<p> Trusses and Vierendeel girders are usually built from a single chord HSS "Hollow Structural Sections", but the largest HSS size as produced in Canada may limit its use for longer span applications. Therefore, the possibility of using double chord sections to enable the use of HSS for longer span trusses without the need for manufacturing new larger sections, presented itself. </p> <p> A new concept utilizing double chord square hollow sections in welded K-joints of Warren trusses is described. The experimental results of 29 tests are reported, including four connections types — standard, channel, bolted and back-to-back. The latter type comprised of gapped, overlapped and gapped with connecting stiffener plates. </p> <p> The results indicate that the standard type is an excellent joint in both strength and stiffness. The channel type is generally susceptible to twisting. It was found adequate only when a significant increase in chord thickness (≃ 50%) was employed. The bolted connection appears to hold promise when on-site assembly of large trusses is necessary. Its performance was further improved by connecting the chords with small tie bars. The back-to-back type needed to be reinforced or fully overlapped to develop full branch member strength. </p> <p> The double chord system of connection reveals itself to be much superior in strength to an equivalent single chord joint. </p> <p> The effects of eccentricity, branch member to chord angle, and chord preloading were investigated. Interaction formulae are presented for the standard and channel type joints which suffered from a chord failure at the connection. </p> <p> Results of four T-type connections using the double chord concept are also reported and were recently published in the ASCE (8). </p> / Thesis / Doctor of Philosophy (PhD)

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An analytical and experimental investigation was conducted to study the six bolt flush moment end-plate connection configuration which is used in steel frame construction. The limit states of plate yielding and bolt fracture were analyzed using yield-line theory to predict endplate thicknesses and a split-tee analogy to develop a method to predict bolt forces. Five experimental tests were conducted on four configurations within a matrix of geometric parameters. The predicted ultimate moment showed good . correlation to the yield moment obtained from the experimental deflection plots. The experimental bolt forces correlated well with the predicted bolt forces when plotted versus the applied moment. Additionally, an equation to model the moment-rotation relationship was developed from a regression analysis to determine the construction type suitable for a given connection configuration. Finally, a method of designing the six-bolt flush end-plate configuration is presented and an example given. / Master of Science

A self-sensing and self-healing bolted joint has been developed. This concept encompasses the areas of health monitoring, joint dynamics and smart materials. In order to detect looseness in a joint the impedance health monitoring method is used. A new method of making impedance measurements for health monitoring that greatly reduces the equipment cost and equipment size was developed. This facilitates implementation of the impedance technique in real-life field applications. Several proof of concept experiments are presented and compared to the traditional method of making impedance measurements. Investigations of bolted joint dynamics were conducted. A literature review of bolted joints and their diagnostics is presented. The application of the transfer impedance method is compared to standard modal tests on various bolt tensions. An investigation of damping in bolted joints was also made comparing a bolted and monolithic beam. Practical issues in adaptive bolted joints are investigated. This includes issues on activating/heating SMA actuators, connecting the actuators to the power source, size selection of SMA actuators and insulations. These issues are examined both experimentally and theoretically. / Master of Science

This thesis presents the results of testing to determine if spacing between bolts in a multiple-bolt, single-shear connection subjected to natural hazard loading affects seven strength and serviceability parameters: maximum load, failure load, E.E.P. yield load, 5% offset load, elastic stiffness, E.E.P. energy, and ductility ratio. This research also determines if a statistical difference exists between previously published research for 4D spacing as compared to results produced by this research for five alternate spacings: 8D, 7D, 6D, 5D, and 3D. Finally, this research determines which of the spacings examined: 8D, 7D, 6D, 5D, 3D; produced the most optimal results for each examined strength and serviceability parameter where optimization is based on economy and performance. Three connection configurations with five different spacings between bolts were subjected to reverse cyclic loading for a total of one hundred and fifty tests. The reverse cyclic protocol was based on recommendations by the Consortium of Universities for Research in Earthquake Engineering (CUREE) for testing woodframe structures. The same connection configurations were also subjected to monotonic loading for an additional forty-five tests. Results of this research can be used to evaluate the current design recommendation presented in the National Design Specification (NDS) for Wood Construction (AF&PA, 2001) of spacing bolts at four times the bolt diameter (4D) to determine if a different spacing should be recommended for natural hazard loading conditions. / Master of Science

This study investigates the structural integrity of hydrofoils under three scenarios: regular boating, turning, and collision with an underwater obstacle. To analyse the forces acting on the hydrofoil, calculations were performed and simulations were conducted in SolidWorks using a CAD model of the hydrofoil.The simulations reveal that the weld between the struts and the wing undergoes plastic deformation during both regular boating and turning. This deformation is particularly problematic during turning, as the forces on the weld increase significantly. Under the collision scenario, the bolts at the breakpoint fail before critical damage occurs to the components above.The results highlight the weakness of the weld and the need for a redesign of the hydrofoil to eliminate it. An alternative fastening method, such as bolted joints with watertight sealing, should be considered.

Este trabalho realiza estudo teórico e experimental de ligações parafusadas em chapas finas onduladas, com aço de alta resistência, submetidas a esforços de tração em situação de cisalhamento simples. A aplicação deste tipo de ligação ocorre em paredes de silos cilíndricos metálicos. Também foi avaliada a utilização de montagem com chapas duplas, utilizadas na prática para aumentar a espessura total da parede, devido a demanda por silos cada vez maiores. O programa experimental compreendeu 137 ensaios, nos quais foram variados parâmetros de interesse com aplicações práticas, resultando em dois modos de falha distintos, ruptura da chapa na seção líquida e esmagamento do aço na parede do furo. Foram propostas novas equações para o cálculo da resistência deste tipo de ligação. Os resultados experimentais obtidos mostraram que em ligações com falha por ruptura na seção líquida, reduzir a área líquida à uma área efetiva por meio de um coeficiente redutor resulta em valores conservadores para a resistência deste tipo de ligação. As ligações com chapas duplas apresentaram resistência elevada, superior à condição de chapa simples. / This work presents a theoretical and experimental study of bolted connections with thin, corrugated, high strength steel sheets, subjected to tension in simple shear condition. This type of connection is applicable in walls of cylindrical steel silos. It also was evaluated the case of double sheet assemblage, that is used in practice to increase the total wall thickness, due to the demand for bigger silos. The experimental program comprised 137 tests, in which it were varied chosen parameters of practical interest, providing failure by net section tension rupture and bearing of the sheet. New equations were proposed for the strength calculation of this type of connection. The experimental results indicated that in connections subject net section rupture, to reduce the net section area to an effective area through a reduction coefficient returns conservative values of resistance for this type of connection. The connections with double sheet exhibited high values of resistance, which resulted bigger than for simple sheet cases.