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1 PDH · about 60 minutes · Course no. BR-D02 · Instructor: Michael Craig, PE
Michael Craig, PE is Senior Vice President and Southeast Director at Strinteg Corporation, leading bridge inspection and structural engineering across eight states and Puerto Rico. In 27+ years he has inspected over 4,000 structures and completed 3,000+ load ratings and 160+ load tests. He has managed repair and preservation design for complex bridges, including cable-stayed bridges. He holds PE licenses in twelve states, DC and Puerto Rico, SPRAT Level 1, and FAA Part 107 credentials.
The HL-93 notional live load is the starting point for almost every highway bridge superstructure designed to the AASHTO LRFD Bridge Design Specifications. This course explains what HL-93 is and why it was built the way it was, the design truck, design tandem and design lane load, the special cases for negative moment, deflection and fatigue, the dynamic load allowance (IM) of Article 3.6.2, the multiple presence factors of Article 3.6.1.1.2, and practical rules for placing load longitudinally and transversely to get the extreme force effect. Load values were checked against public restatements of Article 3.6 in the FHWA Steel Bridge Design Handbook, the Caltrans Bridge Design Practice manual (Chapter 3, October 2022), an NCDOT LRFD seminar handout and STRUCTURE magazine. Worked example numbers are illustrative teaching values computed for this course unless a source is named. Always check the edition and interim revisions your owner has adopted, and the owner's own design manual, which may add permit or state-specific vehicles.