Page 318 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 7 BRIDGE WIDENING AND DECK REPLACEMENT STRATEGY 293

6. Accident potential: Geometrics, such as substandard sight distances, grades, and super eleva-
tions which contain clear potential for accidents, need to be improved. Those improvements
may favor replacement. The review of geometrics should include bridge width, horizontal
clearances, alignments, etc.
7. Live load restriction: When considering rehabilitation, the load rating will be checked,
especially if it is posted.
8. Accelerated construction: The resulting rehabilitation or reconstruction activities would
require temporary closures or detours, thereby causing significant reduction in the public’s

mobility. It would lead to traffic congestion, delays, and work zone accidents. Interruptions
interfere with the ability to reliably plan travel time and adversely affect commerce and

Table 7.6 Comparative study of bridge rehabilitation (REH) versus replacement (REP).
Subject Impact Reconstruction Option
1. Historic Bridge? Yes REP not feasible
No REH or REP
2. Defi cient geometry or Number of fatal accidents < statewide Warning signs to be posted for defi ciency
road condition causing average but no potential for accidents
fatal accidents? Number of fatal accidents < statewide REH or REP to correct safety problem
average but potential for accidents
Number of fatal accidents 9 statewide average REP
Impact of defi ciency affects highway, navigable REP
waterway, or railroad traffi c below bridge
3. Relative cost of REH/REP 9 1.5 REH
rehabilitation/
replacement?
REP/REH 3 1.33 TO 1.5 REH or REP
REP/REH 9 1.33 REP
4. Redundancy of bridge? Non-redundant REH or REP by adding redundancy
Redundant REH or REP
5. Fatigue sensitive Yes REH or REP by removing critical details
details?
6. Bridge conforms to Conforms to standards REH or REP
AASHTO and state
code standards?
Deviation from standards are acceptable -do-
Can be brought up to standards by REH REH
Cannot be brought up to standards by REH REP
7. Inadequacy of river Hydraulic inadequacy REP with span adjustment
opening size or poor
No hydraulic inadequacy REH or REP
stream alignment?
8. Maintenance and Construction staging is feasible -do-
protection of traffi c?
Detour is feasible -do-
Bridge on new alignment is feasible -do-
Temporary structure is feasible -do-