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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 bridge design concept stemmed from previous competition bridge designs that included an over arch and horizontal tie system. The concept was to provide many pathways to transfer the test loads and real-world loads throughout the bridge system. The load transfers through many different members which all have a specific purpose. First the load is applied to the tongue and groove deck system. By using this type of system, the load is transferred more efficiently to the horizontal glulam tie and to the transverse deck members. The load is then transferred from the horizontal glulam tie and the transverse deck members to the plywood tension board and the glulam arch. The glulam arch is also held in place by the glulam tie. In order to optimize stiffness, the arch and horizontal tie were constructed using glulam technology. Thin strips were cut from 2x6 pressure treated Hem-Fir and glued to create the shape and size of the glulam arch. Sheets of plywood were placed between the outside and inside faces of the glulam arch to increase stiffness and to provide strength in tension. In order to optimize stiffness while minimizing weight for the deck system, the system was built using a tongue and groove technique. This technique allowed the deck load to be transferred efficiently while minimizing the number of transverse members necessary for the system. | ||
| 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 bridge behaved exactly as intended under loading. The inclusion of the plywood tension boards made the bridge very efficient in transferring the deck loads to the glulam arch. With such a minimal deflection, it was difficult to see how the bridge reacted under the large test load. Although the tongue and groove deck was not constructed so that each of the boards attached to one another, this was still a very efficient system. The deck only deflected half of what was allowed under the competition rules. When testing for the whole bridge deflection, the bridge hardly deflected at all. The load was therefore effectively transferred to the glulam arch via the plywood and the decking system. The arch was also effectively held in place by the glulam horizontal tie, and therefore did not buckle. | ||
| 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: | Glulam made of 2x6 Hem Fir cut in thin strips | Deck: | 2x6 treated Hem Fir cut with tongue and groove pattern |
| Floor Beams: | ||
| Suspension: | Glulam Arch made of 2x6 Hem Fir cut in thin strips | |
| Unique: | Plywood sheets placed between glulam arch and tie to provide extra strength and stiffness | |
| 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 | ||
| The preservative treatment used on all of the wood products used in this competition was ACQ(alkaline copper quaternary) at O.4 pcf for all members. The Orange Team used ACQ because we wanted to use all commercially available pressure treated wood, and therefore not have to treat the wood on site, which is difficult and costly. | ||
| 7. Special Considerations | ||
| The project was extremely beneficial to both the design and the construction teams. This was the first wood design project for most of the students and therefore required much iteration. First both the construction and design teams met to discuss possible bridge designs. As a team, the current design concept was decided upon. Next, the design team met to discuss specifics including how to attach the plywood to the glulam members and how the deck would be laid out. The connections team (part of the design team) had to learn material for the connections design without being taught how to design for them in the wood design class. This problem also arose for the rest of the construction | ||
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Programming by:Keith Mazer
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