Swiss Tunnelling Society

<p>The maintenance of bridges significantly impacts overall life-cycle costs, often matching construction costs over time. Rehabilitation projects not only incur direct costs but also pose challenges such as traffic disruptions and environmental impacts, especially when temporary structures are required to maintain road capacities. To enhance sustainability, incorporating user and environmental costs into bridge maintenance decision-making is critical. This study presents a novel integrated methodology utilizing Discrete Event Simulations (DES) to accurately estimate these costs. By evaluating both user and environmental impacts, this approach enables the development of optimized, sustainable maintenance strategies across a bridge’s life cycle. A case study illustrates the application of this model, demonstrating its effectiveness in integrating user and environmental costs into life-cycle cost analyses, ultimately leading to more efficient intervention planning.</p>

An experimental setup was designed to study the impact of concrete bulk resistivity on the rate of chloride‐induced reinforcement corrosion. Small pieces of mild steel were used to simulate pits (anodes) that form when chlorides come into contact with the reinforcement. The galvanic current was measured between the simulated anodes and a large cathode network. Comparisons were made between the corrosion rates calculated from the galvanic currents and the bulk resistivity. The bulk resistivity was varied using two mortar mixes (made of plain Portland cement and a Portland cement—fly ash blend), which were exposed in different temperature and moisture conditions. Despite a high scatter in the results, it was clear that the relationship between bulk resistivity and corrosion rate depended on the mortars tested. The findings presented in this article and the accompanying work strongly indicate that bulk resistivity alone does not provide sufficient information for assessment of the corrosion rate for chloride‐induced macro‐cell corrosion.

Abstract A long‐lasting rainstorm event from 20 to 22 August 2005 affected a large part of the northern Alps and Prealps in Switzerland. It resulted in elevated discharges and flooding in many headwater catchments and mountain rivers. The associated geomorphic processes included shallow landslides, deep‐seated slope instabilities, debris flows, and fluvial sediment transport. In many parts of the affected areas human activities are important, including many buildings, traffic lines and other infrastructure. In the steeper parts, geomorphic processes were mainly responsible for flow overtopping and sediment deposition both in and outside of the channel network. In the lower parts, lateral erosion and exceedance of the channel discharge capacity were the main reasons for morphologic channel modification and flooding. Sediment‐related processes contributed a lot to the overall damage. Copyright © 2015 John Wiley & Sons, Ltd.

Comparison of Energy-Based and Damage-Related Fatigue Life Models for Aluminium Components Under TMF Loading

Abstract Durch die Zugabe von 2 kg/m3 PP‐Fasern kann ein Abplatzen von Innenschalenbeton auch unter den extremen Bedingungen eines Brandes im Tunnel zuverlässig verhindert werden. Durch die Fasern werden die Betoneigenschaften verändert. Insbesondere bei bewehrten Innenschalen werden die Einbaueigenschaften negativ beeinflußt. Im vorliegenden Beitrag werden die diesbezüglichen Erkenntnisse aus Laborversuchen erläutert, welche nach der baupraktischen Erprobung bereits erfolgreich auf einer Baustelle in Wien eingesetzt werden konnten. Des weiteren werden Hinweise auf zu beachtende Einflußfaktoren gegeben.

Der Begriff Sicherheit wird definiert als Zustand des Seins ohne Bedrohung, der sich objektiv ergibt aus dem Vorhandensein von Schutzeinrichtungen oder dem Fehlen von Gefahren und subjektiv von Individuen oder sozialen Gruppenals Gewisheit uber die Zuverlassigkeit von Sicherungs- und Schutzeinrichtungen empfunden wird. Sicherheitsbetrachtungen setzen deswegen das Erkennen von Gefahren und der sich daraus ergebenden Risiken voraus.