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Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 159-165). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 79-80). Also available via the Internet.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Choi, Seung-Kyum; Committee Member: Muhanna, Rafi; Committee Member: Rosen, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2006. / Includes bibliographical references (p. 235-236).

This research program investigates the performance of a steel truss bridge when subjected to both localized web damage and a subsequent post-tensioned strengthening approach. The investigation utilizes a combined approach involving an experimental scale model bridge and a numerical computer model generated using the commercial finite element software RISA 3-D. The numerical model is validated using test data and further extended to parametric studies in order to investigate the theoretical load rating, strain energy, load redistribution, mode shapes and frequency of the bridge for control, damaged and strengthened states. The presence and severity of damage are found to significantly influence the global safety and reliability of the bridge. Also, higher order modes are more susceptible to changes in shape and frequency in the presence of damage. A recovery of truss deflection and a reduction of member forces are achieved by the proposed strengthening method.

This study was undertaken in order to determine analytically the magnitude of the secondary (i.e., joint deflection induced) moments in the continuous glued-laminated chords of bowstring timber trusses. Traditionally, these moments have been assumed to be small and therefore neglected. The American Institute of Timber Construction makes no mention of these moments in their recommended design procedure.

Joining wooden rafters with plywood gusset plates using helically threaded nails to form roof trusses has been widely developed in recent years. Actually, the nailed member has proven to be extremely strong and stiff, but it is not perfectly rigid. The effect of non-rigidity of joints in resisting bending and thrust are investigated in this paper. The purpose of this study is to determine the rotation and slip of truss members relative to plywood gussets which influence the moment, shear, and axial load of each member. Experimental work was conducted on several timber joints in an effort to determine their actual characteristics. The theoretical analysis of relative rotation was based on the assumption that a rafter member is supported by a continuous elastic foundation; i.e. by equally spaced nails. It yields results which are reasonably close to those found experimentally. The Moire Fringe effect was introduced to measure the rotation of the wooden chords relative to the gusset plates of small model joints. A model truss with semi-rigid joints was tested. Strain were measured with SR-4 gages and deflections with dial gages The results were applied full scale designs by model analysis techniques / M.S.

A VGT or Variable-Geometry Truss can be thought of as a statically determinate truss that has been modified to contain some number of variable length members. These extensible members allow the truss to vary its configuration in a controlled manner. VGTs are often symmetric. constructed of repeating cells, and have exceptional stiffness to weight ratios. VGTs have been widely recognized as adaptive or collapsing structures for space and military applications. Some of the typical applications envisioned for VGTs are as booms to position equipment in space. as supports for space antennae. and as berthing devices. Lately, they have also been proposed as parallel-actuated. long chain. high dexterity manipulators. This work describes basic VGT theory. and presents criteria to use in the determination of valid VGT unit cells. Four of the VGT unit cells - the tetrahedron. the octahedron, the decahedron. and the dodecahedron are discussed in detail. The typical modeling and formulation procedure for developing the kinematic equations associated with the forward kinematic problem of each of the above is described. Another intent of this work is to present a new and efficient technique for solving the forward kinematics problem of VGTs. All VGT problems lead to systems of equations. Commonly, such systems are solved by an iterative numerical method, usually a Newton method or a variant. For such methods to yield a solution, a starting point sufficiently close to the actual solution must be supplied. For systems of the size of those encountered in VGT problems, this is a formidable task. On the other hand, recently developed methods in homotopy continuation for polynomials are not only global, but also exhaustive; i.e., they do not require good initial guesses and they also guarantee convergence to all solutions. Homotopies are a traditional part of topology and have only recently begun to be used for practical numerical computation. Polynomial continuation is used to track the solutions of the systems of equations describing the kinematics of VGTs. This method has proven to be robust and reliable. It may also prove to be a valuable tool in the analysis of other kinematic devices with a high multiplicity of solutions. / Ph. D.

Full size wood joist floors were built and their frequencies were measured. Double tee-beam floors were built and also cut from the full size floors and their frequencies were measured. The floor joists investigated included: solid sawn, parallel chord floor trusses, and composite I -joists. The first natural frequency of each tee-beam floor was predicted after measuring the deflection under imposed loading. A design procedure is presented to predict the fundamental frequency of wood joist floors from tabulated material properties / Master of Science