Access Type

Open Access Dissertation

Date of Award

January 2021

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

First Advisor

Fatmir Menkulasi

Abstract

ABSTRACTFLEXURE AND PUNCHING SHEAR BEHAVIOR OF UHPC ELEMENTS POST-TENSIONED WITH UNBONDED TENDONS by Mehmet Dogu August 2021 Advisor: Dr. Fatmir Menkulasi Major: Civil and Environmental Engineering (Structural Engineering) Degree: Doctor of Philosophy Procedures for predicting the flexural strength, moment-curvature-deformation response, and punching shear capacity of PT UHPC elements are presented. The prediction method for flexural strength is based on a mechanics based phenomenological model. A set of equations is provided to predict strand stress at the ultimate limit state as a function of plastic hinge length. The procedure for obtaining the moment-curvature-deformation response does not rely on empiricism other than what is included in the assumed material constitutive models, and provides the means to determine the variation of curvature and deflection as the beam is loaded to failure thus providing an avenue to quantify ductility at the cross-section and member level. The method presented for predicting the punching shear capacity of PT UHPC plates supplies simultaneously plate’s punching and rotation capacity by superimposing plate’s load rotation relationship and a rotation dependent failure criterion. The derivation of plates load-rotation relationship is based on engineering mechanics and is informed by the moment curvature relationship of a typical plate strip developed. Criteria are presented for distinguishing between punching and flexural failures in numerical and prediction models. All prediction methods are validated using nonlinear finite element analysis.

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