harbour Bridge’s main bearing.
Rivets (permanent mechanical fasteners) were extensively used in the construction of the Sydney Harbour bridge, the largest scale use of rivets in any steel structure in Australia. The rivets used were mild steel with UTS of 413-482 MPa and high shear strength. More than 6 million rivets were used to assemble the bridge. Rivets with a head on one end were inserted into the plates and the headless end is rounded over whilst the rivet is still very hot using a pneumatic riveting gun.
Figure 4: The pneumatic riveter is operated by hand, and is used both inside and outside the workshops.
Diagram 4: Grain Flow in a rivet (right) machined from hot rolled bar. Note the sharp change in grain flow under the rivet head. Favourable grain flow in rivet (left) after inserting and rounding while hot, analogous to hot forging.
Diagram 5: When a hot rivet cools, it contracts imposing a compressive (clamping) stress on the plates. The rivet itself is then in tension the tensile stress is approximately equal to the yield stress of the rivet material.
3.2 Construction The tied arch is particularly difficult to construct, because the arch thrust is not resisted until the road deck is constructed, but the road deck is unsupported until the arch is built.
Each half arch was built out from each shore supported on each of the main bearings to prevent it from falling into the harbour.
Figure 5: The early construction of Sydney Harbour Bridge.
The southern head of the bridge was constructed a month ahead of the northern head to ensure no errors would be repeated when constructing the northern head.
4.0 Material and Equipment Study 4.1 Material Strength Testing 4.1.1 Types of Fettuccini: Several types of fettuccini were tested for this project: i) Divella Fettuccini ii) San Remo’s standard fettuccini
Figure 6: Divella Fettuccini
Figure 7: Standard Fettuccini
Results: Before carrying out the experiment to determine the strength of different types of fettuccini, we weighed one fettuccini and found that Divella Fettuccini is heavier than San's Remo Standard Fettucini, which are 2g and 1g respectively. Besides, the surfaces of Divella Fettuccini is slightly rounded compare to San Remo's Standard Fettuccini which causes the surface area for gluing is lesser. Therefore, we chose San Remo's Standard Fettuccini as the material for bridge construction in the concern of lighter in weight and flatten surface area for gluing.
Surface of Divella of
/ Fettuccini Surface
San Remo's Standard Fettuccini
Diagram 6: Example of each brand of fettuccini's surface
4.1.2 Orientation Testing of different orientations of single fettuccini to determine which orientation would have more strength to be put into the model design. This was done by placing the fettuccini evenly over a gap of 100mm with pressure applied on both ends of it for support. Weights were placed in a 5g plastic bag that hung in the centre of the fettuccini member.
Figure 8: Placement of fettuccini over 100mm gap
Figure 9 : Horizontal Orientation
Figure 10: Vertical Orientation
Results: Layer Load(g)/Face 50 100 150 200 250 300 350 400
1 Horizontal / / / / / X -
Vertical / / / / / / / X
Table 1 : Breaking point of horizontal and vertical orientation fettuccini members
The outcome of the test was that the horizontal oriented piece broke after 300g of weight were placed and the vertical oriented piece broke after 400g of weight were placed. This concluded that fettuccine has very little bending strength in horizontal orientation. Thus, horizontal member in bridge design would consider using vertical facing.
4.2 Equipment Testing 4.2.1 Glue Types The use of glue on surfaces of fettuccini that binds them together to resists separation and create a rigid joints. The ability of different types of glue to bind the fettuccini, distribution of stress across the joint and aesthetic value of workmanship will affect the efficiency of the bridge. Test of glue is taken to get the efficiency and best result on connection.
Figure 11: Glue Gun
Figure 12: Adhesive Glue
Figure 13: 3-Second Glue
Figure 14: Epoxy Glue
Results: Type of Glues Hot Glue Gun
Advantages - Easy to use
Disadvantages - Joints too flexible - Low Effieciency - Weight increase significantly
Adhensive Glue (UHU)
- Dries Quickly
- Joints slightly flexible when dry
3-Second Glue
- Dries quicker than adhensive glue - Rigid Joint - Clean Joint - Highest Effiency
- Cracked joint found after Storing in room temperature - Expand and shringe occures
Expoxy Glue
- Rigid Joint - High Effiency
- Takes longer time to dry - Require careful mixing - Messy
Table 2: Comparison of advantages and disadvantages each type of glues
From the above table, it can be concluded that different type of glue would have different result on joint and aesthetic value in gluing. As result, 3-second Glue has the best result for rigid joint with clean connection yet has fastest solidify time between connection which result higher efficiency compare to other type of glues.
4.2.2 Gluing Method After get the result of using 3-second glue that create a rigid joint and vertically orientation able to carry greater load, a testing of different way of gluing method is taken to determine does the gluing method affect the load carried and excessive weight of 2 layer of fettuccini. The experiment was done by gluing the joint of fettuccini in two ways : a) spot glue at intervals b) glue entire length
Results:
Diagram 7: Spot glue at intervals
Diagram 8: Glue entire length
Layer Load(g)/Face 50 100 150 200 250 300 350 400 450 500 550 600 650 700
2 Point / / / / / / / / / / / / / X
Entire Surface / / / / / / / / / / / / / X
Table 3: Breaking point of gluing method in point and entire surface of fettuccini
As the result, both gluing method does not affect the load carrying as the breaking point of both gluing method are the same. However, if a number of strands of fettuccine are to be used together as single member, it is suggested to “spot� glue them at intervals of about 1cm as this will provide adequate strength without adding excessive weight as compared to gluing the entire lengths.
4.3 Model Making We used different method to construct our bridge. Our very first bridge, we started by drawing the bridge template on paper. Then we measure the length of each members then cut accordingly. However, to increase the accuracy and efficiency of the other bridges, our next few proposed bridges are first drawn in AutoCAD then printed out on paper. The length of the members are then cut accordingly.
Figure 15: Segments of cut fettucinni
Figure 16: Assembling and gluing the pieces together.
As a group, we constructed the bridge together.
Figure 17: Holding the members together as dries
Figure 18: Group working together to build the bridge
4.4 Working Schedule Date Tested March 31, 2014 April 7, 2014 April 9, 2014 April 13, 2014 April 16, 2014 April 18, 2014 April 21, 2014 April 25, 2014 Table 4: Working schedule
Tasks - Brief of Project 1, Fettuccine Truss Bridge - Get tools and material before started prototype bridge - Study and Experiment of fettuccini strength - First bridge design test model making (based on case study) - 2nd bridge design test model making (Redo first model with lighter weight) - Tutorial with Lecturer regarding the design and load distribution of bridge - Third bridge design with improvements from second bridge - Load carried is tested - Discussion among group members by analysing the bridge design and load distribution of each trusses - Final bridge design making and testing
5.0 Design Process 5.1 Proposed Design - Part 1 1ST BRIDGE DESIGN
Figure 19: First bridge design
2nd BRIDGE DESIGN
Figure 20: Second bridge design
The first and second bridges resemble the design from precedent study —Sydney Harbour Bridge, relying support from the curved arch. The arrangement for bracing members and number of layers of fettucine are tested from both designs. As the load is meant to hang at the bottom, there are 7 hanging members on each side connected to the arch to support the whole the structure. The hanging members are designed in tension to favour the characteristic of fettucine. Not only enchancing aesthetic value of the design, the width is reduced from 8cm to 1cm when going higher as a way to reduce its weight, which in turn contributing to higher efficiency. However, the major support from the arch is in compression which serves as the key drawback to this design.
5. 2 Truss Analysis - Part 1 Compression Tension
Diagram 9: Truss analysis of 1st and 2nd bridge
LOAD
Diagram 10: Orthographic drawing of the 1st and 2nd bridge
1st Bridge Design
2nd Bridge Design
Length Max. height Max. width Mass
Length Max. height Max. width Mass Max. load Efficiency
: 80cm : 14cm : 8cm : 113g
Figure 21: Model testing of 2nd bridge
: 80cm : 14cm : 8cm : 0.103kg : 1.48kg : 21
Figure 22: 2nd bridge’s failure.
5.3 Proposed Design - Part 2 3rd BRIDGE DESIGN
Figure 23: Perspective view of the 3rd bridge
Figure 24: Facade of the bridge
After considering the existence of forces pushing outwards in the triangular shape of previous designs, we intended to focus on achieving higher efficiency rather than on its aesthetic. Thus, a normal truss bridge was experimented, with 5 panels on each side, spanning a length of 14cm on each. The heavier structure with thicker layering is compensated with reducing length and height in the design. Gathering information from precedent study and some other existing bridge, this design follows a height to span length of 1:7. However, due to the 4-side structure, more bracing members are needed to provide overall stability, which could be disadvantage in reaching higher efficiency.
5.4 Truss Analysis - Part 2 LOAD
Diagram 11: Truss Analysis of 3rd bridge
Compression Tension
Digram 12: Orthographic drawing of the 3rd bridge
3rd Bridge Design Length Height Width Mass Max. load Efficiency Figure 25: Model testing of 3rd bridge.
Figure 26: Joint detail of 3rd bridge.
Figure 27: 3rd bridge’s failure.
: 70cm : 10cm : 8cm : 0.125kg : 2.79kg : 62
5.5 Proposed Design - Part 3 4th & 5th BRIDGE DESIGN
4th Bridge Design
5th Bridge Design
Figure 28: 4th and 5th bridge in comparism
These two designs are merging the strength and advantages of previous designs, combining the truss arrangement from design 3 and triangular shape from design 1 and 2. Further exploration on the jointing methods and the proportions to width and height are carried out. 4th Bridge Design
5th Bridge Design
Overlaid Joint
Butt Joint
Figure 29: Excess material can be cut off after assembly
Figure 30: Require careful sizing
Cross section :
Jointing : method
5.6 Truss Analysis - Part 3
Figure 31: Weak point in the 4th bridge joint
The 4th design failed at its joint before it buckled under a load of 4.4kg. It was believed that if that particular joint was properly glued and bonded with other members, it could withstand a much higher load before it collapses. However, the 5th design was a total failure. The horizontal member on the top broke off from other parts while the rest of the bottom part was still in good condition under the load. It was proved that the jointing method between the diagonal truss and the top horizontal member is not workable. Figure 32: Close up of weak point
4th Bridge Design
5th Bridge Design
Figure 33: 4th and 5th bridges’ failure.
4th Bridge Design
5th Bridge Design
Length Max. height Max. width Mass Max. load
Length Max. height Max. width Mass Max. load
: 70cm : 7cm : 8cm : 0.11kg : 4.4kg
: 70cm : 8cm : 5cm : 0.095kg : 3.5kg
5.7 Final Design
Final Bridge Design
Length
: 70cm
Height
: 7cm
Width
: 8cm
Mass
: 0.131kg
Figure 34: Perspective view of final bridge design
The final bridge design is a modification of the 4th design by adding number of panels from 5 to 7 as reducing panel length could contribute higher strength to the structure. Moreover, a panel length of 10cm stays in the range of panel length to span length ratio equals to 1: 6-8. By understanding that fettuccine has a weak compression strength, the truss members which in compression are designed with added layer. The bottom members in T shape are cut with calculated angle in order to be properly glued and bonded with the horizontal strip of both sides to counteract the outward-pushing forces. Also, every surface at joints are worn flat to provide maximize area of bonding. Further strengthening work is applied at the midpoint of the bridge as well as at the point meeting the edges of supporting body at the both sides.
Diagram 13: No bending force in triangular elements
Diagram 14: Presence of bending force in rectangular elemetns
Design Idea and Reasoning All the members at both sides of the bridge are arranged in triangle as there is no bending moment in triangular element. However, in a cubic or rectangular element, the truss strength depends on the bending strength of each member, which is unfavourable for the fettuccine’s properties. Furthermore, as the weight of the bridge is indirectly proportional to the efficiency, bracing members needed to stabilize the cubic or rectangular structure could increase the weight, decreasing the efficiency.
3-layered
LOAD
2-layered
Compression Tension Diagram 15: Truss Analysis for final bridge design
Detail 2
Detail 1
Detail 3
Diagram 16: Orthographic drawing of final bridge
Diagram 17: Detail 1
Figure 35: Joints at the middle of the bridge.
Diagram 18: Detail 2
Diagram 19: Detail 3
Figure 36: View of joints from bottom.
6.0 Model Testing A raffia string was used to tie at the top of the horizontal interconnecting member in the centre between the two planar trusses of the bridge and a 'S' hook was hung onto the raffia string. Starting at 2kg, we continued to put 500g load into the load carrier with 10 seconds intervals until we reached 8kg. At this point, there is no more 500g load to be use, so we exchanged our 500g weights that was already in the bag with two 2kg disc for 8 pieces of 500g load. We used the 500g loads until the our bridge reached its breaking point.
Figure 37: A raffia string used to tie at the top of the bridge
6.1 Observation As the experiment goes on, and the load gets heavier. There is a slight creaking sound and also, the top part of the fettuccini started to bend. This may be due to the compression acting at the top. The fettuccini bridge reached its breaking point at 12kg.
Figure 38: The top fettuccini bending upward
7.0 Analysis 7.1 Structural Analysis A typical warren truss was selected as our fettuccine bridge design. The tension and compression of the final bridge design were identified and calculated. As the strength of material, type of adhesive, joining method, and orientation of fettuccine is tested in the beginning of the assignment, we came to a conclusion that fettuccine is strong in tension and weak in compression. Therefore, the member with compression force were build with thicker fettuccine (total 3 fettuccine layer) while the member with tension force were joined with thinner fettuccine (total 2 fettuccine layer). The reason is to maintain the strength of the truss in the compression part so that it will able to hold the load for longer period.
We studied and analysed our bridge by doing some calculations and this is what we obtained.
Diagram 20: Labels of each member
Diagram 21: Bridge with complete calculations
The top and bottom horizontal part of the fettuccine act as main structure of the bridge. Therefore, it need to be the strongest part of the whole structure. We built the structure with total 4 fettuccine with alternative joining to avoid failure in certain edges.
Diagram 22 : Compression (red) and tension (blue) acting on the bridge when load is applied.
The force from the load tends to move to the end of the bridge and to the table. The bracing in the middle part of the bridge were designed to hold tension force so that the bridge can support the maximum load. The bracing of the bridge helps to transfer load to both end. Therefore, there is a difference in force in both side of the triangle bracing. In this fettuccine bridge, we tried to make a equilateral triangle in the facade part as well as the sectional part. In the final fettuccine bridge model, our bridge reach the similarity of 92% of the equilateral triangle which the angle is 54.46â ° in both side and 71.08â ° in another side. These enable the bridge to reach the higher efficiency of transferring load.
7.2 Failure Analysis
In the final model testing, result is stated as below: Weight of the bridge: 131g Maximum load: 12kg Efficiency: 1099
After obtaining the result, an investigation of the failure of the bridge is carried out. We found out the reasons for failure with several factors that could be improved.
Reason 1: Uneven load distribution in each members We understand that fettuccine is good in tension and weak in compression. In our bridge design analysis, we found that one side of the bridge is in compression, therefore, we decided to enhance the members under compression by adding the fettuccine up to 3 layers, where the members in tension is only 2 layers. 3-layered 2-layered
Compression Tension Diagram 23: Members in tension used 2 layers, while members in compression used 3 layers.
The strategy of additional layer on members under compression was not a good idea. Although adding more layers would strengthen the compression members, it is very limited as fettuccini has weak ability to withstand compression force.
Reason 2: Condition of external span on two side of table 3-layered 2-layered
Diagram 24: Members that rests on the table plays an important role in supporting the whole bridge
We also realize that the member that rests on the table (external span) plays an important role as a base for supporting the whole bridge. In the final bridge design, only 10cm of the bridge were placed on the table, therefore, when load were added on the bridge, strength of the lower horizontal member results in shear force. The external span of the bridge is not stable enough to perform well in supporting more load as it was not designed to address this issue.
Reason 3: Height of Fettuccine using ratio of Sydney Harbour Bridge in smaller scale In order to achieve better dimension of the bridge, we calculated the height and width of the bridge in ratio with Sydney Harbour Bridge. This results in the height of Fettuccine Bridge being
7cm. After the final model testing, we found out that although the triangle shape is a very rigid structure and it is able to transfer the load from one point to another. The lower height of our bridge does not have a higher opposite force against the load carried. The bridge would be able to withstand a higher load if the height was higher.
Load
Load
Diagram 25: Lower bridge (left) withstands a lower load as compared to the higher bridge (right)
7.3 Design Modification After several model making processes, it is evident that the critical thinking and observation has helped us improve in the final outcome of our model with a 131g fettuccini bridge being able to carry a load up to 12kg, which has the highest efficiency compared to our earlier designs. The strategy is to use minimal material in order to maximize efficiency. However, after the final model testing, we discover that the broken point of the bridge started from base member which 10cm away from the centre point, thus, it is obvious that this bridge design has achieved its maximum load carried as the breaking part are in tension and fettuccini are good in tension.
Figure 39: Broken member of the bridge after testing.
During the final model testing, the placement of external span of bridge was not placed at the centre perfectly as the broken point of bridge is slightly at the side. In the process of loading the weights into the load carrier, the moving hook caused the bridge to move a few centimetre more to another side of table, causing the distribution of the load to be uneven to supporting members. Therefore, a fixed point should be used on both sides to prevent to bridge from moving.
Diagram 26: Green boxes representing a fixed point.
Moreover, there were 3 layers of fettuccine which were used for base members and heading members where it was join vertically because it has better strength in tension. Adding another layer would not be a better solution to carry a higher load as the weight of bridge will increase and the efficiency will decrease respectively.
On the other hand, we must take into account that the bridge is exposed to different temperature, affecting the strength of the fettuccine. Although, we have tried to avoid the difference in outdoor and indoor temperature, in some circumstances, a minor crack is still seen after changing the surrounding temperature from studio (cold and moist) to outdoor (hot and humid). Therefore, the temperature of the working place for model making should avoid low temperature (16’C – 26’C).
Fettuccini is a biodegradable material. Therefore, the opened fettuccini must be kept in a air tight box to avoid air exposure. The fettuccini cannot be exposed to direct sunlight as it will damage the material. Moreover, we cannot construct the bridge too early as it will weaken with time. We cannot construct the bridge too late as the glue needs time to dry. The time estimated to construct the bridge plays an important role in determining the strength of the bridge.
8.0 Conclusion The fettuccine bridge was considered as a successful bridge as it can withstand 12kg of loads, with one of the highest efficiencies which is 1099. In order to have a better understanding of the load distribution of trusses, we have done a structural analysis of the fettuccine bridge to identify the forces acting upon each member, so as to determine the critical member that needs to be strengthened. By constructing a truss bridge using fettuccine, we need to make sure the materials given are to be used at its full potential. Not to mention that good workmanship is essential to achieve quality, it is also very important to have a feasible and well-thought construction sequence throughout the process. As future architects, it is significant for us to take all these factors into consideration when it comes to a real design.
9.0 Appendix A total of 6 trusses are designed for further analysis as an individual task in this assignment. The following are the task distribution for the cases: Case 1: Wong Jia Xin 1101G1277 Case 2: Feiven Chee 0312004 Case 3: Tang Hui Ying 0312089 Case 4: Celine Tan Jean Inn 0303669 Case 5: Astari Razak 1101P11983 Case 6: Hong Si Mun 0312643
10.0 References Australian Government 2008, Sydney Harbour Bridge, viewed 6 April 2014, http://australia.gov.au/about-australia/australian-story/sydney-harbour-bridge
Garrett's Bridges 2011, Pratt Truss, viewed 12 April 2014, http://www.garrettsbridges.com/design/pratt-truss/
RTA timber truss bridge strategy n.d , Allan truss bridge, viewed 13 April 2014, http://www.rms.nsw.gov.au/roadprojects/projects/maintenance/documents/timber_truss_bridges/app endix_1c_bridge_profiles_allan_trusses.pdf
Prof. Markov, I n.d., Truss Simulator, http://ivanmarkov.com/truss-simulator.html