<p> A research project is presented to assess the capabilities of Square Hollow Structural Sections for seismic design. This assessment is based mainly on the energy dissipation and ductility measures. An attempt is made to establish a preliminary guideline of the maximum slenderness ratio that qualify the aforementioned sections for conservative seismic design. </p> <p> An experimental programme on seven different sections was performed to evaluate the loss in flexural capacity due to inelastic cyclic loads, and to construct the load-deflection and moment-curvature hysteresis loops. </p> <p> A comparison is made between the flange slenderness requirements of both HSS and wide flange rot led sections capable of resisting the same level of inelastic strain reversals for the same number of cycles. </p> / Thesis / Master of Engineering (MEngr)

Elliptical hollow sections (EHS) are the newest steel shape to emerge in the industry, but appropriate design guidance is lacking, being completely absent from Canadian codes and guidelines. Geometric property and compressive resistance tables were established to be potentially added to the Canadian guides. The equivalent RHS method, originally proposed by Zhao and Packer in 2009, was simplified and modified to validate its use for the design of EHS columns and beams. An experimental programme was developed to investigate the behaviour of EHS-to-EHS welded connections. Twelve T and X connection tests were performed to study the effect of connection angle, orientation type and loading. Two methods were developed to predict connection capacities and failure modes: the equivalent CHS and the equivalent RHS approaches. Both methods proved to be conservative on average, but the equivalent RHS approach proved to be more successful at capturing the actual failure mode of EHS-to-EHS connections.

Elliptical hollow sections (EHS) are the newest steel shape to emerge in the industry, but appropriate design guidance is lacking, being completely absent from Canadian codes and guidelines. Geometric property and compressive resistance tables were established to be potentially added to the Canadian guides. The equivalent RHS method, originally proposed by Zhao and Packer in 2009, was simplified and modified to validate its use for the design of EHS columns and beams. An experimental programme was developed to investigate the behaviour of EHS-to-EHS welded connections. Twelve T and X connection tests were performed to study the effect of connection angle, orientation type and loading. Two methods were developed to predict connection capacities and failure modes: the equivalent CHS and the equivalent RHS approaches. Both methods proved to be conservative on average, but the equivalent RHS approach proved to be more successful at capturing the actual failure mode of EHS-to-EHS connections.

abstract: Pultrusion manufacturing technique stands at the forefront for efficient production of continuous, uniform concrete composites for use in large scale structural applications. High volume and low labor, among other benefits such as improved impregnation and better sample consistency, stand as some of the crucial advances found in automated pultrusion. These advantages introduce textile reinforced concrete (TRC) composites as a potential surrogate for wood, light gauge steel, and other common structural materials into an ever changing and broadening market of industrial grade structural sections. With the potential modifications of textile geometry, textile type, section geometry, and connection type, the options presented by TRC sections seem nearly boundless. Automated pultrusion presents the ability to manufacture many different TRC composite types in at a quickened rate opening up a new field of study of structural materials. The objective of this study centered on two studies including the development of an automated pultrusion system for the manufacturing of TRC composites and ultimately the assessment of composites created with the pultrusion technique and their viability as a relevant structural construction material. Upon planning, fabrication, and continued use of an automated pultrusion system in Arizona State University’s Structures Lab, an initial, comparative study of polypropylene microfiber composites was conducted to assess fiber reinforced concrete composites, manufactured with Filament Winding Technique, and textile reinforced concrete composites, manufactured with Automated Pultrusion Technique, in tensile and flexural mechanical response at similar reinforcement dosages. A secondary study was then conducted to measure the mechanical behavior of carbon, polypropylene, and alkali-resistant glass TRC composites and explore the response of full scale TRC structural shapes, including angle and channel sections. Finally, a study was conducted on the connection type for large scale TRC composite structural sections in tension and compression testing. / Dissertation/Thesis / Masters Thesis Civil Engineering 2017

<p> A research programme is presented to more fully understand the behaviour of Round Hollow Structural Sections subjected to inelastic strain reversals. An attempt is made to establish a preliminary guideline for choosing a reasonable value for the slenderness ratio (D/t) that qualifies the Round HSS for cyclic loading. </p> <p> An experimental programme on nine sections was performed to evaluate the loss in load capacity due to inelastic cyclic loading and to construct the load-deflection hysteresis loops. </p> <p> Three different limiting cyclic deflections were imposed to the smallest D/t section and a comparison was made between the performance of the tube in each case. </p> <p> Prasad's computer program was used to select the strain value at which local buckling will appear and to calculate the half buckle wave-length. The results were compared to the experimental results obtained by the author. </p> <p> A comparison is made between two Round HSS having different diameters and thicknesses but the same D/t ratio. </p> <p> A comparison is made between the behaviour of Round HSS and Square HSS subjected to the same cyclic loading programme. </p> <p> An attempt is made to suggest a reasonable curve relating the number of cycles to failure and the D/t ratio. </p> / Thesis / Master of Engineering (ME)

<p> A research programme is presented for assessing the capability of Hollow Structural Sections in Plastic Design. This investigation attempts to relate the flange slenderness and yield stress to the rotation capacity of Hollow Structural Sections subjected to both constant moment regions and to moment gradients. </p> <p> An experimental programme was performed on 31 different cross sections to evaluate the moment-curvature relationship which is of fundamental importance in Plastic Methods. The occurrence of local buckling for some sections in the compression flange and the consequent reduction in moment resistance is the critical factor which separates members into compact and non compact categories. </p> <p> The moment-curvature relations from tests are compared with analytical predictions. The plastic hinge rotations delivered by the present test sections are compared with the maximum practical requirements for plastically designed continuous beams. Theoretical elastic and inelastic buckling solutions of plate elements are also presented to relate to possible local buckling of the flats of square and rectangular hollow structural sections. </p> <p> Plate ratios of compression flanges are then selected for use in plastic design of hollow structural sections. Such a separation permits segregation into compact and non compact categories and can be used in working stress or elastic design methods. </p> / Thesis / Master of Engineering (ME)

Although branch plate connections with circular hollow section (CHS) members are simple to fabricate and cost-effective, they are generally very flexible under low load application resulting in the limit states design resistance being governed by an imposed deformation limit. Restricting the ultimate capacity of a branch plate connection by a deformation limit results in the inherent strength of the CHS member being under-utilized, highlighting the need to develop connection stiffening methods. Two methods to stiffen branch plate-to-CHS connections are examined: a through plate connection and a grout-filled CHS branch plate connection. Further, the current design guidelines of various plate-to-CHS connection types are reexamined including the effect of chord axial stress and chord length on connection behaviour. Finally, the behaviour of connections with non-orthogonal or skew plate orientation, which has not previously been examined, was studied in depth.The behaviour of these uniplanar connection types under quasi-static axial loading was studied through 16 large-scale laboratory experiments and 682 numerical finite element analyses, as well as an extensive review of all previous international experimental and numerical findings. The extensive study formed the basis for a complete set of proposed design guidelines and provided insight into plate-to-CHS connection behaviour. For all plate-to-CHS connection types, the plate thickness is shown to effect connection capacity, though previously this was thought not to have significant impact on connection behaviour. The existing ideology of using the same design recommendations for tension- and compression-loaded connections, which was developed from compression results, under-utilizes an inherent increase in capacity provided by a connection primarily loaded in tension. As such, the recommended design guidelines split the two load senses into separate expressions that reflect the difference in behaviour. Stiffened through plate connection behaviour was determined to be the summation of branch plate behaviour in compression and tension, leading to a significant increase in capacity and identical behaviour regardless of branch load sense. The skewed branch plate connection behaviour was found to relate directly to the established behaviour of longitudinal and transverse plate connections. A design function was developed that interpolates the capacities of intermediate angles by using the proposed design recommendations of the two extreme connection types. Finally, the examination of chord axial stress and chord length for plate-to-CHS connections yielded results similar to previous international studies on CHS-to-CHS connections. The effect of chord length, however, has wide-reaching implications as to how experimental and numerical FE research programs are developed.

Although branch plate connections with circular hollow section (CHS) members are simple to fabricate and cost-effective, they are generally very flexible under low load application resulting in the limit states design resistance being governed by an imposed deformation limit. Restricting the ultimate capacity of a branch plate connection by a deformation limit results in the inherent strength of the CHS member being under-utilized, highlighting the need to develop connection stiffening methods. Two methods to stiffen branch plate-to-CHS connections are examined: a through plate connection and a grout-filled CHS branch plate connection. Further, the current design guidelines of various plate-to-CHS connection types are reexamined including the effect of chord axial stress and chord length on connection behaviour. Finally, the behaviour of connections with non-orthogonal or skew plate orientation, which has not previously been examined, was studied in depth.The behaviour of these uniplanar connection types under quasi-static axial loading was studied through 16 large-scale laboratory experiments and 682 numerical finite element analyses, as well as an extensive review of all previous international experimental and numerical findings. The extensive study formed the basis for a complete set of proposed design guidelines and provided insight into plate-to-CHS connection behaviour. For all plate-to-CHS connection types, the plate thickness is shown to effect connection capacity, though previously this was thought not to have significant impact on connection behaviour. The existing ideology of using the same design recommendations for tension- and compression-loaded connections, which was developed from compression results, under-utilizes an inherent increase in capacity provided by a connection primarily loaded in tension. As such, the recommended design guidelines split the two load senses into separate expressions that reflect the difference in behaviour. Stiffened through plate connection behaviour was determined to be the summation of branch plate behaviour in compression and tension, leading to a significant increase in capacity and identical behaviour regardless of branch load sense. The skewed branch plate connection behaviour was found to relate directly to the established behaviour of longitudinal and transverse plate connections. A design function was developed that interpolates the capacities of intermediate angles by using the proposed design recommendations of the two extreme connection types. Finally, the examination of chord axial stress and chord length for plate-to-CHS connections yielded results similar to previous international studies on CHS-to-CHS connections. The effect of chord length, however, has wide-reaching implications as to how experimental and numerical FE research programs are developed.