ET3 Modular Tube Plan

Colorado School of Mines

OCTOBER 9, 2013

Design Epics 2 FALL 2013

Section E&F

ROBERT NEUKIRCHNER

EVACUATED TUBE TRANSPORT TECHNOLOGIES

TEAM ENGINEERS:

DAEVIN DEV

GARY NORTH

JOE WAITE

RYAN MAIDHOF

STEVEN HANENBERG

TYLER JOHNSON

December 2, 2013

Mr. Daryl Oster, Founder ET3

5425 County Road 32 Unit 28

Longmont, CO 80504

Dear Mr. Daryl Oster,

We are submitting the attached report for Evacuated Tube Transport Technologies’

modularity project. The purpose of this report is to show Evacuated Tube transport Technologies

Fast Track Tech’s final design for the project, explain our major alternative designs, and provide

a cost estimate for the proposed design. We were asked by Daryl Oster and Jack Panter to design

certain parts of this project in order to improve the modularity of ET3’s new mode of transit [1].

For this project we designed the tube sections, the joints between the tube sections, and the

supports that hold the tube.

The design that our team is proposing consists of three main parts: the tube sections, the

joints, and the supports. The design for each tube section is a hollow cylinder made of ductal®

concrete with grooves for the mag/lev track. There are lips on each end to attach to the joints

between tube sections. Each tube section is connected to the one in front and behind it by a joint.

The joint design is based off of a commercially available pipe joint that allows for axial

expansion and contraction, keeps the tubes airtight, and has the same bending properties of the

tube sections. The support design is basically a tripod with a cradle on the top that holds the tube.

This allows for the ground to move without moving the tube. All of these components were

designed to help make the system as modular, cost effective, and resistant to the elements as

possible.

The team of Fast Track Tech is very thankful to have being given the opportunity to work

on this project, and we are very interested in continuing development of our designs. We would

greatly appreciate any feedback or questions about our proposed designs, and we ask for your

permission to continue with this project. Feel free to contact our team liaison Joe Waite by phone

at 651-808-4258 or by email at jwaite@mines.edu.

Sincerely,

Joe Waite

Cc: Robert Neukirchner

Daevin Dev

Steven Hanenberg

Tyler Johnson

Ryan Maidhof

Gary North

Executive Summary

The purpose of this project was to design certain aspects of Evacuated Tube Transport

Technologies’ new mode of transit in order to improve the modularity of the system [1]. For this

project we designed the tube sections that the capsules will be sent through, the joint sections

that connect the tube sections, and the supports that hold the tube above the ground. Each part

was designed to allow for a capsule with a mass of up to 550 kilograms sent through it at up to

6500 kilometers per hour, and was designed to be easy to remove and replace if needed, resistant

to external environmental factors, and cost efficient [2]. The parts were also designed to be used

in either straight or curved sections.

Our team researched multiple types of piping joints and support designs and considered

many designs for the tube sections before coming up with our final designs for the parts. The

tube section needed to be easy to remove and replace and the right shape for capsules to be sent

through it. Our final design for the tube section was a hollow cylinder with grooves running

through it for the mag/lev track and lips at both ends to attach it to the joint section next to it. The

joint design needed to be airtight, able to expand or contract as the temperature changed, and

have the same bending properties as the tube sections. Our final design for the joint includes a

rubber seal that keeps it airtight while allowing for expansion and compression and includes long

rods made of ductal concrete that surround the joint to give it the same bending properties of the

tube sections. Our support design needed to be able to accommodate shifting land and tidal

movements of the Earth’s crust, and needed to be capable of use over land of varying heights. To

fulfill these requirements, our final support design is a tripod with legs that can be adjusted that

attaches to a cradle which holds the tube above the ground.

The modularity of these designs is their biggest advantage. The tube sections and joints

can be easily removed from the system and replaced and are capable of being used in straight or

curved sections of track. The supports are capable of use in multiple types of land and will

accommodate it when it shifts. All of the designed parts will also hold up under large changes in

temperature, high winds, and other common environmental factors. The designs described in this

report will play a role in shaping what Evacuated Tube Transport Technologies’ final design for

their new mode of transit looks like. Our project will be of huge importance given that this mode

of transit may one day be the most common form of long-distance travel. Our designs will allow

the tube sections, joints, and supports to be as modular as possible.

Table of Contents

List of Tables and Figures…………………………………..……………………………….…..1

Introduction………………………..………………………………………………………….....2

Alternative Designs…………………………………………………………………………...….2

Final Design……………………..……………………………………….……………………….4

Cost Estimate……………………………………………………………….……………...……11

Assembly/Operating Instructions……………………………………………………...………11

Summary………………………………………………………………………………………...12

References……………………………………………………………………...………………..14

Appendices…………………………………………………………………………………..…..16

List of Tables and Figures

Figures

Figure 0: Overall Design

Figure 1: Tube Overall Design

Figure 2: Combined Tube Alignment

Figure 3: Removing and Replacing Tubes

Figure 4: Joint Design Isometric View

Figure 5: Joint Design

Figure 6: Joint Cross Section

Figure 7: Tube/Joint Interface

Figure 8: Cap Design

Figure 9: Rod Design

Figure 10: Support

Figure 11: Rod

Figure 12: Turnbuckle

Figure 13: Turnbuckle With Rod

Figure 14: Ball and Socket Assembly

Figure 15: Support Top Assembly

Figure 16: Pin Slot

Figure 17: Tube Cradles

Figure 18: Proper Concrete Pipe Handling

Tables

Table 1: Cost Estimate

Introduction

Fast Track Tech. was asked by Daryl Oster and Jack Panter of Evacuated Tube Transport

Technologies to design certain parts of an Evacuated Transport Tube in order to improve the

modularity of their new mode of transit. Our team must design the tube sections, the joints

between the tube sections, and the supports that hold up the tube to be reliable, durable, cost

effective, and easy to remove and replace [1]. Our design must allow for capsules weighing up to

550 kilograms to be sent through the tube at up to 6500 kilometers per hour and must also

accommodate common environmental factors such as changing temperatures, and shifting land.

The concept for our overall design includes three main parts: the tube sections, the joints, and the

supports. (Figure 0) The tube sections are hollow cylinders made of Ductal concrete with an

outer radius of 1.8 m, a length of 25 m, and a thickness of 2 cm. Each tube has a lip on each end

that allows it to be bolted to a joint. The joint design is similar to the commercially available

pressure piping expansion joint. This design has a rubber seal that will keep the tubes airtight

while also allowing for axial expansion and compression to allow the tubes to expand and

contract under changing temperatures [2]. Our design also has large bolts made of Ductal

concrete that surround the rubber seal to provide structural support. The size and number of these

bolts can be changed in order to change the flexibility of the joints to match that of the tube

sections. The final component of the project, the supports, is designed like a tripod with three

legs that go from the ground to the tube. At the top of the support, is a cradle-like part that holds

the tube allowing the tube to move relative to the supports if the land beneath it shifts.

Alternative Designs

Alternate Tube Designs

1). Fitted End

The fitted end tube design included a cylindrical cuff that has a slightly larger radius than the rest

of the tube located at one end of each tube. The non-cuffed end of one tube would fit into the

cuffed end of the next tube. This design was considered because being able to slide one tube into

the next would create a great amount of structural support. This design would also make it so that

if there was a breakage in one of the seals, there would be less air leakage than with the regular

design in which the ends of the tubes are pressed up against each other. The main flaw with this

design is the difficulty of removing and replacing the tubes. The tubes attached to the front and

back of a tube that needs to be replaced could not simply be moved apart, so it would be

impossible to remove and replace a tube without destroying it.

2). Flat Bottom

This design was one in which the bottom of the inside of the tube was flat instead of round. The

main benefit to this design was that it would make it easier for capsules to merge from one tube

to another at junctions because the capsule would not have to be perfectly aligned with the tube it

was merging into. It would also allow a maintenance shaft to be located between the inside flat

part and the rounded outside of the tube. This design was rejected because the Mag/Lev track

will be strong enough to keep the capsule on the right path whether the bottom of the tube is flat

or round. Also, this design would require the bottom of the capsule to be flat as well, preventing

any cargo or luggage from being stored in the bottom, and would also require more material per

tube to construct.

Alternate Joint Designs

1). Threaded Tube Ends

The threaded tube end design incorporates two concrete tubes having an interlocking design in

which a particular male tube end can be screwed into a female tube end. This would enable an

interlocking tube system that has qualities that are rigid, durable, and cost effective. The strength

of this design is in having a long-lasting connecting potential that is immune to most external

elements and in having minor effect on the overall tube manufacturing process while condensing

the joint and tube manufacturing processes into one process. The weakness of the design is in the

repair process in which it would be required to dismantle multiple sections of tube to repair a

particular section. This design meets the overall criteria of our project in its ability to not be

affected by external elements but has its shortcomings in how tedious and drawn out the repair

process is.

2). Bolt Connector Coupling

The bolt connector design uses an extant bracket with edges, wherein threaded bolt holes are

located, that jut outward perpendicularly to the direction the tube is running. A bracket is fixed to

each end of each tube enabling the brackets to be bolted together. This design enables a tube

system having the tube joints outside the tube. The strength of this design is in having an

expedient and simple installment as well as repair process that are almost identical in nature. The

weakness of this design is in not being able to handle relatively heavy loads, which is crucial due

to the fact that each joint will be located between any given pair of supports. This design meets

the overall criteria of our project in how quickly each section of tube can be connected but has its

fatal flaw in the fact that it is a weak support due to the location of the joints on the tube.

Alternate Support Designs

1). Circle Rotating Around Tube with Piston Base

This design involved a circular collar that would go around the tube. This collar would fit loosely

around the tube, and not actually be attached to it, thus allowing for slight expansion of the tube,

as well as rotation around it and longitudinal movement. Two beams coming off of the collar

would be anchored to the ground independently, and would essentially be large hydraulic shocks.

Thus, when the earth moved, each leg would be able to move independently and the collar would

rotate around the tube. In this way, the tube would not actually move if the earth were to move

sideways – instead, the collar would move around it. The biggest issue with this design was the

complexity of the support beams, which would make it both more expensive and just more

difficult to build. The other problem was that with the supports moving out from under the tube,

there would be a distinct possibility of the tube tipping over the support structure and falling.

2). Alaskan Oil Pipeline

This design mimics that of the supports used to design the Alaskan oil pipeline. There would be

two different types of supports, designated A and B. The A supports would be elaborate pillars,

made utilizing a vertical truss structure. They would surround the pipeline, and would

completely lock it in place. These would allow no movement whatsoever, and would be almost

comparable to setting the tube in a giant block of concrete. The A supports would be few and far

between, essentially serving as bases. There would be more B supports in between each of the A

supports. These would be pillars which the tube would simply rest on top of. There would be

vertical supports on either side of the tube to prevent it from sliding horizontally off the support,

but it would not be otherwise anchored at all, thus allowing for expansion and movement in any

and all directions. The issue with this design was the flex allowance. While the B supports allow

for a lot of flex, the A supports don’t allow any at all. This will mean that these supports will put

major stresses on the tubes because these parts are not given any room to move.

3). Two Fixed Supports

The two fixed supports is a more traditional way of holding something up. this is simply two

solid pillars anchored on one end to the tube, and on the other to the ground. The advantage of

this is that it is very well established, simple and cheap to construct, and has proven durability.

The problem with this is that it does not allow for any flexibility at all. With it being fixed both

at the ground and the tube, there is no way for it to move which means that any ground tremors,

pipe expansion/contraction, or other disruptions will place huge stresses on the tubes and

possibly cause failure. The most important criteria for this support structure is that it must be

able to cope with the movement of the earth and the pipe without causing excessive stresses.

Final Design

Scope of Tube Design

Tube Design Overview

The tube system of the ET3 is responsible for containing and aligning the capsules during travel.

The tubes will join to other tubes using rubber seals and Ductal®

concrete rods. A proper tube

design will ensure a smooth turning along curved banks and smooth travel at high velocities. The

assumption incorporated into this design is that each tube will bend minimally relative to each

other, hence allowing for the tubes to have a slightly bigger diameter lip at end points which

would not constitute a rigid point.

Tube Design Details

The tubes proposed here are round bottomed (circular cross section) with a slightly bigger

diameter lipped end. Each tube section will have a length of 24.81m. When combined with the

tube joint, it will have a combined length of 25m. The circular cross section minimizes stresses

and weights which the tube will have to bear when high speed capsules pass through it. Circular

cross section also allows for easier maneuvering of capsules into different tube branches at high

speeds. The tubes will have a thickness about 0.5inches or 1.27cm. At this thickness, the

production cost is minimized but not at the expense of structural integrity. The interior of the

tube will have two permanent magnetic strips and a linear motor coil running parallel to each

other along the bottom curvature of the tube. (Figure 1) The magnetic strips levitate the capsule

within the tube while the linear motor coil accelerates the capsule along a given distance. The

whole tube will be made of Ductal®

concrete which provides the required amount of flexural and

structural strength needed. Each end of the tube will have a slightly bigger diameter lip. The lips

of the tube will have bolt holes surrounding the lips that allow for the rubber seal to join with the

tube. Long cylindrical Ductal® rods will run directly from one end of the tube to the other,

bypassing the rubber seals, to provide extra structural support and to maintain uniform bending

properties along a combined tube length.

Design Basis

The following criteria were used in analyzing and deciding upon an appropriate design for the

tube. Each criteria is explained in detail below

Capsule Compatibility

The tube design and structure would have to accommodate capsules up to about 1.3m in diameter

and of weights up to 550 kg. As such, the thickness of the tube would have to be significant

enough to handle the stresses produced by that weight. [3] The interior design of the tube would

have to align with the levitation and nitrogen cooling devices on the capsules. Proper alignment

of these devices is crucial for a smooth and safe travel along the tube. (Figure 2) There should

also be empty space between the tube and capsule to avoid contact. [4]

Ease of maintenance

The tube should be easy to remove and replace along any section of the tube system. By having

vertical lips that aren’t fitted ends, any damaged tubes can be vertically removed independently

and replaced by just untightening the bolts and rods. (Figure 3)

Vacuum Load per Linear Length of Tube

Being a vacuum based technology; the tubes would have to be able to withstand external

atmospheric pressures pushing onto the tubes. The vacuum load per unit length is the amount of

stress due to external pressure that is exerted on a unit length of the tube. External pressure

failures can be costly and dangerous. [5] This stress is proportional to the internal diameter of the

tube; which is why a relatively low tube internal diameter of 1.4746m was decided upon.

Calculations show that these stresses are within a safe limit of the allowable stress of Ductal®

concrete at a tube thickness of 0.0127m.

Tube Natural Frequency

Excessive piping/tube vibrations occur when the mechanical natural frequency of the tube is

excited by some pulsations or mechanical forces. Piping vibrations have been causes of major

disasters in industries. The tube natural (vibration) frequency depends purely on material and

geometric properties such as modulus of elasticity, moment of inertia and weight. To avoid

excessive vibrations, it is ideal to minimize the natural frequency. The natural frequency is

proportional to the moment of inertia and inversely proportional to length of individual tube

sections. [6] These are additional reasons for having a small tube thickness of 0.0127m and a

tube length of only 24.81m. Thinner tubes have a lower moment of inertia.

Interfaces

The tubes will be joined to each other via the rubber seals and also by Ductal® concrete rods.

(Figure 2) The rubber seals will meet the tubes at the tube lips on its end points. The tube lips

and rubber lips will have 20 bolts, each having a diameter of 0.02m. The tubes and rubber seal

will be bolted together via the bolts which are made of basalt fiber. To increase structural

integrity and to maintain uniform bending properties, additional Ductal® concrete rods will run

across the rubber seals (bypassing them) from one seal lip to the other. As for the supports, the

tubes will lay directly on top the cradle-like structures of the supports.

Joint Design

Subsystem Overview

This subsystem includes the design and dimensions of the joint section that will be located

between the tubes. The joint will provide structural support between the tubes, maintain the

vacuum inside of them, and allow them to expand and contract under changing temperatures. It

is also designed to have the same flexibility as the tube sections (Figure 4). This design assumes

that the surrounding temperature will never be above the hottest recorded temperature of 58

degrees Celsius or below the lowest recorded temperature (excluding Antarctica) -68 degrees

Celsius [7]. All of the graphics were made to be accurate at a temperature of 20 degrees Celsius.

Subsystem Details

The design for this subsystem was based heavily on the commercially available Series 320 Hand-

Built Pressure Piping Expansion Joint. The inside of the joint has two unconnected, hollow,

coaxial cylinders made of ductal® concrete [8]. There is a small gap between these two cylinders

to allow them to move together and apart as the tube sections expand and contract due to

surrounding temperature changes. These cylinders have a lip on each end that will be bolted to

the lip of the tube sections being connected by the joint (Figure 4 and 5).

There is a Teflon seal that goes around both cylinders to prevent air leakage. 955 Teflon from

Holz rubber is specifically designed for large outdoor seals like the ones incorporated in the

design, and Teflon is immune to many corrosive agents that could destroy other seals.[9] The

middle of the seal has an arch going around its circumference which will allow the joint to

expand and contract as needed without there being a significant resultant axial force. Each side

of the rubber seal is bolted in place between a ring of ductal® concrete and the lip of each side of

the joint to hold it in place using bolts made of basalt rebar (Figure 6). The main purpose of the

cylinders on the inside of the seal is to prevent the joint from compressing too much and

crushing the rubber seal.

The design also includes long rods made of ductal® concrete that go from one side of the joint to

the other. The rods are attached to the ends of the joint via rounded triangular flanges that attach

to the lips of the surrounding tube sections. There is a removable cap at one end of each rod that

prevents it from sliding out. These rods are included to provide the structural support needed

between each tube section in order to make sure they always remain lined up perfectly. The

number and thickness of these rods were decided in order to give the joint the same flexibility as

the tube sections to prevent strong or weak spots in the tube. This will cause the tube to have a

consistent turn radius (Figure 7). These rods were also designed to be long enough to leave a

small gap between the caps on each end of the rod and the lips on the surrounding tube sections.

This will allow the ends of the surrounding tube sections to move relative to one another as the

temperature changes without creating a stress on the joint itself.

This design fulfills the clients need of a joint that can expand and contract to accommodate

changing temperatures while remaining completely airtight and having the same rigidity of the

tube sections. This joint will be fairly easy to remove and replace if needed because it makes no

permanent attachments with the tube itself and all of the parts can be easily removed. If a joint

needs to be removed, one would simply remove the flanges and the ductal® rods, and then slide

the joint out from between the tube sections (Figures 8 and 9). This would be a fairly simple

process as it would not require any parts to be broken and also would not require any parts to be

tampered with aside from the one being removed. Also, because it has the same rigidity as the

tube sections, the same joint design can be used for straight or curved sections of track.

Design Basis

Ductal® concrete was chosen as the material for the cylinders, the rods, and the lips of the joint

due to its high strength and ductility which will allow it to bend as needed. It is also not a metal,

so it will not interfere with the Mag/Lev track. The inner radius of the cylinders is 0.7373 meters

to match that of the tube sections. The thickness of the ductal® concrete cylinders was decided

by the minimum suggested design thickness: 1.27 cm. The distance between the cylinders on the

inside of the joints and the length of the rods were decided by how much each tube section might

need to expand as the temperature changes. Because these components of the joints are made of

the same material as the tube, the intrinsic properties such as the modulus of elasticity will be the

same and geometrical influences and thermal expansion are the only concerns that must be taken

into account as long as these components are produced in the same manner as the tubes[10].This

was calculated using the thermal dilation of ductal® concrete - 12 μm/m/˚C - and the range of

temperatures it might experience [11]. A safety factor of 2 was used for this calculation. The

number and thickness of the rods were determined by what number and thickness would cause

the joint section to have the same rigidity as the tube sections. The thickness of the flanges

connecting the rods to the joint was decided by what thickness would make the bending

properties of the flanges negligible compared to the bending properties of the rods.

Interfaces

The joints will connect two sections of tube by having the lips of the joints bolted to the lips of

the tube sections using custom bolts made of basalt fiber rebar that will not interfere with the

magnets in the tube. 20 bolts will go through the lip of the tube and the joint to secure the two

subsystems, the Teflon seal, and the supporting flanges. (Figure 7)

Support Design and Installation

Overview

The support was designed to be placed in low risk areas where earthquake are not abundant. The

main factors taken into account were wind and earth movements due to tidal forces. The support

design and installation contains multiple components. First, the support design will be discussed.

The support design contains five main parts. These parts are as follows:

1) Support legs

2) Turnbuckle

3) Ball and socket joint

4) Support top

5) Tube cradles

The design of the support is a tripod-like design (Figure 10). Three legs support the tubes similar

to how a camera tripod supports a camera. There are two rods in each leg that are connected with

a turnbuckle. The three legs come together at the support truss and are connect to the truss with

three ball and socket joints. The tube cradles are connected to the support top using two

protruding pins from the tube cradle base that rest in a holder. This allows the cradles to rotate.

Each of these components will be discussed in further detail below.

The installation of the supports also contains a few components. These components are as

follows:

1) Support separation

2) Labor costs for installation

The separation of the supports was calculated based on the bending properties of the tube. The

tubes were separated a distance that gave a sufficient safety factor but also kept costs low.

Support Legs

The support legs consist of two hollow support rods that are threaded on each end and contain a

ball joint (Figure 11). The purpose of the threads is so the two rods can be connected together by

a turnbuckle. The two rods that make up each leg will have threading in opposite directions of

each other to allow the turnbuckle to function properly. The purpose of the ball joint on the other

end of each rod is to connect the legs to the ground and to the support top. The length of the legs

varies based on terrain. To avoid buckling, the overall length of the leg should never exceed 40

times to length of the outer radius of the rod. This will keep the rods classified as short, which

means that the first mechanism that will fail is the compressive strength, not buckling. Each rod

will be hollow with walls that are 8 centimeters thick, ensuring that the cross sectional area is

large enough to keep the working stress far below the critical compressive strength of the steel.

Turnbuckle

This device is a cylinder that has threading on either end of it (Figure 12). This threading

matches the inner threading of the rods. The purpose of this device is to connect the two rods

together to form a leg of the support and to allow fine adjustments to be made to the length of the

support legs (Figure 13). Such adjustments may be necessary if tidal movements of the Earth

cause the ground beneath the supports to shift. Earth tides can cause the ground to shift upwards

of 30cm in a given day [12]. If the support is caused to shift out of the tolerable alignment, the

turnbuckles can be used to lengthen or shorten the legs until the support puts the tube back in

alignment. This works by utilizing the opposite threading of the rods. If an adjustment needs to

be made, the turnbuckle will be twisted to make the legs elongate or shorten depending on what

adjustments are necessary.

Ball and Socket Joint

The ball and socket joints are simple joints that allow rotation in any direction. These will be

used to connect the legs to the support truss. This joint was chosen because it will allow the legs

to rotate in any direction. This allows for flexibility where the legs contact the ground. The ball

connecting the legs to the support top contains two parts: The ball and the connector cone. The

ball is what connects the support top to the connector cone, and the connector cone connects the

ball to the support leg (Figure 14). These pieces are all connected using threads and are screwed

together. The socket is a hollow, partial steel sphere into which the ball will slide securely.

Support Top

The support top is what connects the legs to the tube cradles. This top contains two pieces. The

bottom piece and the top piece come together by screwing them together with a threaded rod

(Figure 15). The top piece also has two pieces on the top that are where the cradles will be

placed. These pieces have a slot for the pins on the cradle to rest to allow for tilting (Figure 16).

This tilting allows the tubes to rest at any reasonable angle.

Tube Cradles

The tube cradles are where the interface between the tubes and supports occur. The cradles are

designed to allow the tubes to rest on the support with few restrictions (Figure 17). The tubes can

slide longitudinally to compensate for thermal expansion and compression. The tubes are only

restricted perpendicular to the path of the tube. This restriction is so wind cannot cause the tube

to shift outside of its tolerable alignment. The cradles will have the tubes situated side by side.

This is to reduce the amount of torque put on the supports due to wind. The decreased cross-

sectional surface area of the tubes with respect to the wind direction is what reduces this force.

Support Separation

When determining what distance the supports should be placed apart, the bending properties of

the tubes were considered. The tubes contain certain bending properties that cause them to bend

due to gravitational forces. The calculation done was based on the minimum turn radius of the

tube at a capsule speed of 500 kilometers per hour. This minimum turn radius is 1,950 meters

[13]. The calculation of the amount of bending that would occur was based off of a beam with

simple supports [10]. The Young’s Modulus elasticity constant of the tube material Ductal® that

was used was 50 gigapascals [11]. Upon completion of the necessary calculations, it was

determined that the tubes should be placed 25 meters apart. This separation distance has a safety

factor of over 3.5 to 1 with respect to the minimum turn radius at 500 kilometers per hour.

Cost Estimate

The cost estimate for this system is on a per kilometer basis. Factors that were taken into account

when estimating the cost were labor cost, material cost, and equipment cost. The final cost

estimate was $977,333.40 per kilometer. This figure is based on the factors stated above

assuming the supports are 25 meters apart, and that there are two tubes and two joints for every

25 meters. Please refer to the detailed cost table for a breakdown of this estimate (Table 1).

Assembly/Operating Instructions

Tube

In terms of tube assembly, it is crucial that the permanent magnets and linear motor coil from

one tube to the other are accurately aligned with one another. At very high speeds, a slight

misalignment can be felt as a huge bump while in the capsule. Severe misalignments may cause

disasters. Proper alignment can be achieved by ensuring the tubes are bolted together at the joint

at the right bolt holes. Indexing the bolt holes on the tube and joint should make it easy to

identify which bolt holes should line up together during installation. Where bent sections are

required, the tubes should be made to gradually bend, minimally relative to each other, over a

particular range. The tubes should form a smooth function instead of having abrupt

discontinuous points along the curvature. In addition, extra precaution should be taken when

transporting, loading and unloading these concrete pipes as mishandling it may result in shape

deformations which would cause misalignments. The American Concrete Pipe Association has

some general handling guidelines which are appended in the graphics section. (Figure 18) As for

maintenance, this tube design facilitates simple tube removal and replacement. Any tube section

can be removed by simply removing the bolts and rods and vertically sliding the tube section out

of place. (Figure 3)

Joint

The distance from the outside of one lip on the joint to the other must be 19 cm at 20˚C. If this is

not the temperature when the joint is installed, the distance should be calculated by the following

equation where d is the distance and T is the temperature: d=19.6cm-0.03cm/˚C*T. This distance

can be achieved by compressing or expanding the joint. Achieving this distance will ensure that

the joint always has enough room to expand or contract under changing temperatures regardless

of the temperature when it was installed. A joint may become damaged from time to time. If this

is the case, the section of tube it occupies will need to be temporarily shut down and the joint

must be removed and replaced as quickly as possible.

Support

The supports will be installed 25m apart in order to maintain an acceptable amount of sagging in

the tubes between supports, with the supports in the middle of each tube, halfway between joints.

This will simplify the construction, allowing for a support to be built and then simply set the tube

on top of it without the joint interfering. The supports will be prefabricated in pieces (concrete

pad, socket, legs, turnbuckle, and truss) and then simply assembled on site. The concrete pad can

be set down, the socket bolted onto it, and then the legs inserted into the socket all with the use

of a crane. These supports will be largely self sufficient, but if they shift out of tolerance then a

maintenance crew can use the turnbuckle to adjust the length of the legs back into tolerance. This

is something that could potentially be made to be self regulating with the use of a custom made

software program which would measure the strain on the joint and automatically move the

turnbuckle to compensate.

Summary

In conclusion, this project regarding modularity of ET3’s tube design involves three main

components. The first component is the composition and design of the tube sections between

joints. The second component of the project is the joints of the tubes. The design of this

component is a sealed joint supported by large Ductal rods that maintain a consistent flexural

strength throughout the entire tube. The third component is the supports of the tube to keep them

above the ground. The design is like a tripod with three legs that go from the ground to the tube.

The tube will rest in a cradle-like structure at the top of the tripod to ensure that it can move

relative to the support should the land beneath it shift.

We would like to express our gratitude for this project ET3 has allowed us to work on. The

innovation involved and the opportunity to work with people who are changing the future of

transportation is truly remarkable. From this point forward, we feel that reviewing our designs

with a professional team and working on supports for high risk areas is the best way to proceed

with the modular tube approach.We hope that we have been able to offer you an effective design,

and if you have any questions please contact Joe Waite via email at jwaite@mines.edu or by

phone at 651-808-4258.

References

[1] Oster, Daryl, and Jack Panter. Letter to Dr.Natalie Van Tyne. 20 Aug. 2013. MS. N.p.

[2] Evacuated Tube Transport Technologies, Why ET3? ET3.com, 2013. [Online]. Available:

et3.com [Accessed: 23 Nov. 2013]

[3] Evacuated Tube Transport Technologies [Online] Available: http://et3.com/faq

[4] Oster, Daryl, “Evacuated Tube Transport”, U.S Patent 5 950 543, Sept, 14, 1999

[5] Brundrett, Laurence (2012, July, 5) External Pressure [Online] Available:

http://www.pveng.com/ASME/ASMEComment/ExternalPressure/ExternalPressure.php

[6] Wachel, J.C, “Piping Vibration Analysis” Engineering Dynamics Incorporated. San

Antonio, Texas.

[7] NCDC, Global Measured Extremes of Temperatures and Precipitation, ncdc.noaa.gov,

20 Aug. 2008. [Online]. Available: http://www.ncdc.noaa.gov/oa/climate/globalextremes.

html [Accessed: 30 Oct. 2013]

[8] Holz Rubber Company, Pipe Expansion Joints, holzrubber.com, [Online]. Available:

http://holzrubber.com/expansion-joints/pipe-expansion-joints/ [Accessed: 29 Oct. 2013]

[9] Elastomer Specification Tables, Holz Rubber. [Online]. Available:

http://holzrubber.com/wp-content/uploads/downloads/2013/08/Holz-ELASTOMER-

tables.pdf [Accessed: 30 October, 2013]

[10] Bending Stress For Simple Shapes, ATC Publications. [Online]. Available:

http://www.atcpublications.com/Sample_pages_from_FDG.pdf [Accessed: 30 Oct. 2013]

[11] Mechanical Properties, Lafarge. [Online]. Available: http://www.ductal-

lafarge.com/wps/portal/ductal/6_5-Mechanical_performances [Accessed: 28 Oct. 2013]

[12] Milbert, Dennis. Solid Earth Tides. [Online].

http://home.comcast.net/~dmilbert/softs/solid.htm [Accessed: 27 Oct. 2013]

[13] Rail vs. ETT. [Online]. http://et3.com/rail-vs-ett [Accessed: 25 Oct. 2013]

[14] Bigge Crane and Rigging Co. Crane Rental Rates. [Online].

http://www.bigge.com/crane-rental/crane-rental-rates.html [Accessed 28 Oct. 2013]

Appendix A: Calculations

Tube:

Weight of Tube Mechanics (Fixed ends support):

w = V ρg/L

V = πh(ro2-ri

2)

ρ = .5417 ton/m

E = 50 GPa

L = 25 m

ro = .75 m

ri = .7373 m

w = 4.824 kN/m

σflexure = My/I

σflexure = 30 MPa /F.S.

F.S. = 1.5

I = π/4(ro4 – ri

4)

Mmax = wL2/12

Mmax = 125.6 kN*m

deflextion = wL4/384EI

radius of curvature = 13 km

E = 50 GPa

Bending Mechanics (Cantilever Beam):

Fmax = σflexure I/Ly

Deformation = Fmax L3/3EI

radius of curvature = 9.23 km

Joint:

Thermal Expansion:

-68 oC < T < 58

oC

ΔL = ΔT*k

k = 12 mm/m/ o

C

ΔL = 3.78 cm

At 20 oC

ΔL = 1.2 cm

Length of Long Rods:

end to end flange length, L = 19 cm + 6.5*2 cm + 2*2 cm = 36 cm

expansion at coldest = 5.16 cm

L = 41.16 cm

At 20 oC

ΔL = 1 mm

End to End Length of Joint:

d = L + ΔL = 19 cm + ΔT*k

d = 19.6 cm - .03 cm/ oC*T

Thickness of Flanges:

L1 = length of long rods = 19 cm

L2 = distance from edge of lip to long bolt = 1.25 cm

t1 = thickness of long rods = 6.5 cm

t2 = thickness of flange

10L2/t2 = L1/t1

t2 = 6.5 cm

Width of long rods:

r = radius of long rods

L = length of long rods

n = number of bolts

r = (L/n/578.78)1/3

r = 3.2 cm ~> 6.5 cm

Support:

A = πr^2

σ = F/A

σw ≤ σc

σc = 152 MPa

Ac < F/ σc

Rc = (Ac/π)½

Rc = .00250 m

L/r < 40

L = 10 m

R = .25 m

Tube Overall Design

Tube lip has

a slightly

bigger

diameter

Figure D1: Tube Overall Design

DAEVIN DEV

Lip End Cross

Section

Isometric

View

Isometric View Zoomed

In

Tube Middle Cross-

Section

Tube Side

View

Lip End Cross

Section

Combined Tube Alignment

Figure D2: Combined Tube Alignment

DAEVIN DEV

Combined Tube Top View Cross-

Section

Tube

1 Tube 2

Rubber Joint

Seal

Ductal® concrete rods

that bypass rubber

seals

Proper Concrete Pipe Handling

Figure D4: Concrete Pipe Handling

DAEVIN DEV

Removing & Replacing Tubes

Figure D3: Removing & Replacing Tubes

DAEVIN DEV