Page 47 - Bridge and Highway Structure Rehabilitation and Repair

22 SECTION 1 ADMINISTRATIVE ISSUES

3. Diagnosis of defects and classification of deficiencies are based on procedures provided in

the AASHTO Recording and Coding Guide. The sufficiency rating method is used.
4. Rating analysis is carried out for acceptable live load trucks. Inventory ratings and operating
ratings are computed based on formulae for load capacity.

5. Condition rating and sufficiency rating are evaluated.
6. In addition to live load ratings, ratings for extreme events such as scour suffi ciency rating
and seismic rating are computed using special methods.
7. A structural team prepares diagnostic design and construction documents based on recom-
mendations from the inspection report.
8. A rehabilitation report is prepared for record purposes and includes a feasibility analysis
and approximate costs.

1.7.3 Developing a Maintenance Manual for the Owner
1. Since many times the highway agency is overseen by a non-technical person, the importance
of the engineering aspects of maintenance may not be fully appreciated. If a prescribed
manual is made available in simple terms highlighting the importance of rehabilitation,
methodology, and life cycle costs, it can make decision making for funding easier and more
timely.
2. For minimizing future life cycle costs, a maintenance manual (akin to that of a maintenance
manual provided with a car at the time of purchase) should be developed and provided for
future use by maintenance engineers.
3. Most highway agencies appoint consulting teams for inspection and rehabilitation of thousands
of bridges each year. In such situations, a maintenance manual is required for uniformity of
methods for all the bridges under the control of the agency.
4. Methods for repairing an old bridge are different from the newer types due to the materials
used, span length, lane width, etc. A maintenance manual should address the uniqueness of
each material. It will be unique for each type of bridge since the technology used for timber,
steel, or concrete bridges would be different.
5. Sections 2 and 3 of this book address the theoretical and practical concepts and procedures
for the rehabilitation, repairs, and computer aided design, which form the basis of a main-
tenance manual. Guidelines given in the manual will be different for each bridge and will
depend upon the type of bridge, its function, and performance.

1.7.4 Maintenance Manual Contents

1. A maintenance manual may be included in the scope of work of the structural engineer or
the owner’s representative. A maintenance checklist needs to be provided which includes:
• Inspection methods
• Structural health monitoring
• Rating and structural evaluation
• Diagnostic design, repair, or retrofit methods including repainting.

2. Contract documents: The following documents shall be made available with the proposed
maintenance manual for future use and reference:
• As-built drawings
• Ready access to construction history and any special features to be monitored
• Technical specifi cations
• Actual strengths of concrete, steel, and other materials from laboratory tests
• Details of vendor supplied products such as bearings and connections.