Design Examples

The below documents consist of a comprehensive steel girder bridge design example, with instructional commentary based on the AASHTO LRFD Bridge Design Specifications (Second Edition, 1998, including interims for 1999 through 2002). The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation of the AASHTO LRFD Bridge Design Specifications, and is offered in both US Customary Units and Standard International Units.

This project includes a detailed outline and a series of flowcharts that serve as the basis for the design example. The design example includes detailed design computations for the following bridge features: concrete deck, steel plate girder, bolted field splice, shear connectors, bearing stiffeners, welded connections, elastomeric bearing, cantilever abutment and wingwall, hammerhead pier, and pile foundations. To make this reference user-friendly, the numbers and titles of the design steps are consistent between the detailed outline, the flowcharts, and the design example.

In addition to design computations, the design example also includes many tables and figures to illustrate the various design procedures and many AASHTO references. AASHTO references are presented in a dedicated column in the right margin of each page, immediately adjacent to the corresponding design procedure. The design example also includes commentary to explain the design logic in a user-friendly way. Additionally, tip boxes are used throughout the design example computations to present useful information, common practices, and rules of thumb for the bridge designer. Tips do not explain what must be done based on the design specifications; rather, they present suggested alternatives for the designer to consider. A figure is generally provided at the end of each design step, summarizing the design results for that particular bridge element.

Steel Superstructure SI.pdf
Steel Superstructure.pdf

The below documents consist of a comprehensive design example of a prestressed concrete girder bridge. The superstructure consists of two simple spans made continuous for live loads. The substructure consists of integral end abutments and a multi-column intermediate bent. The document also includes instructional commentary based on the AASHTO-LRFD Bridge Design Specifications (Second Edition, 1998, including interims for 1999 through 2002). The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation of the AASHTOLRFD Bridge Design Specifications. This document is offered in US Customary Units. An accompanying document in Standard International (SI) Units is offered under report No. FHWA NHI-04-044.

This document includes detailed flowcharts outlining the design steps for all components of the bridge. The flowcharts are cross-referenced to the relevant specification articles to allow easy navigation of the specifications. Detailed design computations for the following components are included: concrete deck, prestressed concrete I-girders, elastomeric bearing, integral abutments and wing walls, multi-column bent and pile and spread footing foundations.

In addition to explaining the design steps of the design example, the comprehensive commentary goes beyond the specifics of the design example to offer guidance on different situations that may be encountered in other bridges.

Concrete Design Example - US units
Concrete Example - SI.pdf

Below are design examples for Horizontally Curved I-Girders and Box-Girders, current to the 2005 LRFD Interims

Horizontally Curved Box Girder Example
Horizontally Curved Box Girder Example: mathcad
Horizontally Curved I-Girder example
Horizontally Curved I-Girder Example : mathcad file

Below are design examples for State Route 45 (Old Hickory Blvd.)/I-65, Davidson County. This is a 2-span welded girder design on a tangent alignment.

Design Build Total

Below are design examples for I-55/Mallory Avenue, Shelby County. this a 3-span horizontally curved welded plate girder design, current to 2005 Interims.

I55_LRFD.PDF
LAYOUT.pdf

Below are additional design examples:

index.pdf
LRFD slab transverse reinforcement.pdf
LRFD slab negative moment.pdf
LRFD pre-stressed beam.pdf
LRFD bent 7 Spread Footing.pdf
LRFD bent 6 pile footing.pdf
LRFD bent 5 cap beam.pdf
LRFD bent 4 column sqare with cutout.pdf
LRFD bent 4 column rectangular.pdf
LRFD bent 4 column rectangular with round ends.pdf
LRFD bent 2 other.pdf