National Timber Bridge Design Competition - 2019

1. National Timber Bridge Design Competition - 2019 College or University Name: Oklahoma State University Student Chapter (ASCE or FPS): ASCE Address: 207 Engineering South, Stillwater, OK 74078 Website Address: http://cive.okstate.edu Faculty Advisor: Dr. Robert Emerson Email: Robert.emerson@okstate.edu Phone: (405)-334-1439 Student Member in Charge of Project: Josh Fisher Email: josh.fisher10@okstate.edu Phone: (918)-691-2521

2. Hours Spent on This Project Students: 50 hours Faculty: 5 hours Cost of Materials Donated: ~ $150 Purchased:

3. Abstract (Maximum 500 Word Narrative): Explain the bridge design concept and what was done to optimize stiffness wile attempting to minimize weight of the structure. The concept of our bridge was to build a Howe truss because our team found this to be the most aesthetically pleasing while also contributing to carrying the load throughout the truss to the supports. For the diagonal and vertical members of the truss, we used 2x4’s and to optimize stiffness and strength of the truss we used 2x6’s to sandwich the top and bottom of those members. The bottom chord consisted of three 2x6 members which were spliced together with metal plate connectors. To connect the truss vertical and diagonal members, we used ½” and 5/8” bolts. To decide the needed bolt we conducted analysis through Mastan to configure the loading being applied at those points. We also put in a total of 8 screws (#8 – 2-1/2”) at each intersection of the chords and the vertical/diagonal members of the truss Our transverse members in the deck were 2x6’s. To increase stiffness and have less weight, we used joist hangers to connect to the bottom chords of the trusses and then created a box beam by applying ½” plywood on the bottom of the bridge and 3/8” plywood on the deck. Each joist hanger and plywood connection used #9 – 1-5/8” screws.

4. 2. Deflection Table (Deflection – millimeters rounded to 2 decimal places) • Loading Increments • Bridge – As measured at midspan of the longitudinal beam receiving greatest loading. • Beam L – As measured under the longitudinal beam to left of selected deck monitoring point. • Beam R – As measured under the longitudinal beam to right of selected deck monitoring point. • Average (L & R) – Average of 3 and 4, above. • Gross Deck – As measured under the loading point expected to experience maximum deflection. • Net Deck – Column 6 minus Column 5. Deck Span: Transverse distance between main longitudinal bridge support members measured from inside edge to inside edge = __1500___mm ÷ 100 = _______15_____mm = maximum allowable net deck deflection.

5. 3. Materials List

6. 4. Summary – Describe Bridge and Its Behavior Under Load (max. 500 words) Our bridge passed all deflection tests and held up very well. The load was carried through the transverse 2x6 members of the deck to the bottom chord of the truss then up through the vertical tension member to the top chord and then out to the diagonals and to the supports. Overall, our deck was well within its boundaries of deflection and the one side of the truss endured more deflection, however, as a whole it passed.

7. Side Drawing (insert below)

8. End Drawing (insert below)

9. Trimetric Drawing (insert below)

10. Drawing Clearly Showing Location of Loading and Deflection Gage Points in Relation to Longitudinal Members (insert below)NOTE: Repeat slide if loading set-up was moved to measure deck deflection.

11. Drawing Clearly Showing Location of Loading and Deflection Gage Points in Relation to Transverse Members (insert below)NOTE: Repeat slide if loading set-up was moved to measure deck deflection.

12. PHOTO Showing SIDE View of Loading Setup for Measuring Bridge Deflection (insert below)NOTE: Repeat slide if loading set-up was moved to measure deck deflection.

13. PHOTO Showing END View of Loading Setup for Measuring Bridge Deflection (insert below)NOTE: Repeat slide if loading set-up was moved to measure deck deflection.

14. End Photo of Finished Bridge

15. Side Photo of Finished Bridge

16. Trimetric Photo of Finished Bridge

17. Team Photo (with bridge in the foreground, where possible)

18. 6. Bridge Component Details

19. 7. Preservative Treatment: Describe the preservative treatment applied to 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. If treatment was not selected, explain why. Our wood was treated with copper azole preservative for our southern pine grade 2. For the specific usage we designed for this preservative process helps the wood withstand environmental conditions and protects against termites, microorganisms, and fungal decay. This treatment is applied by forcing this chemical compound into the lumber by pressure. Our treated lumber is predicted to last 20 years. The issues we ran into in construction were due to the lumber being so green it prevented the full effectiveness of our tools. Also considering we did not use galvanized bolts, they will degrade over time due to the pressure treatment in the lumber. We chose this treatment because we wanted to use southern pine grade 2 and this treatment was readily available to us in our location.

20. 8. Special Considerations –Indicate the End Use of Your Bridge The end use of our bridge is to use the bridge on campus at Oklahoma State. Every year the timber bridge teams are contacted for potential use and we hope to have the opportunity to be chosen. Until a location is chosen, it will be on display at the Bert Cooper lab.

21. 9. Summarize the Team’s Experience from Participation in this Competition. Was it beneficial? What steps would you recommend to improve the experience? • Overall, our team learned a lot about team work and our individual strengths and weaknesses. We all learned about wood work and the best ways to make cuts. For future classes, having a better understanding of the appropriate checks to make in advance to the construction process would be very beneficial. We also could have benefitted from measuring twice and cutting once to the correct dimensions.

22. Photo of Bridge Weighing

23. One photo of each deflection gauge at full loading, with identification sign indicating DECK, BEAM LEFT, BEAM RIGHT, BRIDGE.

24. Add as many photos as you wish showing the bridge construction process. Especially consider photos of internal structural components that may not be visible to judges from observing the finished bridge.

25. Add as many photos as you wish showing the bridge construction process. Especially consider photos of internal structural components that may not be visible to judges from observing the finished bridge.