16,644 research outputs found
Methodology for Diagnostic Load Testing
No full textThis chapter deals with the methodology for diagnostic load testing. All aspects of diagnostic load testing that are shared with other load testing methods have been discussed in Part II. In this chapter, the particularities of diagnostic load testing of new and existing bridges are discussed. These elements include loading procedures, monitoring behavior during the test, reviewing test data, calibrating analytical models, and evaluating the test results.Accepted Author ManuscriptConcrete Structure
Methodology for Proof Load Testing
No full textThis chapter deals with the methodology for proof load testing. All aspects of proof load testing that are shared with other load testing methods have been discussed in Part II of Volume 12. In this chapter, the particularities of proof load testing are discussed. These elements include the determination of the target proof load, the procedures followed during a proof load test (loading method, instrumentation, and stop criteria), and the post-processing of proof load test data, including the assessment of a bridge after a proof load test.Accepted Author ManuscriptConcrete Structure
Preparation of Load Tests
No full textThis chapter discusses the aspects related to the preparation of load tests, regardless of the chosen type of load test. After determination of the test objectives, the first step should be a technical inspection of the bridge and bridge site. With this information, the preparatory calculations (assessment for existing bridges and expected behavior during the test) can be carried out. Once the analytical results are available, the practical aspects of testing can be prepared: planning, required personnel, method for applying the load, considerations regarding traffic control and safety, and the development of the sensor and data acquisition plan. It is good practice to summarize all preparatory aspects in a preparation report and provide this information to the client/owner and all parties involved with the load test.Accepted Author ManuscriptConcrete Structure
General Considerations for the Execution of Load Tests
No full textThis chapter discusses the aspects related to the execution of load tests regardless of the chosen type of load test. The main elements required for the execution of the load test are the equipment for applying the load and the equipment for measuring and displaying (if required) the structural responses. This chapter reviews the commonly used equipment for applying the loading and discusses all aspects related to the measurements. The next topic is the practical aspects related to the execution. This topic deals with communication on site during the load test and important safety aspects during a load test.Accepted Author ManuscriptConcrete Structure
Example of Proof Load Testing from Europe
No full textThis chapter describes the proof load testing of viaduct Zijlweg at a position that is critical for bending moment and at a position that is critical for shear. The viaduct Zijlweg has cracking caused by alkali-silica reaction, and the effect of material degradation on the capacity is uncertain. Therefore, the assessment of this viaduct was carried out with a proof load test. This chapter details the preparation, execution, and evaluation of viaduct Zijlweg. The outcome of the proof load test is, according to the currently used methods for proof load testing, that the viaduct fulfills the code requirements, and that strengthening or posting is not required.Accepted Author ManuscriptConcrete Structure
A new coordinated design of sectionalizing scheme and load restoration process considering reliability of transmission system
No full textOne of the most important processes during load restoration is to use a suitable sectionalizing scheme to enhance the stability, especially when two islands are synchronized. In this regard, this paper provides a new scheme for the coordination of sectionalizing and load restoration to enhance the power system performance before and during the synchronization of islands. In doing so, there will be contradictory objective functions including maximizing the quality of sectionalizing process, minimizing the maximum standing phase angle (SPA) between islands, and minimizing the sum of energy not supplied (ENS) with unavailable energy capability (UEC) between all N-1 contingencies. Therefore, a multi-objective problem is defined as a mixed integer non-linear problem (MINLP). Also, a reliability-based index is defined to determine the quality of each island. Then, the θ-based water cycle algorithm (θ-WCA) is used to obtain the best Pareto optimal set. Two IEEE 39-bus and 118-bus power systems are used for validating the proposed method. The simulation results imply that the system can benefit from this scheme not only to have the good quality of sectionalizing, but also to enhance the power system performance during load restoration and the synchronization of islands
Implementation of spreadsheet for power system load flow analysis / Wan Abd Khalid Abd Razak
No full textPower flow analysis is the backbone of power system analysis and design. They are necessary for planning, operation, economic scheduling and exchange of power between utilities. The principal information of power flow analysis is to find the magnitude and phase angle of voltage at each bus and the real and reactive power flowing in each transmission lines. Power flow analysis is an importance tool involving numerical analysis applied to a power system. In this analysis, iterative techniques are used due to there no known analytical method to solve the problem. To finish this analysis there are methods of mathematical calculations which consist plenty of step depend on the size of system. This process is difficult and takes a lot of times to perform by hand. This objective of this project describes the development of power system load flow analysis using Excel which employed two iteration technique namely Newton Raphson and Gauss Seidel. This application is meant to assist under-graduate students in the studies in load flow analysis. Feedback shows that the application could enable the student to understand the load flow concept easily due to its interactive design and user friendly
Cognitive load measurements and stimulated recall interviews for studying the effects of information and communications technology
No full textMany researchers use information and communications technology (ICT)-tools to augment learning in a great variety of tasks. Their effects are generally measured in terms of intended outcomes. This article argues for the use of additional, more general measures to obtain a more complete impression of the effects of ICT-tools. The first study presented in this article shows why tools should not only be studied in terms of their specific intended outcomes, but also in terms of their effects on working memory, and the cognitive mechanisms needed to achieve the intended outcomes. The second study uses cognitive load measurements and stimulated recall interviews to obtain a more comprehensive view of the effects of learning tools. Results suggest that traditional outcome measures need to be complemented with quantitative and qualitative measures of cognitive processes to substantiate conclusions about intended effects of ICT-tools.Technology, Policy and Managemen
General Considerations
No full textThis chapter discusses aspects that should be considered prior to every load test. The first questions that needs to be answered are “Is this bridge suitable for load testing?” and “If so, what are the goals of the load test?” To answer these questions, information must be gathered and preliminary calculations should be carried out. In order to evaluate if a bridge is suitable for load testing, different types of testing are shown, the topic of when to load test a bridge is discussed, and structure type considerations are debated. Finally, some safety precautions that should be fulfilled during a load test are discussed.Accepted Author ManuscriptConcrete Structure
Post-Processing and Bridge Assessment
No full textThis chapter discusses the aspects related to processing the results of a load test after the test. The way in which the data are processed depends on the goals of the test. As such, the report that summarizes the preparation, execution, and post-processing of the load test should clearly state the goal of the load test, how the test addressed this goal, and what can be concluded based on an analysis of the test results. Typical elements of the post-processing stage include discussing the applied load, the measured structural responses, and then evaluating the bridge based on the results of the load test.Accepted Author ManuscriptConcrete Structure
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