@article{rosenboom_rizkalla_2008, title={Experimental study of intermediate crack debonding in fiber-reinforced polymer strengthened beams}, volume={105}, DOI={10.14359/19067}, abstractNote={Inteiface crack propagation of fiber-reinforced polymer (FRP)­ strengthened reinforced or prestressed concrete flexural members is often initiated from the toes of the intermediate cracks and propagates toward the supports. This type of FRP delamination is commonly tenned intennediate crack (IC) debonding alld is common for flexural members with high shear span-to-depth ratios. This paper describes an experimental program where six 30ft (9.14 m) lOllg prestressed concrete bridge girders were tested monotonically to fail ure to evalllate the bond characteristics of carbon FRP (CFRP) strengthening systems. Four of the beams Jailed due to Ie debondillg, one failed due to FRP rupture, alld the ul1strengtitened control girderfailed due to concrete crushillg. The results of this study were combined with the results from other tests ill the literature to create a useful experimelllal database. The database was used to assess the analytical models currellliy available in the national code documems. The analysis indicated that the current models do not correlate well with the experimental database and the needfor a new analytical model is highlighted. This paper briefly discusses a proposed model for Ie debonding that predicts the measured values tested by olher researchers well.}, number={1}, journal={ACI Structural Journal}, author={Rosenboom, O. and Rizkalla, S. H.}, year={2008}, pages={41–50} }
 @article{rosenboom_hassan_rizkalla_2007, title={Flexural behavior of aged prestressed concrete girders strengthened with various FRP systems}, volume={21}, ISSN={0950-0618}, url={http://dx.doi.org/10.1016/j.conbuildmat.2006.06.007}, DOI={10.1016/j.conbuildmat.2006.06.007}, abstractNote={Many prestressed concrete bridges are in need of upgrading in order to increase their posted capacities. Departments of transportation across the country have been faced with large financial burdens on the maintenance budget, negative psychological effects on highway users, long traffic delays during maintenance, potential safety hazards, and reduced service life as a result of the deficiencies. In response to considerable consultation with the North Carolina Department of Transportation (NCDOT), a research project with practical goals was initiated to evaluate the cost-effectiveness and value engineering of Carbon Fiber Reinforced Polymer (CFRP) repair and strengthening systems for prestressed concrete bridge girders. This paper presents the first phase of the research program, involving the testing under static loading conditions of eight prestressed concrete bridge girders, six strengthened with various CFRP systems. Results show that the ultimate capacity of prestressed concrete bridge girders can be increased by as much as 73% using CFRP without sacrificing the ductility of the original member. Transverse CFRP U-wrap reinforcements are recommended along the length of the girder to control debonding type failures. The second phase of the research will examine the fatigue behavior of the strengthened girders, and provide analysis under service loading conditions.}, number={4}, journal={Construction and Building Materials}, publisher={Elsevier BV}, author={Rosenboom, Owen and Hassan, Tare K. and Rizkalla, Sami}, year={2007}, month={Apr}, pages={764–776} }
 @article{rosenboom_rizkalla_2006, title={Behavior of prestressed concrete strengthened with various CFRP systems subjected to fatigue loading}, volume={10}, DOI={10.1061/(ASCE)1090-0268(2006)10:6(492)}, abstractNote={Many prestressed concrete bridges are in need of upgrades to increase their posted capacities. The use of carbon fiber-reinforced polymer (CFRP) materials is gaining credibility as a strengthening option for reinforced concrete, yet few studies have been undertaken to determine their effectiveness for strengthening prestressed concrete. The effect of the CFRP strengthening on the induced fatigue stress ratio in the prestressing strand during service loading conditions is not well defined. This paper explores the fatigue behavior of prestressed concrete bridge girders strengthened with CFRP through examining the behavior of seven decommissioned 9.14 m (30 ft) girders strengthened with various CFRP systems including near-surface-mounted bars and strips, and externally bonded strips and sheets. Various levels of strengthening, prestressing configurations, and fatigue loading range are examined. The experimental results are used to provide recommendations on the effectiveness of each strengthening configurati...}, number={6}, journal={Journal of Composites for Construction}, author={Rosenboom, O. and Rizkalla, S.}, year={2006}, pages={492–502} }
 @article{rosenboom_kowalsky_2004, title={Reversed in-plane cyclic behavior of posttensioned clay brick masonry walls}, volume={130}, DOI={10.1061/(asce)0733-9445(2004)130:5(787)}, abstractNote={A series of five large scale clay brick masonry structural walls are subjected to in-plane simulated seismic forces. The walls utilize posttensioning steel to provide flexural strength. The primary objective of the research is to investigate five basic configurations of posttensioning to determine which has the most desirable characteristics for seismic performance. In the study, the variables of interest were ! 1" bonded versus unbonded posttensioning steel, ! 2" confined versus unconfined masonry, ! 3" grouted versus ungrouted masonry, and ! 4" application of supplemental mild steel for energy dissipation. Following the results of the tests, it was shown that the best performing configuration utilized unbonded posttensioning and confinement. By utilizing unbonded posttensioning, walls have little residual deformation after loading, thus yielding structures that would require very little repair, even after large seismic events. Such behavior comes with the price of reduced energy dissipation, however. Presented in the paper are the results of the tests as well as results of a simple analysis method for prediction of wall capacity.}, number={5}, journal={Journal of Structural Engineering (New York, N.Y.)}, author={Rosenboom, O. A. and Kowalsky, M. J.}, year={2004}, pages={787–798} }