The steel bridge system referred to as Simple for Dead load and Continuous for Live load (SDCL) has gained popularity in non-seismic areas of the country. Accordingly, it results in many advantages including enhanced service life and lower inspection and maintenance costs as compared to conventional steel systems. To-date, no research studies have been carried out to evaluate the behavior of the SDCL steel bridge system in seismic areas. The main objective of this research was to extend the application of SDCL to seismic areas. The concept of the SDCL system was developed at the University of Nebraska-Lincoln and a complete summary of the research is provided in five AISC Engineering Journal papers. The SDCL system is providing steel bridges with new horizons and opportunities for developing economical bridge systems, especially in cases for which accelerating the construction process is a priority. The SDCL steel bridge system also provides an attractive alternative for use in seismic areas. The SDCL concept for seismic areas needed a suitable connection between the girder and pier. In this research, an integral SDCL bridge system was considered for further investigation. The structural behavior and force resistance mechanism of the proposed seismic detail considered through analytical study. The proposed connection evaluated under push-up, push-down, inverse and axial loading to find the sequence of failure modes. The global and local behavior of the system under push-down forces was mainly similar to non-seismic detail. The nonlinear time history analysis indicated that there is a high probability that bottom flange sustains tension forces under seismic events. The finite element model subjected to push-up forces to simulate the response of the system under the vertical component of seismic loads. However, the demand-capacity ratio was low for vertical excitation of seismic loads. Besides finite element results showed that continuity of bottom flange increased ductility and capacity of the system. While the bottom flange was not continuous, tie bars helped the system to increase the ultimate moment capacity. To model the longitudinal effect of earthquake loads, the model subjected under inverse forces as well as axial forces at one end. In this case scenario, dowel bars were most critical elements of the system. Several finite element analyses performed to investigate the role of each component of preliminary and revised detail. All the results demonstrated that continuity of the bottom flange, bolts area (in the preliminary detail), tie bars over the bottom flange (in the revised detail) were not able to provide more moment capacity for the system. The only component increased the moment capacity was dowel bars. In fact, increasing the volume ratio of dowel bars could be able to increase the moment capacity and prevent premature failure of the system. This project was Phase I of an envisioned effort that culminated in the development of a set of details and associated design provisions to develop a version of the SDCL steel bridge system, suitable for the seismic application. Phase II of this project is an ongoing project and currently the component specimen design and test setup are under consideration. The test specimen is going to be constructed and tested in the structures lab of Florida International University. A cyclic loading will be applied to the specimen to investigate the possible damages and load resistance mechanism. These results will be compared with the analysis results. In the next step, as phase III, a complete bridge with all the components will be constructed in the structures lab at the University of Nevada-Reno. The connection between steel girders will be an SDCL connection and the bridge will be subjected to a shake table test to study the real performance of the connection due to earthquake excitation.

The path along which a high voltage cable needs to travel within the production facility is designed by a combination of straight and curved segments. As segments are available only in standard sizes, the path must be standardized. The transformation of an initial path into standardized path is a manual and time-consuming process. Tools are developed to automate this process using Knowledge-Based Engineering (KBE). The MOKA-methodology has been followed to capture and store the knowledge behind the standardization of the path. Designs of truss segments which are currently in use are studied and modified to make the models more efficient. Finite Element Analysis (FEA) is performed to evaluate the strength of segments of both old and new models which shows that new models are more efficient. To rapidly obtain segments of different dimensions, parametric models of segments are designed.

Disc brake calipers are subjected to complex mechanical loading and interaction of individual components in a typical brake assembly makes design improvement very challenging. To analyse caliper behaviour, complex Finite Element models were created and successfully validated using a variety of experimental techniques, including exceptionally suitable Digital Image Correlation. A novel methodology to optimise caliper design was developed, using non-linear contact Finite Element Analysis and topology optimisation, to generate lightweight, high performance brake calipers. The method was used on a Formula 1 brake assembly and significant improvement in structural design was achieved, with the new caliper being lighter and stiffer than the original. The same approach was used on more conventional 4 pistons calipers using various boundary conditions with particular focus on mass reduction and considerably lighter designs were achieved. The influence of specific features of the optimised calipers on the structural performance was also successfully investigated.

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Wind-induced damages on low-slope roofs are a major and common problem that many buildings located in high wind areas suffer from. Most of these damages are initiated when the metal roof edge fails first, leading to overall roof failure. This is because peak wind pressures occur at the edges and corners of low-slope roof buildings. Currently, there are not enough wind design guidelines for the Canadian roofing community to quantify the dynamic wind uplift resistance of the roof edge system. The objective of this research is to evaluate the effect of wind-induced loads on roof edges using a finite element model, verify the numerical results with those obtained from controlled experiments, and perform parametric investigations for various design variables. In this research, the overall roof edge system was modelled using the commercial finite element software package ABAQUS, by simulating the roof edge system with shell elements and applying a uniform static pressure against the face of the edge cleat or coping. Results of the modelling were compared to the experimental ones in terms of deflection of the coping under uniform pressure. The results of the numerical model and the experiments show a good agreement. Furthermore, a parametric analysis of the system was conducted under the effect of varying parameters. i.e., coping gauge, nail spacing, coping and cleat length and wind and thermal load application.

Structural steel design standards recognize lateral torsional buckling as a failure mode governing the capacity of long span unsupported beams with wide flange cross-sections. Standard solutions start with the closed form solution of the Vlasov thin-walled beam theory for the case of a simply supported beam under uniform moments, and modify the solution to accommodate various moment distributions through moment gradient expressions. The Vlasov theory solution is based on the assumption that cross-sectional distortional effects have a negligible effect on the predicted elastic critical moment. The present study systematically examines the validity of the Vlasov assumption related to cross-section distortion through a parametric study. A series of elastic shell finite element eigen-value buckling analyses is conducted on simply supported beams subject to uniform moments, linear moments and mid span point loads as well as cantilevers subject to top flange loading acting at the tip. Cross-sectional dimensions are selected to represent structural steel cross-section geometries used in practice. Particular attention is paid to model end connection details commonly used in practice involving moment connections with two pairs of stiffeners, simply supported ends with a pair of transverse stiffeners, simply supported ends with cleat angle details, and built in fixation at cantilever roots. The critical moments obtained from the FEA are compared to those based on conventional critical moment equations in various Standards and published solutions. The effects of web slenderness, flange slenderness, web height to flange width ratio, and span to height ratios on the critical moment ratio are systematically quantified. For some combinations of section geometries and connection details, it is shown that present solutions derived from the Vlasov theory can overestimate the lateral torsional buckling resistance for beams.

A software program was written that implements a finite element analysis (FEA) solution as the basis of an optimization function used for guiding the inverse design problem of aligning fibres, minimizing displacements in a fibre-reinforced polymer composite part in response to a given loading condition, for various part geometries. The FEA solution makes use of the superlinear RGNTet4 element, which includes 3 displacement and 3 rotational degrees of freedom at 4 nodes. Convergence testing verified the accuracy of the solver versus symbolic results for simple cases. Multivariate optimization over fibre orientations and volume fractions was carried out for a simple test case using the NLOpt nonlinear optimization library. Both derivative-free and gradient-based algorithms were tested. Low-Storage Broyden-Fletcher-Goldfarb-Shannon was the most effective algorithm. Four more complex cases were examined, and by varying fibre orientations, reductions of 48%, 66%, 58% and 32% were achieved in displacements at the loaded nodes.

Three-dimensional (3-D) medical imaging creates notable opportunities as input toward engineering analyses, whether for basic understanding of the normal function or patho-physiology of an organ, or for the simulation of virtual surgical procedures. These analyses most often require finite element (FE) models to be constructed from patient-specific 3-D medical images. However, creation of such models can be extremely labor-intensive; in addition, image processing and mesh generation are often operator-dependent, lack robustness and may be of suboptimal quality. Focusing on the human aorta, the goal of the present work is to create a fast and robust methodology for quadrilateral surface and hexahedral volume meshing from 3-D medical images with minimal user input. By making use of the segmentation capabilities of the 3-D gradient vector flow field combined with original ray-tracing and orientation control algorithms, we will demonstrate that it is possible to incrementally grow a structured quadrilateral surface mesh of the inner wall of the aorta. The process does not only require minimal input from the user, it is also robust and very fast compared to existing methods; it effectively combines segmentation and meshing into one single effort. After successfully testing the methodology and measuring the quality of the meshes produced by it from synthetic as well as real medical image datasets, we will make use of the surface mesh of the inner aortic wall to derive hexahedral meshes of the aortic wall thickness and of the fluid domain inside the aorta. We will finally outline a tentative approach to merge several structured meshes to process the main branches of the aorta.

A pipe consisting of Inconel 600 welded to grade 106-B Carbon-Steel using Inconel 182 weld filler is used to transport heavy water in nuclear reactors. A confidential report concluded that cracking is one of the problems these pipes are currently facing. Before cracking can be fully understood the mechanical properties of the weld must be determined. This thesis analyzed the pipe at various length-scales using optical microscopy, micro-hardness testing, small and large scale tensile testing and digital image correlation (DIC). This thesis successfully achieved it goals of determining the mechanical properties and creating a model of the Inconel dissimilar metal weld. It partially met the goal of observing fracture mechanisms as it was able to observe fracture in tensile samples but was not able to successfully track crack growth.

Fibre reinforced plastics (FRP) have been used widely in civil engineering in order to improve the structural response (deformation and stress). Most of the current codes for the strengthening of RC structures do not provide enough provision for the design of the column-slab connections strengthened with externally bonded reinforcement (EBR) due to the lack of research covering this area. This study is to investigate, both experimentally and analytically, the effectiveness of bonding pre-stressed carbon fibre plates to the tension surface of concrete column-slab connections in both the serviceability and ultimate limit state. The experimental programme comprises five full-scale specimens that are designed and fabricated to simulate an interior column-slab connection. The prestressing technique, application procedure and prestressing device are described in detail in this study. Different prestressing forces are applied to the FRP plates bonded to the concrete substrate. The structural response of the strengthened specimens are compared with a reference specimen in terms of punching shear strength, deflection profile, strain, crack opening displacement and failure modes. Furthermore, a finite element model using ABAQUS is built to obtain a further insight into the punching behaviour of the test slabs. Both experimental and numerical results are compared, and a parametric study on the effect of the FRP-concrete interface on the structural integrity is conducted. Results are also compared with Eurocode 2 and ACI for the prediction of the punching strength. It was found that bonding of prestressed FRP plates to the tensile face of the concrete slabs improved the serviceability, but was not able to enhance the ultimate behaviour as much as the non-prestressed FRP plates. The development of the critical diagonal crack (CDC) was the main reason for diminishing the ultimate strength of the strengthened slabs.