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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 Washington University design team decided to try to build a composite decked bridge with handmade I-joist members as girders, to try to minimize weight while also providing a stiff structure. 2x6 and 2x8 members were assembled longitudinally as the deck members, with the joints staggered as to not have a continuous weakness at the center of the bridge. 3/4" plywood was used as the web material for the girders. 1x4 purlins were spaced at 15" O.C. to help distribute the load on the deck to the girders, although we ran out of purlins during construction, and had to omit the purlin at midspan. The bottom chord of the girders consisted of 2x4 members glued to the sides of the plywood. Clamps and wood screws were used in the construction of the bridge, with the screws merely holding the members together while the wood glue was setting. | ||
| 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 load was applied with a hydraulic press supported by a rigid steel frame. The load was transferred to the bridge via 3 I-beams in an H formation. The point selected for the deck deflection was at midspan, in between 2 of the girders. For the deck test, 20 kN was applied, and the deflections were measured (we were unaware that this test must be applied for 1 hour along with the bridge deflection test). The bridge was then moved into position for the bridge deflection test. The load setup was the same as required in the MSRCD materials. The bridge performed very well, meeting both the deck deflection criteria (L/100, not L/400) and the max bridge deflection criteria. | ||
| 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: | (4)griders - plywood web with 2x4 bottom chords | Deck: | 2x6, 2x8 members laid flatwise longitudinally |
| Floor Beams: | 1x4 purlins | |
| 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 | ||
| Chromated Copper Arsenate (CCA-C), 0.4 pcf. The wood was allowed to dry for several weeks before construction, so the preservative treatment posed no problems. | ||
| 7. Special Considerations | ||
| After the bridge test, we decided to find the maximum load the bridge could carry. The load cell used could only read up to 15,000 lbs (about 66.7 kN, more than 3 times the test load), and the bridge did not break with this load. | ||
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Programming by:Keith Mazer
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