Doctoral Dissertations


"Reinforced concrete (RC) columns of skewed and curved bridges with unequal spans and column heights can be subjected to combined loading including axial, flexure, shear, and torsion loads during earthquakes. The combination of axial loads, shear force, and flexural and torsional moments can result in complex failure modes of RC bridge columns. This study carried out experimental and analytical studies to investigate the seismic performance of circular RC columns under combined loading including torsion. The main variables considered here were (i) the ratio of torsion-to-bending moment (T/M), (ii) the ratio of bending moment-to-shear (M/V) or shear span (H/D), and (iii) the level of detailing for high and moderate seismicity (high or low spiral ratio). In particular, the effects of the spiral reinforcement ratio and shear span on strength and ductility of circular RC columns under combined loading were addressed. In addition, the effects of torsional loading on the bending moment-curvature, ductility, and energy dissipation characteristics were also considered. The analytical investigation examined the development of existing models for flexure and pure torsion. Interaction diagrams between bending, shear and torsional loads were established from a semi-empirical approach. A damage-based design approach for circular RC columns under combined loads was proposed by decoupling damage index models for flexure and torsion. Experimental and analytical results showed that the progression of damage was amplified by an increase in torsional moment. An increase in the transverse spiral reinforcement ratio delayed the progression of damage and changed the torsional-dominated behavior to flexural-dominated behavior under combined flexural and torsional moments"--Abstract, page iii.


Belarbi, Abdeldjelil

Committee Member(s)

Myers, John
LaBoube, Roger A.
Kwon, Oh-Sung
Chandrashekhara, K.


Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering


National Science Foundation (U.S.)
National University Transportation Center
Network for Earthquake Engineering Simulation


Missouri University of Science and Technology

Publication Date

Fall 2009


xviii, 316 pages

Note about bibliography

Includes bibliographical references (pages 304-315).


© 2009 Suriya Prakash Shanmugam, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Axial loads -- Testing
Columns, Concrete -- Fatigue
Concrete bridges -- Foundations and piers
Reinforced concrete construction

Thesis Number

T 9562

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