Access Type
Open Access Embargo
Date of Award
January 2024
Degree Type
Dissertation
Degree Name
Ph.D.
Department
Civil and Environmental Engineering
First Advisor
Fatmir F. Menkulasi
Abstract
A methodology is presented that accurately and consistently predicts the complete moment-curvature (M-χ) response of UHPC cross-sections. Furthermore, a computational framework is presented to characterize the response of UHPC flat plates subjected to perpendicular axisymmetric concentrated loads. The presented framework is concerned with the prediction of the complete flexural response and punching shear capacity of UHPC flat plates thus addressing two fundamental limit states related to the design of UHPC flat plates. Guidance is provided for how to convert continuous flat plates supported by discrete columns into isolated plates supported by a single column in terms of plate dimensions and boundary conditions. Such plates are then converted into circular plates for the purpose of obtaining the load-rotation (V-ψ) response of the plate. The response of the circular plate is then characterized by considering the kinematics and internal force distribution in a representative slice. This requires the provision of the M-χ response of representative strips of unit width. Once the complete flexural response is obtained, a nonlinear regression-based failure criterion is used to identify punching shear failures and distinguish them from flexural failures. A total of seven different methods, Level I to Level Vc, are presented to predict the V-ψ response of the reinforced UHPC (R-UHPC) plates. In addition, a regression based formulation is developed to predict the punching shear capacity of R-UHPC plates. The contribution of this study applies to the following three themes: 1) the development of an algorithm that is capable of supplying the entire M-χ response of UR- and R-UHPC cross-sections; 2) the development of a computational framework for obtaining the complete V-ψ relationship of a R-UHPC plate subjected to concentrated loads; and 3) the provision of a failure criterion, which together with the V-ψ response of the plate are used to determine the punching shear capacity of the plate. The accuracy of the exiting methodologies for predicting punching shear strength is evaluated using a database of 64 tested plates, 39 of which are reinforced and 25 are unreinforced. A total of 13 existing methodologies are evaluated in terms of their ability to accurately predict the punching shear capacity of UHPC plates, and they lead to average ratios of tested to predicted punching shear strength and coefficients of variation (CoV) that range from 0.50-2.42 and 36%-58%, respectively, suggesting an urgent need to develop more accurate and consistent methods. The proposed methods when applied to R-UHPC plates supply an average ratio of tested to predicted punching shear strength between 1.11-1.25 with 22.8-24.3% CoV, suggesting largely improved accuracy and consistency. Similarly, the predicted load versus rotation response of UHPC plates that exhibit a flexural failure is compared with the tested response leading to good agreement. A computer program iRes is developed to characterize the response and predict the punching shear capacity of UHPC plates.
Recommended Citation
Cakmak, Furkan, "Response Characterization And Prediction Of Uhpc Flat Plates Subjected To Perpendicular Axisymmetric Concentrated Loads" (2024). Wayne State University Dissertations. 4071.
https://digitalcommons.wayne.edu/oa_dissertations/4071