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| College & Team Information | |||
| College or University: | Student Chapter: | ||
| Address: | |||
| Phone: | Fax: | E-mail: | |
| Website address: | Faculty Advisor: | ||
| Person In Charge of Project: | |||
| Team Member | Class | Team Member | Class |
| Hours spent on project: | Cost of Material ($ Amount) | ||
| Student: | Faculty: | Donated: | Purchased: |
| 1. Abstract - (Max 500 word narrative) | ||
| The design concept was based on four goals. To produce a bridge that has maximum performance is simple, easily constructed, and cost effective. In order to achieve maximum performance stiffness was placed as the main concern. Therefore all calculations and design decisions were made with minimal deflection in mind. In response to this, the decision was made to use vertically glued-laminated T-beams. The beams were constructed with three quarter inch plywood as a wide web and dimension lumber as the flange. The deck was laid transversely across the beams. The system of beams utilized one large center beam (7.5 inches thick), and two smaller outside beams (3.5 inches thick). Two by fours were employed as flanges which provided the beams a good connection surface for decking as well as a connection to lateral bracing. Considering placement of the bridge in the design, Pressure Treated Southern Pine was utilized. The bridge developed more than adequate stiffness to minimize deflections. This allowed the bridge to easily meet the performance standards set in the competition rules. Overall the requirements set forth by the 2008 competition rules and instructions were met as well as the design criteria set forth by the design team. | ||
| 2. Deflection Table | ||||||
| Deflection (millimeters - rounded to 2 decimal places) | ||||||
| Loading Inc. | Bridge | Beam L | Beam R | Average (L&R) | Gross Deck | Net Deck |
| 5 kN | ||||||
| 10 kN | ||||||
| 15 kN | ||||||
| 20 kN - 0 min. | ||||||
| 20 kN - 15 min. | ||||||
| 20 kN - 30 min. | ||||||
| 20 kN - 45 min. | ||||||
| 20 kN - 60 min. | ||||||
| 1) Loading Increments. | ||||||
| 2) Bridge - As measured at midspan of the longitudinal beam receiving greatest loading. | ||||||
| 3) Beam L - As measured under the longitudinal beam to left of selected deck monitoring point. | ||||||
| 4) Beam R - As measured under the longitudinal beam to right of selected deck monitoring point. | ||||||
| 5) Average (L&R) - Average of 3 and 4. | ||||||
| 6) Gross Deck - As measured under the loading point expected to experience maximum deflection. | ||||||
| 7) Net Deck - Column 6 minus column 5. | ||||||
| Deck span (transverse distance between main longitudinal bridge support members measured from inside edge to inside edge) = mm / 100 = mm (max. allowable net deck deflection) | ||||||
| 3. Materials List | |
| Material Item | Weight (kg) |
| Total Weight (Kg) | |
| Weight Non-wood (Kg) | |
| Percent Non-wood | |
| 4. Summary -Describe Bridge and behavior under load - (Max 500 words) | ||
| The glued-laminated beam bridge design consisted of one center T-beam (7.5 inches thick) and two smaller outside T-beams (3.75 inches thick). The beams were laterally braced using two by four and two by twelve dimension lumber in a frame pattern, and was connected by the two by four flanges we considered part of the beams. Two layers of one half inch plywood and one layer of two by six dimension lumber lay transversely across the T-beams. The decision to use a larger center T-beam than the two outside beams was based on the fact that the interior beam will carry more of the load than the outside beams. This was reflected in the testing results. The bridge deflection followed a linear behavior throughout testing. Creep effects faded within 45 minutes of loading, which suggested that the deflections would increase less over the remaining loads being tested. The center T-beam, while taking more of the load did distribute the load away to the outside beams. Though there were variations in the deflections of the outside beams, the design teaam agreed that those variations may have occurred due to variations in materials or connections during construction. | ||
| 5. Project Drawings and Photos | ||||
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| Longitudinal Cross Section | Tranverse Cross Section | Trimetric View | Project Photo | Team Photo |
| Click on drawing or photo above for larger view. | ||||
| 6. Component Details | ||
| In ten (10) words or less per each component below, describe the bridge: | ||
| Stringers/Girders: | Vertically Glued-Laminated Composite beams with screws for connection strength | Deck: | Three layers, two of plywood and one of 2x6s |
| Floor Beams: | ||
| Suspension: | ||
| Unique: | ||
| Describe preservative treatment for all wood members. Include type and concentrations. Also include a short statement of why this treatment was selected. Did the treatment requirement present any special problems? If yes, provide details | ||
| All wood material purchased was pretreated by the manufacturer for ground contact use. This material was chosen due to accessibility from local suppliers. The chemical used was chromated copper arsenate. There were no problems associated with this treatment that the design team encountered other than a fairly moist product. | ||
| 7. Special Considerations | ||
| In creating a design for this bridge a goal was ease of construction. This design may be constructed off site after simple measurements are taken, which would minimize the impact of humans and machinery on the watershed being crossed. End uses are still being pursued but may include use on a golf course, farm, community center, or several other uses. | ||
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Programming by:Keith Mazer
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