Contenido Simplified LRFD Bridge Design

Developed to comply with the fifth edition of the AASHTO LFRD Bridge Design Specifications [2010]––Simplified LRFD Bridge Design is "How To" use the Specifications book. Most engineering books utilize traditional deductive practices, beginning with in-depth theories and progressing to the application of theories. The inductive method in the book uses alternative approaches, literally teaching backwards. The book introduces topics by presenting specific design examples. Theories can be understood by students because they appear in the text only after specific design examples are presented, establishing the need to know theories.

The emphasis of the book is on step-by-step design procedures of highway bridges by the LRFD method, and "How to Use" the AASHTO Specifications to solve design problems.

Some of the design examples and practice problems covered include:

    Load combinations and load factors
    Strength limit states for superstructure design
    Design Live Load HL- 93
    Un-factored and Factored Design Loads
    Fatigue Limit State and fatigue life; Service Limit State
    Number of design lanes
    Multiple presence factor of live load
    Dynamic load allowance
    Distribution of Live Loads per Lane
    Wind Loads, Earthquake Loads
    Plastic moment capacity of composite steel-concrete beam
    LRFR Load Rating

Simplified LRFD Bridge Design is a study guide for engineers preparing for the PE examination as well as a classroom text for civil engineering students and a reference for practicing engineers. Eight design examples and three practice problems describe and introduce the use of articles, tables, and figures from the AASHTO LFRD Bridge Design Specifications. Whenever articles, tables, and figures in examples appear throughout the text, AASHTO LRFD specification numbers are also cited, so that users can cross-reference the material.

Contents

LRFD Method of Bridge Design

Limit States

Load Combinations and Load Factors

Strength Limit States for Superstructure Design

Resistance Factors, Φ, for Strength Limits

Design Live Load HL-93

Fatigue Live Load

Number of Design Lanes, NL

Multiple Presence Factor of Live Load, m

Dynamic Load Allowance, IM

Live Load Distribution Factors

Load Combinations for the Strength I Limit State

Simple Beam Live Load Moments and Shears Carrying Moving Concentrated Loads per Lane

Live Load Moments and Shears for Beams (Girders)

Design Examples

Design Example 1: Reinforced Concrete T-Beam Bridge

Design Example 2: Load Rating of Reinforced Concrete T-Beam by the Load and Resistance Factor Rating (LRFR) Method

Design Example 3: Composite Steel–Concrete Bridge

Design Example 4: Longitudinal Steel Girder

Design Example 5: Reinforced Concrete Slabs

Design Example 6: Prestressed Interior Concrete Girder

Design Example 7: Flexural and Transverse Reinforcement for 50 ft Reinforced Concrete Girder

Design Example 8: Determination of Load Effects Due to Wind Loads, Braking Force, Temperature Changes, and Earthquake Loads Acting on an Abutment

Practice Problems

Practice Problem 1: Noncomposite 60 ft Steel Beam Bridge for Limit States Strength I, Fatigue II, and Service

Practice Problem 2: 161 ft Steel I-Beam Bridge with Concrete Slab

Practice Problem 3: Interior Prestressed Concrete I-Beam References

Primary References

Supplementary References

Appendix A: Distribution of Live Loads per Lane for Moment in Interior Beams (AASHTO Table 4.6.2.2.2b-1)

Appendix B: Distribution of Live Loads per Lane for Moment in Exterior Longitudinal Beams

(AASHTO Table 4.6.2.2.2d-1)

Appendix C: Distribution of Live Load per Lane for Shear in Interior Beams (AASHTO Table 4.6.2.2.3a-1)

Appendix D: Distribution of Live Load per Lane for Shear in Exterior Beams (AASHTO Table 4.6.2.2.3b-1)

Appendix E: U.S. Customary Units and Their SI Equivalents

Index