It has been demonstrated that transverse reinforcement not only provides the strength and stiffness for reinforced concrete (RC) members through direct resistance to external force demands, but also helps confine the inner core concrete. The confinement effect can lead to improved overall structural performance by delaying the onset of concrete fracture and allowing more inelastic energy dissipation through an increase in both strength and deformability of RC members. The objective of this research was to evaluate the effect of confinement due to the transverse reinforcement on enhancing the shear performance of RC members. A new constitutive model of RC members was proposed by extending the Modified Compression Field Theory (MCFT) to incorporate the effect of confinement due to transverse reinforcement by adjusting the peak stress and peak strain of confined concrete in compression. The peak stress of confined concrete was determined from the five-parameter failure surface for concrete developed by Willam and Warnke (1974). The peak strain adjustment was carried out using a relationship proposed by Mander et al. (1988). The proposed analytical model was compared with results from an experimental program on sixteen RC bent caps with varied longitudinal and transverse reinforcement details. Two-dimensional Finite Element Modeling (FEM) using the proposed constitutive model was conducted to numerically simulate the RC bent cap response. Results showed that the proposed analytical model yielded good results on the prediction of the strength but significantly overestimated the post-cracking stiffness of the RC bent cap specimens. The results also indicated that the confinement effect led to enhanced overall performance by increasing both the strength and deformability of the RC bent caps. Two potential causes of the discrepancy in the underestimation of the RC bent cap deformations, namely the effects of concrete shrinkage and interfacial bond-slip between the concrete and main flexural reinforcement in the bent caps, were discussed. Parametric studies showed that the tension-stiffening in the proposed constitutive models to implicitly take into account the bond-slip between the concrete and main flexural reinforcement was the major cause of the overestimation of the post-cracking stiffness of RC bent caps. The explicit use of bond-link elements with modified local bond stress-slip laws to simulate the slip between the concrete and main flexural reinforcement led to good predictions of both strength and deformation.

Gravity load designed (GLD) reinforced concrete (RC) buildings represent a common type of construction in the Mid-America Region. These buildings have limited lateral resistance and are susceptible to story mechanisms during earthquake loading. Fragility estimates are developed to assess the seismic vulnerability of GLD RC buildings in the Mid-America Region. Fragility is defined as the conditional probability of reaching or exceeding a performance level for a given earthquake intensity measure. Five sample buildings of various story heights (1, 2, 3, 6, and 10 stories) are used to represent generic RC frame buildings of 1 to 10 stories tall. A Bayesian methodology is used to develop probabilistic demand models to predict the maximum inter story drift given the spectral acceleration at the fundamental period of the building. The unknown parameters of the demand models are estimated using the simulated response data obtained from nonlinear time history analyses of the structural models for a suite of synthetic ground motions, developed for Memphis, Tennessee. Seismic structural capacity values are selected corresponding to the performance levels or damage states as specified in FEMA-356 and as computed by nonlinear pushover analyses. For the sample buildings, fragility estimates are developed using the predicted drift demands and structural capacity values. Confidence bounds are developed to represent the epistemic uncertainty inherent in the fragility estimates. In addition, bivariate fragility estimates, formulated as a function of spectral acceleration and the fundamental building period, are developed from the fragility estimates of the individual buildings. The bivariate fragilities can be used to quantify the seismic vulnerability of GLD RC frame buildings of 1 to 10 stories. Using the Bayesian approach, a framework is developed to update the analytical fragility estimates using observed damage data or experimental test data. As an illustration of the updating framework, the analytical bivariate fragility estimates for the sample buildings in the Mid-America Region are updated using the damage data obtained from 1994 Northridge, California earthquake. Furthermore, to investigate and demonstrate the increase in seismic performance of the GLD RC frame buildings, the columns of the 2 and 3 story buildings are retrofitted by column strengthening. Fragility estimates developed for the retrofitted buildings show the effectiveness of the retrofit technique by the improved seismic performance of GLD RC frame buildings.

Thesis (M.S. in civil engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Dec. 28, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 51).

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains viii, 79 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-54).

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaf 184). Also available via World Wide Web.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains x, 92 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 79-83).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Mar. 3, 2010). Bibliography: leaves 87-91.