Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item An investigation of a prefabricated steel truss girder bridge with a composite concrete deck(Montana State University - Bozeman, College of Engineering, 2018) Kuehl, Tyler William; Chairperson, Graduate Committee: Damon FickSteel truss girder bridges are an efficient and aesthetic option for highway crossings. Their relatively light weight compared with steel plate girder systems make them a desirable alternative for both material savings and constructability. A prototype of a welded steel truss girder constructed with an integral concrete deck has been proposed as a potential alternative for accelerated bridge construction (ABC) projects in Montana. This system consists of a prefabricated welded steel truss girder topped with a concrete deck that can be cast at the fabrication facility (for ABC projects) or in the field after erection (for conventional projects). To investigate possible solutions to the fatigue limitations of certain welded member connections in these steel truss girders, bolted connections between the diagonal tension members and the top and bottom chords of the steel truss girders were evaluated. A 3D finite element model was used to more accurately represent the distribution of lane and truckloads to the individual steel truss girders. This distribution was compared to an approximate factor calculated using an equivalent moment of inertia with expressions for steel plate girders from AASHTO. A 2D analytical model was used to investigate the fatigue strength of the bolted and welded connections for both a conventional cast in place deck system and an accelerated bridge deck system (cast integral with the steel truss girder). Truss members and connections for both construction alternatives were designed using loads from AASHTO Strength I, Fatigue I, Fatigue II, and Service II load combinations. A comparison was made between the two steel truss girder configurations and 205 ft. steel plate girder used in a previously designed bridge over the Swan River. Material and fabrication estimates suggest the cost of the conventional and accelerated construction methods is 10% and 26% less, respectively, than the steel plate girder designed for the Swan River crossing.Item Manufacturing reliability for C-channel composite beams(Montana State University - Bozeman, College of Engineering, 2014) Bauer, Michael Wayne; Chairperson, Graduate Committee: Douglas S. CairnsA new manufacturing method has been developed for fabricating c-channel composite beams. The beams are to be used as test articles in four point bending tests. The motivation behind this thesis is to study the effects that specific manufacturing parameters have on the resulting amounts of porosity and fiber volume in these three-dimensional sub-scale structures. The parameters considered are number of layers of flow media, fabric architecture, flow rate of the resin, temperature of the resin, and level of vacuum pressure used. The manufacturing parameters were varied in a 1/2 factorial design of experiments where sixteen beams were manufactured, all with varying values for each parameter. A taguchi design of experiments was also formed to provide a comparison. The resulting average porosity percentages and fiber volume percentages were then determined for every beam. In addition, compression and tension tests were conducted to find the average maximum stresses for each. Once all the data had been gathered an Analysis of Variance (ANOVA) study was conducted to determine the effects and their levels of significance. It was found that the level of vacuum pressure has the most significant effect on the porosity while the fabric architecture has the most significant effect on the fiber volume. Overall, every parameter has some sort of quantifiable effect on porosity and fiber volume. There are also significant two and three way interaction effects present for each. Additionally, the 1/2 factorial design seemed to provide more accurate results compared with the taguchi design, which was inherently not comprised of data with a normal distribution and does not include interaction effects. Regression models were developed for the output levels of porosity and fiber volume. This allows manufacturers to create these beams with predetermined output levels for each and can improve testing capabilities. Also, using two layers of flow media greatly improved the consistency of the beams, while reducing porosity and slightly reducing fiber volume percentage. It is recommended to further implement the use of two layers of flow media into large sub-scale structures and potentially full scale turbine blades.Item The forced vibration of viscus damped, N-beam structures(Montana State University - Bozeman, College of Engineering, 1970) Prill, Daniel FranklinItem Energy dissipation in prestressed concrete beams(Montana State University - Bozeman, College of Engineering, 1964) Vira, Khimji N.Item Error involved in isolating one floor of a building frame for design purposes(Montana State University - Bozeman, College of Engineering, 1952) Boyaci, PeteItem The maximum deflection of a blast loaded cantilever beam by the modified Galerkin method(Montana State University - Bozeman, College of Engineering, 1969) Koszuta, Daniel MichaelItem An analytical study of the behavior of composite girder bridges subjected to loads applied parallel to the plane of the slab(Montana State University - Bozeman, College of Engineering, 1969) Khanna, Jagannath KishanchandItem Judging the relative qualities and merits of Galerkin's approximate solutions to a dynamically loaded beam system(Montana State University - Bozeman, College of Engineering, 1970) Hanson, Thomas MichaelGalerkin's method is applied to a beam structure that is forced to nonlinear behavior by a dynamic load. Nonlinearities in the system include a nonlinear stress-strain relation and consideration of geometry changes due to large deflections. Several trial deflection shapes are assumed as approximate solutions of the problem and these trial shapes are combined in various manners in an effort to produce a better quality solution. All resulting solutions are studied in the light of three criteria that are postulated in an attempt to define the relative merits and qualities of approximate solutions. It is concluded that although the criteria are good guidelines to finding reasonable solutions, they are not strict in defining a good quality solution.