1. Design Document
For
Project Tensioned Building Construction
Submitted by:
Luke Skelly
Rob Lewis
Dani Jackson
Diana C. Etheridge
Dr. Matthew Gordon
05/29/15
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Change History Page
10/02/14 Original document created
11/10/14 Changes made to document prior to End of Quarter Design Review
01/07/15 Changes made to document to incorporate winter interterm work
02/04/15 Changes made to document prior to Proof of Concept Design Review
03/07/15 Additional analysis including the floor, brackets, and rope and changes made to
reflect Dr. DeLyser’s comments.
05/09/15 Changes made to document for resizing of structure
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1. INTRODUCTION
1.1 Purpose
Structures are necessary all over the world from suburban homes to office buildings to
makeshift huts in the desert. In many cases, expense and speed are two very important
qualities that must be taken into consideration for these structures. This brings a need for a
simple building that will maintain stability in various conditions and can be easily built.
Because this is such a widespread problem in the world, many organizations have
systems already in place. The UNHCR (United Nations High Commissioner for Refugees)
commonly uses canvas tents when aiding refugees and internally displaced people [1]. While
these tents are inexpensive with only one unit costing $500 [2], living in one provides very
little dignity to the user. Despite over millions of internally displaced people and refugees,
there are very few international standards when it comes to humanitarian aid, specifically
with the use of temporary structures. There are some standards on general fire safety,
structural strength of tent fabrics and specifications of structures; however, these do not
provide much adequate guidance when it comes to environmental risks. Tents are also very
inefficient in terms of insulation. With just a thin layer of fabric between the interior and the
environment, the tents do not provide adequate shelter to the user. Heat is lost through
thermal conduction through the tent fabric, infiltration loss through leaks and holes, and heat
transfer to the ground. With such limited resources at their disposal, fuel is often an
extravagance that is neither affordable nor accessible. With fuel unavailable, alternatives
must be considered to keep the interior at a livable temperature. One such alternative that
should be considered is providing insulation within the structure [2].
Various patents have been granted describing a temporary structure that is more stable
than a tent. One such example was a structure that operates using tensioned cables as the
main framework with the cables tightened using a scissor frame design [3]. This design
however can be unstable and can be complicated to assemble. A building with a tensioned
cable frame that is simple to assemble is ideal. The design concept for this building, which
utilizes turnbuckles to tension the frame system was created and patented by Diana
Etheridge [4].
The purpose of this section is to describe the requirements to be met by the Tensioned
Building being designed for Diana Etheridge by the Tensioned Building Construction design
team. This document is intended for Diana Etheridge. It is also intended for the members of
the Engineering Design Class, the instructor, and Dr. Gordon, the faculty consultant for the
project.
The motivation for this projects stems from Diana Etheridge’s patent for a building
construction with an integrated tensioned support system [4]. This system allows for the
rapid and inexpensive construction of conventionally appearing buildings in areas with
limited resources (both economically and physically), limited access, or both.
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1.2 Scope
This document describes the design and subsystems of the Tensioned Building. The
system has been divided into 5 subsystems: the foundation system, the tension system, the
structural system, the enclosure system, and the insulation system. This document will
describe the conditions that are imposed on each system and provide a basis for the expected
conditions that this system will be able to support.
1.3 Definitions, Abbreviations, Acronyms
Compressive strength – the capacity of a material or structure to withstand loads tending to
reduce size; can be measured by plotting applied force against deformation.
PVC – polyvinyl chloride
R Value – a measure of thermal resistance used in building and construction industries.
Flexural strength - a material’s ability to resist deformation due to load.
Live load – temporary or moving load which includes considerations such as impact,
momentum, vibration, slosh dynamics of fluids and material fatigue.
2. APPLICABLE DOCUMENTS AND REFERENCES
2.1 Legal Documents
Building Construction for Tensioned Support System patent [4].
Wind or Fire Protection System for Structures patent application [5].
2.2 Project Documents
Tensioned Building Construction RFP [6].
Requirements document for Tensioned Building Construction design project [7].
3. ASSUMPTIONS AND DEPENDENCIES
This design is operating under the assumption that the structure will not be operating within
an extreme environment (i.e. sand, swamp, snow).
The tensioned system will be operated using turn buckles [4].
The tensioned system will be attached to the foundation using hooks and rings [4].
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4. DESIGN OVERVIEW AND SYSTEM DESCRIPTION
4.1 Top Level Context Diagram
A Top Level Context Diagram, shown in Figure 1, can be used to better understand the system
development process. All of the inputs are evaluated based on what is desired of the system.
The customer plays an important role in this because it is being designed for use by the customer
in the long run. The system must be easily assembled and transported so that it may easily be
distributed to the customer. It must also be inexpensive to manufacture to help keep costs down
and enable more customers to purchase the product. While function is necessary for the design
to work properly, it must also be aesthetically pleasing for the enjoyment of the customer. The
intended use of the system is for everything from manufactured homes and offices, temporary
shelters, and to military structures.
There are also business needs that the system must meet. Because of how easily assembled and
transported the system is, it will be more accessible for use in remote locations. From a business
standpoint, this would mean it is possible for more people to use the system, and by making
simple, effective, and easy to build shelter systems it is possible to provide shelter to those who
can’t afford it.
There aren’t many controls that change how we have to achieve the desired system specified in
the inputs. No standards, both nationally and internationally, have been found that would
influence the system. There is a huge window of opportunity for the system though, because
there is a global need for a low cost and easy to build shelter. The enablers include those
individuals and organizations that are directly involved in the design of the system. This
includes subject matter experts like Mrs. Diana Etheridge with Flex systems, and John Buckley,
who can provide insight into the details of the entire manufacturing process. This also includes
Dr. Matthew Gordon, the project advisor, who advises on the engineering analysis and overall
project ideas. The University of Denver Engineering Design Team is directly responsible for the
design and prototyping of the system. The design team will use all of the above information to
develop and implement a design for the Tensioned Building Construction system.
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Controls
-Windows of Opportunity
Need for low cost, easy to
build structures across the
world
Inputs
-Customer Needs
Easily assembled/transported
Inexpensive to manufacture
Aesthetically
pleasing/functional
-Intended Use
Manufactured homes/offices
& temporary shelters
Military structures
-Business Needs
Simple, effective, and easy to
build structures for sheltering
displaced families
Accessible in remote locations
System
Development
Process
Outputs
-Implemented Design
Tensioned Building
Construction
-Complete Design
Documentation
(includes requirements, test
reports, schematics, drawings,
process instructions, V&V
documentation)
Enablers
-Subject Matter Experts
Mrs. Etheridge
(Flexsystems)
John Buckley
(Manufacturing)
Dr. Matthew Gordon
(Analysis)
-University of Denver
Engineering Design Team
-Conceptual Prototypes
Figure 1. Top Level Context Diagram
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4.2 Functional Decomposition
Figure 2, shown below, is the system functional decomposition for the tensioned building
structure. Each functional block consists of the function that the system will have and the
requirements that the function will fulfill in brackets. The entire system has been divided into 5
separate subsystems: the foundation, the tension system, the structure, the insulation, and the
enclosure. The enclosure subsystem works with the insulation system to ensure that the structure
is insulated and protected from environmental factors. These environmental factors include
precipitation and wind. The enclosure system consists of two main parts with an exterior
enclosure material and an interior enclosure material. These two materials are connected to either
side of the insulation section. The tension subsystem works with the foundation to maintain
stability within the structure. This is done by connecting the tensioned cables directly to the
concrete foundational blocks. The tensioned cables within the tension subsystem must be easily
and quickly tensioned, this means that it should not require a large number of tools or strength to
tension the system. One main function of this design is ease of assembly and transportation of
the entire system. This system should be able to be shipped anywhere in the world. The system
should also not require extensive engineering knowledge in order to assemble it. All parts will be
fabricated and require few tools to assemble them.
Figure 2. Functional Decomposition
Overall System
Enclosure Subsystem
Enclosure protects interior
from environment (i.e.
snow, rain, sun)
[1.1, 5.1, 5.2, 5.3, 6.1]
TensionedSubsystem and
Foundation
Abilityto be Tensionedby
non-engineer within90
minutes
[3.2]
Tensionedto anchor
blocks to maintain stability
[2.1, 2.2, 3.1, 4.1]
Assembly
Portable/easilyshipped
[1.4, 1.5]
Construction doesn't
require anyengineering
knowledge
[1.5, 1.6]
Inexpensive Living Space
[1.2, 1.4, 1.7]
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4.3 Systems Diagram
The systems diagram in Figure 3 provides a detailed cross section view of the subsystems which
are integrated into the overall system. Each subsystem is shown in the cross section view and
labeled in the provided legend. The structure subsystem is shown by blue lines, which represent
the frame of the building. Running in between all of those blue lines is the tension subsystem,
shown with a single solid green line. This green line represents the path of the cable used to
tension the entire building. The red zigzag hatching shows the location of the insulation
subsystem. All of the insulation will be placed above the ceiling and in between the interior and
exterior walls of the enclosure subsystem, shown as the layer of black dots around frame. The
materials used for the inner and outer walls will differ, as explained in section 5.3, but because
each wall encloses the insulation and frame of the building they are part of the same subsystem.
The concrete blocks and the floor of the building are both part of the foundation subsystem,
because both are supporting the structure and enclosure subsystems. The concrete blocks must
be secured underground because they are supporting the entire load of the tension subsystem and
the structure. The cross beam in between the inner and outer wall of the structure doesn’t have a
cable running through it for tensioning.
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4.4 Functional Traceability Analysis
The table below creates a direct connection between the functions that were shown in the
functional decomposition above (Figure 2), and the requirements as given in the Requirements
document. This shows how each requirement ties into a function of the Tensioned Building
System. The requirements for the insulation and enclosure subsystems tie directly to the
building’s insulation and protection functions. The requirements for the tension, structural, and
foundation subsystems tie directly to the building’s ease of tensioning and stability functions.
The requirements detailing the shipping dimensions and ease of assembly tie directly to the
portability of the structure and the lack of engineering expertise functions. The requirements
detailing the cost of the system and the house-like quality tie directly to the inexpensive living
space function.
Table 1. Functional Traceability Analysis
Requirements 5.x.x
Function 1.1 1.2 1.3 1.4 1.5 1.6 2.1 2.2 3.1 3.2 4.1 5.1 5.2 5.3
Protectionfromenvironment X X X X
Easily/Quicklytensioned X
Anchorblocksfor stability X X X X
Portable X X
InexpensiveLivingSpace X X X
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4.5 System Traceability Analysis
The table below depicts the system traceability analysis, which shows which
requirements are connected to each Subsystem. The first section of requirements (1.1-1.7)
describes general requirements that the entire system must conform to. Each subsequent section
of requirements refers to a specific subsystem and can clearly be seen in the table below. The last
section of requirements (7.1 and 7.2) refers to second-tier requirements or requirements that are
not necessary, and should only be implemented if time and money allow.
Table 2.System Traceability Analysis
Requirements
System 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2.1 2.2 3.1 3.2 4.1 5.1 5.2 5.3
Foundational X X X X X X X X X
Tensioning X X X X X X X X X
Structural X X X X X X X X
Enclosure X X X X X X X X X X
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4.6 System-Level DesignAlternatives
Designs can be modified on a system level by adjusting the size of the overall structure.
This can be done to either increase functionality or decrease cost. Different sizes of this system
will result in different organizations of the structural beams. Because longer beams will buckle
under large loads, as the length of the overall system is increased, the number of cross sectional
beams will need to be increased. This can be seen in the Figures 5 and 6 below. The standard
size of the structure, which was used for all analysis of the structure, is seen in Figure 4. This
structure requires one cross-sectional beam to be added in the center of the structure. This is
done to support the weight of the roof. If a 30’ long building was desired by the customer then an
additional cross-sectional beam within the interior of the structure would be required. Cost of
construction per square foot will be given to give different size possibilities.
Figure 4: 13’ Structural Current Design
85.25
134.375
15.625
12.00
36.00
147.375
18.00 18.00
36.00
119.4375
33.00
Full Assembly
Tensioned Structure System
WEIGHT:
A3
SHEET 1 OF 1SCALE:1:50
DWG NO.
TITLE:
REVISIONDO NOT SCALE DRAWING
MATERIAL:
DATESIGNATURENAME
DEBUR AND
BREAK SHARP
EDGES
FINISH:UNLESS OTHERWISE SPECIFIED:
DIMENSIONS ARE IN MILLIMETERS
SURFACE FINISH:
TOLERANCES:
LINEAR:
ANGULAR:
Q.A
MFG
APPV'D
CHK'D
DRAWN
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4.7 Budget Overview
The preliminary budget for the design process was used as tool to do quick cost analysis.
This was done by splitting up the budget by sub-system, and then inserting separate options with
different units and prices to determine quantities and total cost. This allows for different options
to be swapped in and out in order to see how different design alternatives will affect the budget.
The source and relevant specs were also included for easy reference. The functionality of the
budget was crucial when analyzing design alternatives to ensure that the options chosen based on
the quantitative ranking scale are not going to put the design over budget. The budget does not
take into account donated materials obtained at this point in time. As more donated materials are
obtained, the cost will be subtracted from the working budget but will still be included in the
overall cost for reproduction.
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4.8 Limiting Requirements
The most limiting requirements within this project are requirements 5.1.2 and 5.1.4 and the 5.5.0
section of requirements. Requirement 5.1.2 constricts the budget to $2000.00. This requirement
has severely limited the materials that are available for this project, and has made acquiring some
necessary components of this project difficult. There were many times when the ideal material
was not available for use due to limited expenses. An example of this is using aluminum to
manufacture brackets, when a different material such as steel would be stronger and more stable.
The manufacture of these brackets was also impacted by the limited budget. Outsourcing the
manufacture of the brackets would increase the quality of the product; however, there is no room
in the budget for this. This means that all brackets must be manufactured in-house.
Requirement 5.1.3 constricts the size of the materials when shipped. This is also done to restrict
transportation costs. This requirement made a large impact on the weight and size of the
materials that were chosen. Similar to the limitations with the cost, lighter materials were chosen
over heavy materials such as aluminum over steel.
The requirements stated in section 5.5.0 of the Requirements document dictate the enclosure that
surrounds the structure. Requiring a door and window that are separate from the enclosure
material (still connected to the enclosure but not the same material) has restricted the budget.
Having the door and window be interfacing with the enclosure material requires more of the
budget to be allocated to the enclosure subsystem. The system used to connect the enclosure to
the structure required a lot of considerations to be made about the system as a whole. It required
deciding how the enclosure would be deployed around the structure, how the enclosure could be
maintained in tension around the structure, and how the enclosure would be connected to the
floor of the structure.
Overall, these requirements caused many different design alternatives to be considered to follow
the requirements, both set by the customer and by the project team.
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4.9 Key Technical Issues
The key technical issues of this project are the interfaces between the subsystems and
between the components of each subsystem. A good example of this is the brackets which
connect the PVC beams within the structural system. These brackets experience the majority of
the load and therefore are critical in design and manufacturing. Another example of this is
connecting the structural and tension subsystems to the foundational subsystem. The majority of
these connections will utilize the setting concrete to hold the subsystems in place. Another key
technical issue is connecting the exterior and interior to the structural subsystem. While Silicon
will be used to connect the fabric to the PVC, the application will take some skill. Overall these
interfaces will need to be closely monitored to ensure that the overall structure is stable.
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4.10 Impact on Society
The details of the impact that this design will have on society can be found in Appendix A. This
will discuss the following considerations of the design: economic, environmental, social,
political, ethical, health and safety, manufacturability and sustainability.
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4.11 Fabrication Plan
The fabrication plan, which details the fabrication of each of the parts of this design, can be
found in Appendix D.
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4.12 Project Location
For this project, a fairly large building location is required. Finding a location on campus was
the ideal case, because it would provide convenient access for the design team. Unfortunately,
due to the size of the structure and the digging involved for building the foundation subsystem,
no suitable location on campus was available. Alternative locations for building the project were
considered, and after speaking with John Buckley, the machine shop manager, he recommended
contacting Justin Wiley with the University of Denver Applied Research and Technology
Institute (ARTI). ARTI has a location off campus called the East Range, located east of Denver
on approximately 130 acres of open range land. Justin put us in contact with the East Range
Manager Donald New, and after meeting with him he approved building on the property. An
aerial view of the property location relative to Denver is shown in figure 9. Figures 10 and 11
show more specific aerial views of the exact building location.
Figure 9: Building Location relative to Denver, CO.
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Figure 10: Aerial view of Building Location on Property.
Figure 11: Aerial view of exact building location on property.
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Figure 11 shows the exact building location of the Tensioned Structure System. This location is
ideal for building on the ARTI east range property due to the easy access of bringing materials to
the location. The location is also chosen since the ground is level and doesn’t require any
leveling work to the ground.
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5. SUBSYSTEM/MODULE DESCRIPTION
5.1 Foundation System
This subsystem includes the foundational concrete blocks that are below ground, the system of
rods that connect the blocks, the J hooks that attach the rope to the blocks, and the base of the
floor. The requirements that affect this subsystem are 5.1.3, 5.2.1 and 5.2.2.
5.1.1 DesignAlternatives
The location of the anchor blocks was based on which design was the most cost efficient,
number of blocks needed in tension, as well as the amount of blocks needed. One key technical
issue that arose for the anchor blocks was the connection between the anchor blocks. This
includes whether or not the cables tensioning the blocks to each other will be underground and
how they’re connected to the foundational system (floor base).
The tensioning criteria entails the amount of blocks needed to be in tension, which affects
the amount of turnbuckles and tensioning rope needed and accounting for the advantage of
having a shared foundation block between the inner and outer wall vertical supports. The
different options for the location of anchor blocks varies the amount of blocks needed in tension
between 6 and 22 blocks.
The ease of implementation criterion entails the amount of anchor blocks placed to
provide a base for the structure. From the different design options shown in the table above,
there will be 6 to 17 blocks to anchor the structure to the ground.
For weighing the importance of each criterion, the cost of constructing the blocks was the
most critical criterion due to having a limited budget. The ease of implementation was the second
most critical criterion. This is due to the desire to limit the amount of material needed. The
amount of blocks in tension was considered, but not very much. This is due to the cost of
turnbuckles and tensioning rope being very inexpensive and the ability for the structure to be
completely tensioned not being affected very little by the tensioning between the anchor blocks.
The material of the floor base was based on which design was the most cost efficient,
compressive strength of the material, and the time required to construct the base.
Table 3. Foundation Design Matrix
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When analyzing the most cost effective option, creating a floor base out of wood is
almost twice the cost as concrete. Although the concrete is the most cost efficient, the wood
would take roughly 12 hours to construct while the concrete would take almost 48 hours due to
the concrete having to set and dry for over 24 hours. The compressive strength of the floor base
measures the material’s ability to not deform under large loads. The compressive strength for the
concrete is 30MPa, whereas wood is only 20MPa at its strongest point and 5MPa at the weakest
points. Thus the concrete provides a much greater structural support than wood.
When weighting the importance of the criterion, the cost was the most important. The
compressive strength was the second most important criteria due to the floor base’s requirement
of supporting at least 1000 pounds of weight. The amount of time required to construct the floor
base was not critical to the design, but it was for the building time.
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5.1.2 Selection of Primary Design
The selected anchor block layout design was a shared anchor block between inner and
outer vertical posts. This design is the most structurally stable since there is no room for
movement between the inner and outer supports making the structure as strong as possible. For
each primary anchor block there is a secondary anchor block secured to it to increase stability of
the overall structure.
Each corner block will hold three vertical posts for the structure. The basic CAD drawing
for the concrete portion of the corner block can be seen below.
Figure 12. CornerFoundational Block CAD
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Each of these blocks will be interconnected using the ½” polypropylene wire. The
following figure shows the connection of each of the primary foundational blocks.
Figure 13. Primary Foundation Blocks with Tension
This is just a simple outline of the foundation. A closer look will show how these pieces
are assembled together.
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Figure 14. CornerFoundation Block Assembly
This diagram shows how the foundation blocks will be connected. There will be three
aluminum joints connected to the primary block. These joints will be connected to the concrete
while it is drying so that they are permanently inside. These joints will be submerged into the
concrete at least 3 in.
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The selected floor base material was concrete. This is due to concrete having much
greater compressive strength than wood with only being half the cost of a wood base. The
following diagram shows the basic outline of the concrete slab that will act as the floor.
Figure 15. Concrete SlabCAD
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The following diagram shows how the concrete flooring will match up with foundational
blocks. The above blocks will go into the holes seen in the diagram below. The floor will be
level with the ground and occupy 2” of the space below the surface. Then the top of the
foundational blocks will be flush with the floor, however there will be a space in the floor for the
PVC and tensioning rope. Each foundation block is 1’ deep.
Figure 16. Concrete Slabin relation to Ground
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5.2 Tension System
This subsystem includes the turnbuckles and rope. The requirements that affect this subsystem
are 5.1.3 and 5.3.1.
5.2.1 DesignAlternatives
Table 4. Tension Design Matrix
The type of turnbuckle chosen was based on cost per turnbuckle, the tensile strength of
the turnbuckle’s material, and the working load limit of each type of turnbuckle. The working
load limit and material’s tensile strength both account for the strength and durability of the
turnbuckle. Size was also considered since it must be capable of fitting inside pipes with
diameters less than 6”. This neglects any turnbuckles that require a wrench or other tensioning
tool.
The tensile strength of the turnbuckle’s material accounts for the amount of force it can
withstand without the material itself deforming or failing. The working load limit measures how
many pounds of force the turnbuckle can hold before the possibility of failure. This would be the
threaded connection becoming distorted and failing.
When weighting the chosen criterion, the cost was the most critical in the selection
process. The working load limit was weighed almost as high as the cost, but not as high due to
all the options having a minimum of 400 pounds working load limit. The material tensile
strength was weighed the least. This is due to the turnbuckle’s very high probability of failing
due to an excess of a working load before failing due to an excess tensile stress on the material
itself. This says that the turnbuckle components will become unthreaded before the entire
turnbuckle is strained or stretched.
The tensioning rope material chosen to implement in the design was based on the cost,
breaking strength, and shipping weight criterion. The cost and shipping weight don’t directly
affect the structure, but do affect the budget and requirement 4.1.4 in the requirements document.
The breaking strength of the material is the amount of pounds of force it can withstand before
encountering the possibility of failure, which is critical for the strength and durability of the
structure. Failure in the tensioning rope will result in an inefficient structure and the possibility
of additional structural failures.
The cost and breaking strength criterion were both weighted for 2/5th of the overall
selection weight. The breaking strength is most critical, but the cost is also substantial since the
difference in prices of the materials is up to $800. The price difference inhibited certain materials
to be plausible due to budgeting constraints. The shipping weight was taken into account;
however, it wouldn’t inhibit any materials from being able to be used.
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5.2.2 Selection for Primary Design
For the turnbuckles, the galvanized steel hook and eye turnbuckle was chosen to
implement in the design. The hook and eye turnbuckle cost only $2.90 each, which is 1/5th the
price of the second cheapest option. It has a working load limit of 700 pounds. Although it cant
support as large of a load as the J-hook lever load binder turnbuckle, it still provides a sufficient
safety factor greater than 2.
½” Polypropylene rope was chosen as the tensioning material. The ½” polypropylene was
the most cost efficient other than the 3/8” polypropylene rope, but has a 3800 pound breaking
strength compared to only 2450 pound breaking strength for the 3/8” rope. This provides the
structure with 1350 additional pounds of force until failure, with only a $30 price difference.
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5.3 Structure System
This subsystem includes the rods that guide the tensioned rope throughout the system,
and the brackets that connect the rods. The requirement that affects this subsystem is 5.4.1.
5.3.1 Structure DesignAlternatives
Table 5. Structure Design Matrix
The material chosen to use as the structural support material was based on the cost, yield
strength, and shipping weight criterion. The cost criteria is crucial due to desired material being
too expensive, such as the 2” aluminum piping being priced at $4024 with an overall budget of
half that cost. The compressive strength is the amount of compression the material can withstand
before failure. Due to the support structure being in tension, the structural support material is in
compression at all times, unless not tensioned. The shipping weight was a chosen criterion due to
shipping and packaging constraints.
The cost and compressive strength were weighted the greatest. The cost was weighted
high due to specific desired materials being too high in cost. The compressive strength was
highly weighted due to structural safety purposes. Since the chosen material will endure most of
the environmental forces, it is required to withstand the greatest possible amount of compression
when the turnbuckles and rope are fully tensioned. The weight was considered due to shipping
purposes.
The brackets connecting the structural support materials selection criterion were cost,
yield strength, and shipping weight. There are 38 different brackets implemented into the design
consisting of 62.42 feet of tubing for fabrication. The yield strength was chosen as a criterion to
ensure structural safely. Failure in the brackets will result in failure of the entire structure.
Shipping weight was considered for shipping purposes.
For weighting the criterion, the cost was weighted the greatest due to the price of 56.25
feet of metal tubing. The cost difference of the materials selected to quantitatively choose from
was $120 to $800. Since $800 is more than what the budget is capable of allotting, this was a
critical criterion. Since the three different selected possible materials are metals, the yield
strength for the different material was weighted the same as the shipping weight criterion, which
is 1/5th the total weight.
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5.3.2 Key Technical Issues
Key technical issues for the structure system consist of the brackets connecting PVC
frame pieces together, installation of the door, and installation and support of the windows. For
the brackets, 2 ½” pipe will be used so that the 2” PVC can easily fit inside the brackets. A
stopper will be created within the circular bracket base so that the PVC sits well inside the
bracket. The brackets will be made from aluminum so that the angled pieces can be welded into
the correct angles upon fabrication. Stress analysis on each bracket will be done. The brackets
have been designed to account for all key technical issues identified.
A doorframe will have to be built to install and support the door for the structure. The
doorframe will be constructed out of either wood or metal, whichever is more reasonable in cost
and lightweight. One side of the doorframe will be attached to the middle PVC piece on the side
of the structure to provide extra support for the door and frame. There are two options for the
installation of the windows for the structure. The first option is a floor to ceiling window, which
would be supported by the floor, top PVC cross piece, and horizontal pieces on the sides of the
window for additional support. The second option is to cut a piece out of the outer wall material
and adhesively stick the window frame to the wall directly with the window consisting of a very
light weight material such as thin Plexiglas. The second option is preferred; analysis on the
amount of stress the walls can hold before failing will be completed.
Figure 12. Joint Locations
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Figure 21. Hinge Joint
Figures 13.21 are the designs for the different brackets corresponding to the labeled bracket
locations in figure 12. Each of the brackets is made out of 2.5” outer diameter metal tubing with
an inner diameter of 2.4”. The brackets were constructed so that all 90-degree angle connections
are welded together for a greater structural support and the other angle connections are attached
using the hinge assembly. The hinged connections are used for ease of fabrication. There are 24
brackets implemented into the design. There are open sides of the brackets to allow access to the
turnbuckles located within them. The brackets allow access to the turnbuckles when either fully
open or fully closed, which is a difference in length of 4.5”. On the ends of each connection for
the brackets before the opening for the turnbuckle access points, there is a small stopper ring
inside the tube in order for the PVC to have no movement when connected to the brackets.
Tables 6 and 7 below show the bracket material usage for each bracket (Joint). This includes
accounting for every pin, hinge, bolt, nut, washer and foot of aluminum tubing. Table 6 accounts
for the length of tube for each bracket in inches and feet and the total tube length used per
bracket number. The bottom right is number is the total tubing used in feet for the fabrication of
all brackets. The bottom right is the total tubing used for the fabrication of all the joints in feet.
Table 7 accounts for the different hardware used in each joint number and the bottom is the total
material used for each piece of hardware in all brackets fabricated.
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5.3.3 Selection for Primary Design
2” PVC was chosen as the structural support material due to affordability and having a
yield strength great enough to ensure structural stability. Aluminum pipe has the greatest
compressive strength and would be the most structurally safe, but was too expensive to
implement in the design. The 2” PVC is half the price of 3” PVC while having a 55MPa
compressive strength, which isn’t much less than the 63MPa compressive strength of the 3”
PVC. 1 ½” PVC was cheaper than the 2” PVC by only $75 and has a compressive strength of 42
MPa. Since the structural support material withstands the greatest stress, it was determined more
important to pay $75 more for 13MPa more in compressive strength.
309 Stainless Steel was the chosen bracket material for a variety of reasons. It is the
substantially most cost efficient material due to our ability to get recycled 309 Stainless Steel for
$2 per pound making 65 feet cost only $136. 309 Stainless Steel is also the easiest metal to weld.
Since the welding process is the final step in the bracket fabrication process, weaker metals are
easier to burn holes in resulting in a loss of materials and time. The stress concentrations on the
structure from stress applied on the sides and top of the structure due to heavy winds are on the
brackets. The material has a yield strength of 621 MPa, making it the safest material to use.
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5.4 Enclosure System
This subsystem includes the material that surrounds the interior, the material that surrounds the
exterior, the floor, the windows, the door, and the roof. The requirements that affect this
subsystem are 5.5.1, 5.5.2, and 5.5.3.
5.4.1 Enclosure Design Alternatives
Table 8. Enclosure Design Matrix
The outside enclosure material selection criterion was cost, shipping weight, and
breaking strength using the grab method. Cost and shipping weight don’t affect structural
stability, but are necessary to consider due to budgeting and shipping constraints. The breaking
strength is critical since the outside enclosure material will be affected the greatest by
environmental conditions. The breaking strength grab method is measured by the amount of
pounds of force the material can be pulled before deformation and failure. It’s a more specific
way of measuring the yield strength for thin fabrics.
Since all the chosen materials are similar in price and weight varying from $317-$447
and 23lbs-35lbs, which are not substantial differences, the breaking strength was weighted the
greatest for the chosen criterion. Cost and weight are each weighted one third the amount of the
breaking strength.
The interior enclosure material selection criterion was cost, shipping weight, and
breaking strength. It’s the same selection criterion as the outside enclosure material. The interior
material doesn’t endure as much force and environmental conditions as the outside enclosure
making the weighting of the criterion more on the cost and less on the strength. For the amount
of material needed, the price difference in the selection of materials was greater than the outside
enclosure material, varying in price by $85. The cost and breaking strength were both weighted
at 0.4 and shipping weight at 0.2.
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5.4.2 Key Technical Issues
There are two key technical issues present in the enclosure system. These issues consist of
easily installed connection of the walls to the frame and the installation of the structure’s roof.
For connecting the walls to the structure frame, Adhesives will be used to stick the walls to the
bottom and side of the base floor of the structure as well as the sides of the PVC that are in
contact with the walls. Alternative approaches to this issue that have been researched consist of;
creating a sleeve sewing outside walls together to perfectly fit the structure frame and sliding the
walls over the structure with connection at the bottom of the floor base or frame. Another
approach is connection of walls to the anchor blocks by means of hooks for the connection.
For the roofing installation issue, we have explored possible materials to use for the roof.
Tyvek or nylon sheets will be used for the base of the roof if cheaper materials are not readily
found. Duro-last Shingle-Ply roofing system will be incorporated on top of the base roof
material by means of adhesives to provide waterproof insulation and give it a more home like
look. Further analysis will be completed on materials that provide as much insulation and
support as Tyvek or nylon with a lower cost.
Table 9. Forces on Walls
WindSpeed= 25 mph
Pressure = 55 Pa
Force = 613.162 N
Wall Area:11.1484 m^2
A wind speed of 25 mph creates a pressure of 55 Pa. For the wall with the greatest area
without supports, which is the end walls, has a wall area of 11.1484 m^2. This is where the wall
material will see the greatest forces.
Table 10. Fabric Properties
210 Denier Fabric 70 Denier Fabric
X-Direction(Warp)
Y-Direction
(Fill)
X-Direction
(Warp)
Y-Direction
(Fill)
BreakingStrength 200 lb/in. 150 lb/in. 65 lb/in. 55 lb/in.
Max Force before
Failure: 13.34 KN 5.34 KN 3.47 KN 1.96 KN
The 210 is the exterior wall material and the 70 Denier is the interior wall material. The
table shows the breaking strength and max force before failure. The 210 Denier Fabric, since it’s
the exterior enclosure material, sees the majority of environmental forces. These numbers say
that the wall can safely have up to 5.34 KN of force before failure. This is a greater number than
will be seen in the building environment.
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5.4.3 Selection for Primary Design
70 Denier Ripstop Nylon Fabric was chosen to implement as the interior wall material.
The Litelok nylon fabric has the greatest breaking strength, but is $70 more expensive than the
chosen material. Litelok fabric also has a breaking strength two times greater than 70 Denier
Fabric, but is not necessary to have a 150 pound breaking strength for the chosen application
where 75MPa is sufficient for structural stability. Tyvek is similar in price and strength to 70
Denier Fabric, but is a heavier material, thus 70 Denier Fabric is the most suitable material to
use.
210 Denier Double-Wall Ripstop Nylon, Polyester, DMC material was chosen as the
outside enclosure material. Although it is the most expensive costing $447.30, its breaking
strength is 205 pounds. The material with the second greatest breaking strength, 1.9oz Coated
Ripstop Nylon Fabric, is only 115 pounds. Due to durability and the longevity of the structure,
the increase in strength outweighed the price difference compared to the other choices. Although
210 Denier Double-Wall Ripstop fabric was chosen, due to the supplier being out of stock of this
material since March 25th and is still not in stock the interior enclosure wall material is used for
the outside enclosure wall material as well.
47. Tensioned Building Construction 05/29/2015 Page 46 of 106
6. REFERENCES
[1] UNHCR – UN Refugee Agency Shelter, n.d., “Shelter.” from
www.unhcr.org/pages/49c3646cf2.html
[2] Manfield, P and Ashmore, J and Corsellis, T. 2004. “Design of humanitarian tents for use
in cold climate” Building and Research Information, 32(5) pp. 368-378
[3] Ziegler, Theodore R. Mechanically deployable expandable and collapsible structure and
method for deploying structure. World Shelters, Inc., assignee. Patent 7533498. 19 May
2009. Print.
[4] Etheridge, Diana C. Building Construction with Tensioned Support System. Diana C.
Etheridge, assignee. Patent 5,930,971. 3 August 1999. Print.
[5] Etheridge, Diana C. Wind or Fire Protection System for Structures. Diana C. Etheridge,
assignee. Patent Application 14/311,634. 23 June 2014. Print.
[6] Etheridge, Diana C. (2014) Request for Proposal. University of Denver’s School of
Engineering and Computer Science.
[7] Lewis, Robert, David Dredge, Danielle Jackson, and Luke Skelly. Tensioned Structure
System Design Document. 6 October 2014. Print.
[8] www.engineersedge.com/civil-engineering/concrete/floor_slab_stress.htm
[9] www.aboutcivil.org/flextural-strength-of-concrete.html
[10] Bolin, B., 2006. Race, Class, Ethnicity, and Disaster Vulnerability. In Rodríguez, H.,
Quarantelli, E. L., and Dynes, R. R. (eds.), Handbook of Disaster Research. New York:
Springer, pp. 113–129
[11] Enarson, E., Fothergill, A., and Peek, L., 2006. Gender and disaster: foundations and
directions. In Rodríguez, H., Quarantelli, E. L., and Dynes, R. R. (eds.), Handbook of
Disaster Research. New York: Springer, pp. 130–146
[12] Girard, C., and Peacock, W. G., 1997. Ethnicity and segregation: post-hurricane relocation.
In Peacock, W. G., Morrow, B. H., and Gladwin, H. (eds.), Hurricane Andrew: Ethnicity,
Gender and the Sociology of Disasters. New York: Routledge, pp. 191–205.
[13] Dash, N., Peacock, W. G., and Morrow, B. H., 1997. And the poor get poorer: a neglected
black community. In Peacock, W. G., Morrow, B. H., and Gladwin, H. (eds.), Hurricane
Andrew: Ethnicity, Gender and the Sociology of Disaster. London: Routledge, pp. 206–
225.
[14] Yelvington, K. A., 1997. Coping in a temporary way: the tent cities. In Peacock, W. G.,
Morrow, B. H., and Gladwin, H. (eds.), Hurricane Andrew: Ethnicity, Gender and the
Sociology of Disaster. London: Routledge, pp. 92–115.
[15] Bolin, R. C., 1993. Household and Community Recovery After Earthquakes. Boulder, CO:
University of Colorado Institute of Behavioral Science.
[16] Sprung, n.d., “Comparison Matrix.” from http://www.sprung.com/sprung-
advantage/comparison-matrix
[17] Manfield, P and Ashmore, J and Corsellis, T. 2004. “Design of humanitarian tents for use in
cold climate” Building and Research Information, 32(5) pp. 368-378
[18] Select Bipartisan Committee to Investigate the Preparation for and Response to Hurricane
Katrina, February 15, 2006, “A Failure of Initiative.” 2nd Session of 109th Congress U.S.
House of Representatives
48. Tensioned Building Construction 05/29/2015 Page 47 of 106
[19] Cohen, C. and Werker, E., 2008, “The Political Economy of ‘Natural’ Disasters.” Working
paper.
[20] Environmental Building News, 1993, “Cement and Concrete: Environmental
Considerations.” Volume 2, No. 2
[21] Fluegel, L. and Rein, B., 1989, “Arc Welding Safety.” University of Arizona Cooperative
Extension.
[22] McDowell, M. A., et al. October 22, 2008, “Anthropometric Reference Data for Children
and Adults: United States, 2003-2006.” National Health Statistics Reports 10.
[23] Safety Info, n.d. “Concrete Mixing and Placement.” from
https://www.safetyinfo.com/guest-library/materials/written-safety-programs/concrete-
mixing-pouring-safety-program
[24] Sawisch, M., n.d., “Deadly CO Emissions: How to Prevent Carbon Monoxide Poisoning.”
from http://www.electricgeneratorsdirect.com/stories/7-How-to-Prevent-Carbon-
Monoxide-Poisoning.html
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7. APPENDICES
Appendix A: Impact on Society
Appendix B: Foundation System Analysis
Appendix C: Structural System Analysis
Appendix D: Fabrication Plan
50. Tensioned Building Construction 05/29/2015 Page 49 of 106
Appendix A: Impact on Society
Introduction
Because one of the main uses of the Tensioned Building Construction project is for
humanitarian aid purposes, the project will have a large impact on society in many different
ways. Disasters occur throughout the world and in many different circumstances. In almost every
case of a natural disaster, people are forced to leave their homes, whether due to structural
failure, flooding, or continuous dangerous conditions. With a mass exodus of people fleeing their
homes, a means of temporary housing is ideal. Temporary housing is ideal because of the few
long-lasting effects that it has on the environment, while maintaining a safe living space for those
occupying it.
Social
The Tensioned Building Project will have an enormous social impact through its use in
humanitarian aid. One of the main concerns in prevention of natural disasters is the
disproportionate effect that they have on the members of society with regards to the
socioeconomic status of its members. Because of their lower socioeconomic statuses, people are
more likely to live in hazard-prone locations and physically vulnerable structures [10] [11]. Once
these people are subjected to a natural disaster in which they require aid, the lower-income
people often have fewer resources on which to draw for recovery. Because of this, those families
are unable to return to their homes for much longer than those of a higher income and require
temporary housing for a longer amount of time [12]. This can have a huge impact on a society. If
there is a lack of alternative housing after the destruction of a residential area within that same
area, then people are more likely to move to a new location that has not been as severely
affected. In one case, after Hurricane Andrew, many homeowners left the Miami area with
population losses up to 31%. Many of those unable to leave were forced to remain in severely
damaged or condemned buildings [13] [14]. Through the use of the Tensioned Building Project,
temporary housing can be deployed in many different disaster-stricken areas, preventing the
societal collapse of that area.
Economic
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Because the majority of those that require temporary housing are of lower socioeconomic
statuses, as stated in the above section, the economic recovery of stricken areas is significantly
slower. It was seen that the larger the family and the lower the socioeconomic status, the less
likely the household was to receive disaster relief, have adequate insurance or receive adequate
aid despite being more likely to require it. Households with lower incomes, the number of which
is often much greater than the number of households with high incomes, are unable to reenter
society and provide for their families. It was also seen that those who suffer the greatest loss to
material resources are likely to experience the most psychological distress [15]. The Tensioned
Building Construction project could be used to speed up the economic recovery of a disaster-
stricken area due to its inexpensive nature. While some modifications can be made to enhance
either the insulation quality, size, or stability these require an increase in price. The base
specifications of the structure remain under $10 per square foot, while most temporary structures
today range between $25 and $55 per square foot [16]. While these structures are not identical in
nature, they are manufactured for the same purpose of temporary housing.
Ethical
An ethical theory is the theory that the rights set forth by a society are protected and
given the highest priority. One of the rights set by our society is the right to shelter, which was
shown during Hurricane Katrina when the government, through FEMA, attempted to house all
those displaced by the storm. Because FEMA was unable to do so with the materials at hand,
ethically they needed an alternative solution. Because the Tensioned Building is inexpensive and
quick to produce this would have benefited society’s ethical belief that those people had the right
to shelter
While the Tensioned Building is more inexpensive then most temporary structures, it is
more expensive than the average tent. The UNHCR (United Nations High Commissioner for
Refugees) commonly uses canvas tents when aiding internally displaced people [1]. While these
tents are inexpensive with only one unit costing $500 [17], living in one provides very little
dignity to the user. Tents provide no dignity because the user does not feel adequately housed,
nor is the structure properly insulated. A large amount of heat is lost through both the ground and
the canvas fabric. Having a firm structure with adequate housing provides a dignified space
52. Tensioned Building Construction 05/29/2015 Page 51 of 106
where displaced people can live until more permanent housing can be arranged. Most
considerations of ethics take into consideration the need to do the most good. Providing dignity
to those in need falls under this category.
Political
The impact that disaster relief has on politics can be seen throughout the world. When
there is a natural disaster somewhere, that area is overwhelmed with humanitarian aid and,
depending on the location, this aid can come from within the country or from another country
altogether. Within many different regions of the world, contingencies such as levees are put in
place by the government in cases of natural disasters. One example that shows these
contingencies within the United States is during Hurricane Katrina which saw one of the most
controversial disaster relief responses seen in modern day times when the levees failed to hold
back the higher water levels in New Orleans, Louisiana. Some relief problems that were
encountered with Hurricane Katrina were that the buildings used as temporary shelter after the
storm were not prepared for that type of use, there was no database of available relief and over
200,000 trailers were ordered as temporary homes for the displaced people of the southern region
of the United States but only 6000 units could be manufactured per month [18]. These kinds of
problems are encountered all over the world, but in many cases the outcome could have been
much worse. After Hurricane Katrina over 85,000 hotel rooms nationwide were utilized as
temporary housing; however, this is not always an option in poorer countries and more remote
areas [18]. The Tensioned Building would alleviate some of these problems with its simple and
inexpensive design, while maintaining structural integrity.
Another impact that this design could have on politics is its ability to allow poorer
countries to provide aid to its own people in times of need. Often times these countries rely on
international humanitarian aid and will under-invest in disaster prevention because they know
they will be bailed out of these types of situations by wealthier countries [19]. While the
Tensioned Building will not entirely fix this problem, having an inexpensive system of
temporary housing could allow a country to utilize its finances to better aid their own citizens. In
the long-run this could help provide a more stable infrastructure for the country.
Environmental
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The impact that this design will have on the environment is very limited. The main
concern for the environment in this design is the production of the concrete for the foundational
blocks. The main component of concrete is cement which has one of the most energy-intensive
productions of all industrial manufacturing processes. However, all of the other components of
concrete—sand, crushed stone and water—take significantly less energy for production. Within
cement production, kilns are used to heat the cement. Within these kilns, hazardous waste is
burned as fuel including motor oil, spent solvents, printing inks, paint residues, cleaning fluids
and scrap tires. In fact in many cases cement kilns are the only way to safely burn the waste. The
production of concrete does produce CO2 emissions and waste water pollution. However,
looking at all structural material production, the only material that has an overall lower embodied
energy (the energy consumed by all of the processes associated with the production) is wood. All
other structural materials require more energy to manufacture and produce [20]. Also due to the
design of this project, significantly less concrete is used than in a standard housing unit. Looking
at the dimensions as given by the design document, 15’ x 23’, the concrete foundation of a
standard housing unit with these dimensions (assuming a 3’ depth for the foundation), 115.25
cubic feet of concrete would be required as opposed to the 47.75 cubic feet required for the
Tensioned Building. There is such a great difference in these sizes because most homes have a
concrete foundation throughout the entirety of the house, while the Tensioned Building only has
concrete under the structure supports. Overall this design will only impact the environment in the
production of the cement.
Health and Safety
With any form of engineered product, there will be some exposure to hazards and unsafe
situations whether it is in the manufacture of the product or in the consumer’s use of the product.
The main workplace hazard that will be seen in the manufacture of the Tensioned Building is in
the welding of the brackets that hold the structure in place. The following are the main concerns
for welding as determined by OSHA, the Occupational Health and Safety Administration. The
first is inadequate ventilation. According to OSHA the welding area should have a ventilation
system that moves a minimum of 2000 cubic feet per minute of air per welder. [13] Another
concern is fire. Metal sheets or fire resistant curtains should be used as fire barriers, welding
54. Tensioned Building Construction 05/29/2015 Page 53 of 106
should be done on a concrete floor and there should be suitable fire extinguishing equipment
readily available. The next concern is the personal protection of the welder. Due to the high heat,
sparks and ultraviolet rays produced, the welder should wear a protective face shield with filter
lens, a flame proof shell cap, a buttoned collar, long sleeves, fire-resistant gauntlet gloves and
steel-toed boots. Finally, because arc-welding requires electricity to operate, electric shocks are a
large concern. To prevent these, welding should be done on an insulating mat or other non-
conductive material [21]. In addition to these safety precautions, all brackets were designed to
optimize the simplicity of the welding.
Due to the simple onsite construction, there are few safety concerns for the consumer of
the Tensioned Building. One safety concern is entrapment, or when a body part is pinched
between or trapped beneath some form of equipment. In the construction of the tensioning and
structural subsystems different body parts such as fingers or hair could get caught in the
turnbuckles or in the brackets. To prevent this gloves should be worn during construction and all
loose hair should be tied back. Also through manufacturing, some edges of the brackets could
have sharp edges. While these edges will be smoothed within the manufacturing process, to
prevent injury gloves should be worn and care should be taken when operating the brackets.
Because the structure (11.75 ft.) is taller than the average man’s height (5 ft. 10 in.) a ladder will
be necessary to complete the assembly of the structure [22]. The safety instructions that the
ladder provides should be carefully adhered to. Finally the pouring of the concrete for the
foundational blocks will present some hazards to the user. Engulfment, skin irritant, form
blowout, noise exposure, eye hazards and impact and pinch points are all possible safety
concerns when pouring concrete. By following OSHA standards and using proper moisture
content according to design specifications, following the appropriate procedure and wearing eye
and hand protection the concrete can be safely poured [23].
Once the product is in use, the main safety concern is the ventilation of the structure. The
structure should not remain entirely sealed, with all windows, doors and interior and exterior
fabrics completely closed for extended periods of time. Also with the limited ventilation of the
structure, fuel-based generators should not be used within the structure. If these are used within
the structure the user will potentially be exposed to carbon monoxide poisoning [24].
Manufacturability
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Many aspects of this design are simple to manufacture or can be purchased. The
structural and tensioning materials can be simply cut to the correct length. This can be done via
shears for the tensioning material, and can be done via band saw or hack saw for the structural
material. However, the two areas of the structure critical in manufacturing are the brackets and
the foundation.
The brackets will be manufactured out of aluminum tubing while the structural members
will be made out of PVC tubing. There are a couple of reasons for this. First, the area of
maximum stress for all simulations done was located in the joints of the structure where the
brackets will be located so the brackets joint interfaces need to have high yield strengths and this
can be obtained through welding. This leads to the second reason, which is that aluminum is
much easier to manipulate and manufacture than PVC, mainly because you cannot weld PVC.
Pre-fabrication for welding will include using the drill press and a hole saw to cut the correct
curvature out of the piece of tubing that will be welded onto another tube. This curvature is
needed so that the sides of the tube will be flush and allow for easier welds. Once this is
completed so that all of the pieces will mate correctly for welding, the mill will be used to
complete the rest of the pre-fabrication. This can be done using two separate programs with the
mill for all pieces. This will include cutting the hole for accessing the turnbuckle as well as
placing each pin hole. Once this is completed the pieces will be welded. This will complete the
manufacturing for all bracket joints that are right angles. All angles less than ninety degrees will
be manufactured using hinge joints that can be purchased. These joints can be easily integrated
into the already manufactured brackets by simply being bolted to the section closest to the actual
joint interface. Lastly the pins can be easily inserted to function as an anchor for the turnbuckle
as well as stoppers for the PVC.
The foundation will require some manufacturing work as well. The foundation is almost
entirely made up of concrete. There is a first layer of anchor blocks located at the vertical
structural support posts as well as a second layer of anchor blocks located further underground
between the anchor blocks on the first layer. In order to manufacture these blocks, the anchor
blocks locations will have holes dug out for them to be poured and set. The digging process will
be completed using either shovels or a digging tool dependent on the building site ground
composition. Using QUIKRETE®® concrete, creating the concrete to be poured is very
56. Tensioned Building Construction 05/29/2015 Page 55 of 106
simplistic and consists of following the instructions given when purchasing the material. The
mixing of the QUIKRETE®® may require renting a concrete mixer due to the amount of
concrete needed to be made. When making the anchor blocks, aluminum tubing will be placed
vertically in the blocks when they’re initially poured and set to provide a holder and support for
the vertical PVC structural support members. The aluminum tubing will also be placed
horizontally so that the tensioning wire for the anchor blocks will be able to attach to each block
easily. To simplify this manufacturing process, single right angle aluminum tubing will be placed
in the blocks to function as the support structure holder and anchor block tensioning material
attachment. Clamps will be used to hold the aluminum tubing in place at the correct angles and a
level to insure correct placement of the components. The concrete foundation is a 1.5” thick slab
that will be sit on top of the anchor blocks. Manufacturing this consists of mixing, pouring and
setting the concrete. This is done the same way that the concrete is set for the anchor blocks. To
avoid the mixed, unset concrete spilling over and setting where it’s undesired, trench support
material will be put around the perimeter of the desired concrete location.
Sustainability
Until an indestructible and low-cost structure is designed, there will always be a need for
temporary structures. Natural disasters are a very common occurrence, causing the displacement
of people in every single one. Because temporary shelter will always be necessary, this design is
very sustainability. Also, as referenced in the environmental section above, because production
of this design has a limited environmental impact, it aids in the sustainability of the entire planet.
Conclusion
The greatest impact that this project will have is on society’s ability to respond to a natural
disaster and temporarily house the people displaced by that disaster. Due to its inexpensive
production and assembly costs, this product can be used all throughout the world when needed.
With its low impact on the environment, this product can be used and maintain its sustainability.
Overall this product will have a very positive impact on the world.
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Appendix B: Foundation Subsystem Analysis
When deciding the thickness of the concrete floor, the force that it can withstand is the main
component studied. To determine the force that a concrete slab on the ground can withstand the
following equation is used:
𝑤 = 257.876 ∙ 𝑠 ∙ √
𝑘 ∙ ℎ
𝐸
Where w is the maximum allowable distributed stationary live load (lbs/ft2), s is the allowable
extreme fiber stress in tension excluding shrinkage stress and is assumed to be equal to ½ the
normal 28 day concrete flexural strength (lbs/in2), k is the modulus of subgrade reaction (lbs/in3),
h is the slab thickness (in) and E is the modulus of Elasticity for the slab (lbs/in2). E is typically 4
x 106 lbs/in2 so in this case it will be assumed that this is the case [8]. According to the
specifications sheet of QUIKRETE®® the compressive strength is equal to 4000 psi with a 28
day cure. The flexural strength can be assumed to be 10-20% of the compressive strength [9]
which is equal to 800 psi. Knowing that the slab thickness is 1.5 in we can determine the
maximum allowable load.
Table B1. Constant Values for Concrete
s (psi) 435.1
h (in) 1.5
E (psi) 4.00E+06
The following table is an outline of the moduli of subgrade reaction for different types of soil.
These were given in a range so the maximum allowable loading will also be given in a range.
Table B2. Moduli of Subgrade Reactions for Different Soiltypes
GroundDescription k range (psi/in)
Well-gradedgravel 300 450
Siltysands 300 400
Well-gradedsands,gravellysands 200 400
Fine sand(beachsand) 150 350
Clayeysands 150 350
Fat (high-plasticity) clays 40 225
Lean (low-plasticity) clays,sandy 25 225
Silts,sandysilts 25 200
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Using these values the following allowable loads for QUIKRETE®® are determined.
Table B3. Range for Maximum Allowable Live Load for Concrete
GroundDescription w range (lbs/ft2)
Well-gradedgravel 1.09E+03 1.34E+03
Siltysands 1.09E+03 1.26E+03
Well-gradedsands,gravellysands 8.93E+02 1.26E+03
Fine sand(beachsand) 7.74E+02 1.18E+03
Clayeysands 7.74E+02 1.18E+03
Fat (high-plasticity) clays 3.99E+02 9.47E+02
Lean (low-plasticity) clays,sandy 3.16E+02 9.47E+02
Silts,sandysilts 3.16E+02 8.93E+02
To determine if this is a better material to use than wood, knowing the compressive strength of
wood to be a range between 2900 and 725 psi, maximum allowable load for a wood floor can be
determined.
Table B4. Range for Maximum Allowable Live Load for Strongest Point of Wood
GroundDescription w range (lbs/ft2)
Well-gradedgravel 7.93E+02 9.71E+02
Siltysands 7.93E+02 9.16E+02
Well-gradedsands,gravellysands 6.48E+02 9.16E+02
Fine sand(beachsand) 5.61E+02 8.57E+02
Clayeysands 5.61E+02 8.57E+02
Fat (high-plasticity) clays 2.90E+02 6.87E+02
Lean (low-plasticity) clays,sandy 2.29E+02 6.87E+02
Silts,sandysilts 2.29E+02 6.48E+02
Table B5. Range for Maximum Allowable Live Load for Weakest Point of Wood
GroundDescription w range (lbs/ft2)
Well-gradedgravel 1.98E+02 2.43E+02
Siltysands 1.98E+02 2.29E+02
Well-gradedsands,gravellysands 1.62E+02 2.29E+02
Fine sand(beachsand) 1.40E+02 2.14E+02
Clayeysands 1.40E+02 2.14E+02
Fat (high-plasticity) clays 7.24E+01 1.72E+02
Lean (low-plasticity) clays,sandy 5.72E+01 1.72E+02
Silts,sandysilts 5.72E+01 1.62E+02
59. Tensioned Building Construction 05/29/2015 Page 58 of 106
As seen above even a ½” slab of concrete built on the worst ground is able to maintain larger
loading then the strongest point of a slab of wood. This verifies that the concrete should be
chosen over the wood.
The stationary live load is analyzed in this scenario because this is the load that will
affect the floor the most. The other type of stationary load (the dead load) encompasses the
weight of the roof and walls. Because the primary structure consists of stainless steel and PVC,
these loads will not have a great effect on the loading of the floor. Also because the structure is
directly connected to the foundation blocks which are not directly connected to the floor the
structure does not impose a large load on the floor.
To determine the tensioning required for this system it is first necessary to determine the
forces that might be introduced to the system throughout its use. One of the main environmental
concerns for this structure is extreme winds. Because air blowing around an object is categorized
as turbulent flow this complicates the calculations. To simulate wind flowing over the structure
ANSYS Fluent was used. When using Fluent the space that is used to solve the calculations is
the space that the fluid occupies. In this case, this is the air flowing around the house. This means
that the following shape had to be constructed to determine the flow.
The large space on either side and above the structure allows Fluent to do the correct
amount of calculations to see how the pressure and velocity propagate. Once this shape was
meshed the solution could be setup. In this case it was assumed that the flow was low-speed and
incompressible. By setting the gauge pressure as the ambient pressure and assuming that the
lower and upper walls had slip, the pressure and velocity profiles could be determined. These
calculations were done assuming that the wind velocity was at Mach 0.1 which is equal to 34.03
m/s or 76.12 mph. The following figures show the contours of the static pressure. The first figure
is the entire fluid that was tested in Fluent. The second figure is a zoomed-in portion that shows
the area immediately around the structure. The static pressure is the pressure that would be
Figure B1. FluidMesh
60. Tensioned Building Construction 05/29/2015 Page 59 of 106
measured if one were moving along with the fluid. For practical purposes, static pressure is
synonymous with pressure.
Figure B2. Fit View of Contours of the StaticPressure
Figure B3. Close-upof Contours of StaticPressure Around Structure
These figures show that the pressure is at its greatest point on the left vertical wall. At
this wall the pressure is about 45.6 Pa and as the fluid makes contact with the left roof the
pressure decreases. This pressure also causes there to be a force in the positive y direction.
The following figures show the total pressure acting on the structure. The total pressure is
the sum of the static pressure and the dynamic pressure, where the dynamic pressure is the
kinetic energy per unit volume of a fluid particle.
61. Tensioned Building Construction 05/29/2015 Page 60 of 106
Figure B4. Fit View of Contours of Total Pressure
Figure B5. Close-upViewof Contours of Total Pressure
These figures show that the total pressure that acts on the structure does not exceed 59.5
Pa and on the opposite side of the structure a vacuum is formed.
The following figures show the velocity in the x direction as it makes contact with the
structure. Looking at these figures, it can be confirmed that the figures above are correct. This is
because as the fluid approaches the structure and contacts it, the velocity decreases causing an
increase in the pressure.
62. Tensioned Building Construction 05/29/2015 Page 61 of 106
Figure B6. Fit View of Contours of X Velocity
Figure B7. Close-upViewof Contours of X Velocity
By looking at all of the data found in ANSYS Fluent, the pressure that should be applied
to the structure frame to simulate large winds can be determined. Knowing this, the tension
required within the system can be calculated.
63. Tensioned Building Construction 05/29/2015 Page 62 of 106
Table B6. 1/2" Polypropylene Properties
MinimumBreakingStrength 16.8 KN
Safe Load (S.F.=12) 1.4N
Max AppliedLoadS.F.
63 (267 N
load)
Table B7. 1/2" Polypropylene Length and Elongation
T=267 N T= 26 N
PVCLength
(ft)
Rope Length
(ft) Length(m)
Elongation
(mm)
Elongation
(mm)
2.27 1.52 0.463296 7.412736 0.7412736
2.35 1.6 0.48768 7.80288 0.780288
5.5625 4.8125 1.46685 23.4696 2.34696
6.04 5.29 1.612392 25.798272 2.5798272
6.625 5.875 1.7907 28.6512 2.86512
7.64 6.89 2.100072 33.601152 3.3601152
7.855 7.105 2.165604 34.649664 3.4649664
9.5625 8.8125 2.68605 42.9768 4.29768
10 9.25 2.8194 45.1104 4.51104
Tables 10 and 11 shows the ½” Polypropylene rope length and desired elongation for the
minimum and maximum tension seen in the rope. This shows the amount that the turnbuckle
needs to be tensioned to acquire the desired forces for the structure to be stable.
64. Tensioned Building Construction 05/29/2015 Page 63 of 106
Appendix C: Structural Subsystem Analysis
Calculations were completed to determine under what force the structural members will
begin buckling. These calculations were done assuming the structures were built from rigid PVC.
These were the base line calculations done to determine the failure load and stress for each
member. These loads are plotted in Figure 11 and are used to determine whether or not certain
members are going to fail based on the local stresses given from the structural simulations
discussed above.
Buckling Calculations
Critical Buckling Load: 𝑃𝑐𝑟 =
𝜋2
𝐸𝐼
(𝐾𝐿)2
Critical Buckling Stress: 𝜎𝑐𝑟 =
𝜋2
𝐸
( 𝐾𝐿/𝑟)2
Where: 𝑟 = √ 𝐼/𝐴
For both ends fixed: 𝐾 = 0.5
For pinned and fixed ends: 𝐾 = 0.7
For both pinned ends: 𝐾 = 1.0
These calculations will assume that one end is fixed to the foundation, and the other end is
pinned give a more conservative calculation. While the other end could be considered fixed, it is
not entirely secure, however it is more secure than a pin joint. This assumption will put these
calculations on the conservative side of error for safety.
Area Moment of Inertia: 𝐼 =
𝜋
4
( 𝑟2
4
− 𝑟1
4)
Area: 𝐴 = 𝜋( 𝑟2
2
− 𝑟1
2)
Where: 𝑟1 = 1 𝑖𝑛; 𝑟2 = 1.1875 𝑖𝑛
For Rigid PVC
Young’s modulus: 𝐸 = 2.41 𝐺𝑃𝑎 = 349540 𝑝𝑠𝑖
Shear modulus: 𝐺 = 866.7 𝑀𝑃𝑎
Poison’s Ratio: 𝑣 = 0.3825
𝐴 = 𝜋(1.18752
− 12 ) = 1.2885 𝑖𝑛2
𝐼 =
𝜋
4
(1.18754
− 14) = 0.7764 𝑖𝑛4
𝑟 = √0.7764/1.2885 = 0.7762 𝑖𝑛
𝐿 = 3.75𝑓𝑡 = 45𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 45)2
= 2699.4 𝑙𝑏𝑠
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𝜎𝑐𝑟 =
𝜋2(349540)
(0.7 ∗ 45/0.7762)2
= 2094.9 𝑝𝑠𝑖
𝐿 = 7.5𝑓𝑡 = 90𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 90)2
= 674.84 𝑙𝑏𝑠
𝜎𝑐𝑟 =
𝜋2(349540)
(0.7 ∗ 90/0.7762)2
= 523.72 𝑝𝑠𝑖
𝐿 = 8𝑓𝑡 = 96𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 96)2
= 593.12 𝑙𝑏𝑠
𝜎𝑐𝑟 =
𝜋2(2.41 ∗ 109)
(0.7 ∗ 96/0.7762)2
= 460.30 𝑝𝑠𝑖
𝐿 = 8.14𝑓𝑡 = 97.68𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 97.68)2
= 572.89 𝑙𝑏𝑠
𝜎𝑐𝑟 =
𝜋2(349540)
(0.7 ∗ 97.68/0.7762)2
= 444.61 𝑝𝑠𝑖
𝐿 = 8.39𝑓𝑡 = 100.68𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 100.68)2
= 539.26 𝑙𝑏𝑠
𝜎𝑐𝑟 =
𝜋2(349540)
(0.7 ∗ 100.68/0.7762)2
= 418.51 𝑝𝑠𝑖
𝐿 = 11.5𝑓𝑡 = 138𝑖𝑛:
𝑃𝑐𝑟 =
𝜋2(349540)0.7764
(0.7 ∗ 138)2
= 287.03 𝑙𝑏𝑠
𝜎𝑐𝑟 =
𝜋2(349540)
(0.7 ∗ 138/0.7762)2
= 222.76 𝑝𝑠𝑖
Knowing these calculations the critical buckling load and stress can be completed for varying
lengths of PVC. This allows the optimum length to be chosen for each structural member in the
building. The graph showing the relation of the length of the PVC to the buckling strength
(Figure 35) shows that the shorter the length of the PVC the higher the buckling strength. At the
same time a shorter length of tubing will create connection problems if multiple sets of PVC
must be joined to complete one structural member. The free body diagram of the loading of each
length of PVC can be seen in Figure C1.
66. Tensioned Building Construction 05/29/2015 Page 65 of 106
Figure C1. PVC Buckling Loads
Figure C2. Buckling Load vs. Tubing Length
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Addition of Structural Member:
The initial structure was analyzed via SolidWorks, including both stress and deformation
simulations. The initial load applied was based off the typical conservative value for wind load
on a surface for most UK buildings, which was 1.2kN/m2 (engineering toolbox). This value
corresponds to the wind load for just less than 38 m/s (1.24kN/m2). When converted to English
units this would estimate an 85 mph wind gust creating a pressure of 25.1 psf or 0.17 psi. Three
tests were done initially, Simulations 1, 2, and 3. These simulations were done with the
properties of rigid PVC on SolidWorks with accurate cross sections for 2” PVC (2.000” ID and
2.375” OD) and joints were defined as either fixed or hinged based on the design. Simulation 1
had a wind load applied only to the side, Simulation 2 (Figure 36) had a wind load applied only
to the front, and Simulation 3 had a wind load applied to both the front and the side. Upon
analysis of Simulation 2 it was noticed that there was significant deformation in the front cross
beam when compared to the deformation in the other two simulations. To account for this a
structural member was added in the center of this cross beam and extends to the back end of the
structure, adding symmetrical support to the back cross beam. The same three simulations were
performed again, Simulations 4, 5, and 6. When analyzing Simulation 5, which had the same
constraints as Simulation 2, it was noted that the maximum deformation was approximately 33%
less and was centralized in the entire roof structure instead of one beam. Therefore there are
more structural members absorbing the wind load as opposed to just the center cross beam. The
figures below show exaggerated deformations of a scale 10:1 for the structure before and after
the member was added.
Figure C3. SolidWorks Simulation2: Displacement
69. Tensioned Building Construction 05/29/2015 Page 68 of 106
The deformation result of Simulation 2 is on the left, showing the maximum deformation
is just over three inches and is located in the center of the front crossbeam. This deformation is
not ideal in that much of the load is being absorbed by only two structural members in one
specific spot on the members. In order to compensate for this an additional support member was
added through the center of the ceiling of the structure. Simulation 5, for the deformation of the
new structure on the right, shows that the maximum deformation for the same load applied is
only two inches, but more importantly it is dispersed amongst the roof structure. It can be seen
that maximum deformation is now located within the entire top beam, while the additional
member sees slightly less deformation, yet still more than the rest of the structure. This design
adjustment was crucial in that it results in more structural members absorbing the deformation
allowing the entire roof structure (all three cross brace triangles) to support the load and not just
the first cross brace. As described above, Simulations 1, 2, and 3 have identical fixtures and
loadings when compared to Simulations 4, 5, and 6, respectively. When comparing Simulation 1
with Simulation 4, and Simulation 2 with Simulation 6, it was clear that the structure with the
added member reduced the amount of stress and deformation of the structure, and the locations
of maximum stress and deformation remained identical. For this reason only, the analysis of the
simulations was focused on Simulations 4, 5, and 6 for the new structure.
Figure C5. Side viewof Simulation 2: Displacement
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Figure C6. Side viewof Simulation 5: Displacement
Once again, the exaggerated deformation results of Simulation 2, on the left, and
Simulation 5 (Figures C5 and C6) are shown above, but this time from the side view. Here it can
be clearly seen that the first cross brace is deformed much more in Simulation 2 than any of them
in Simulation 5. It can also be seen that the top beam sees less transverse deformation, but rather
more of an axial shift.
Figure C7. Isometricview of Simulation 7: Deformation
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Figure C8. Top view of Simulation 7: Deformation
Figure C7 and C8 show an isometric and top view of the deformation of Simulation 7.
Simulation 7 has the same constraints as Simulations 1 and 4 except the force on each member
was calculated through the ANSYS Simulation above. This gave a total pressure 16.08 kPa on
side of the structure which correlated to a wind of 76.12 mph which is just qualifying as
hurricane force winds. The maximum deformation takes place in the long beams on the top and
side of the roof at a value of 18 inches. Note that this deformation is high due to the extreme
conditions. However, it is not enough to cause buckling.
Figure C9. Isometricview of Simulation 7: Stress
72. Tensioned Building Construction 05/29/2015 Page 71 of 106
Figure C10. IsometricClose up view of Simulation 7: Stress
Both figures C9 and C10 above show the results from Simulation 7. Here it can be noted
that the maximum stress does not occur in the members but at the joints. Figure C9 gives an
overall view of the stress distribution and it can be seen that none of the members are at the
maximum (red) stress level. In Figure C10 it can be more clearly seen that the maximum stress
occurs at the middle side joint and the middle top bracket. This indicates that these two brackets
will be most critical for a wind load coming directly from the side.
73. Tensioned Building Construction 05/29/2015 Page 72 of 106
ResizedStructural Analysis:
After reassessing the scope of the project after the loss of a member, the size of the
structure was scaled down. Because this new structure is very similar to the old structure, just a
smaller version, the results will be compared to the analysis done on the previous design. These
simulations will be labeled Simulations 8-10 and also have identical configurations as
Simulations 1-3 respectively. Simulation 8 in Figures C11-C14 shows the first configuration
with the wind pressure only coming from the side.
Figure C11. Isometricview of Simulation 8: Stress
Figure C12. Close-UpIsometric view of Simulation 8: Stress
74. Tensioned Building Construction 05/29/2015 Page 73 of 106
Both figures C11 and C12 above show the stress for Simulation 8 at a side wind speed of
30 mph. Here the maximum stress was found to be only 1,300 psi and was located at the bottom
of each vertical member that will be fixed by the concrete blocks. This is much different than the
30 mph analysis on the previous structure, which had a maximum stress of 1,400 psi. While the
stress under the same conditions was lower it was also located in the bottom brackets instead of
the top brackets. This will allow more of the stress to be supported by the lower brackets that are
embedded in the concrete foundation blocks.
Figure C13. Isometricview of Simulation 8: Displacement
75. Tensioned Building Construction 05/29/2015 Page 74 of 106
Figure C14. Close-UpIsometric view of Simulation 8: Displacement
Figures C13 and C14 above show that the displacement for this simulation was only 3.6
inches which is roughly the same as the 3.3 inch displacement found in the simulation on the
previous design. Figures C15 through C17 show the results from the simulation on the previous
structure; the simulation to which these results are being compared to. The maximum stress if
1,400 psi can be seen in Figures C15 and C16, while the location of this maximum stress can be
seen in Figure C16. For the previous structure the maximum stress is locate on the diagonal PVC
members between the double walls. The results for the new design show that the new design has
the maximum stress in the brackets instead of the PVC. And because the stainless steel brackets
are much stronger than the structural PVC, the new design is more ideal than the previous.
Figure C17 shows the displacement for the previous design. It can be seen that the dispalcements
are nearly identical and located in the same spot.
76. Tensioned Building Construction 05/29/2015 Page 75 of 106
Figure C15. Isometricview of Previous Simulation: Stress
Figure C16. Close-UpIsometric view of Previous Simulation: Stress
77. Tensioned Building Construction 05/29/2015 Page 76 of 106
Figure C17. Isometricview of Previous Simulation: Displacement
Figures C18-C21 below show the results for Simulations 9 and 10. The results of these
simulations showed the same trend as Simulation 8 in comparison to the results of the
simulations on the previous design. The results for Simulation 9 can be seen in Figures C18 and
C19, while the results for Simulation 10 can be seen in Figures C20 and C21.
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Figure C18. Isometricview of Simulation 9: Stress
Figure C19. Isometricview of Simulation 9: Displacement
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Figure C20. Isometricview of Simulation 10: Stress
Figure C21. Isometricview of Simulation 8: Displacement
80. Tensioned Building Construction 05/29/2015 Page 79 of 106
Bracket Analysis:
Pre-Load:
Figure C19. Stress Causedby 60 lb. Pre-Load
81. Tensioned Building Construction 05/29/2015 Page 80 of 106
Figure C20. Close-Upof Pre-Load Simulation
Both figures C19 and C20 above show the results of the final simulation with respect to
the preload of the tension system. This was done by simulating equal and opposite forces on the
lower 7/16” pin and the top of the PVC that is resting on the two 5/16” pins. This was done at
various loads to determine an upper bound on the preload based on the stress created by the load
on the pins. Loads that were tested were 50, 60, 80, and 100 lbs. From these simulations it was
found that a 60 lb. preload is an appropriate maximum preload based on the stresses created in
the aluminum tubing of the bracket by the pin. This can be seen as the green area around the
lower pin in Figure C19 with a stress around 1100 psi. As seen in Figure C20 the maximum
stress is going to occur in the 7/16” pin as a result of the concentrated load from the turnbuckle.
This will require steel pins instead of aluminum.
82. Tensioned Building Construction 05/29/2015 Page 81 of 106
Structural Bracket Analysis:
Figure C21. Structural Bracket Analysis
Figure C21 shows the setup for multiple tests done on the brackets. This test was done
with the same technique as for the simulations on the PVC, except the cross sections and
material were changed to that of the brackets. Analyses were done for the cross section being
used in this construction. At 20 mph the maximum stress for the 309 stainless steel tubing being
used is at nearly 5,000 psi. While this seems like a lot compared to the PVC cross sections, 309
stainless steel has a yield strength of 45,000 psi which gives a safety factor of 9 on the location
of the most stress.
Table C1: PVC properties
PVCProperties:
YieldStrength=55.16 MPa
SafetyFactor= 2
Max Axial Load= 22.93 KN
Our Max AppliedLoad= 267 N
83. Tensioned Building Construction 05/29/2015 Page 82 of 106
Table C2: PVC Lengths, Buckling, andDeflection
PVCLength
(ft)
Critical Load
(N) BucklingStress(Pa)
Max Deflection
(m)
AppliedLoadDeflection
(mm)
1.244791667 2134.668367 5135629.944 1.643794972 0.055626519
1.411458333 1660.304078 3994394.385 0.371896564 0.069398515
3.536458333 264.4762436 636282.4955 1.559506924 0.249986198
4.078125 198.8853035 478482.4357 1.677927374 1.87838521
4.515625 74.43773336 179083.8606 0.841618783 0.550880516
4.536458333 66.54961158 160106.4517 1.192454365 0.644074393
5.578925 106.2729443 255673.679 1.558216182 1.987477103
5.703125 101.6946201 244659.0505 1.998812366 0.378610042
9.661458333 27.33621545 65766.04065 1.992668317 1.154205111
Table C1 contains the different desired PVC tube lengths. It also shows the critical load
that makes the piece start to buckle, the stress due to buckling and deflection due to buckling.
Table C2 shows the strength of the material as well as the applied loads to obtain a safety factor
of 2. This shows the required compression on the PVC from the brackets for the structure to be
stable and safe, which is a max of 2135 N and a minimum of 27 N.
84. Tensioned Building Construction 05/29/2015 Page 83 of 106
Appendix D: Fabrication Plan
1.0 INTRODUCTION
1.1 Purpose
The purpose of this document is to outline the fabrication plan which incorporates each
fabricated part and their assembly. By the end of this document, the reader should have a
complete understanding of the fabrication of each part and its general assembly.
1.2 Scope
This document describes the fabrication plan of the Tensioned Building. Within the fabrication
plan the following will be detailed: the facilities, equipment, tools, materials and personnel
resources required to build and assemble the product; the special safety considerations during
construction and assembly; the procedures and sequences of construction and assembly tasks; the
team responsibilities during fabrication; and the financial considerations for fabrication.
2.0 FABRICATION DESCRIPTION
2.1 Facilities
For fabricating the different components for the structure, each individual part will be fabricated
in the University of Denver machine shop except for the concrete anchor blocks and floor base.
Once all parts are fabricated, the concrete will be made and set at the building site, which is the
property near the Aurora Reservoir owned by the University of Denver. The components
fabricated in the machine shop will then be put together at the building site.
2.2 Equipment, Tools and Materials
2.2.1 Anchor blocks and floor base: The anchor blocks and floor base materials
will consist of QUIKRETE®, 2.5” 309 Stainless Steel tubing, and 2’x4’
wood. The tools and equipment will consist of shovels, a level, drill press,
end mill, stationary ban saw, gas cement mixer, and a measuring tape.
2.2.2 PVC structure supports: The PVC structural supports will consist of 2”
inner diameter PVC tubing material, measuring tape, and a stationary band
saw.
2.2.3 Rope: The rope material consists of ½” polypropylene rope and the tools
used are rope clams, measuring tape, hammer, and large shears.
2.2.4 Brackets: The bracket material will consist of 2.5” Stainless Steel tubing,
7/16” steel clevis pins, 5/16” steel clevis pins, hitch pin clips, 2.5”
structural pipe fittings, 3/8” steel bolts, 3/8” nuts, 3/8” lock washers, and
MAG wire. The tools consist of a drill press, measuring tape, 2.5” hole
saw, end mill, stationary ban saw, table grinder, and a MIG welder.
2.2.5 The turnbuckle material will consist of only galvanized steel 4½” hook
and hook turnbuckles.
2.2.6 Windows: The window material will be made up of a 2’x4’x0.093” clear
acrylic sheet and silicon caulking. The tools will consist of a measuring
tape, caulking gun, and a ban saw.
