Image
Bridges Marily M.
PLA
ANNING
DRIVING Q
How can I en strongest brid most efficient u
QUESTION
ngineer the dge with the use of material?
RUBRIC CRITERION
LT
NOV
INVESTIGATION
Understanding and applying a systems thinking, design cycle, or scientific investigation approach.
Presenting, manipulating, and analyzing data from scientific experiments and design cycle investigations by explaining patterns and trends, drawing inferences and stating conclusions.
Identify the engineer building a bridge
5a.1
5b.3
-
Planning Forces What will I d
List the data collect investigation and id trends material pro truss memb
VICE
ring process of
do for my bridge
ted during the dentify the basic
operty bers
SPECIALIST
Analyze how the process is used in while building my bridge -
Make connections (mind map or boxes connecting)
Analyze the data and apply the conclusion to my final bridge design
SKILLS AND TECHNIQUES Evaluating experimental methods, techniques, raw data and conclusions, identifying limitations and suggesting improvements.
Analyzing properties of shape, size, and space in art, architecture, design, or nature; making the best of the unique location / cultural and artistic perspective.
Identify the techniques build a pasta truss 5b.4
-
How to glue How to do a blue
Understand what is as s 3d.2
Identify the types of brid structures
CREATE AND REFINE
Translating geometric properties to different dimensions and/or planes.
Identify the geometric p that will be used on the 3d.3
-
Triangles, circles 2D and 3D
needed to
eprint
structure
dge
properties bridge
s, angles, etc
Experiment by building pasta trusses and analyze how to improve by trial and error. -
Which sections need to be reinforced Identifying limitations
Analyze my final structure -
Is it a strong structure Does it include all the needed members to be strong Which are its strengths What can I change for future models to be stronger
Execute a translation from 2D to 3D model -
From blueprint to spaghetti
Identify and list th weak shapes in bui Using spatial visualization to model geometric structures and solve problems;
Evaluating solutions and conclusions in the context of the problem through estimation, measurement accuracy, error, and tolerances.
Solving problems by applying principles of computational and algorithmic thinking (including formulating problems and organizing data in a way that allows for a computer to solve them, automating solutions through algorithmic thinking, and reducing an existing solution to a more efficient version).
3d.1
3a.2
-
Recognising if a so not fit a set of data knowledge. -
3a.4
First activ Properties or weak
Weight str Calculatio
Identify all the nec solve a basic calcu calculation of resis to weight ratio. All listed.
he components of strong and ilding structures.
vity with the book s that make a shape strong
olution is incorrect or does a, by estimation and previous
rength ratio ons from John
cessary steps to attempt to ulation force of member, sting members, and strength l steps must be explicitly
Experimentations with shapes, length of members, joins, angles, in 2D design and 3D builds.
Implement the strength/weight ratio, force of the members to identify the strength of my bridge and be able to make smart changes.
Applies all the necessary step to: Use the software Bridge Designer to test the strength of my bridge and delete the useless members Solve mathematical equations to find the strength of each member of the bridge
FINAL PR
Project
Link to
RODUCT
t Brief
o doc
INVE
ESTIGATION
PARTS OF THE B
BRIDGE Vocabulary With this image, it will be easier to understand exactly what I will be talking about all over the Process Portfolio. I am putting the image to have an easy and fast reference in case I need it.
3d.2 N
STRUC
My definition: Different shapes that are put together t
According to Designing Building Wiki, a structure is: an interrelated parts with a fixed location on the ground. designed to bear loads, even if it is not intended to be
Structural Engineers ● ●
Design, assess and inspect structures to ensure that they are efficient and stable They work on buildings, bridges, oil rigs, and so on.
CTURES
that end up doing a bigger thing.
nything that is constructed or built from different It can also be any body of connected parts that is occupied by people.
Civil Engineers ● ●
Design, construct, maintain and improve the physical environment include infrastructure such as pipelines, transportation, environmental engineering, maritime engineering, and so on
Source: Designing Building Wiki
5a.1 N 5b.3 N
The following information are notes from our guest speaker John
Important aspects ● ● ● ●
Safety Longevity Design Sustainability
It is important to cover this aspects before starting with the design and building part to ensure the safety and effectiveness of the bridge
Planning P
The planer is the p involved on the pr ● Structural E ● Roads Desi ● Traffic Engi ● Drainage E ● Geotechnic ● Acoustic Sp ● Scientists (fl ● Urban Desi ● Landscape ● Sustainabili They also need to ● ● ●
Contamina Heritage Erosion Con
PLANNING
Process
person in charge of coordinating with all the people roject: Engineers igner ineers Engineers cal pecialist flora and fauna) igners Architects (planting with the existing flora) ity Experts cover important aspects such as:
ation
ntrol
5a.1 N 5b.3 N
PLANNING
The planner needs to have a good engagem with the stakeholders which are:
Organization between all parts is essential to get to a solid plan that benefits all parts. All parts need to get together to measure the pros and cons, budget, people’s point of view, etc. Getting all parts to agree with the project, ensures the fairness of the project because it takes in consideration all the areas that will be affected in this case by the bridge.
ment
Types of Bridges
3d.2 N
BEAM Most basic type of bridge invention Literally just a beam deck going across, supported by two piles Traditionally made of Wood Beam bridges are supported by an abutment or pier at each end.
● ● ● ●
Advantages ● ● ● ● ●
It does not take long to build a beam bridge. Can use the most simple material to build Multiple design options are available to incorporate this bridge into. Can be multiplied chain and build many sections Cost is minimal
Disadvantages ● ● ● ● ●
Can snap in the middle if sections are long - there are no support in the middle. or sag in the center as it ages. Build-in short sections - you will rarely find a single span of more than 250 feet Not a whole of of aesthetic value Not a very flexible bridge
3d.2 N
ARCH/KEYSTONE ● ● ●
Works by transferring the weight of the bridge and it horizontal thrust restrained by the abutments at eith Instead of pushing straight down, the load of an arch outward along the curve of the arch to the supports As the structure begins to go through the ageing pro design begins to get stronger. That's because the co placed on each side of it will begin to flatten out the creating a U shape with less rounding.
Advantages ● ● ● ● ● ●
Great natural strength. Provide higher levels of resistance. The design is good when it comes to pressure. They come with no distortion. Become stronger through time. Economically advantageous
ts loads partially into a her side. h bridge is carried at each end. ocess, this bridge ompression that gets arch somewhat,
Disadvantages ● ● ● ● ●
Challenging to build Short spans unfortunately Can’t be built just anywhere. Need regular maintenance. Can be expensive
3d.2 N
TRUSSES ● ● ● ●
It’s a structure of connected elements (usually forming triangles) Usually require small amount of material for the weight they can carry The components are mainly stressed in axial tens or compression. Carries vertical loads by bending.
Advantages ● ● ● ● ● ● ●
The construction is less time-consuming. Easy to mantle An average level of expertise is needed to build it up. Can be constructed in unfavorable weather. Land Sliding does not damage these bridges. Earthquake-proof. Easily dismantled
D
sion
Disadvantages ●
● ● ●
In the regions of the hot climate, the metallic elements expand due to heat provided by sunlight in the daytime. Prone to rust. In moist conditions, rusting and oxidation weaken the strength of the bridges. Flexible due to the nature of the material they are built. The vibration caused by running vehicles cracks the joints of the elements of the bridge.
3d.2 N
SUSPENSION ● ● ● ●
The deck is hung below suspension cables. This mak the deck the most vulnerable part Can carry pedestrians, bicycles, livestock, cars, trucks light rail Normal it is done for medium to long bridges Carries vertical loads through curved cables in tensio These loads are transferred both to the towers, which carry them by vertical compression to the ground
Advantages ● ● ●
●
Can be built high up There can be a great distance leaving big spans. It is more flexible than other bridges. This helps to stay in good shape when natural disasters happen No access is needed from below so it is a simple construction
kes
s,
on. h
Disadvantages ●
●
●
It is too flexible so if there were extreme winds or the load on the bridge is to heavy it needs to be closed It can’t support high traffic because of the little support It is very expensive
3d.2 N
CANTILEVER Uses cantilevers which are beams that extend horizontally and are only attached at one end. They are an idea developed from Beam bridges and truss bridges.
● ●
Advantages ● ● ● ●
● ●
Create the least destruction during construction. Strong and reliable. Support is only required on one side of each cantile Don't require much falsework (a temporary structu built to support the construction of the permanent structure). Ideal for deep/rocky gorges. Navigation below the bridge is not affected during construction
ever. ure t
Disadvantages ● ● ● ● ●
Heavy and more expensive than the average. Since they are heavier, require larger and stronger support beams. Not optimal for places with extreme weather conditions. Not suited for earthquake-prone areas. They are very complex structures which are hard to build and maintain.
3d.2 N
CABLE STAYED Have at least 1 tower, the cables are connected with the tower to support the deck Four major classes of rigging on cable-stayed bridges: mono, harp, fan, and star. Costs less than other types of bridge Spans are longer than cantilever bridges and shorter than suspension bridges
● ● ● ●
Advantages ● ● ● ●
Takes less time to build Can be constructed to almost any length Multiple design options The design of the cable-stayed bridge supports itself
Disadvantages ● ● ●
Design option can become unstable in specific environments Challenging to inspect and repair Strength advantages typically apply to short spans, the other types of bridge offered more durability.
KEY TERMS & CONCE Bruttle Plasticity Corrosion
The property of a material that fractures whe
is the ability of a solid material to undergo pe
is a natural process that converts a refined me sulfide. It is the gradual destruction of materi their environment.
Bending
Becomes curved
Torsion
Twist. It is usually caused by the wind. If the b
Load
The weight that the bridge has. It has dead loa the non permanent weight like cars, people, w
EPTS
en subjected to stress but has a little tendency to deform before rupture
ermanent deformation, a non-reversible change of shape in response to applied forces
etal into a more chemically stable form such as oxide, hydroxide, or ials (usually a metal) by chemical and/or electrochemical reaction with
bridge isn’t build evenly, torsion happens.
ad which is all the permanent weight and the alive weight which is all wind, etc.
EXTRA VOCABULARY
5b.3 N
BUILDING M Physical Properties Material
Bulk density
Durability
Wood
154 - 165 kg/m3
Many years. Requires regular maintenance
Stone
1602 kg/m3
Not all stones are durable
Iron
7860 kg/m
Durable. Requires regular maintenance
Steel
Text
37850 kg/m3
Long term durability
MATERIALS Weathering Resistance
Water Absorption
Rots, swells and burns easily
Absorbs water by direct contact and vapor. There are paints to make it waterproof.
Resists humidity, heat, wind, oater and sun effects
Depends on the posterity of the stone
Get too hot in the summer and cold in winter. Water and oxygen leads it to corrosion.
Doesn’t absorb water
Good corrosion resistance
Doesn’t absorb water
5b.3 N
BUILDING M Mechanical Properties Material
Strength
Hardness
Elasticity
Plasticity
Wood
36.6 MPa
460 lb
0.064 Gpa
Depends on the weather
Stone
131 MPa
N/A
50 Gpa
No more than 6%
Iron
540 MPa
110 - 807 lb
160 Gpa
N/A
Steel
250 MPa
64 HRC
200 Gpa
550 Mpa
Text
W an
Ca an
Th
MATERIALS Brittleness
Corrosion Resistance
Doesn’t break easily. Withstand a lot of tension nd compression without snapping
Resistant to many corrosive chemicals and conditions that may affect other materials
N/A
N/A
ast iron with high carbon d silicon content is brittle and will fracture.
Relatively resistant to corrosion because of the high carbon content
he most brittle from the metal.
THe steel is designed to tolerate corrosion or is protected against it.
SKILLS & T
TECHNIQUES
5a.1 N
F
FORCES “The two key types of forces involved in building any structure are tension and compression. Every material has the ability to hold up to a certain amount of tension and a certain amount of compression” (TeachEngineering) Tension: Pulls the material apart Compression: squeezes material together
Source: TeachEngineering
3d.1 N
ACTIVITY
Using a single she the floor.
My first thought was that I needed to do some folds to know that every part had a 4cm height. Once I had them, I try to see if it could hold the tension that a the book did. I placed it on top and saw it wasn’t strong enough to do it. To make it stronger, I did some extra folds on both directions to have more support. I did a fold on the middle of each of the squares made on the corners. Each fold was directed to the inside.
eet of paper support a book 4 cm or more off I did extra folds on the corners to make it thicker and have even more support. I did this because I observed that all the compression was mainly directed to the corners. My next step was to tape everything to stay in place. Between the middle folds, I put some tape to have better tension. On the corners I added a little to keep the folds in place.
To have more tension all over the structure, I placed tape in an ¨x¨shape in both sides (top and bottom). Once I had everything secured, I put one book and it stayed there; I tried with one more book but the structure wasn’t strong enough to stay up.
3d.3 N
GEOMETRIC PROP 01
Triangles ● ● ●
●
The sum of all interior angles = 180. The sum of all exterior angles = 360 An exterior angle of a triangle is equal to the sum of its two interior opposite angles. The sum of the lengths of any two sides of a triangle is always greater than the length of the third side.
02 ● ●
● ●
●
R O A an ∠ In ∠ O qu ∠ Ta a le
PERTIES Circles
Radius is the same length: OA = OC Angle at center is twice ngle at circumference: 2x ∠ABC = ∠AOC nscribed angle theorem: ∠ABC = ∠APC Opposite angles in a cyclic uadrilateral: ∠ABC+∠CDA=180 angents to the circle from point have the same ength: TA = TC
Properties of a Triangle Properties of a Circle
3d.1 N 3d.3 N
GEOMETRIC PROP 03
Rectangles ●
● ●
All the properties of a parallelogram apply (the ones that matter here are parallel sides, opposite sides are congruent, and diagonals bisect each other). All angles are right angles by definition. The diagonals are congruent.
PERTIES 04
Rhombuses ●
● ● ●
All the properties of a parallelogram apply (the ones that matter here are parallel sides, opposite angles are congruent, and consecutive angles are supplementary). All sides are congruent by definition. The diagonals bisect the angles. The diagonals are perpendicular bisectors of each other.
Observation: All the geometric shapes I analyzed get stronger because of triangles creating the shape. These leads me to think that triangles are the shape that make any geometric figure strong
Properties of Rhombuses, Rectangles and Squares
3d.3 N
GEOMETRIC PROP 05
Cubes ●
● ●
A cube is a solid that has six square faces of equal size that meet each other at right angles. Has eight vertices (corners) and 12 edges. All the edges have the same length, and every corner in the cube has an angle of 90 degrees
PERTIES 06
Pyramids ● ● ●
Is a polyhedron formed by connecting a polygonal base and a point, called the apex. Each base edge and apex form a triangle, called a lateral face. It is a conic solid with polygonal base. A pyramid with an n-sided base has n + 1 vertices, n + 1 faces, and 2n edges.
Geometric Properties of Cubes Geometric Properties of Pyramids
5a.1 N 5b.3 N
BUILDING SPAGH Plan I will build small structures simulating trusses of the bridge. I want to use different techniques of bridges to test which is the best one. I will be considering the following points: ● ● ●
Resistance to tension and compression Amount of material required Difficulty level to build it
Types o
HETTI TRUSSES
of Trusses
3d.1 N 3d.3 S
D
Be ne pa
Th de are as
DESIGN TRUSSES
efore building the trusses, I eed to have the design on aper.
he images on the left are the esigns I will be testing. They e made in scale so I can use it s an exact reference
5b.3 S 5b.4 S 3d.1 S 3d.3 S
I built 5 different bridges to try which truss structure was better. I decided do build: ● Howe ● Double intersection ● Bowstring ● Pennsylvania ● Waddell “A” Truss Before starting to build, I first draw the truss on paper with the measures the bridges would be.
TRUSSES WADDELL ● ● ● ●
This model is the most efficient use of material. I don’t think it will be able to support a high amount of tension and compression I only added a single layer of spaghetti on the bottom so it wasn’t a strong structure. If it had a stronger deck or a double layer in the main spaghetties, it can be stronger
5b.3 S 5b.4 S 3d.1 S 3d.3 S
HOWE ● ●
●
● ●
This was the first bridge I built I observed that the structure wasn’t strong enough, so I decided to add an extra layer of past on the bottom part of each truss. It is the only bridge I built in triangular size but it was difficult to glue it. When I do it in a bigger scale it is going to be impossible. It had just little glue so it didn’t stay everything in the right place I didn’t considered the pedestrian
Double Intersection ●
ta
●
t
● ●
n
It was easy and fast to build. Took me no longer than 1:30 hours. The “x” have a better resistance to tension because they are connected in the middle I added a double layer of spaghetti in the bottom The spaghetties in the upper part connecting the two trusses were weak. For next time they need either to be in an “s” shape or have more.
5b.3 S 5b.4 S 3d.1 S 3d.3 S
BOWSTRING ● ●
●
It was very easy to build and glue. The complicated part was the arch I added a double layer of spaghetti in the bottom but this time like a sandwich; with the joints of the trusses in the middle. Where the spaghetti intersects in the “x”, I added some glue to make it stronger
m
d
PENNSYLVANIA ● ● ●
●
The most difficult bridge to build Too complicated to glue and cut the spaghetti After building the trusses, I connected them with 5 spaghettis on the top and two on each side of the anchorage section. It has a double spaghetti layer in the deck part put as a sandwich.
TEST To test the bridges, I used fruit and vegetables and then weight it to know how much each bridge was able to support.
For next time, I will use other thing to weight it. Some of the fruits got damaged and were rotten the next day
5b.3 S 5b.4 S 3d.1 S 3d.3 S
I rebuild the two best brid one I will be using for my
DOUBLE INTERSECTION ● ●
●
●
I think is the strongest structure for spaghetti bridges. I added extra layers on the bottom. Instead of having two spaghettis, I have 4. This way, it didn’t break in the part where the weight was pulled For the pedestrian, I added 4 “x” and two spaghettis going from one side to another for extra support. On top I added more “x” to make it even stronger
As I predicted, this is the strongest bridge. It was able to carry 9.5kg
dges to decide which is the y final design.
BOWSING ● ● ●
I added extra layers on the bottom. Instead of having two spaghettis, I have 4 On the top, I added spaghetti on both sides to keep everything where it needs to go. It broke from the section where the weight pulls. Maybe it wasn’t well glued, or the structure isn’t strong in that section of the bridge.
5b.4 N
How to… GLUE
For the gluing part, I only added glue to the ends of the spaghetti and the point where it intersects with another o This helped me to have a better control of where I was ad glue and not to put too much. I observed that I need to b to glue it before it gets cold. When I was faster, it was easi glue and it didn’t fall apart
To have a better stability while gluing, I first glued the main spaghetti to the blueprint so it doesn’t move.
If I had to build a spaghetti, I would ad glue in the joins f deck so there is no ex
To have long members, I need to glue spaghetties. To instead of putting them one over another, I observed th better to put an extra spaghetti on top of them so it conti perfect horizontal line
one. dding be fast ier to
another dd less for the xcess.
do so, hat it is inues a
5b.4 N 3a.4 N
To create my blueprint, I first designed in a small scale adding all the elements that I considered important. Once I had the model in a notebook, I translated it into what will be my real scale. I draw it first with pencil and once I was 100% sure of the design I remarked with a marker.
● ● ● ● ●
Have the design in a smaller scale With a pencil, draw the principal lines (deck, main towers, arch) Draw the trusses for the deck and arch Decide if something needs to be changed Use a marker to draw the lines
DES
In this d an arch I thoug move. O buildin bridge, much w it off.
How to… BLUEPRINT
SIGN IN NOTEBOOK
design, there is h. When I drew it, ght it was a smart Once I started ng the actual , I felt it was too weight to I took
BLUEPRINT
3a.4 N
BRIDGES BRIDGE
STRENGTH
WEIGHT (
Howe
2350g
21
Double intersection
4900g
32
Pennsylvania
3950g
33
Waddell A
2010g
17
Bowstring
5650g
34
2nd Double inter
9500g
60
2nd Bowstring
7360g
64
(BRIDGE)
STRENGTH/WEIGHT
1g
111.90
2g
153.12
3g
119.69
7g
118.23
4g
166.17
0g
158.33
4g
135.15
The table from the lect, is the weight/strength ratio of all the trusses I tested. The ones who are in bold, are the best ones of their category. The lightest, the strongest and the beast balance. For me, the most important column is the strength one. If the bridge can carry way more than the other options, I will go with that option. Still, the last column is important and that is why I will go with the DOuble Intersection for my model. It has a high number and was able to carry 9.5kg.
3a.2 3a.4 S 5b.3 S
BRIDGE DESIGNER ●
● ●
To test our bridges, we used a software called Bridge Designer to test if it is going to be a useful bridge or if it’s going to break easily. I tested mine and it looks great. I’ll stay with it. The things I added based on my old design is the arch in the bottom.
3a.2 3a.4 S 5b.3 S
BRIDGE DESIGNER 2N ● ●
●
The members from the deck and the top need to be reinforced The number and member marked with reed are not strong enough and need to be changed I observed that if the tension and compression are above 1.00, they won't resist the load
ND TRY
3a.2 3a.4 S 5b.3 S
BRIDGE DESIGNER 3R ●
●
●
●
The deck and top of the bridge was reinforced. Instead of using 140x140 thickness, I doubled it 280x280 None of the members are highlighted in red or blue - this means the tension and compression is well distributed. There are some members that doesn’t require to stay (all of the ones who are 0.00) I didn’t take them off the design because the app doesn’t let me test it without them
RD TRY
3a.2 3a.4 5b.3 S
CALCULATING FORCES IN MEMB
Identify each joint with a letter
Have all the forces and analyze where I need to reinforce
The mem need rein will just a layers of s
BERS MANUALLY Identify the load and lengths and angles
mbers that nforcement, I add extra spaghetti
Find Sin & Cos
Obtain TAC & TAB
Repeat the process with every member
3a.2 3a.4 5b.3 S
CALCULATING FORCES IN MEMB Set up the app for a specific type of bridge
Design the bridge and analyze the data
Final forces in member
BERS WITH AN APP
With this process, it’s easier to catch the errors on an early stage and make changes
Test
d
rs
Make changes
Test
CRE
EATE & REFINE
5a.1 S 3d.3 S
BUILDING THE BRIDG Truss
Deck Glue every section
Cut members
Guides of each member
Rejoined the each spaghet trusses
GE
trusses. I glued tti directly to the
Join all the sections The way I glued the bridge, makes it unstable The humidity made the spaghetti softer
3d.2 S 3d.3 S
TESTING It is a strong structure -
It includes all the members needed to be strong
Bridge: 290g Weight: 5850 Ratio: 20.17
It broke only on one side in the middle
g 0g
Every other section stayed in great shape
I used a knife because the wide was bigger than the wood stick
- Strong structure - Missing member in the middle of the bottom part. - The trusses are extremely strong - Moving forward, I will add support in the middle of the deck