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.

The modified Riks/Wempner method was examined for elastic, geometrically nonlinear space trusses. A computer program, RWCNR, was developed using the Riks/Wempner algorithm. The study includes an examination of three trusses, of which two exhibit bifurcation. A method of branching onto secondary equilibrium paths was studied, and the computer program incorporates this concept. This method of branching was found to work well provided the intersection of the fundamental and secondary equilibrium paths is good. The computer program was found to be very useful and reliable. It successfully traced fundamental equilibrium paths, located critical points (load levels), and branched onto secondary equilibrium paths. The modified Riks/Wempner method was found to be a very reliable method of obtaining equilibrium paths up to, and beyond, limit points, and it could branch onto secondary equilibrium paths. / Master of Science

A procedure for analyzing a two and three dimensional truss-rigid-frame with elope deflection method is investigated in this thesis. In the first few chapters of this thesis the elope deflection equations for solving the trussed-rigid-frame problem were derived. The point of great importance in deriving slope deflection equations is that the imaginary plates or bars are added at separated domains or parts. Because of the existence of imaginary plates or bars the whole trussed-rigid-frame can be regarded as the rigid beam frame. The equations for determining the coefficients for the equivalent slope deflection equations of the separate domains can be formulated by applying the Castigliano’s theorems. The reactions and the stresses in every member of the trusses can be calculated after the reactions at the “joints” have been determined. In the last few chapters an illustrative example is given. Its solutions are checked with the solutions obtained by applying Castigliano's theorem to the whole frame. This proves that it is possible to analyze the trussed-rigid-frame by using the procedure mentioned in this thesis. The advantage in using this method is that the whole structure may be separated into domains when the number of members increases to such an extent that the capacity of a computer is exceeded. / Master of Science

M.S.

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.