AN ABSTRACT OF THE THESIS OF TARUN KUMAR DONGA, for the Master of Science degree in Civil Engineering, Presented on August 29th 2017, at Southern Illinois University Carbondale. TITLE: EFFECT OF TEMPERATURE INCREASE ON BUCKLING OF AXIALLY RESTRAINED BEAM-COLUMNS WITH DOUBLE CURVATURE MAJOR PROFESSOR: Dr. Aslam Kassimali, Ph.D. The main objective of this research was to study the buckling and post-buckling response of axially restrained beam-columns under thermal loading. Also the effects of slenderness ratios on pre-buckling and post-buckling behavior which is neglected in (AISC 2010 specification) for Structural Steel Buildings, was examined. The results of this study indicate that: a) The deflection and end moment amplification factors are significantly smaller for the restrained beam-columns under temperature increase than the corresponding unrestrained beam-columns under mechanical axial loads. - b) The deflection amplification and moment amplification factors tend to increase with increasing ratio of end moments. c) Thermal amplification factors, even in the pre buckling range, were found to be smaller than the AISC (2010) specification values, the difference was more significant for longer beam columns as compared to shorter ones.

The three differential equations describing the behavior of the beam columns in three dimensions are derived and presented in finite difference form. A computer model is developed to solve the simultaneous equations in the elastic regions and predict the member behavior. The computer program is checked by comparing the results obtained from the program with data from other investigators, and classical analytical techniques.

This thesis illustrates the specific aspects that influence or limit the application of remotely-sensed data for information retrieval from coastal marine, estuarine and riverine environments. The thesis is drawn principally from ten separate studies and is divided into discrete sections, or experiments, that provide an understanding of the fundamental aspects of the effects of the atmosphere, water surface, water column and bottom on sensor-received reflected signal.The results show the importance of precise calculation of acquisition parameters and the absolute importance of relevant reference data. Most instrumentation for remote sensing at visible wavelengths has been developed for terrestrial applications where signal is rarely limiting and target features are relatively static. For in-water applications, where signal is small and noise can be large, the features to be sensed may be temporally dynamic and obscured.However, the work presented also shows the great benefit and spatial cost-effectiveness that can be obtained if the spectral and temporal specification is adequately considered. The prime motivation for such applications usually comes from the requirement to detect and quantify water column characteristics, such as phytoplankton forming as algal blooms, and bottom stratigraphic condition, such as benthic habitat mapping for fishery or conservation purposes.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

The use of metallic foams as a filler in thin-walled structures can enhance their crashworthiness characteristics. It is believed that, tailoring the properties of the foam filler would enhance the effectiveness of these characteristics. This view is also supported by recent works in the literature. It is the objective of this study to examine the crush behaviour of functionally graded foam-filled tubes and evaluate the effect of discretely graded density upon the specific energy absorbed. Nonlinear parametric finite element simulations of the foam-filled tube were developed to estimate the most favourable foam density gradient in the lateral and axial directions. The effect of various design parameters such as density grading, number of grading layers, and thickness of the interactive layer upon the resulting specific energy absorption was investigated. The results show that the specific energy absorption of a tube filled with functionally graded foam is better than uniform density foam.

Low phosphate fertilizer efficiency in high pH soils is primarily due to the retardation of P movement in the soil-P fertilizer reaction zone. The objective of this study was to obtain fundamental information on the influence of multi-ionic interactions on the solubility and diffusion of P in columns containing a model soil system and two soil types. The study also aimed to identify the salt combinations and factors that have the potential to enhance the solubility and movement of P in calcareous soil condition. The results showed that the interaction of NH4+ and SO42- was consistent at enhancing the water solubility and movement of P under a high soil pH condition. This effect was attributed to the combination of various mechanistic factors associated with (NH4)2SO4 compound including significant pH reduction, cation exchange reaction of NH4+ with the exchangeable Ca2+, and anionic competition of SO42- with P for precipitation with Ca2+. / October 2006

A database of composite column tests was augmented and utilized to evaluate the proposed AISC 2005 provisions. The database consists of column and beam-column steel-concrete columns (or encased, SRC), circular concrete filled tubes (CCFT), and rectangular concrete filled tube (RCFT). Information on material and geometric properties on each specimen was summarized. The database includes 119 SRC columns, 136 SRC beam-columns, 312 circular CFT columns, 198 circular CFT beam-columns, 222 rectangular CFT columns and 194 rectangular CFT beam-columns. The database has a total of 1181 specimens, an addition of 451 specimens over those in the original database (Aho 1996). The data on each specimen was analyzed and compared with current design provision for composite columns (AISC 1999 and Eurocode 4), and reassessed by the upcoming 2005 AISC specification. The data indicates that the Eurocode gives good predictions for columns and the AISC 2005 method performs very well for beam-columns. For rectangular CFT columns, all three methods predict the ultimate capacity very well. The main improvement for the AISC 2005 method is its ability to handle specimens which have high yield stress and/or high strength concrete.

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 226-236).

Based on first author's dissertation. / "December 2002." Includes bibliographical references.