Engineering Commons^™

Non-Linear Evaluation Of Concrete-Filled Steel Tubular Columns, Mohammad Hassan Shams

Dissertations

Concrete-filled steel tubular (CFT) columns have become increasingly popular in structural applications due to their high strength, high ductility, and large energy absorption capacity. These structural properties are the result of integral behavior of the concrete core and the steel tube. This research provides an analysis of the interaction of the concrete core and the steel tube in CFT columns.

While there have been many experimental studies of CFT columns, there has been no analytical work modeling the confining effect of the steel tube on the concrete core. Furthermore, current design procedures tend to underestimate the ultimate strengths of CFTs …

Behavior Of Concrete And Slender Reinforced Concrete Columns Under Cyclic Axial Compression With Bidirectional Eccentricities, Byong Youl Bahn

Dissertations

A rational analysis of reinforced concrete (R/C) structures requires satisfactory modeling of the behavior of concrete under general loading patterns. The behavioral characteristics of concrete dominantly depends upon its load history. For the study of concrete behavior, parametric study and experimental investigation into the behavior of concrete under load history of random cycles are performed. Through parametric study, the applicability of the previous concrete models is examined and a physically motivated modeling for the cyclic stress-strain relationships is proposed. The present modeling of concrete under general cyclic loading is initiated to provide substantial applicability, flexibility of mathematical expressions and furthermore …

Behavior Of Biaxially Loaded Concrete-Encased Composite Columns, Pedro Ricardo Munoz

Dissertations

The theory of nonlinear behavior of biaxially loaded short and slender composite columns is used to study the load-deformation and moment-curvature of four pin-ended composite column specimens tested under axial compressive load and biaxial bending moments in a single curvature. The accuracy of the test results is verified by comparison with analytical results obtained by a method of analysis that includes the nonlinear material properties of concrete and steel and covers the ascending and descending branches of the linear segmented column specimen. A computational method is presented to model the analytical behavior of the biaxially loaded composite column. Its validity …

Behavior Of R/C Columns Under Nonproportional Variations In Axial And Lateral Loads, Kaniz Fatema Ahsan

Theses

The study on the behavior of reinforced concrete columns subjected to the motion of earthquake suggests that the structure may experience nonproportional variations in axial and lateral forces. In order to assess the capacity of a reinforced concrete structure under nonproportional loadings, an analytical model is developed using the fiber modeling technique.

The method is based on detailed analytical description of the geometry and material properties used in evaluating the behavior of the critical regions rather than a simplified and predefined set of hysteresis rules. The present study has two principal components of investigation. First, the analyses are done at …

Behavior Of High Strength Concrete And Slender Reinforced Concrete Columns With And Without Steel Fibers, Lin Showmay Hsu

Dissertations

A series of compression tests are conducted on 3 in. by 6 in. cylindrical specimens using a modified testing method that give the complete stress-strain behavior for both plain and fibrous high strength concretes with or without tie confinements. The volume fractions of fiber in the concrete are 0%, 0.5%, 0.75%, and 1.0%, respectively. Empirical equations are proposed herein to represent the complete stress-strain relationships of high strength and high strength fibrous concretes with compressive strength exceeding 10,000 psi. Various parameters are studied and their relationships are experimentally determined. The comparison between the experimental and analytical results shows to have …

Three-Dimensional Beam-Columns, Mohammad Hassan Shams

Theses

This thesis explores several special cases of three-dimensional beam-columns and suggests that the method of finite differences can be used when a solution of general case is required. The thesis begins with a review of the three-dimensional beam-column equations and then shows how these equations can be used to generate the member stiffness matrix for the nonlinear analysis of three-dimensional frames. Examples are included which discuss the differences between the analytical and numerical solutions.

Behavior Of Square And L-Shaped Slender Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Wen Hu Tsao

Dissertations

A numerical analysis was developed to evaluate the complete load-deflection and moment-curvature relationships for square and L-shaped slender reinforced concrete columns subjected to biaxial bending and axial load. This computer model can be used for any cross section geometry and material properties of normal concrete. The analysis was based on a deformation control and both the ascending and descending branches of curves can be studied. The finite difference method was introduced to calculate the deflections which satisfy the compatibility equations. Six square slender columns and eight L-shaped slender columns were tested to compare their experimental load-deformation results with the analytical …

Behavior Of Thin-Walled Channel Shaped Reinforced Concrete Columns Under Combined Biaxial Bending And Compression, Subash Yalamarthy

Theses

Next to rectangular, circular and L shapes, Channel section may be the most frequently encountered reinforced concrete columns since they can be used as box wall for elevators. Nevertheless, information about the load deformation behavior is not generally available to structural engineers. Most of the investigations have been emphasized on the ultimate strength of column sections under combined biaxial bending and axial compression and the resulting interaction surface. No attention is paid to load deformation behavior.

Current code provisions do not provide adequate guidelines for assessing the strength and ductility of biaxially-loaded reinforced concrete columns. Therefore, this investigation is aimed …

Behavior Of L-Shaped Reinforced Concrete Columns Under Combined Biaxial Bending And Compression, Amar Shah

Theses

Combined biaxial and axial compression for L-shaped reinforced concrete short columns is a common design Problem. Current code, provisions and the available design aids do not offer an insight into the determination of strength and ductility of biaxially loaded reinforced concrete column. An experimental and analytical investigation of the moment-deformation behavior of biaxially loaded L-shaped short columns were undertaken. Four 1/2 scaled specimens were tested till failure. Moment-curvature and load-deflection curves were developed from the experimental and the analytical results. The analytical results were obtained using a computer program developed by Hsu (1). From the investigation it is deduced that …

Behavior Of Tee-Shaped Reinforced Concrete Columns Subjected To Biaxial Bending And Axial Compression, Antoun Romanos Nader

Theses

The investigation deals with the effect of eccentric loading on the moment-curvature relationship of reinforced concrete tee columns.

The test program consisted of two series of tee-shaped reinforced concrete columns, loaded biaxially at constant angle from the principle axes. Their end conditions were assumed to be pinned-ended.

Loads, at constant rate, were gradually applied until failure. At each loading stage, measurements were made for the strains and deflections at the mid span section.

The experimental and theoretical results of the load- deformation and moment-curvature were compared and found that the analytical approach proposed by Hsu is applicable to irregular sections …

Behavior Of Channel-Shaped Reinforced Concrete Columns Under Combined Biaxial Bending And Compression, Dureseti Chidambarrao

Theses

The inelastic behavior of irregular shaped reinforced concrete columns has been a constant concern for a structural engineer, to design a safe and economic structure in modern buildings and bridge piers. The shape of the elements in a reinforced concrete structure may be used to optimize its structural strength, to make better use of the available space, to improve the aesthetic appearance of the structure, or to facilitate construction. Due to the locations of the columns, the shapes of the buildings and the nature of the applied loads, many columns are subject to combined biaxial bending and axial load.

Seven …

Analysis And Tests [Of] L-Shaped Reinforced Concrete Column Under Combined Biaxial Bending And Axial Compression, Alaedin Majlesi

Theses

A total of five tests on biaxially loaded column specimens were conducted to investigate the complete behavior of load-deformation characteristics from zero load until failure. The specimens were tested under horizontal position with 60 ton hydrolic jack. Pin end was used for both ends to obtain higher accuracy of plotting curves.

Two specimens were tested with dial gages to obtain load-deflection curves and the other three specimens were tested with demec and strain gages to obtain load strain and moment-curvature curves. The strain gages were measured by weston bridge and deme-gages were measured by mechanical dial gage.

The above moment-curvature …

Failure Surface For L-Shaped Reinforced Concrete Short Columns, Mon-Chen Liu

Theses

Combined bending and axial compression for L-shaped reinforced concrete short columns is a common problem. But the present ACI Building Code (ACI 318-77), handbooks and texbooks pay no attention to this problem. A numerical analysis and computer program developed by Hsu fora reinforced concrete member subject to biaxial bending and axial load has been used Using this computer program, the interaction diagrams and failure surface were developed for L-shaped members under combined bending and axial compression. A comparison between theoretical and experimental results was included to examine the validity of failure surface.