Bicycle-sharing systems stations are often imbalanced. Stations are said to be in excess when there is no empty dock for users willing to deposit their bicycle. Conversely, stations aresaidtobeinshortagewhenthereisnoavailablebicycle. Rebalancingcanbeachievedby night when the system is closed and when the users are not permitted to move the bicycles. Insuchcase, rebalancingissaidtobestatic. Whenitisperformedduringthedaywhilethe users are moving the bicycles, rebalancing is said to be dynamic. The present work deals with the dynamic rebalancing of bicycle-sharing systems. Truck-based and pricing-based regulation heuristics are designed and implemented. Their performance is assessed and compared using real instances of up to 30 stations from Washington bicycle-sharing system. The contribution of this study resides in the development of easy-to-implement yet effective and high-impact heuristics.
The brittle nature of glass need for accurate safety concepts when glass is applied in a structural manner. Glass is particularly sensitive to crack-opening tensile stresses because of the presence of flaws on the glass surface resulting from the production process and handling of glass elements. For structural glass beams, specific safety concepts have been developed over the past years that make use of the composite action between glass and tendons placed along the edges of the glass beam. Different systems have been studied in particular by Dr. Cupać and allowable post-tensioning preload and flexural resistance can be determined based on the provided analytical expressions. An application of this work at EPFL was made within the ATLAS student project, which is a 6 m span glass bench. The design was mainly made on the beams failure load under uniform loading. The overall objective of this master project is to explore the effective behaviour (stiffness, first cracking, and up to failure) of such beams thru experimental work and by extending analytical models previously developed. 3 tests are planned, and since the tests will be carried out under four-point bending, the influence of the shear span will also be take into account. Another interest in highlighting the shear span failure mode is to be able to study this phenomenon and better understand it in further studies. As it is well known in concrete, it is perfectly unknown in glass which can lead to trouble when it comes to use glass as a structural material. Indeed, the current glass design takes into account the flexural resistance. Or the critical shear crack mode of failure decreases significantly the flexural strength as seen in figure 11. The lack of knowledge of this effect can lead to an overestimated resistance of the glass during the design. This study report will first see a short introduction on materials used during the tests, glass, the test sample of this study, the post tensioning process, then the four-point bending procedure and the results of the different test.