@article{goodnight_kowalsky_nau_2017, title={Closure to "Modified Plastic-Hinge Method for Circular RC Bridge Columns" by Jason C. Goodnight, Mervyn J. Kowalsky, and James M. Nau}, volume={143}, ISSN={["1943-541X"]}, DOI={10.1061/(asce)st.1943-541x.0001867}, number={9}, journal={JOURNAL OF STRUCTURAL ENGINEERING}, author={Goodnight, Jason C. and Kowalsky, Mervyn J. and Nau, James M.}, year={2017}, month={Sep} }
 @article{goodnight_kowalsky_nau_2016, title={Modified Plastic-Hinge Method for Circular RC Bridge Columns}, volume={142}, ISSN={0733-9445 1943-541X}, url={http://dx.doi.org/10.1061/(ASCE)ST.1943-541X.0001570}, DOI={10.1061/(asce)st.1943-541x.0001570}, abstractNote={AbstractThis paper discusses a research program aimed at defining accurate limit-state displacements that relate to specific levels of damage in reinforced concrete bridge columns subjected to seismic hazards. In design, concrete compressive and steel tensile strain limits are related to column deformations through the use of an equivalent curvature distribution. An experimental study was carried out to assess the performance of 30 circular well-confined bridge columns. Material strains, cross-section curvatures, and fixed-end rotations attributed to strain penetration of reinforcement into the adjoining member were quantified by using a three-dimesional (3D) position monitoring system. An equivalent curvature distribution was created that reflects the measured spread of plasticity and components of deformation. When compared with the current approach, the proposed modified plastic-hinge method improved the accuracy of both tensile and compressive strain-displacement predictions, while maintaining similar...}, number={11}, journal={Journal of Structural Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Goodnight, Jason C. and Kowalsky, Mervyn J. and Nau, James M.}, year={2016}, month={Nov}, pages={04016103} }
 @article{goodnight_kowalsky_nau_2016, title={Strain Limit States for Circular RC Bridge Columns}, volume={32}, ISSN={["1944-8201"]}, DOI={10.1193/030315eqs036m}, abstractNote={ Described in this paper are strain limit states for reinforced concrete bridge columns. A total of 30 large scale reinforced concrete bridge columns were subjected to either reversed cyclic loading or real seismic load histories as part of this research program. Through the use of a non-contact three-dimensional (3-D) position measurement system, accurate strain measurements that are not possible with conventional instrumentation were made, which allowed for development of strain limits for serviceability, spiral yielding, and reinforcing bar buckling limit states. The proposed bar buckling strain limit was compared to an existing drift-based approach and one formulated using finite element analysis for columns in the data set and the literature. }, number={3}, journal={EARTHQUAKE SPECTRA}, author={Goodnight, Jason C. and Kowalsky, Mervyn J. and Nau, James M.}, year={2016}, month={Aug}, pages={1627–1652} }
 @article{goodnight_kowalsky_nau_2013, title={Effect of Load History on Performance Limit States of Circular Bridge Columns}, volume={18}, ISSN={["1943-5592"]}, DOI={10.1061/(asce)be.1943-5592.0000495}, abstractNote={In this paper, the importance of displacement history and its effects on performance limit states, the relationship between strain and displacement, and the spread of plasticity in RC structures is explored. An experimental study is underway to assess the performance of 30 circular, well-confined, bridge columns with varying lateral displacement history, transverse reinforcement detailing, axial load, aspect ratio, and longitudinal steel content. Eight of these columns, with similar geometry and detailing, were subjected to various unidirectional displacement histories including standardized laboratory reversed cyclic loading and re-creations of the displacement responses obtained from a nonlinear time-history analysis of multiple earthquakes with distinct characteristics. Longitudinal reinforcing bars were instrumented to obtain strain hysteresis, vertical strain profiles, cross section curvatures, curvature distributions, and fixed-end rotations attributable to strain penetration. Results have shown that the limit state of reinforcement bar buckling was influenced by load history, but the relationship between strain and displacement along the envelope curve was not. The main impact of load history on bar buckling is its influence on accumulated strains within the longitudinal reinforcement and transverse steel.}, number={12}, journal={JOURNAL OF BRIDGE ENGINEERING}, author={Goodnight, Jason C. and Kowalsky, Mervyn J. and Nau, James M.}, year={2013}, month={Dec}, pages={1383–1396} }