@article{hassan_seliem_dwairi_rizkalla_zia_2008, title={Shear behavior of large concrete beams reinforced with high-strength steel}, volume={105}, number={2}, journal={ACI Structural Journal}, author={Hassan, T. K. and Seliem, H. M. and Dwairi, H. and Rizkalla, S. H. and Zia, P.}, year={2008}, pages={173–179} }
 @article{dwairi_kowalsky_nau_2007, title={Equivalent damping in support of direct displacement-based design}, volume={11}, ISSN={["1363-2469"]}, DOI={10.1080/13632460601033884}, abstractNote={The concept of equivalent linearization of nonlinear system response as applied to direct displacement-based design is evaluated. Until now, Jacobsen's equivalent damping approach combined with the secant stiffness method has been adopted for the linearization process in direct displacement-based design. Four types of hysteretic models and a catalog of 100 ground motion records were considered. The evaluation process revealed significant errors in approximating maximum inelastic displacements due to overestimation of the equivalent damping values in the intermediate to long period range. Conversely, underestimation of the equivalent damping led to overestimation of displacements in the short period range, in particular for effective periods less than 0.4 seconds. The scatter in the results ranged between 20% and 40% as a function of ductility. New equivalent damping relations for four structural systems, based upon nonlinear system ductility and maximum displacement, are proposed. The accuracy of the new equivalent damping relations is assessed, yielding a significant reduction of the error in predicting inelastic displacements. Minimal improvement in the scatter of the results was achieved, however. While many significant studies have been conducted on equivalent damping over the last 40 years, this study has the following specific aims: (1) identify the scatter associated with Jacobsen's equivalent damping combined with the secant stiffness as utilized in Direct Displacement-Based Design; and (2) improve the accuracy of the Direct Displacement-Based Design approach by providing alternative equivalent damping expressions.}, number={4}, journal={JOURNAL OF EARTHQUAKE ENGINEERING}, author={Dwairi, H. M. and Kowalsky, M. J. and Nau, J. M.}, year={2007}, month={Jul}, pages={512–530} }
 @article{dwairi_kowalsky_2006, title={Implementation of inelastic displacement patterns in direct displacement-based design of continuous bridge structures}, volume={22}, ISSN={["8755-2930"]}, DOI={10.1193/1.2220577}, abstractNote={ Through the use of nonlinear time-history analysis, the displacement patterns of bridges subjected to transverse seismic attack are investigated. The variables considered in the study consist of bridge geometry, superstructure stiffness, substructure strength and stiffness, abutment support conditions, and earthquake ground motion. A series of three inelastic displacement pattern scenarios were identified: (1) rigid body translation (2) rigid body translation with rotation, and (3) flexible pattern. A relative stiffness index that is a function of the superstructure and substructure stiffness was shown to be a key variable in determining the type of displacement pattern a bridge is likely to follow. The results described in this paper have significant implications for performance-based seismic design procedures such as direct displacement-based design (DDBD). If the displacement pattern for a bridge can be identified with significant confidence at the start of the design process, application of approaches such as DDBD can be simplified. However, if the characteristics of the bridge are such that prescribing a pattern at the start of the process is not feasible, then an alternative approach must be employed for DDBD to proceed. Of the three displacement pattern scenarios defined in this paper, the first two require minimal effort in the design. For the third scenario, an iterative algorithm is proposed. Lastly, as a means for verification and demonstration, a series of bridges with various configurations was designed using DDBD for rigid body translation and flexible pattern scenarios. The designs for the flexible scenario showed good agreement with selected target profiles for bridges with up to five spans. }, number={3}, journal={EARTHQUAKE SPECTRA}, author={Dwairi, Hazim and Kowalsky, Mervyn}, year={2006}, month={Aug}, pages={631–662} }