AASHTO - American Association of State Highway and Transportation Officials
Scope
This Manual has been developed to assist Bridge Owners by establishing inspection procedures and evaluation practices that meet the National Bridge Inspection Standards (NBIS). The Manual has been divided into eight Sections@ with each Section representing a distinct phase of an overall bridge inspection and evaluation program. Section 1 contains introductory and background information on the maintenance inspection of bridges as well as definitions of general interest terms. Key components of a comprehensive bridge file are defined in Section 2. The record of each bridge in the file provides the foundation against which changes in physical condition can be measured. Changes in condition are determined by field inspections. A bridge management system is an effective tool in allocating limited resources to bridge related activities. An overview of bridge management systems is included in Section 3. The types and frequency of field inspections are discussed in Section 4@ as are specific inspection techniques and requirements. Conditions at a bridge site or the absence of information from original construction may warrant more elaborate material tests@ and various testing methods are discussed in Section 5. Section 6 discusses the load rating of bridges and includes the Load and Resistance Factor method@ the Load Factor method and the Allowable Stress method. No preference is placed on any rating method. The evaluation of existing bridges for fatigue is discussed in Section 7. Field load testing is a means of supplementing analytical procedures in determining the live-load capacity of a bridge and for improving the confidence in the assumptions used in modeling the bridge. Load test procedures are described in Section 8. The successful application of this Manual is directly related to the organizational structure established by the Bridge Owner. Such a structure should be both effective and responsive so that the unique characteristics and special problems of individual bridges are considered in developing an appropriate inspection plan and load capacity determination. This Manual replaces both the 1994 AASHTO Manual for Condition Evaluation of Bridges and the 2003 AASHTO Guide Manual for Condition Evaluation and Load and Resistance Factor Rating (LRFR) of Highway Bridges. It serves as a single standard for the evaluation of highway bridges of all types. Much of the 2003 AASHTO Guide Manual for Condition Evaluation and Load and Resistance Factor Rating (LRFR) of Highway Bridges has been incorporated and updated in this Manual. Section 6 of this Manual includes the load ratings provisions of both the 2003 AASHTO Guide Manual for Condition Evaluation and Load and Resistance Factor Rating (LRFR) of Highway Bridges and the 1994 AASHTO Manual for Condition Evaluation of Bridges. PURPOSE This Manual serves as a standard and provides uniformity in the procedures and policies for determining the physical condition@ maintenance needs@ and load capacity of the nation's highway bridges.