Date of Submission


Document Type


Degree Name

Master of Science in Civil Engineering


Civil and Environmental Engineering


Dr. Byungik Chang

Committee Member

Dr. Samuel Bogan Daniels

Committee Member

Dr. Goli Nossoni


Incremental launching method, I-girder, Contract stress nomogram, Support roller, Hertz contact theory


Environmentally sensitive areas, Bridges--Design and construction, Finite element method


The incremental launching method (ILM) is one of the methods of bridge construction located in environmentally sensitive areas. During the bridge launching, there are significant contact stress issues at the contact regions between the launching system and the steel bridge girders. The Iowa River Bridge (IRB) is a case study of bridge construction that used the ILM during a steel I-girders installation. Contact stress can cause severe defects during launch, which can occur within the material where the material could be damaged.

Hertz contact theory is applied for calculating contact stress between two solid surfaces, which is initially derived from the contact between cylinder and plane surface. However, Hertz contact theory can calculate only the contact area and stress between two elastic solids with specific modeling in equilibrium. The solutions of the launching girder bridge construction's contact stress are not usually possible with closed-form Hertz contact theory solutions because of the complex geometries, loads, and material properties.

Typically, the issues, including complicated structural systems, need to rely on numerical modeling such as the finite element analysis (FEA) from ANSYS® . The primary objective of this study is to provide an estimate the relationship of the maximum contact stress between an I-girder and a roller using a nomogram. The nomogram is built based on a parametric study with various roller dimensions and vertical loads by numerical modeling. A total of 180 numerical models were used to develop the contract stress nomogram. The maximum contact stress from the nomogram can be useful tool in designing a bridge girder on a support roller.