Experimental and Numerical Study of Octagonal Composite Column Subject to Various Loading

In this study, experimental tests of the behaviour of steel and partially encased composite (PEC) columns subjected to compressive loading is performed. Evaluation of this type of composite column under axial loading and numerical analysis of its behaviour under combined torsional and axial loading are the main objectives of this study. At first, a parametric study of PEC columns under axial loading was performed in order to find the relationship between flange slenderness ratio of steel column section and concrete confinement. Width-to-thickness ratio of the flange, diameter and spacing of the transverse links were considered as variables in this study. It was observed that dimension of transverse links had almost no effect on the capacity of the specimens, however smaller transverse links spacing increased both capacity and deformability of the specimens. The comparison of the code equations given in CSA S16-14 and EN 1994-1-1 revealed that the equation in CSA S16-14 underestimates the capacity. Furthermore, different types of retrofit of cross-shaped steel column including concrete encasement, use of stiffener plates and transverse links were investigated in this research. Results revealed that concrete confinement and use of transverse links had respectively the most and the least effect on increasing torsional capacity of the specimens

Experimental and Numerical Investigation of Octagonal Partially Encased Composite Columns Subject to Axial and Torsion Moment Loading

This paper includes experimental and numerical study of the octagonal partially encased composite (PEC) columns specimens under axial and torsion loading. The major difference between them was the concrete reinforcement details. The parameters investigated in the experimental and numerical study were the type of reinforcement details, the failure mode, width-to-thickness ratio of flange, transverse links spacing and diameter. The results were presented as load-deformation curves. Numerical model was validated using finite element method and the results indicated acceptable accuracy with tests results in the form of capacity and ductility. In the analytical phase, the experimental results in the compressive loading were compared with those obtained from CSA S16-14 and EN 1994-1-1 equations. Also, the new concrete confinement factor in proportion to the web width to thickness ratio was presented to octagonal PEC columns under pure compressive load. Furthermore, different types of retrofit of cross-shaped steel column including concrete encasement, use of stiffener plates and transverse links were investigated in this research. Results revealed that concrete confinement and use of transverse links had respectively the most and the least effect on increasing torsional capacity of the specimens

Effect of seismic soil-pile-structure interaction on midand high-rise steel buildings resting on a group of pile foundations

A series of numerical simulations were carried out on two types of superstructures and six types of piled raft foundations to investigate the effects of seismic soil-pile-structure interaction (SSPSI) on the seismic responses of the superstructures. In this research, the effectiveness of a piled raft application was assessed; the pile optimum numbers, locations, and configurations were estimated; and finally, a comparison was made between the nonlinear structural responses of the obtained two-dimensional (2D) and three-dimensional (3D) models. Parametric studies were conducted to achieve strategies for optimized designs of piled raft foundations subjected to the low-to-high intensities of real earthquake records as the input motions. The numerical results represented a reasonable correlation between the shaking intensity rates (SIRs) and maximum interstory drifts of the structures. It was discovered that the performance levels of the structures on a softened ground were a function of the area replacement ratios, lengths, diameters, and spaces between the piles; ground motion features; and height/width ratios of the structures. These important aspects had to be regarded to achieve a reliable design. The aim of this investigation was to ameliorate the characteristics of a system of long-short combined piled raft foundations based on an understanding of the interaction mechanics. © 2018 American Society of Civil Engineers

Three-Dimensional Printing of Structural Members with Shotcrete Technique: Design, Construction, and Future Directions

This paper provides a comprehensive review of the current state of 3D printing technology in the construction industry, highlighting the potential applications, benefits, and future directions of this emerging field. The review indicates that 3D printing technology has the potential to revolutionize the construction industry by offering more efficient, precise, and sustainable methods of construction. The technology offers numerous advantages, including the ability to create complex geometries and custom components, improved precision and accuracy, reduction in waste materials, improved worker safety, and potential for use in remote or inaccessible locations. Furthermore, the advent of additive manufacturing, colloquially known as 3D printing, presents prospects for the advancement of novel material compositions, printing methodologies, and cybernetic systems that have the potential to optimize the efficiency and effectiveness of the construction domain. Future research should focus on developing larger printers with more efficient support structures, improving the accuracy and speed of printing, and exploring the potential of using new and innovative materials in the construction process. Additionally, the environmental impact of 3D printing technology should be further examined, particularly in terms of its potential for reducing waste and energy consumption in the construction industry. Overall, the potential utilizations and advantageous outcomes stemming from the implementation of 3D printing technology within the construction sector are momentous. Persistent exploration and innovation within this realm hold the capacity to engender noteworthy strides in construction technology and foster heightened sustainability within building methodologies

Numerical 3D Finite Element Assessment of Bending Moment-Resisting Frame Equipped with Semi-Disconnected Steel Plate Shear Wall and Yielding Plate Connection

Steel plate shear walls (SPSWs) have advantages such as high elastic stiffness, stable hysteresis behavior, high energy absorption capacity, and decent ductility. However, one of the main drawbacks of SPSWs is their buckling under lateral loading. To address this issue, a simple and practical solution in the form of using a trapezoidal plate moment connection (PMC) and a narrow gap between the infill plate and columns is presented. The PMC will act as an energy absorber, similar to a yielding steel plate, and keep the other structural members in an elastic state. Extensive three-dimensional finite element (FE) models of the SPSW system were investigated under monotonic and cyclic loading. The results revealed that by separating the infill plate from the vertical boundary elements and using two vertical edge stiffeners at both edges of the wall, the same lateral bearing capacity of the conventional system can be achieved. In addition, by increasing the thickness of the PMC from 6.5 to 26 mm, the load-bearing capacity, energy dissipation, and elastic stiffness increased approximately 2, 2.5, and 3.2 times, respectively. It was also found that the flexural capacity ratio of the connection to the beam had little effect on the overall force–displacement behavior. However, it can affect the system failure mechanism. Finally, the tension field inclination angle for such SPSWs was proposed in the range of 30 to 35°