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Full-Text Articles in Social and Behavioral Sciences

Computational Simulation Of Eccentrically Loaded Circular Thin-Walled Concrete-Filled Double Steel Tubular Slender Columns, Mizan Ahmed, Qing Liang, Vipulkumar Patel, Muhammad N. S Hadi Jan 2020

Computational Simulation Of Eccentrically Loaded Circular Thin-Walled Concrete-Filled Double Steel Tubular Slender Columns, Mizan Ahmed, Qing Liang, Vipulkumar Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

The concrete confinement provided by the circular steel tubes improves the performance of circular concretefilled double steel tubular (CFDST) columns, which have increasingly been employed as high-performance structural members in tall buildings. This paper presents computational and design models for the simulation and design of high strength CFDST slender columns composed of circular thin-walled sections that are eccentrically loaded. The formulation of the computational model is described, which takes into account the influences of concrete confinement, geometric imperfection, second-order, gradual plasticity of steel, and geometric and material nonlinearities. The inverse quadratic method is implemented in computational algorithms which solve the …


Experimental And Numerical Investigations Of Eccentrically Loaded Rectangular Concrete-Filled Double Steel Tubular Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi Jan 2020

Experimental And Numerical Investigations Of Eccentrically Loaded Rectangular Concrete-Filled Double Steel Tubular Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Rectangular concrete-filled double steel tubular (CFDST) columns have increasingly been utilized in high-rise buildings to support heavy loads. However, the responses of eccentrically loaded rectangular CFDST short columns have rarely been studied. This paper reports experimental and numerical investigations into the behavior of rectangular thin-walled short CFDST columns composed of a rectangular inner steel tube loaded eccentrically. Tests on rectangular and square CFDST short columns under eccentric loading and axial loading were carried out to examine their responses to various design parameters, including the cross-sectional dimensions, loading eccentricity, and width-to-thickness ratios of the external and internal tubes. The experimental program …


Numerical Analysis Of Axially Loaded Rectangular Concrete-Filled Steel Tubular Short Columns At Elevated Temperatures, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi Jan 2019

Numerical Analysis Of Axially Loaded Rectangular Concrete-Filled Steel Tubular Short Columns At Elevated Temperatures, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Elevated temperatures significantly reduce the local buckling strengths of steel tubes and the ultimate strengths of rectangular concrete-filled steel tubular (CFST) columns exposed to fire. No fiber-based models have been developed that include local buckling effects on the fire-resistance of rectangular CFST columns. This paper presents a new fiber element model for the fire-resistance predictions of axially loaded rectangular CFST short columns at elevated temperatures considering local buckling. The thermal analysis problem of a CFST column is solved by the finite difference method to determine the temperature distribution within its cross-section including an air gap, concrete moisture content and the …


Numerical Analysis Of Axially Loaded Circular High Strength Concrete-Filled Double Steel Tubular Short Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi Jan 2019

Numerical Analysis Of Axially Loaded Circular High Strength Concrete-Filled Double Steel Tubular Short Columns, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Circular high-strength concrete-filled double steel tubular (CFDST) columns are high performance members where the internal and external steel tubes offer significant confinement to the concrete infill. The confinement remarkably improves the concrete compressive strength and ductility. However, no fiber element models have been formulated for computing the responses of CFDST columns with circular steel tubes filled with high-strength concrete incorporating accurate confinement to the core and sandwiched concrete. In this paper, a new fiber-based numerical model is developed that computes the axial load-strain responses of circular high-strength CFDST short columns under axial loading. Based on existing experimental results, a new …


Fiber Element Simulation Of Interaction Behavior Of Local And Global Buckling In Axially Loaded Rectangular Concrete-Filled Steel Tubular Slender Columns Under Fire Exposure, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi Jan 2019

Fiber Element Simulation Of Interaction Behavior Of Local And Global Buckling In Axially Loaded Rectangular Concrete-Filled Steel Tubular Slender Columns Under Fire Exposure, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Slender rectangular thin-walled concrete-filled steel tubular (CFST) columns in composite building structures exposed to fire may experience the interaction of local and global buckling. Numerical investigations on the interaction buckling responses of such columns under fire exposure have been rarely reported. This paper describes a fiber-based computational model for the prediction of the fire-resistance and interaction responses of local and global buckling of concentrically-loaded slender CFST columns made of rectangular sections exposed to fire. The thermal analysis is undertaken to calculate the distribution of temperatures in the column cross-section considering the effects of the air gap between concrete and steel, …


Nonlinear Post-Fire Simulation Of Concentrically Loaded Rectangular Thin-Walled Concrete-Filled Steel Tubular Short Columns Accounting For Progressive Local Buckling, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi Jan 2019

Nonlinear Post-Fire Simulation Of Concentrically Loaded Rectangular Thin-Walled Concrete-Filled Steel Tubular Short Columns Accounting For Progressive Local Buckling, Ghanim Mohammed Kamil, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

The repair of fire-damaged thin-walled rectangular concrete-filled steel tubular (CFST) columns in engineering structures after fire exposure requires the assessment of their residual strength and stiffness. Existing numerical models have not accounted for the effects of local buckling on the post-fire behavior of CFST columns with rectangular thin-walled sections. This paper describes a nonlinear post-fire simulation technique underlying the theory of fiber analysis for determining the residual strengths and post-fire responses of concentrically loaded short thin-walled rectangular CFST columns accounting for progressive local buckling. The post-fire stress-strain laws for concrete in rectangular CFST columns are proposed based on available test …


Behavior Of Eccentrically Loaded Double Circular Steel Tubular Short Columns Filled With Concrete, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi Jan 2019

Behavior Of Eccentrically Loaded Double Circular Steel Tubular Short Columns Filled With Concrete, Mizen Ahmed, Qing Quan Liang, Vipulkumar I. Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part B

Circular concrete-filled double steel tubular (CFDST) columns in high-rise building structures possess high ductility and strength performance owing to the concrete confinement exerted by the external and internal circular steel tubes. However, the behavior of circular CFDST short columns that are loaded eccentrically has not been investigated either experimentally or numerically. Particularly, numerical studies on the moment-curvature responses, strength envelopes, confinement effects and moment distributions in circular CFDST beam-columns have not been reported. In this paper, experimental and computational investigations into the structural responses of circular CFDST short columns loaded eccentrically are presented. Nineteen short circular CFDST columns with various …


Nonlinear Analysis Of Biaxially Loaded Rectangular Concrete-Filled Stainless Steel Tubular Slender Beam-Columns, Vipulkumar I. Patel, Qing Quan Liang, Muhammad N. S Hadi Jan 2017

Nonlinear Analysis Of Biaxially Loaded Rectangular Concrete-Filled Stainless Steel Tubular Slender Beam-Columns, Vipulkumar I. Patel, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

Rectangular concrete-filled stainless steel tubular (CFSST) beam-columns utilized as supporting members for building frames may experience axial compression and biaxial moments. A numerical simulation considering the local buckling effects for thin-walled rectangular CFSST slender beam-columns has not been performed. This paper reports a stability modeling on the structural characteristics of rectangular CFSST slender beam-columns accounting for different strain-hardening of stainless steel under tension and compression. The influences of local buckling are considered in the simulation utilizing the existing effective width formulations. The developed numerical model simulates the strength interaction and load-deflection behavior of CFSST slender beam-columns. Comparisons of computed results …


Case Studies On Response Of Laterally Loaded Nonlinear Piles, Wei Dong Guo Jan 2014

Case Studies On Response Of Laterally Loaded Nonlinear Piles, Wei Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

Closed-form solutions for laterally loaded free and fixed-head piles in elastic-plastic media have been developed and implemented into a spreadsheet program called GASLFP. Underpinned by a generic limiting force profile (LFP), the solutions offer an expeditious and sufficiently accurate method for predicting response of lateral piles. They also allow parameters to be deduced using measured pile response, as is evident in the study to date on -70 test (elastic) piles. The solutions also well capture the impact of structure nonlinearity of pile body by employing reduced pile bending stiffness (EpIp). The law of the reduction in EpIp, however, needs to …


Limiting Force Profile And Laterally Loaded Rigid Piles In Sand, Hongyu Qin, Wei Dong Guo Jan 2014

Limiting Force Profile And Laterally Loaded Rigid Piles In Sand, Hongyu Qin, Wei Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, closed-form solutions were used to analyze the response of eight laterally loaded rigid piles obtained from field test, centrifuge test, and 1g laboratory model tests, allowing the modulus of subgrade reaction and the profile of limiting lateral resistance force per unit length (LFP, pu profile) to be back calculated. The study shows that (1) with a constant modulus of subgrade reaction, a linear increasing LFP and elasto-plastic p ~ y curves, the response of laterally loaded rigid piles can be well predicted in the framework of load transfer approach; (2) the gradient of the LFP is 0.64 …


Nonlinear Analysis Of Axially Loaded Cicular Concrete-Filled Stainless Steel Tubular Short Columns, Vipulkumar Patel, Qing Quan Liang, Muhammad N. S Hadi Jan 2014

Nonlinear Analysis Of Axially Loaded Cicular Concrete-Filled Stainless Steel Tubular Short Columns, Vipulkumar Patel, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

The experiments indicate that stainless steels in tension deform plastically more than stainless steels in compression. Therefore, the strain hardening of stainless steels in compression is much faster than that of stainless steels in tension. The full-range two-stage constitutive model for stainless steels assumes that stainless steels follow the same stress-strain behavior in compression and tension, which may underestimate the compressive strength of stainless steel tubes. This paper presents a fiber element model incorporating the recently developed full-range three-stage stress-strain relationships based on experimentally observed behavior for stainless steels for the nonlinear analysis of circular concrete-filled stainless steel tubular (CFSST) …


Laterally Loaded Rigid Piles With Rotational Constraints, Wei Dong Guo Jan 2013

Laterally Loaded Rigid Piles With Rotational Constraints, Wei Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

Elastic-plastic, closed-form solutions were developed recently by the author, to capture the nonlinear response of laterally loaded rigid piles. Presented in compact form, the solutions are convenient to use, and sufficiently accurate despite using only two input parameters of the net limiting force per unit length pu along the pile, and a subgrade modulus k. Nevertheless, piles may be subjected to limited cap-restraints or loading below ground surface, which alter the response remarkably.This paper provides explicit expressions for estimating loading capacity of anchored piles and develops new solutions for lateral piles with cap-rotation by stipulating a constant pu or a …


Nonlinear Analysis Of Biaxially Loaded High Strength Rectangular Concrete-Filled Steel Tubular Slender Beam-Columns, Part I: Theory, Qing Quan Liang, Vipulkumar Ishvarbhai Patel, Muhammad N. S Hadi Jan 2012

Nonlinear Analysis Of Biaxially Loaded High Strength Rectangular Concrete-Filled Steel Tubular Slender Beam-Columns, Part I: Theory, Qing Quan Liang, Vipulkumar Ishvarbhai Patel, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a new numerical model for the nonlinear inelastic analysis of biaxially loaded high strength thin-walled rectangular concrete-filled steel tubular (CFST) slender beam-columns. The numerical model considers the effects of progressive local buckling, initial geometric imperfections, high strength materials and second order. The accurate fiber element method is used to model the inelastic behavior of composite cross-sections. Theoretical models are developed that simulate the load-deflection responses and strength envelopes of thin-walled rectangular CFST slender beamcolumns under biaxial loads. New computational algorithms based on the M􀂗􁈷 ller's method are developed to adjust the depth and orientation of the neutral …


Response Of 20 Laterally Loaded Piles In Sand, Wei-Dong Guo, Bi Tang Zhu Jan 2010

Response Of 20 Laterally Loaded Piles In Sand, Wei-Dong Guo, Bi Tang Zhu

Faculty of Engineering and Information Sciences - Papers: Part A

Closed-form solutions and their associated spreadsheet program (GASLFP) were developed by the first author for laterally loaded free- head piles in elastic-plastic media. The solutions show behaviour of a laterally loaded pile is dominated by net limiting force per unit length (LFP) fully mobilised along the pile to a depth called slip depth. They are characterised by three parameters of Ng, α o and n (to describe the LFP) and the soil shear modulus (Gs). Conversely, these parameters may be deduced by matching the predicted with measured response. To facilitate practical design, in this paper, the input values of Ng, …


Laterally Loaded Rigid Piles In Cohesionless Soil, Wei-Dong Guo Jan 2008

Laterally Loaded Rigid Piles In Cohesionless Soil, Wei-Dong Guo

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, limiting force profile for laterally loaded rigid piles in sand and is differentiated from the on-pile force profile, from which elastic-plastic solutions are established and presented in explicity expressioins. Nonlinear responses of the piles are characterized by slip depths mobilized from mudline and the pile-tip. At the states of tip-yield and rotation point yield, expressions for some critical depths are developed, which allow the on-pile force profiles to be constructed. The solutions and the expressions are developed concerning a constant subgrade modulus (k) and a linearly incresing modulus with depth (Gibson k), respectively. capitalized on three measurable …