Preface.
1. The Bridge Program and Bridge Needs.
The Status of the Nation's Highways and Bridges: Conditions and Performance. The National Bridge Inventory (NBI) and Other Programs. Bridge Management Systems: An Overview. Recording and Coding Policies. Priority Ranking. Systemwide Analysis of Bridges. FHWA Ongoing Programs. References.
2. Cost-Effectiveness Analysis and Service Life Estimates.
Project-Level Analysis. Cost Effectiveness of Evaluative Method. Analytical Models. Sensitivity Analysis of Economic Model: Example. Incremental Benefit/Cost Ratio. Bridge Deterioration Studies and Service Life Estimates. Needs Prediction Models. Network Level Analysis. Overview of FHWA Philosophy. References.
3. Assessment of Bridge Deficiencies.
Inspection Policies and Procedures. Bridge Systems, General Overview. Defects and Definitions. Inspection of Bridge Members. Procedures for Detecting Defects and Deterioration. Assessment of Deficiencies Below the Waterline. Full-Scale Testing. Current Practice. References.
4. Structural Capacity Analysis.
Overall Structure Adequacy Appraisal. Specifications for Checking Capacities of Existing Bridges. Allowable Stress Design (ASD). Load Factor Design (Strength Design). Design Examples, Steel Beams: Load Factor. Design Examples, Concrete Superstructure: Load Factor Method. Special Considerations for Bridge Foundations. Design Example, Substructure Capacity Analysis: Timber Pile Foundations. Assessment of Truss Members. Design Example 4-5, Truss Bridge. Prestressed Concrete. Special Considerations for Columns. Design Example 4-7, Capacity Analysis: Pile Foundations and Spread Footings. 2-Girder Steel Bridges: Capacity Analysis and Rating. References.
5. Methods of Strengthening Existing Bridges.
Background and Objectives. Bridges in Need of Strengthening: Statistical Data. Composite Action Between Deck and Beams. Increasing the Strength of Bridge Members. Increasing the Geotechnical Capacity of Bridge Foundations. Strengthening Critical Connections. Modification of Transverse Stiffness. The Use of Posttensioning to Improve Strength. Design Example 5-3, Posttensioning of Steel Beam Bridge. Design Example 5-4, Strengthening of Truss Members. Design Example 5-5, Transverse Stiffness Effects. Design Example 5-6, Addition of Steel Cover Plates. Design Example 5-7, Prestressed Precast Box Beams. Further Considerations of Posttensioning. Epoxy-Bonded Steel Plates. Strengthening Steel Beams by Testing Existing Steel. References.
6. Retrofit Procedures and Analysis.
Background. Adding or Replacing Members. Retrofit to Provide Continuity. Integral Conversions (Retrofitting). Design Example 6-1: Modification of Simple Spans. Seismic Resistance of Bridges: General Principles. AASHTO Requirements for Seismic Design. Bridge Eligibility and Evaluation or Seismic Retrofitting. Capacity/Demand Ratio Analysis. Seismic Retrofitting Concepts and Details. Design Example 6-2, Seismic Retrofit. Development of Column Vulnerability Rating. Simplified Restrainer Analysis, CalTrans Method. References.
7. General Repair Methods.
Repair of Concrete Elements. Repair of Prestressed Concrete. Repair of Steel Members. The Use of Welding to Repair Cracks in Steel Members. Increasing the Fatigue Strength of Welded Joints. Repair of Accidental Damage. Repair of Timber Members. References.
8. Repair of Superstructures.
Concrete Bridge Decks-Typical Conditions and Repairs. Long-Term Programs for Salt-Contaminated Bridge Decks. Wearing Surfaces. Steel Beams and Girders-Problems and Repairs. Prestressed Concrete Beams. Deck Joints. Bearing Assemblies. Curbs, Sidewalks, and Railings. Geometric Deficiencies. Effects of Overload on Deterioration of Concrete Bridges. References.
9. Repair of Substructures.
Substructure and Foundation Requirements. Scour at Bridge Sites. Collision Damage. Problems Caused by Foundation Settlement. The Option of Strengthening. Substructures Below the Waterline: Problems and Deterioration. Substructure Below the Waterline: Procedures to Arrest Deterioration. General Repair Techniques. References.
10. Rehabilitation of Special Bridges.
Trusses, Problems, and Repair Procedures. Examples of Truss Repairs. Arch Bridges. Grid and Orthotropic Decks. Suspension Bridges. Steel Railroad Bridges. Movable Bridges. References.
11. The Replacement Option.
The Rationale of Analysis: Replacement Versus Repair and Strengthening. Repair and Replacement Resulting From Damage of Steel Members. Partial Replacement of Steel Members. Replacement of Prestressed Concrete Beams. Replacement of Deck Joints. Replacement of Bearings. Redecking and Widening. Overview of Replacement Systems. Examples of Concrete Deck Replacement Systems. Example of Steel Replacement Systems for Superstructure. Example of Timber Replacement Systems for Superstructure. Lightweight Deck, Uses and Applications. Lightweight Decks, Technical and Economic Considerations. Prefabricated Bridge Elements, A Commentary. Permanent Bridge Deck Forms. Substructure Replacement Systems. State Replacement Policies and Examples. Removal of Existing Structures. References.
12. Bridge Designs to Reduce Maintenance and Repair Needs.
Background and Overview. Design and Use of Suitable Materials. Accessiblity. Provisions for Rehabilitation and Continuous Use. Preventive Maintenance, Case Study. Corrosion Protection. References.
13. Traffic Maintenance.
General Requirements. Detours. Detour Plans. Traffic Control.
INDEX.
