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Concrete Canoe Team2005
WEST POINT Presents
TEAM AMERICATEAM AMERICA
WEST POINT TEAM AMERICA
TABLE OF CONTENTS
Executive Summary i
Hull Design 1
Development & Testing 3
Project Management & Construction 5
Organization Chart 6
Project Schedule 7
Design Drawing #1 8
Design Drawing #2 9
Appendix A: References 10
Appendix B: Mixture Proportions 11
Appendix C: Gradation Curves and Tables 12
EXECUTIVE SUMMARY The United States Military Academy at West Point is situated in prime canoeing territory
50 miles north of NYC in the scenic Hudson Valley. From this historic ground, tread by world famous patriots: Washington, Grant, Eisenhower, Patton, MacArthur, and many others, comes an equally outstanding group of young patriots. Team America was formed not only to preserve the liberties of the free world, but also to design an innovative concrete canoe to be explained in detail on subsequent pages.
West Point is a four-year undergraduate institution. It produces commissioned officers for our United States Army and also intelligent engineers, as it is among the top undergraduate Civil Engineering Programs in the country. West Point has a 30 year history of participation in the ASCE CCC at a competitive level. Team America is 195 long, 2-6 wide, and 1-3 deep. The hull is on average thick and Team America weighs in at approximately 264 lbs. The concrete strength is approximately 815 psi at 28 days with a unit weight of 59 pcf. It is reinforced with steel Hardwire and is a rich black color with gold lettering.
The concrete mix uses an innovative aggregate composite of multiple grades of polystyrene resins, 3M glass microspheres, and very low-density heat expanded polystyrene. The hull dimensions were designed by the team and incorporated into a very complex and labor-intensive female style mold. The mold was constructed using precise cross-sections surfaced with thin wooden strips, spackle, four layers of paint, and generous applications of form-release agent. During casting, the team used a template to roller-compact concrete strips, ensuring a uniform thickness throughout the hull. Finished with West Point and the Armys colors black and gold it presents a formidable opponent for any competitor.
WEST POINT TEAM AMERICA
1. Hull Design TEAM AMERICA is proud to present West Points first ever computer-aided hull design for this years Concrete Canoe Competition. This year marks the 30th anniversary of the West Point Concrete Canoe Team program, and this is the first time that a West Point canoe was molded from an original computer created design and not from an actual canoe. While this meant more work and venturing into uncharted waters, TEAM AMERICA was up to the challenge. Our hull design is based on commercial canoe dimensions as well as recommended dimension ratios as specified in naval architecture literature (Gillmer and Johnson 1982). The desired range versus our actual design ratios can be seen below: Table 1.1. Design Geometry.
Hull Geometry Length 20' Beam (width) 2' 6" Depth 1' 3" Volume 34.71ft3
Surface Area 67.61 ft2
Max Displacement 2220.75 lb Design Draft*** 9"
***Based off design of 4 inches of freeboard Table 1.2. Design Considerations.
Our Design Recommended
Length/Width Ratio 8.4 3 to 12 Length/Draft Ratio 28 7 to 30 Beam/Draft Ratio 2 1.8 to 4
Our canoe was specifically designed to be long and sleek, with our canoe length being longer than those canoes produced by West Point in previous years. This is based on the concept of hull velocity, which is a function of wavelength and waterline length (Gilmer 1975). By making our canoe long and sleek, it
increases the wavelength of waves the canoe produces, thus increasing its potential speed. Also, by using the naval architecture ratios of length/beam, length/draft, and beam/draft we were able to ensure our canoe was designed with sound engineering principles. In order to design the canoe efficiently, TEAM AMERICA used the software program Maxsurf, which is used by ship builders for projects ranging from sailboats to nuclear submarines. While the program was initially difficult to use, the tutorial quickly made the design user friendly.
Figure 1.1. Plan view of TEAM AMERICA.
Figure 1.2. Elevation view of TEAM AMERICA. By using Maxsurf we were able to generate cross sections at specified intervals and then to plot full-size cross sections. Also, Maxsurf gave us the capability to plan for the amount of reinforcing and mix that would be needed for construction by providing important geometric calculations. Finally, the program calculated important hydrostatic relationships which helped validate our design.
Figure 1.3. Cross Sectional View of TEAM AMERICAs hull.
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WEST POINT TEAM AMERICA
2. Analysis 2.1 Hull Analysis The first design goal for the hull was to ensure that the design strength was greater than the required strength for all limit states, including positive and negative moment flexure, shear, punching shear, and plate bending. Positive bending moment creates the greatest potential for cracking. Our second goal was to limit cracking by ensuring the hull was compression-controlled (net tensile strain in steel, t, less than 0.002 at nominal) for positive moment in accordance with ACI 318-02, 9.3.2. In order to achieve our goals, we iterated the thickness and reinforcing configuration until our design goals were met. We selected Hardwire-3X2-4WPI mesh reinforcing for use in our hull. The Hardwire had the following properties: yield stress of 60 ksi, elastic modulus of 30,000 ksi, and 4 strands of wire per inch of mesh. We also conservatively assumed the compressive strength of our concrete to be 800 psi with a unit weight of 62.4 pcf. Using the computer program Visual Analysis, we constructed an equivalent beam that would model the size of thirty different cross-sections of the canoe over its 20-foot length. We modeled the canoe cross-sections as idealized U-Shapes with differing moments of inertia. After constructing the equivalent beam, we modeled three different load cases on the canoe. The first load case modeled the canoe in the water with four paddlers. We placed four single point loads of 200-lbs at even intervals along the canoe, as shown in Figure 2.1.
Figure 2.1: FBD of hull with passengers.
The next two load cases modeled the hull as a simply supported canoe (carried by a person at each end) supporting its own self-
weight. One load case modeled the positive moment, and the other modeled the negative moment. The two are equal and opposite; loading is shown in Figure 2.2.
Figure 2.2: FBD of hull with self-weight.
Required punching shear, normal shear, and local bending moment were all calculated using a column footing analogy. We modeled a rowers two knees as a 10-inch square column with a maximum load of 200 lbs. We assumed that the base of the hull would act as the footing. The results from Required Strength calculations are presented in Table 2.1. 2.2 Design Strength The design strengths for positive and negative moment were calculated in accordance with ACI 318-02, using the technique of strain compatibility and internal force equilibrium. The normal shear design Strength is taken from ACI 18.104.22.168, punching shear design strength is from ACI 22.214.171.124, and local bending moment is from ACI 10.2. Results of the design strength calculations are summarized in Table 2.1. Table 2.1: Summary of Design and Required Strengths.
Steel Strain (in/in)
Positive Moment 0.0019 3088.7 ft-lbs
Negative Moment 0.2378 2561.8 ft-lbs
Local Bending 0.0025 57.8 ft-lbs
Normal Shear - 475.2
lbs 82.2 lbs
Punching Shear - 718.7
In conclusion the final canoe design, with inch of thickness and 1 layer of Hardwire, meets our design goals for all five limit states.
200 lbs 200 lbs
200 lbs 200 lbs
WEST POINT TEAM AMERICA
3. Development and Testing The primary focus of the development
was on the concrete mixture itself. Our team identified the concrete mix as the controlling aspect which dictated the other facets of design (i.e. reinforcement, hull design). The goal concrete mix must be both stronger than 800 psi and less dense than water. Reinforcement must then be selected which will increase the tensile and flexural strength of the canoe as determined by the hull analysis. 3.1 Concrete Mixture Development
Aggregate - The 2005 concrete mixture was driven by the requirement of aggregate to be graded within the bounds of ASTM C33 for fine aggregates. In addition to meeting the grade requirement, properties desired for the aggregate composite are: relatively strong, does not crush or deform with mixing, easily obtainable, and lighter than water to counter-act the higher density of binders within the mix. Many aggregates tested, including charcoal, perlite, and sawdust, removed water from the paste due to their absorptive properties, increasing the density and resulting in very little or no workability in the concrete. Some of these aggregates, more specifically perlite, was often pulver