Page 266 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 6 APPLICATIONS OF BRIDGE DESIGN AND RATING METHODS 241

Some states such as Pennsylvania and New Jersey have modifi cations to
AASHTO legal loads. Pennsylvania has adopted a four-axle 18 ft long vehicle
known as ML-80. New Jersey has adopted legal vehicles types 3 and 3-3 but

modified vehicle type 3S2.
6.3.3 Defi cient Bridge

Detailed structural evaluation is required to establish deficiency. The steps include:

1. Frequent inspection
2. Material testing to assess strength of structural components and condition of materials
3. Load rating
4. Nondestructive load testing
5. Remaining fatigue life evaluation.
For conventional bridges, if there is a functional or structural defi ciency the following op-
tions are available:
• Repair
• Rehabilitate
• Replace
• Widen
• Load posting
• Abandon or no action.

6.3.4 Bridge Design and Rating Engineering
A designer has to face nitty-gritty of developing design calculations; CADD drawings and
the related documentation. It appears that in the recent years this multi-disciplinary task has
become specialized and requires the following:

• Public outreach to educate about staging; temporary lane closure and detour
• Obtaining as-built drawings
• Field visit and reconnaissance
• Generating geometric data
• Performing deck drainage calculations and providing scuppers.
• Coordinating with the following disciplines:

1. Highway engineer to obtain alignment; baseline and profile grade line

2. Surveyor to obtain field survey results for topography; grade elevation;
3. Hydraulics engineer for river characteristics such as flood elevation; size of

opening
4. Environmental engineer for maintaining air quality or water quality

5. Traffic engineer for number of lanes; acceleration and deceleration lanes; location
of sign structures
6. Geotechnical engineer for soil information; shallow and deep foundations
7. Utilities engineer for bridge mounted utilities
8. Right of way engineer to allow access to site during construction and materials
storage
9. Electrical engineer for bridge lighting