Page 262 - Bridge and Highway Structure Rehabilitation and Repair
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6
Applications of
Bridge Design
and Rating
Methods
6.1 INTRODUCTION
In earlier chapters, LRFD and LRFR methods based on ultimate strength
design for bridge members were introduced for the purpose of rehabilitation
design and replacement of bridges. This chapter deals with an extension of
the methods covered earlier. Prime equations and formulae are developed for
fl exural capacity under moving H-15 and H-20 truck loads for single spans
using LRFD and LRFR methods, including application of shear design us-
ing MCFT. Strengthening and Repair Work
Examples for deck slab, reinforced concrete, prestressed concrete and
steel beams, and connections design are presented. It is possible to program Section 2
the extended formulae, such as for construction load combinations for the
routine design of members:
1. Using Excel spreadsheets.
2. Using Mathcad.
3. Developing commercial software.
AASHTO bridge design methods are expressed in detail.
6.2 LIMIT STATES DESIGN EQUATION
6.2.1 Design Methods and Details
The three criteria for choosing a design method are:
1. Strength control or stress criteria.
2. Defl ection control.
3. Crack control.
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