Date of Award

Spring 2017

Document Type


Degree Name

Doctor of Philosophy (PhD)


Civil & Environmental Engineering

Committee Director

Zia Razzaq

Committee Member

Duc T. Nguyen

Committee Member

Julie Hao

Committee Member

Sirjani Mojtaba


The Hillman Composite Beam (HCB) is a recent innovation used for the first time in 2008 for a bridge construction in USA. It essentially consists of an FRP outer shell, concrete arch inside the shell and steel strands used to tie the two ends of the arch. Being new in the field, the behavior of HCB has not been thoroughly studied. This dissertation presents a study of the flexural behavior and strength of HCB up to the collapse as well as explores the influence of using carbon reinforced polymer (CFRP) retrofitting and prestressed steel for a further increase in HCB stiffness and strength. Materially nonlinear computational algorithms are formulated and programmed to develop moment-curvature relations which are then combined with a finite-difference scheme to predict HCB behavior and strength using Bernoulli beam approach. The nonlinear analysis is performed for various cross sectional configuration of the HCB. A tied arch-and-beam model for predicting the elastic response of HCB is also developed. This model as well as that based on Bernoulli beam approach provided results which are in good agreement with HC Bridge company experiment. A new method involving the combined use of CFRP and steel prestressing resulting in increasing HCB strength by a factor of more than two-and-a-half times is also presented.


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