Page 312 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 7 BRIDGE WIDENING AND DECK REPLACEMENT STRATEGY 287

3. Value engineering.
4. Satisfactory functional requirements.
5. Aesthetics.
6. Public involvement.

7.3.4 Tips for Good Planning
Good planning includes the following:

1. Planning for geometry, minimum skew or curvature, adequate sight distance, suffi cient
horizontal or vertical clearances, and adequate opening over waterway.
2. Meeting the functional requirements such as providing an adequate number of lanes to
prevent overload, and posting of warning signs and directions ahead of the bridge.
3. Using design aspects resulting in minimum deflection and vibration of girders, using joint-

less deck, keeping deck surfacing uncracked, unrestricted bearing movements, and ductility
of joints.
4. Providing facilities for ease of maintenance such as a provision for inspection chambers,
structural health monitoring by remote sensors, and nondestructive testing.
5. The construction industry has also benefited from the use of new machinery, cranes, and

tractor trailer vehicles for freight. Precast concrete technology and pre-assembled replacement
bridges offer quick and reliable solutions by minimizing delays and reducing construction
time.
6. Using modern high strength and corrosion resistant materials.
Experience has shown that if any of these is lacking, indirect costs in terms of structural
damage, accidents, or delays (which were not provided for in the original budget) will accrue.

7.3.5 Further Planning Considerations
1. Tables 7.1 to 7.3 list a variety of available options between minor and major repairs, retrofi t,
rehabilitation, and replacement. In general, replacement alternatives for a substructure need
not be considered. In considering superstructure replacement, the substructures must fi rst
be evaluated. This evaluation may include in-depth inspection, performing NDT, and taking
cores to verify their condition.
2. For historic bridges, replacement is generally not an option except for safety reasons, and
rehabilitation is to be carried out.
3. The functional importance and how important a bridge is to the overall transportation system
of the area need to be considered. In addition to structural adequacy there are other social,
political, and capacity related considerations.
4. Accident history and potential must be examined.
They must be examined for the bridge project. In terms of safety for the RH/RP decision,
accident history is the most important element. The accident history can be determined

by examining the accident reports on file. Although sometimes inconclusive, this review
should look for trends in accident patterns that would point to whether the bridge caused or
contributed to the accidents.
5. Expected useful life.

Tables 7.2 and 7.3 show a comparative study of expected useful life.