Evaluation of an earth heated bridge deck.

Details

• Creators:
  Nydahl, John ; Pell, Kynric ; Lee, Ron ; Sackos, John
• Corporate Creators:
  University of Wyoming
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  Bridge Decks Bridge Design Bridges--Floors Bridges--Snow And Ice Control Cost Effectiveness Evaluation Heating-pipes Heat Pipes Snow And Ice Control
• Publication/ Report Number:
  FHWA-WY-84-001
• Resource Type:
  Tech Report
• Geographical Coverage:
  Wyoming
• Edition:
  Final report.
• Corporate Publisher:
  Wyoming. State Highway Department
• Abstract:
  The design, construction, performance and analysis of the first ground heat pipe
  
  system to heat an entire bridge deck are detailed. Each of the sixty heat pipes in
  
  this system is comprised of a 6 em (2.4") diameter, 31 m (lOO')_long vertical ground
  
  evaporator, and a condenser that was forme~ by manifolding 2.5-cm (1") pipe on 15 ~m
  
  (6") centers to heat 7.6 m2 (82 ft2 ) of deck surface. Ammonia vaporizes in an
  
  evaporator anytime the encompassing ground is warmer than the bridge deck, and this
  
  vapor ascends into the condenser section where it releases its heat of vaporization
  
  to the deck.
  
  The integration of the heat pipes into the bridge deck did not have a
  
  significant impact on the bridge construction. The heat pipes increased the deck's
  
  weekly averaged surface temperature up to l0°C (l8°F), preventing preferential
  
  freezing of the deck relative to the adjacent road. Sno:w cover duration was decreased·
  
  by 50% despite a ground temperature of only soc (46°F). The m~n~mum dynamic
  
  conductance of this system during major heating events appears to be between 8 and 11
  
  watts per m2 of deck per oc temperature difference between the far-field ground and
  
  the deck surface. A thermal model was developed to accurately handle the complex •
  
  dynamic interactions between the heat pipes, the deck, and the ·ground. Parametric:
  
  studies based on this model were used to formulate a heat pipe system thermal design•
  
  procedure which is presented in the design manual. The heat pipes accounted fo.r 59% ,
  
  of the total bridge cost with the evaporators generating 69% of the system's expense;'
  
  but it wo~ld be economically viable to utilize a few ground source heat pipes to heat
  
  only the tire tracks and gutters.
  
  
• Format:
  PDF
• Funding:
  DTFH61-80-C-00053
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:bfc7e63f0ba2317196c77f43c98b2a4b5c22c1a83c3b722266d71b3a1e95c10c
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25905/dot_25905_DS1.pdf
• File Type:
  [PDF - 7.75 MB ]