The Snake Road Bridge was retrofitted 6 years ago in 2015. This assessment lists findings of how the the bridge has aged in the past 6 years, and how we can learn about design, construction and maintenance of future timber structures by examining how they are aging.
1. Decay of Deck Support
Objective Evidence of Degradation: Here the top of the vertical member supporting the railing was left unprotected. The column is cracking and is allowing water to seem into the bright wood.
Long Term Consequences: Left unaddressed the humidity and moisture will seep into the member leading to fungal decay.
Root Cause: The design overlooked the need for adequate drainage on the vertical members.
Immediate Correction: Install a cap similar to a newel post cap.
Long Term Corrective Action: Apply a fumigant (Borate) to kill fungus and pests, apply wood filler.
2. Untreated Damage to the Deck Railing
Objective Evidence of Degradation: The left railing is damaged. The damage appears cosmetic and not structural.
Long Term Consequences: Left unaddressed the bright-wood will be susceptible to fungal decay.
Root Cause: Design oversight.
Immediate Correction: Fumigate and protect.
Long Term Corrective Action: Grind or plane end to create a smooth finish. Apply xxx and an end cap?
3. Cracks in Horizontal Deck Member
Objective Evidence of Degradation : Here the horizontal deck member is cracking and exposing the bright wood
Long Term Consequences: Bright wood is exposed and will decay over time.
Root Cause: The timber was not dry when used for fabrication.
Immediate Correction: Apply fumigant.
Long term Corrective Action:
4. Fungal & Lichen Growth on Railing
Objective Evidence of Degradation: Here the top of the railing shows growth of lichen and possibly fungus.
Long Term Consequences: The wood will decay.
Root Cause: The railing was not treated.
Immediate Correction: TBD
Long term Corrective Action: TBD
5. Exposed Knot in Railing
Objective Evidence of Degradation:
Long Term Consequences:
Root Cause:
Immediate Correction:
Long term Corrective Action:
6. Sinking Tarmac
Water Stains Under Deck
Objective Evidence of Degradation: Sections of the deck are sinking. Water is seeping through deck and reaching the underside.
Long Term Consequences: Deck will decay sooner than expected.
Root Cause: Tarmac wasn’t applied correctly.
Immediate Correction:
Long term Corrective Action:
7: Splitting of Railing Ends
Objective Evidence: The ends of the railing are splitting
Consequences: Bright wood will get exposed and will decay.
Root Cause: Not known.
Immediate Correction:
Long Term Corrective Action: