Structural retrofitting of rescue tunnels in single shell shotcrete construction – requirements and experiences

As a result of the devastating fire events in the transalpine tunnels at the turn of the millennium, the EU Tunnel Directive (2004/54/EC) was developed. The Directive provides that the distances between the emergency exits shall not be more than 300 m. The national implementation of the Directive in Germany was the Guidelines for the Equipment and Operation of Road Tunnels (RABT) 2006. The stipulations in the RABT created the re-equipment needs of the - at that time - round about 200 existing federal road tunnels. To ensure the lower emergency exit distances several cross passages, rescue shafts and – since about 50% of the existing tunnels are operated bi-directionally – rescue tunnels had to be build. Please click Additional Files below to see the full abstract

Possible applications of a highly ductile sprayed concrete as a measure for ground support and structural upgrade

The possible impacts to our underground infrastructure that might occur during its operational phase are subsequently correlating with the types of goods we are transporting as well as the overall threats to our society. With that in mind, explosions and huge fires, resulting from terroristic attacks or huge accidents, have become valid threats to our tunnels and underground hubs, especially in countries like Great Britain, the United States or Germany. Unfortunately, there are only a limited amount of measures and technical systems available for the systematic upgrade of such underground facilities, especially when talking about combined scenarios (explosion plus fire). The problem is, that most of these protective systems are based on ultra-high performance concrete approaches with a huge amount of reinforcement and additional additives for increasing the explosion and fire resistance of the concrete. For reasons of manufacturing and fabricating such protective layers and shells, these systems can often only be applied to plane structures with simple geometries and clearly defined boundaries. This is not necessarily a typical description of an underground structure, where arches and curved planes are more or less common. Therefore, a highly ductile sprayed concrete, with high fibre or steel content, could help closing this gap, at least in theory. Please click Additional Files below to see the full abstract

Ausführungsmöglichkeiten von Rettungsstollen bei deutschen Straßentunneln

Infolge der gestiegenen Sicherheitsanforderungen für Straßentunnel und des daraus folgenden umfangreichen sicherheitstechnischen Nachrüstungsprogramms werden im Straßentunnelbau häufiger Rettungsstollen realisiert. Die Ausführung von Rettungsstollen wurde bisher projektspezifisch festgelegt. Mit Aufnahme der Anforderungen an Rettungsstollen in das technische Regelwerk wird die einschalige Spritzbetonbauweise als Regelbauweise festgelegt, sofern die hydrogeologischen Bedingungen dies zulassen. Durch den Einsatz von wasserundurchlässigen Spritzbeton - gegebenenfalls unter Zugabe von Stahlfasern - kann die Dichtigkeitsklasse 3 nach der ZTV-ING sicher erreicht werden. Die Läenge eines begehbaren Rettungsstollens mit einem lichten Querschnitt von 2,25 m x 2,25 m ist auf 3000 m begrenzt. Bei längeren Rettungsstollen ist ein befahrbarer Querschnitt von 3,50 m x 3,50 m vorzusehen.Due to the increased safety requirements for road tunnels and the resultant comprehensive safety retrofitting programme rescue galleries are realized frequently in road tunnel construction. The design of rescue galleries was defined project specific so far. Depending on the local hydro-geological conditions the technical requirements for the design of rescue galleries demand a single shell shotcrete lining as standard construction. With the application of waterproof shotcrete - if necessary including steel fibres - the waterproof class 3 according to the ZTV-ING could be securely achieved. The length of a walk-in rescue gallery with a cross-section of 2.25 m x 2.25 m is limited to 3,000 m. In case of longer rescue galleries a cross section of 3.50 x 3.50 m, which is accessible by vehicle, should be foreseen

Building Information Modeling (BIM) in tunnel construction

Im Zuge des Betriebs und der Erhaltung von Tunnelbauwerken des Bundesfernstraßennetzes resul-tieren erhöhte Anforderungen für den Betreiber bzw. für das Betriebspersonal. Dies gilt insbesondere im Hinblick auf eine sichere Tunnelnutzung als auch bezüglich der immer wichtiger werdenden ökonomi¬schen Optimierung im Hinblick auf die Lebenszykluskosten des gesamten Bauwerks und der Auf¬rechterhaltung bzw. der Erhöhung seiner Verfügbarkeit im Netz. Ein Ansatz, der in Zeiten zunehmender Digitalisierung und durch politische Initiativen wie den BMVI-Stufenplan an Bedeutung gewinnt, ist die kooperative Arbeitsmethodik Building Information Modeling (BIM). Dadurch sollen einzelne Betriebsprozesse auf Basis eines digitalen Modells optimiert bzw. effi¬zienter gestaltet werden. Ein BIM-basiertes Betriebsmodell wird dabei in der Regel im Zuge eines Handover-Prozesses (dt.: Übergabe) aus einem Ausführungs-bzw. As-built-Modell abgeleitet. Bisherige Entwicklungen zeigen jedoch, dass derzeit der Fokus verstärkt im Bereich der Planung und Ausführung von Tunnelbauwerken liegt und betriebliche bzw. erhaltungstechnische Aspekte weitestgehend nicht berücksichtigt werden. Daher wurden im Forschungsprojekt die Grundlagen für ein BIM-basiertes Betriebsmodell von Stra-ßentunneln entwickelt. Hierzu wurden zum einen die bereits bestehenden, modelltheoretischen Grundsätze analysiert und ergänzend dazu Anforderungen von Bauherren und Betreibern unter Berücksichtigung der betrieblichen Aspekte während des Lebenszyklus erfasst. Darauf aufbauend wurden für einzelne Anwendungsfälle die Informationsanforderungen für ein BIM basiertes Betriebs-und Erhaltungsmanagement abgeleitet und ein komplementäres Datenmodell – basierend auf dem IFC-Standard – entwickelt. Die Ergebnisse wurden anhand eines Demonstrator-Modells veranschaulicht und evaluiert.In the course of the operation and maintenance of tunnel structures of the federal trunk road network, increased requirements result for the operator and for the operating personnel. This applies in particular with regard to safe tunnel use as well as to the increasingly important economic optimization with regard to the life cycle costs of the entire structure and the maintenance or increase of its availability in the network. One approach that is gaining in importance in times of increasing digitization and through political initiatives such as the BMVI Staged Plan is the cooperative working methodology Building Information Modeling (BIM). This is intended to optimise individual operating processes or make them more efficient on the basis of a digital model. A BIM-based operating model is usually derived from an execution or As-built model in the course of a handover process. However, developments to date show that the focus is currently increasingly on the planning and execution of tunnel structures and that operational and maintenance aspects are largely not taken into account. Therefore, the research project developed the basics for a BIM-based operational model of road tunnels. For this purpose, existing modeltheoretical principles were analysed and, in addition, the requirements of builders and operators were recorded, taking into account the operational aspects during the life cycle. Based on this, the information requirements for a BIM-based operation and maintenance management were derived for individual use cases and a complementary data model – based on the IFC standard – was developed. The results were illustrated and evaluated using a demonstrator model

Human behaviour in severe tunnel accidents: Effects of information and behavioural training

Immediate user self-evacuation is crucial in case of fire in road tunnels. This study investigated the effects of information with or without additional virtual reality (VR) behavioural training on self-evacuation during a simulated emergency situation in a road tunnel. Forty-three participants were randomly assigned to three groups with accumulating preventive training: The control group only filled in questionnaires, the informed group additionally read an information brochure on tunnel safety, and the VR training group received an additional behavioural training in a VR tunnel scenario. One week later, during the test session, all participants conducted a drive through a real road tunnel in which they were confronted with a collision of two vehicles and intense smoke. The informed and the behaviourally trained participants evacuated themselves more reliably from the tunnel than participants of the control group. Trained participants showed better and faster behavioural responses than informed only participants. Interestingly, the few participants in the control group who reacted adequately to the scenario were all female. A 1 year follow-up online questionnaire showed a decrease of safety knowledge, but still the trained group had somewhat more safety relevant knowledge than the two other groups. Information and especially VR behavioural training both seem promising to foster adequate self-evacuation during crisis situations in tunnels, although long term beneficial behavioural effects have to be demonstrated. Measures aiming to improve users/ behaviour should take individual difference such as gender into account

Natriuretic peptides for the detection of paroxysmal atrial fibrillation in patients with cerebral ischemia--the Find-AF study.

BACKGROUND AND PURPOSE: Diagnosis of paroxysmal atrial fibrillation (AF) can be challenging, but it is highly relevant in patients presenting with sinus rhythm and acute cerebral ischemia. We aimed to evaluate prospectively whether natriuretic peptide levels and kinetics identify patients with paroxysmal AF. METHODS: Patients with acute cerebral ischemia were included into the prospective observational Find-AF study. N-terminal pro brain-type natriuretic peptide (NT-proBNP), brain-type natriuretic peptide (BNP) and N-terminal pro atrial-type natriuretic peptide (NT-proANP) plasma levels were measured on admission, after 6 and 24 hours. Patients free from AF at presentation received 7 day Holter monitoring. We prospectively hypothesized that patients presenting in sinus rhythm with NT-proBNP>median were more likely to have paroxysmal AF than patients with NT-proBNP<median. RESULTS: 281 patients were included, of whom 237 (84.3%) presented in sinus rhythm. 220 patients naïve to AF with an evaluable prolonged Holter ECG were analysed. In patients with NT-proBNP>median (239 pg/ml), 17.9% had paroxysmal AF in contrast to 7.4% with NT-proBNP<239 pg/ml (p = 0.025). The ratio of early (0 h) to late (24 h) plasma levels of NT-proBNP showed no difference between both groups. For the detection of paroxysmal atrial fibrillation, BNP, NT-proBNP and NT-proANP at admission had an area under the curve in ROC analysis of 0.747 (0.663-0.831), 0.638 (0.531-0.744) and 0.663 (0.566-0.761), respectively. In multivariate analysis, BNP was the only biomarker to be independently predictive for paroxysmal atrial fibrillation. CONCLUSIONS: BNP is independently predictive of paroxysmal AF detected by prolonged ECG monitoring in patients with cerebral ischemia and may be used to effectively select patients for prolonged Holter monitoring

NT-proBNP and NT-proBNP ratio and paroxysmal atrial fibrillation.

<p>Left panel: Percentage of study participants with paroxysmal atrial fibrillation on Holter monitoring in the two sub-groups of patients with NT-proBNP plasma levels below and above the median NT-proBNP plasma level (239 pg/ml). Right panel: Percentage of study participants with paroxysmal atrial fibrillation below and above the median ratio of early (0 h) to late (24 h) NT-proBNP plasma level (0.78).</p

Test characteristics for different BNP cut-offs and corresponding sensitivity, specificity, positive and negative predictive values and the number of patients needing Holter.

<p>PPV: Positive predictive value. NPV: Negative predictive value.</p>*<p>denotes the Youden point.</p

Study flow of the Find-AF trial. 281 patients were included, 237 had sinus rhythm on the admission ECG.

<p>1 patient withdrew consent, 16 patients were excluded from the analysis for different reasons, given a total of 220 study participants analysed.</p