A test program for the Hybrid-Composite Beam (HCB) was conducted prior to its use for the replacement of a skewed, simply-supported bridge (Tide Mill Bridge). The HCB is an innovative combination of conventional materials and ideas in a structural beam. The beam consists of a concrete arch tied with prestressing strand that is placed within a Fiber-Reinforced Polymer (FRP) box. Behavior in individual HCB's and a three HCB-system was examined to determine the appropriateness of the current design methodology developed by John Hillman and the simplifying assumptions made within it. Such assumptions include strain compatibility and linear-elastic behavior. Three HCB's were tested at the structures laboratory at Virginia Tech. During individual beam tests, the predicted behavior of the FRP box and prestressing strand agreed with experimental results. The tests revealed the arch was susceptible to local bending and behaved far differently from predicted. Overall, the beams were shown to behave linearly. A final test was performed to apply the design live load to the system. Slight non-linear behavior was observed in the beams. Distribution factors for the system were also investigated and compared to AASHTO and Hillman's model. AASHTO factors were conservative for exterior girders but unconservative for interior girders. Hillman's factors were often conservative but were in agreement for the shear in the exterior girder. The current design procedure appeared to predict FRP and strand behavior well, but the behavior of the arch appeared to differ greatly from the other components of the HCB. / Master of Science

Approximately fifty percent of the bridges in the United States are considered deficient. The deterioration of the concrete components is a leading cause of the problem. The deterioration of concrete bridge decks is due primarily to corrosion of the reinforcing steel in the concrete. A promising solution to the problem is the use of fiber reinforced plastics (FRP) as a replacement for reinforcing steel. The use of FRP as reinforcement has the following advantages of lightweight, high tensile strength, corrosion resistance, flexibility, and electromagnetic resistance. This paper looks at the use of FRP as reinforcement in concrete beams and compares the information from deflection measurements of different configurations. Also, a material cost comparison is made to determine the cost of using the FRP reinforcement over standard steel reinforcement. Concrete bridge deck systems are designed using steel and fiber-reinforced plastics and allowable stress and load resistance factor methods. Recommendations for further study and uses of FRP are made. / Master of Science

Context. Virtualized networks are considered a major advancement in the technology of today, virtualized networks are offering plenty of functional benefits compared to todays dedicated networking elements. The virtualization allows network designers to separate networks and adapting the resources depending on the actual loads in other words, Load Balancing. Virtual networks would enable a minimized downtime for deployment of updates and similar tasks by performing a simple migration and then updating the linking after properly testing and preparing the Virtual Machine with the new software. When this technology is successfully proven to be efficient or evaluated and later adapted to the existing flaws. Virtualized networks will at that point claim the tasks of todays dedicated networking elements. But there are still unknown behaviors and effects of the technology for example, how the scheduler or hypervisor handles the virtual separation since they do share the same physical transmission resources.Objectives. By performing the experiments in this thesis, the hope is to learn about the effects of virtualization and how it performs under stress. By learning about the performance under stress it would also increase the knowledge about the efficiency of network virtualization. The experiments are conducted by creating scripts, using already written programs and systems, adding different loads and measuring the effects, this is documented so that other students and researchers can benefit from the research done in this thesis.Methods. In this thesis 5 different methodologies are performed: Experimental validation, statistical comparative analysis, resource sharing, control theory and literature review. Two systems are compared to previous research by evaluating the statistical results and analyzing them. As mentioned earlier the investigation of this thesis is focusing on how the scheduler executes the resource sharing under stress. The first system which is the control test is designed without any interference and a 5 Mbit/s UDP stream which is going through the system under test and being timestamped on measurement points on both the ingress and the egress, the second experiment involves an interfering load of a 5 Mbit/s UDP stream on the same system under test. Since it is a complex system quite some literature reviewing was done but mostly to gain a understanding and an overview of the different parts of the system and so that some obstacles would be able to be avoided.Results. The statistical comparative analysis of the experiments produced two graphs and two tables containing the coefficient of variance of the two experiments. The graph of the control test produced a graph with a quite even distribution over the time intervals with a coefficient of variance difference to the power of 10−3 and increasing somewhat over the larger time intervals. The second experiment with two virtual machines and an interfering packet stream are more distributed over the 0.0025 seconds and the 0.005 seconds intervals with a larger difference than the control test having a difference to the power of 10−2, showing some signs of a bottleneck in the system.Conclusions. Since the performance of the experiments and also the statistical handling of the data took longer than expected the choice was made to not deploy the system using Open Virtual Switch instead of Linux Bridge, hence there is not any other experiments to compare the performance with. But from referred research under related works the researcher concluded that the difference between Open Virtual Switch and Linux Bridge is small when compared without introducing any load. This is also confirmed on the website of Open Virtual Switch which states that Open Virtual Switch uses the same base as Linux Bridge. Linux Bridge is performing according to the expectations, it is a simple yet powerful tool and the results are confirming the previous research which claims that there are bottlenecks in the system. According to the pre-set requirement for validity for this experiment the difference of the CoV would be greater than to the power of 10−5, the measured difference was to the power of 10−2 which gives support to the theory that there are bottlenecks in the system. In the future it would be interesting to examine more about the effects of different hypervisors, virtualization techniques, packet generators etcetera to tackle these problems. A company that have taken countermeasures is Intel who have developed DPDK which confronts these efficiency problems by tailoring the scheduler towards the specific tasks. The downside of Intel’s DPDK is that it limits the user to Intel processors and removes one of the most important benefits of virtualization, the independence. But Intel have tried to keep it as independent as possible by maintaining DPDK as open source.

Thesis (MMed (Orth))--Stellenbosch University, 2014. / No abstract available

No description available.

No description available.

No description available.

The Long Term Bridge Performance (LTBP) program is an organization within the Federal Highway Administration that inspects, tests, analyzes, and observes, for an extended period of time, a variety of bridge types throughout the United States. Part of the program includes periodic testing of select bridges of a span of 20 years. The Kettle River Bridge located outside of Sandstone, Minnesota was selected for study due to its unique design. The Kettle River Bridge is a historical steel cantilevered deck arched Pratt truss bridge. The bridge was instrumented with 151 strain gauges on various floor and truss members along with eight displacement gauges strategically placed along the truss. All gauges were read simultaneously as the bridge underwent non-destructive live loading. The recorded gauge readings were analyzed to determine bridge behavior and then used in the assistance of calibrating a working finite-element model. After a working model was verified the distribution factors for the interior and exterior floor stringers were determined. By using the controlling distribution factor, a load rating for the bridge was determined for both inventory and operating. The distribution factors and load ratings determined using the working finite-element model were then compared to the AAHSTO LRFD specifications.

<p>In this work a study has been performed to show the different kinds of insulated balcony connections exists on the market. In the work there is also a short description of thermal bridges concerning balconies. A description of older solutions for balcony connections is given as well as a calculation of the difference in energy costs for a insulated balcony connection compared to the standard connection. The work includes a short description of the different products. After that there is a short information about their insulation properties, durability, acoustic performance, assembly, computer programme and a short analyses for each product.</p>

The damaging effects of hurricane landfall on US coastal bridges have been studied using physical model testing. Hurricane bridge damage and failure susceptibility has become very evident, especially during hurricane seasons 2004 and 2005 in the Gulf of Mexico. The combination of storm surge and high waves caused by a hurricane can produce substantial loads on bridge decks leading to complete bridge failure. Several theoretical methods have been developed to estimate these forces but have not been tested in a laboratory setting for a typical bridge section. Experiments were done using a large-scale 3-D wave basin located at the Haynes Coastal Engineering Laboratory at Texas A&M University to provide estimates of the horizontal and vertical forces for several conditions to compare with the forces predicted with the existing models. The wave force results show no strong correlation between the actual force measured and the predicted force of existing theoretical methods. A new method is derived from the existing theoretical methods. This model shows a strong correlation with both the measured horizontal and vertical forces.