Table of Contents
Pages
1. Introduction 1.1 Study Objectives ---------------------------------------------------------------------------------------------2 1.2 Report Preview -----------------------------------------------------------------------------------------------2
2. PART 1: Precedent Study 2.1 History ------------------------------------------------------------------------------------------------------4-8 2.2 Structure analysis ----------------------------------------------------------------------------------------9-24
3. PART 2: Design and Built Fettuccini - Methodology 3.1 Requirement ------------------------------------------------------------------------------------------------26 3.2 Work Schedule ----------------------------------------------------------------------------------------------27 3.3 Material and Equipment ------------------------------------------------------------------------------28 -31
4. Fettuccine Analysis 4.1. Day 1 4.2. Day 2
: Material Testing -----------------------------------------------------------32-33 : Adhesive Testing ---------------------------------------------------------34 -35
5. Fettuccine Truss Bridge Construction Process 5.1. Day 3 - 4 5.2. Day 5 - 6
5.3. Day 7 - 8
5.4 Day 9 - 10
5.5 Day 11
: Pratt Truss Model 1-------------------------------------------------------------36 Process ---------------------------------------------------------------------------37 : Parker Truss Model 2 ----------------------------------------------------------38 Process -----------------------------------------------------------------------39-41 Joint -------------------------------------------------------------------------------42 Compressive and tensile force distribution----------------------------------43 Structural analysis---------------------------------------------------------------43 : Model Testing 1-----------------------------------------------------------------44 Critical Members Identification ----------------------------------------------45 Joints -----------------------------------------------------------------------------46 Efficiency calculation----------------------------------------------------------46 : Final Model Problems and solution ----------------------------------------------------------47 Improvement---------------------------------------------------------------------47 : Final Model Testing --------------------------------------------------------48-50 Result -----------------------------------------------------------------------------51
6. Conclusion ------------------------------------------------------------------------------------------- 52 7. Appendix – Exercise Case 1 -6 ---------------------------------------------------------------54-59 8. References ----------------------------------------------------------------------------------------59-60
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1. Introduction 1.1 Project Objectives: Why Study Structure? Structure is one of the most important components to translate architectural design ideas into reality. Structure acts as the supportive element of architectures as how the bony skeletal framework supports human body. Thus, the main purpose of structure is to allow the architecture to perform its functions and at the same time, stays at its own integrity.
Hence, architecture students were required to perform structural analysis and investigation on how structural elements working in its integrity by distribution of tensile and compressive forces. So, in this project, we were required to understand how structures work, from the simplest form of structure, the truss. What is Truss? Definition of Truss In engineering, a truss is a structure that `consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object' (http://en.wikipedia.org/wiki/Truss). Truss is a structure built up of three or more members who are normally considered being pinned and hinged at the joints. The following figure shows different types of trusses. Load applied to the truss is transmitted to joint so that each individual member is in either pure tension or compression. (Project Brief)
1.2 Report Preview: In this project, we were required to form a group of six and work together to achieve the understanding of how truss work. The project has two major parts: Part 1. Precedent Study of a selected truss bridge Part 2. Design and Built a Fettuccini Truss Bridge In our case, we selected Roy Inks Bridge, which located in Texas, USA. We performed a series of analysis on how should truss structure works. At the same time, another unexpected outcome from the research informs us the importance of bridge maintenance and preservation. Throughout the report, we had included our methodology of study and the process of the construction of the bridge from Day 1 to the final model.
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PART 1 PRECEDENT STUDY OF A SELECTED TRUSS BRIDGE
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2. Precedent Study The selected bridge precedent study for this project is the Roy Inks Bridge, located at Llano, Texas, United States, North America. It is located near the centre of the town, as the main entry from the North to downtown area. Roy Inks Bridge has a total of four spans at which, each span is about 800 feet in length. The type of truss that makes up Roy Inks Bridge is Parker truss, which as illustrated in diagram 9. Since the completion on September year 1936, Roy Inks Bridge has now reaches the average daily traffic of at least 9,100 vehicles per days, with human traffic, about 12,100 per day in total.
Diagram 1. Location of Roy Inks Bridge, Llano, Texas, United States, North America. (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
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Diagram 2 Aerial view of Roy Inks Bridge across the Llano River. (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
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Diagram 3 Perspective Views of Roy Inks Bridge (retrieved from http://www. historicbridges.org/)
Diagram 4 Close – up view of Roy Inks Bridge (retrieved from http://www. historicbridges.org/)
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Diagram 5 Views Beside Bridge From Northeast Quadrant (retrieved from http://www. historicbridges.org/) `
Diagram 6 Portals Views Facing North ( retrieved from http://www. historicbridges.org/)
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2.1 History Roy Inks Bridge was built by Austin Bridge Company over Llano River as a replacement of an 1892 structure that was being destroyed in a flood, recorded crest of 42 feet, during year 1935. Roy Inks Bridge has gained its nomination as one of the important historical place in year 1988 by United States of Department Interior National Register of Historic Places. Roy Inks Bridge was named after the name of the former mayor of Llano and original member of LCRA's Board of Directors. The bridge strength was tested for its stability in a flood during 1997 where the river reaches its second-highest crest of 38.6 feet.
Diagram 7 Llano as seen across the Llano River Bridge 1910s photo courtesy Will Beauchamp (Retrieved from http://www.texasescapes.com/TexasHillCountryTowns/LLanoTexas/Llano-River-Texas.htm/)
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2.2 Structure analysis The Roy Inks Bridge of Llano is an example of on-system Bridge. On-system bridges are those on the state highway system, and are found on state highways. (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Roy Inks Bridge is made of the parker truss. Parker truss, by definition, it is the type of truss that made up of a combination of Pratt truss design with a polygonal upper chord. Parker truss can also be named “the camelback truss�. (http://en.m.wikipedia.org/wiki/Truss_bridge)
Diagram 8 Example of Pratt truss. (Retrieved from https://www.cs.princeton.edu/courses/archive/fall09/cos323/assign/truss/truss.html)
Diagram 9 Parker Truss - Llano Bridge profile with dimensions (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
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Roy Inks Bridge Structural Elements Explanation: Truss: “The truss is constructed of rolled W 8x40 sections, (diagonals And the outer most verticals) and built up members (verticals and both top and bottom chords). The built up sections are typically double channels with riveted lacings and/or cover plates. Member details were compiled from either the AISC Manual of Steel Construction (AISC 1994), or for The obsolete truss members, from Structural Data, (Mosher, 1922) or from an AISC manual listing of obsolete sections (AISC 1990).” (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 10 Parker Truss (retrieved from http://www.eng.umd.edu/~austin/)
Bridge Deck: “The bridge deck is a reinforced concrete slab on steel beams and stringersas depicted in Figures 2.5 through 2.8. The slab is 6-½ inches thick with both longitudinal and transverse 5/8-inch reinforcement bars. Longitudinal reinforcement was placed approximately 13” on center between longitudinal steel members, and transverse reinforcement was spaced approximately 6” on center. Transverse reinforcement was bent to accommodate both positive negative moments in the slab”
(Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 11 Example of Truss Bridge (retrieved from http://www.eng.umd.edu/~austin/)
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Gusset Plate: “The path includes components of brace connection to the gusset plate, the gusset plate and beam to column connection which all must withstand the forces they receive and transfer to other structural components. In other words they should serve as a safe and proper path of force transference”
( M.Naghipour, G. Abdollahzadeh and M. Shokri , Analysis and Design Procedure of Corner Gusset Plate Connection in BRBFs, 22 June 2013)
Diagram 12 Example of Gusset Plate (retrieved from http://www.eng.umd.edu/~austin/)
Bracing: “Braces provide stability to the primary girders as well as improving the lateral or torsional stiffness and strength of the bridge system both during construction and service. Depending on the geometry of the bridge, braces may be designed as either primary or secondary members. In the AASHTO LRFD Specifications, the member designation as primary or secondary member.”
Diagram 13 Types of bracing (Steel Bridge Design Handbook Bracing System Design Publication No. FHWA-IF-12-052-Vol.13, U.S. Department of Transportation Federal Highway Administration, Nov 2012)
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Roy Inks Bridge Parker Truss Joints:
Diagram 14 Truss Web (retrieved from http://www. historicbridges.org/)
Diagram 15 Truss Web (retrieved from http://www. historicbridges.org/)
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Diagram 16 Truss Web ( retrieved http://www. historicbridges.org/)
Diagram 17 Top Chord Connections (retrieved from http://www. historicbridges.org/)
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Diagram 18 Top Chord Connections (retrieved from http://www. historicbridges.org/)
Diagram 19 Views From Sidewalk (retrieved from http://www. historicbridges.org/)
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Diagram 20 Truss Web (retrieved from http://www. historicbridges.org/)
Diagram 21 Top Chord Connections (retrieved from http://www. historicbridges.org/)
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Diagram 22 Top Chord Connections (retrieved from http://www. historicbridges.org/)
Diagram 23 Top Chord Connections (retrieved from http://www. historicbridges.org/)
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Diagram 24 Tennessee (retrieved from http://www. historicbridges.org/)
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Diagram 25 Railing Support (retrieved from http://www. historicbridges.org/)
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Diagram 26 End Post (retrieved from http://www. historicbridges.org/)
Diagram 27 Bracing (retrieved from http://www. historicbridges.org/)
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Diagram 28 Portal Bracing (retrieved from http://www. historicbridges.org/)
Diagram 29 Bottom Chord Connections (retrieved from http://www. historicbridges.org/)
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Diagram 30 Replica Railings on Eastern Side (retrieved from http://www. historicbridges.org/)
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Roy Inks Bridge Deck:
Diagram 31 Deck longitudinal stringers and slab (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 32 Longitudinal and transverse reinforcement in the bridge deck (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 33 Bent configuration of transverse reinforcement (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
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Diagram 34 Transverse beam attached to the truss verticals, with connecting longitudinal stringers (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 35 Detail of longitudinal stringer embedment: Longitudinal stringers were attached in such a manner that their top flanges were higher than the top flange of the transverse beam. This distance varied with each member due to the camber of the transverse member, but is on the order of 1 inch. The effect of this connection was that the slab rested directly on top of the transverse beams, but the longitudinal stringers were embedded approximately 1 in. into the bottom of the slab. (Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013)
Diagram 36 Steel Sample Details
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Force Acting On Truss:
Diagram 37 Force acting on the structure – Load applied to the truss is in tension or compression.
.
A
B
Diagram 38 Structure Elements: A and B are relatively small centre diagonal members. In analysis conducted as reported in Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2013, , results show that they were not able to resist compressive force. Thus, any of these members that in compression will be removed from the model
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PART 2 DESIGN AND BUILT A FETTUCCINI TRUSS BRIDGE
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3. Methodology Methodology is the approach of conducting work process. In this project, we were required to design and build a Fettuccini Bridge that with a degree of load capacity and efficiency. The efficiency of the model is then being calculated after load testing.
3.1 Requirement The requirements for this project have been set by the Project Brief, Project 1 Fettuccine Truss Bridge (Taylor’s University School of Architecture, Building and Design, Building Structure ARC2523) as below: Task 1 Refer to Appendix – Exercise, Page 53 onwards Task 2 1. 2. 3. 4.
Form a study group in 5-6 members. One truss bridge precedent study. Design and construct a fettuccini bridge of: 750mm clear span Maximum weight of 200g Test bridge to fail
Other than aesthetic value, the design of the bridge must be ofhigh efficiency, I.e. Using the least material to sustain the higher load.
The efficiency of the bridge is given as following;
In order to achieve higher efficiency, you need to analyse and evaluate each of the following items:
Material strength - By adopting appropriate method, determine the strength of fettucini, i.e. tension and compression strength - By knowing the strength of fettucini, you will be able to determine which members to be strengthened
Structural analysis of the truss - Perform detailed structural analysis of the truss - Identify critical members - Strengthened the critical members if necessary Page 26 of 54
3.2 Work Schedule Time/ Date
Progression
Week 1 Week 1 Week 2 Week 2 Week 3 Week 4 Week 5 Week 6 Week 6
Precedent study analysis, recognition about types of truss Study forces and calculation Choices of material, material and adhesive testing Mock model 1 Mock model 2 at scale Mock model 2 testing Final model Final model testing Report submission Total working time on models : 11 Days
(Day 1 - 2) (Day 3 - 4) (Day 5 - 6) (Day 7 - 8) (Day 9 - 10) (Day 11)
Table 1
Project starting date Project closure date
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: Week 2 (1st September 2014) : Week 6 (3rd October 2014)
3.3 Material and Equipment 3.3 Material For material selection, our group has decided to narrow down into the choice between two brands, which considered the better quality in general, available in market:
1. Kimball Brand Fettuccini
Diagram 39 Kimball Package
General properties of Kimball Fettuccini: Brand Size Strength Weakness
: Kimball (Made In Malaysia) : 21cm (Length) X 0.3cm (Width) : Tensile Strength : Compressive Strength
2. San Remo Brand Fettuccini
Diagram 40 San Remo Package
General properties of San Remo Fettuccini: Brand Size Strength Weakness
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: San Remo (Made In Australia) : 22.8cm (Length) X 0.5cm (Width) : Tensile Strength : Compressive Strength
Comparison between dimension of San Remo and Kimball Fettuccini:
SAN REMO
KIMBALL
Diagram 41 Dimension differences of San Remo and Kimball Fettuccini
Comparison between weight of San Remo and Kimball Fettuccini:
SAN REMO: 10g
Diagram 42 San Remo and Kimball single strand fettuccini on weighing scale.
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KIMBALL: 0.8g
3.3 Equipment Cutting tools
Diagram 43 Cutting Equipment: Blazer (Left) and Scissors (Right)
Adhesive
Super Glue Brand 1 (Cynoacrylate)
White Glue (Water-based)
Uhu Glue (Synthetic Resin)
Super Glue Brand 2 (Cynoacrylate)
Diagram 44 Adhesives
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Data Collection Tools
Diagram 45 Equipment for data collection: Camera and recorder
Measuring Tools
Weighing Scale (g)
Diagram 46 Equipment for measuring
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Ruler
4. Fettuccine Analysis 4.1. Day 1: Material Testing
To test out the material strength of San Remo and Kimball fettuccini, the group has carried out an experiment whereby hanging the equal load to one strand of different brand of fettuccini and observe the reaction of the fettuccini strand when they are under load.
First, we use a half- filled water bottle as the load. The weight of the water bottle filled with water was being weighted on a kitchen-scale.
Observation and result as below: Diagram 47 Kitchen Scale
Diagram 48: The first strand of fettuccini being tested out is the San Remo’s fettuccini.
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Diagram 49: The second strand of fettuccini being tested out is the Kimball’s fettuccini
In conclusion, San Remo Fettuccini has greater resistant to compressive force if compared to Kimball Fettuccini. Hence, San Remo Fettuccini has been selected as the bridge material.
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4.2. Day 2: Adhesive Testing In the following experiment, five strands of fettuccini were glue together with different types of adhesives: Super-glue, Uhu glue and White glue. The purpose of the experiment is to test out:
1. How fettuccini bond with different types of adhesive. 2. Time taken for different adhesives to dry and cure 3.How do fettuccini react after applied with adhesive
White Glue
Uhu Glue
Super Glue
Diagram 50: Above images shows the reaction of cure fettuccini after being applied by compressive force.
Observation 1: The observation shows that after two hours of allowable curing time, fettuccini which applied with white glue has became the most fragile as compared to Uhu glue and super glue. The corresponding increase in strength of fettuccini after curing time as recorded is Uhu glue, and finally the strongest, super glue. Strength of Fettuccini Strands after 2 hours curing: Most Fragile Average White glue Table 2
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Uhu Glue
Strongest Super Glue
White Glue
Uhu Glue
Super Glue
Diagram 51: Above images shows the reaction of cure fettuccini after being applied by compressive force.
Observation 2: The observation shows that after two hours of allowable curing time, fettuccini which applied with Uhu glue has became the most flexible as compared to white glue and super glue. The corresponding increase in the flexibility of fettuccini after curing time as recorded is super glue, and finally the most rigid, white glue.
Flexibility of Fettuccini Strands after 2 hours curing: Most Flexible Average Uhu glue Table 3
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Super Glue
Not Flexible White Glue
5. Fettuccine Truss Bridge Construction Process 5.1. Day 3 - 4: Pratt Truss Model 1
In order to understand well about the ways of jointing system that could be applied on the final model, the group has tested out the possible construction method by the construction of a simple Pratt Truss. Pratt truss was chosen as the first study model is because it is easier to form the shape. It is also one of the simplest trusses to be understood.
Pratt Truss Model 1
Diagram 52: Model 1
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Process
Diagram 53: Process for Model 1
The group has tested out the model with white glue. The model was constructed following the sequence from base to top. However, the model constructed was not following the requirements as stated in Project Brief. Hence, load test was not carried out.
Outcomes White glue is the heaviest glue compared to Uhu glue and Super glue.
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5.2. Day 5 - 6: Parker Truss Model 2
Model 2
Diagram 54: Parker Truss Model 2
For the second model, the group has decided to construct the model based on the precedent study at the requirements. The adhesive used in this model was only super glue. The base strand thickness was made up of four strands of Fettuccini.
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Process
Diagram 55: Parker Truss Model 2 Process
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Diagram 56: Parker Truss Model 2 Process
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Diagram 57: Parker Truss Model 2 Process
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Approach of Joints Used In the Construction of Fettuccini Bridge
Joint
Diagram 58: Joint
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Compressive and Tensile Force Distribution
Diagram 59: Parker Truss Model 2
Structural Analysis
Diagram 60: Parker Truss Model 2 Structural Analysis
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5.3. Day 7 - 8: Model Testing 1 To test the load capacity and efficiency of the Fettuccini bridge, our group has perform a model testing by using water bottled filled with water as the load. First, the model was weighted by a weighing scale to get its current weight. Then, the loads were hung under the bridge. Loads were added to the point the bridge fail. Process
Breaking Point
Diagram 61: Breaking Point
Result Attributes Weight of Fettuccini Bridge, grams Total load capacity, grams Table 4
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Data Collected 140g 3355g
Diagram 62: Parker Truss Model 2
Critical Members Identification
Critical Members Diagram 63: Critical Members Identification
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Joints
Top Chord
Joint
Bracing Supporting Beam
Base Chord
Diagram 64: Joints
Efficiency calculation Result Attributes Weight of Fettuccini Bridge, grams Total load capacity, grams
Data Collected 140g 3355g
80.400X 10続 Table 5
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5.4 Day 9 - 10: Final Model Problems and solution
Diagram 65: Parker Truss Model 2 problems and solutions
The above members highlighted in RED are the members in compressive force. Due to the weakness of fettuccini towards compressive force, hence bracing is needed to add on the fettuccini
Improvement
Diagram 66: Parker Truss Model 2 improvement
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Final Model
Diagram 67: Parker Truss Final Model
Diagram 68: Parker Truss Final Model
Diagram 69: Parker Truss Final Model
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D Diagram 70: Parker Truss Final Model
Diagram 71: Parker Truss Final Model
Diagram 72: Parker Truss Final Model
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Diagram 73: Parker Truss Final Model
Diagram 74: Parker Truss Final Model
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5.5 Day 11: Final Model Testing Result Attributes Weight of Fettuccini Bridge, grams Total load capacity, grams
Data Collected 186g 2000g
22.22X10続
Process
Diagram 75: Parker Truss Final Model Testing
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6. Conclusion
In conclusion, we found that for the structure to transfer load efficiently, the structure must built in at a precise dimension. Other than that, the strength of material, the bonding material and the position of joint are also the critical elements on defining whether the structure will stays on its integrity or it will fail. During the construction of the bridge, it is also important to take note that the bridge members must not in a slanted or distorted orientation. Ignorance of this issue will cause the bridge to fail.
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8. References Electronic data 1. https://ftp.dot.state.tx.us/pub/txdot-info/rti/psr/0-4419-s.pdf 2. http://structurae.net/structures/roy-inks-bridge 3. http://www.texasescapes.com/TexasBridges/Llano-River-Roy-Inks-Bridge-Llano-Texas. htm 4. http://www.bridgemapper.com/bridge_detail.php?ID=1687 5. http://www.historicbridges.org/bridges/browser/?bridgebrowser=texas/llano/# photosvideos 6. http://www.historicbridges.org/bridges/browser/?bridgebrowser=texas/llano/ 7. http://www.bridgemapper.com/bridge_detail.php?ID=1692 8. http://www.historicbridges.org/bridges/browser/map.php?bridgebrowser=texas/llano/ 9. http://www.eng.umd.edu/~austin/ 10. htte://www.opb.org/news/article/gusset-plates-role-bridge-collapse-considered/ 11. http://en.m.wikipedia.org/wiki/Gusset_plate 12. http://m.wisegeek.com/what-is-a-gusset-plate.htm
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Books and Journals 1. M.Naghipour, G. Abdollahzadeh and M. Shokri, 22 June 2013, Analysis and Design Procedure of Corner Gusset Plate Connection in BRBFs. 2. Charles Merrill Bowen, B.S., M.S., M. Eng, Analysis, Testing, and Load Rating of Historic Steel Truss Bridge Decks, May 2003, UMI Number: 3110731 3. The SRI Foundation Rio Rancho, New Mexico, Case Studies On The Rehabilitation Of Historic Bridges, July 5, 2011 4. U.S. Department of Transportation Federal Highway Administration, Steel Bridge Design Handbook Bracing System Design, November 2012, Publication No. FHWA-IF-12-052Vol.13
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