Date of Award


Degree Name



College of Information Technology and Engineering

Type of Degree


Document Type


First Advisor

Dr. Gregory K. Michaelson, P.E., Committee Chairperson

Second Advisor

Dr. James M. Bryce

Third Advisor

Dr. Isaac W. Wait, P.E.


The scope of this thesis project was to refine the development of live load distribution factors for tub girders. This was done in three stages. First, experimental data was gathered to assess live load distribution on the Amish Sawmill Bridge located in Fairbank, Iowa. Then, finite element analysis models were developed to benchmark against experimental data. Finally, a series of parametric studies were performed to explore the distribution factors of steel tub girders under various design conditions and to generate more accurate live load distribution factors. Results drawn from this research project demonstrate that press-brake-formed steel tub girders exhibit consistent performance and are a practical option in short span bridge construction. In addition, it was found that the current AASHTO LRFD Bridge Design Specifications can overestimate distribution factors for interior girders and fails to estimate distribution factors for exterior girders depending on girder spacing and length of bridge.


Author's name on thesis listed as Guilherme de Oliveira Petty Santana.


Finite element method.

Load factor design.