Brace Yourself A Proposal for Cofferdams

Prepared for: SMP - February 2012Prepared by Team Members: Jackson Cunningham (8), Jowe Tombi (8), James Hallgren (7), TK Kim (7)

Team Leader: Anna Sumner Mentors: LT Kurt Kesteloot, MSE, PE, USPHS and Andrew Roche, HDR Inc.  

Westside Middle School 8601 Arbor St. Omaha, NE 68124

Table of Contents

Project Problem Statement 1

The Problem 1

Brace Yourself 1

Journey 2

Idea Development 2

Design Development 3

Solution Development 3

Redesign 4

Design Development Part 2 6

Recommendations 10

Action Plan 13

Implementation 13

Team Organization 14

Lessons Learned 15

Acknowledgements 17

Bibliography 18

Appendix 19

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Project Problem Statement

The Problem

Cofferdams are unstable on slopes. They tend to roll down the slope as flood waters

provide resistance against them. Since cofferdams are used widely to hold back flood

waters, why not use them in a different setting?

Brace Yourself

According to the NASA Earth Observatory, over 520 million people worldwide are affected

by flooding each year. Flooding causes severe damage that takes a considerable amount

of time and money to repair. Our goal is to develop a sustainable bracing system to

increase the value of cofferdams so these dams can protect even more structures from

destructive waters.

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Journey

Idea Development

We started off in SMP class by thinking of problems that we could solve inside, and out-

side, of our community. We came up with about 50 ideas for the first round. Using filters,

we narrowed down our ideas. We used the following filters: “Is it a problem an engineer

could solve?”; “How many people will benefit?”; “Is it within our capabilities?”; and “Will we

be able to do it in our short time frame (one quarter of the school year)?” We also consid-

ered if there was a need for the project, how high of a priority it is, and whether or not it

was cost effective.

We demonstrated whether or not each idea was good by giving a thumbs up, or thumbs

down. By using the filters above, our list was narrowed down to 17 ideas. This list con-

sisted of ideas such as bicycle safety for street riders, problematic school desks, and a

compost pile for the school. (Appendix A)

From the list of 17 ideas, we now had nine very creative ideas. We continued the task of

narrowing down the list using our filters. FInally, we were able to narrow our list to four

possible projects.

Then we broke into small groups, and did some research on the remaining four topics.

This caused us to eliminate two ideas that have already been done, or the necessity level

being too low. We were down to finding a way to make the Keystone Pipeline safe, and a

way to protect critical buildings from dangerous floodwaters. After a heated discussion and

mixed opinions, we finally decided on flooding to be our topic.

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Design Development

After we chose our project topic, we began researching various subtopics in smaller

groups. The following topics we researched included current solutions, types of flooding

(see Appendix B), flood data, and the flooding at Fort Calhoun. Another separate group

wrote a rough draft of the synopsis and then shared it to the rest of the team to see if there

was anything to be added or changed.

 

After presenting our small group research findings to the team, we broke into our same

small groups again. We talked to our mentor, Kurt, about some questions we as a class

had. These included talking to OPPD personnel and people who were affected by flooding.

Solution Development

After completing the research, we began developing possible solutions. We identified with

the difference between residential and commercial, as well as temporary and permanent

options. 

 

We then split the class in half and shared our own individual solutions. We decided if it was

permanent or temporary and residential or commercial. We also looked at what type(s) of

flooding it would work for. After getting a variety of ideas, we decided we needed to

ground ourselves a little. (Appendix C)

The criteria that we used included the appearance, maintenance, sustainability, cost, etc.

We kept in mind who our client would be, the debris that would be in the floodwaters, and

what would be left after flooding. Our team split into four groups to develop one group idea

each. Two of these were commercial, and two were residential. We made a group decision

to stay with commercial. (Appendix D)

 

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The two commercial ideas were our top contenders: “The Dam Wall” and “The Grate Wall”.

One was a wall with a tube system running through it, and the other a pump and grate

system. We went through improvements, pros and cons, and redesigning stages with

these before we took a step back and looked at the big picture. 

 

According to our synopsis we wanted a solution that protects structures from dangerous

waters. There is already a solution, an Aquadam. So we called the Aquadam Company

and asked them if there was anything they felt could be improved on their design. They

felt they had a good product design, the double baffle system is not only effective but will

hold back more water than designed. We then asked them what would improve their de-

sign and Matt (the contact person) said the only problem is that they do not work on an

incline. So, we decided to design a bracing system that will help Aquadams stay in place

on a slope or hill. Matt sent us an idea of what he thought might work. See (Appendix E)

Redesign

Everyone on the team created a possible solution for a brace for an Aquadam. See (Ap-

pendix F). After we finished our prototypes, we tested their effectiveness. In our class-

room, we set up two tubs for testing, each tub had some gravel and tilted at approximately

a 35 degree angle. One by one, we put our braces in the tubs with a scale model of a cof-

ferdam. When it was set up, we poured water into the tubs to see how well it held back

the water.

The following pictures are some of the 21 braces we tested.

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Design Development Part 2The SMP class had ended and now we are the Competition Team.

Before we moved on, we discussed with our mentors the costs of materials that we would

need. We decided to use wood for our braces because it is the least expensive, but still

sturdy.

After we finished the technical stuff, we studied the possible solutions results from our test-

ing. We used what we learned from testing all the braces and combined ideas to create

three new designs. Once they were finished, we studied the force on our designs, did

static calculations, and began sketching a final design.

The following pages show our three final designs, price, and materials. Using RSMeans,

the cost for one linear foot of treated lumber (pine) is $0.73 per foot. They were then calcu-

lated for the total linear feet.

*Please Note: The cost of manufacturing is not included in the cost.

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Design A

This design is a triangle that allows the cofferdam to continue to move and adjust its baf-

fles. To prevent failure, two supports are used at the places where the most water pressure

is found.

Material(Treated Lumber)

Total Feet Price per Foot Price

2x4

2 units

29.25 $0.73 $21.35

58.5 $0.73 $42.70

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Design B

This design is a free standing design. It has many individual units, so that if one unit failed,

the others would remain standing.

Material(Treated Lumber)

Total Feet Price per Foot Price

2x4

4 units

28 $0.73 $20.44

112 $0.73 $81.76

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Design C

This design is basically a ramp. It simply cradles the cofferdam in front of it.

Material(Treated Lumber)

Total Feet Price per Foot Price

2x4

1 unit

34 $0.73 $24.82

34 $0.73 $24.82

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Recommendations

Currently, most commercial solutions to flood control involve the construction of sandbag,

dirt, or concrete levees. The levees, designed only to withstand the force of the water as it

rises, often fail due to the fact that levees can only hold back so much water. Once the

water breaches the levee it will seep. The water level can continue to rise which means it

is only a matter of time before the levee breaks.

When water moves at a pace of 4 mph, which is a brisk walking speed, it exerts a force of

66 pounds per square foot. When levees fail or are not in use, we recommend using a

trademarked cofferdam product such as Aquadam™ for additional protection against

flooding. However, the world is not flat and the cofferdams circular shape allows them to

move and shift to be effective. But, with a slope, they slide and roll. Our brace can be used

in addition to the trademarked cofferdams to make them effective on sloped terrain.

Material Selection

The chart below displays the factors we considered when selecting our bracing material.

Factors Possible Materials

Cost affordable Metal

Sustainability degradable Wood-recycled?

Weight light enough for one person to carry Fibers

Set up time/ease quick and easy

Ability of user pre manufactured or do it yourself -

easy to cut/assemble with tools

available

Time to get materials available locally not special order

Storage assembled or unassembled - space

Backup failure rate will it hold back the water

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Sustainable Principles

Our bracing system is designed with sustainability in mind, with the end of life being a high

concern. Our bracing is cyclic, consisting of reusable material as well as a material that is

biodegrade. It can be made with human power, electric power, or be produced in a factory.

Scrap 2x4’s are often the result of construction debris. This debris can be reused to con-

struct the braces. Other options are to combine new 2x4‘s with debris or use entirely new

material. The metal connectors are made of metal which can be recycled or broken down

naturally in the decomposition cycle.

Design Strength - will it hold up?In selecting the materials and designing a bracing system for a cofferdam the internal mo-

ments and internal shear forces (compression and tension) of resistance the wood pro-

vided was important. The shear and moment forces were also important when consider-

ing the calculations for where a brace should be placed to provide adequate support for a

three foot water filled bladder cofferdam and flood waters up to three feet. Appendix G

shows our calculations and considerations for selecting our material.

Cost

Using RSMeans, it was determined the cost for one linear foot of treated lumber (pine) is

$0.73 per foot. The cost was determined by drawing our design to scale. The total linear

feet could then be measured and calculated.

*The cost of manufacturing or fasteners not included

Material(Treated Lumber)

Total Feet Price per Foot Price

2x4

2 units

29 $0.73 $21.17

58 $0.73 $42.34

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Design Features

The following features were taken into consideration when selecting this design. This de-

sign can withstand the pressure of the water. When the water is at static flow, the force

will be the greatest on the bottom third front of the design. This is reinforced with a brace.

The cofferdam will not get punctured because pinch points do not exist. Storage will be

maximized by stacking each unit one on top of the other or side-by-side. The cost will

vary depending upon pre-manufactured units or units built by the owner. The sustainable

design is fast and easy to build. Finally, stability will be achieved when the cofferdam sits

on the front of the structure. To keep the brace from tipping from side to side, a beam is

placed on the back connecting the units. The beam will allow the user to shape the dam in

a straight or curved manner.

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Weakest point reinforced.

Beam

Action Plan

Implementation

We will submit our final prototype design to Aquadam™. If they do not buy into our idea,

then we plan to place it on a Do It Yourself (DIY) website. “Cofferdam+bracing” will be the

main keywords for a search. To place it on a DIY site, we will develop a set of working

drawings and materials list. See example below.

Assembly:- Wherever two boards meet, use 2 nails/screws.

- The 2 nails/screws should be side be side, going the width of the 2x4.

- When using, place the brace so that the outer edges of the braces are 6

feet from the ends of the Aquadam.

- For each Aquadam, used 2 braces connected by one beam.

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Team Organization

Since the team was extremely small, each member had multiple jobs. The chart below re-

flects the individual assignments each person was responsible for. In addition, team

members designed and built braces to be considered for our final solution.

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Lessons Learned

Jackson Cunningham

In SMP, I have learned many things. One of the more important things that I have learned

is the design process. The design process is a series of steps used to help you create a

new product or invention. There are eight steps to the design process: identify the prob-

lem, criteria and constraints, brainstorm solutions, generate ideas, explore possibilities, se-

lect an approach, build a model/prototype, and refine/redevelop the design.

This is the process that our team used throughout to come up with a solution.

Another thing that I learned in SMP is how to use different tools. For example, I had never

used an architect scale before. While in the model-building stage, we got to figure out

how to use the materials in front of us (wood, glue, pins, and index cards) so that we came

out with a usable model. We learned a lot about the pressures and forces that the water

would put on the brace, so we figured out how many and where to put braces.

James Hallgren

In the SMP class, I learned a lot about engineering this included: what research needs to

be done, the design process, and how to use a scale ruler. This new knowledge helped

me understand what it meant to be an engineer. I really enjoyed the class and hope to do it

again next year.

The SMP team was an extra-curricular activity. I enjoyed the meetings with our mentors

Andrew and Kurt. They taught me the importance of having a plan and understanding the

problem at hand. Thanks to this class, I have broadened my ideas of what I would like to

be when I grow up to include an engineer.

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TK Kim

In SMP, I’ve learned a lot. With my mentors, teachers and peers by my side, I learned more

about engineering and technology than any other class I’ve taken, including “Engineering

and Technology!” I’ve learned where the most force is on a flood, how different materials

are used in a flood brace, and that different floods call for different measures. I got to meet

new people (mostly 8th graders) that I wouldn’t have talked to at all. Now, I’m really

interested in SMP and might do it in 8th Grade or in High School!

My mentors showed us the formula for a flood force and the material cost for building

equipment. I was also shown the Design Brief and Design Process way before I had

“Engineering and Technology.” I got used to the short time on due dates for projects and

got to learn how to use different materials for some challenges. I had fun on the field trips

and contests we went on which helped me with our project!

Jowe Tombi

During SMP this year I have learned a lot. Not only in technical forms but also in moral

forms. I have learned what an engineer does. I have learned what it takes to lead a team

and reach a goal. We have had to overcome struggles of time, patience, and imagination. I

think that we have thoroughly worked as a team. I know that we have worked our very

best together as a team. SMP has made me smarter as well. We have imagined and

expressed our ideas in writing and voice. I have learned things that I most likely would not

have without this class. I feel I am a quick learner and the class was very fast paced. I

enjoyed learning and fixing problems. I am sad that it is ending so soon.

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Acknowledgements

LT Kurt Kesteloot, MSE, PE, USPHS 

For giving us his time, information, work, and patience to help us in whatever needed and for work-

ing with our school for several years. We enjoyed our tour to his workplace.

Andrew Roche, HDR Inc.

For giving his time, especially at 7am, and showing us the importance of pricing. For working with

us on sustainability - this information was crucial to the whole project.

Mrs. Sumner, Mr. Shabram, and Mr. Sumner

For being helpful and awesome teachers during the SMP class and competition team. They were

the only teachers who were doing this program and were the best ones for the job. Mr. Sumner got

us food for the long nights we had to spend working on this fun project.

The Development Team

For given us a great start on this project.

Mike The Bus Driver

For driving us around Lincoln, and around Omaha, NE. Without him, we couldn’t have made it to

Engineering Days.

Custodial Staff

For waiting for us to complete our work so they could do theirs.

Parents

For giving us our brain power and getting us to all the SMP functions.

Westside Middle School

For allowing us to work and meet in the Life Lab area.

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Bibliography

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"Force of Water on Dam Face." Geotechnical, Rock and Water Resources Library. Web. Feb. 2012. <http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=153>.

 "Flood Pictures #2." ReadReidRead. Web. Feb. 2012. <http://readreidread.wordpress.com/2011/05/11/flood-pictures-2/>.

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Podlogar, Megan, Sara Born, Kristin Field, Denali Lander, Lauren Cooper, Timothy Dittrich, and Denise Carl-son. "Dam Forces." Home - Www.TeachEngineering.org. Web. 17 Jan. 2012. <http://www.teachengineering.org/>.

Structural Element Calculators. Jonathan Ochshorn. Web. Feb. 2012. <http://courses.cit.cornell.edu/arch264/calculators>.

"Types of Flooding." ThinkQuest. Oracle Foundation. Web. Oct. 2011. <http://library.thinkquest.org/03oct/02054/floodtype.htm>.

"Types of Flood Barriers." Types of Flood Barrier. Web. Oct. 2011. <http://flood-barrier.co.uk/types-of-flood-barriers.html>.

Wood Handbook - Wood as an Engineering Material. Woodworking Information at WOODWEB. Web. 13 Feb. 2012. <http://www.woodweb.com/knowledge_base/Wood_Handbook.html>.

"Wood Strength and Stiffness." 2001. Encyclopedia of Materials: Science and Technology. Elsevier Science Ltd., 2001. Web. Feb. 2012. <http://www.fpl.fs.fed.us/documnts/pdf2001/green01d.pdf>.

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Appendix

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