Modelling of a rope-free passenger transportation system for active cabin vibration damping

Conventional vertical passenger transportation is performed by lifts. Conventional traction-drive electrical lifts use ropes to transfer the rotational motion of an electrical motor into a vertical motion of the cabin. The vertical passenger transportation system discussed in this paper does not use any ropes, the motor directly provides a driving force, which moves the cabin. This new propulsion is realized through an electrical linear motor. The use of the linear motor requires a new design of the passenger transportation system (PTS), which includes reducing the weight of the car through lightweight construction. The reduced stiffness of the lightweight design renders the construction more vulnerable to vibrations. In order to improve ride quality of the transportation system it is necessary to develop new concepts to damp the vibrations. One way to increase stiffness characteristics of the system is to introduce active damping components to be used alongside passive damping components. It is essential to derive a dynamic model of the system in order to design and also later control these damping components in the best possible way. This paper describes the fundamental steps undertaken to derive a dynamic model for designing and controlling active damping components for the new type of vertical PTS. The model is derived as a Multi-Body System (MBS), where the connections between the bodies are modelled as spring damper elements. The derivation of the MBS is demonstrated on a transportation system, consisting of three main components: a sledge, holding the rotor of the linear motor; a mounting frame, which is used to provide support for the cabin; and the actual cabin. The modelling of the propulsion system, thus the electrical part of the PTS, will not be the focus of this work

THE EFFECTS OF UNMITIGATED IDLE TIME ON THE PERFORMANCE OF MAGNETORHEOLOGICAL DAMPERS AS A STRUCTURAL PROTECTIVE SYSTEM.

This thesis discusses the long-term performance degradation of seismic protective systems due to age and inactivity (termed “idle time effects”). Over the lifetime of a structures there is the potential for a significant reduction in ability for the structural control systems to mitigate earthquakes. This can affect the resilience of the structure and lead to uncertainty in engineering judgement when designing seismic protective systems. Further research into these idle time effects could help to create solutions to mitigate age-dependent performance loss. This paper will use magneto-rheological (MR) dampers, which serve as a good analog for other semi-active control devices, to study idle time effects on seismic protection. MR dampers provide controllable damping through the magnetization of small MR particles in a carrier fluid. These particles can settle over time, influencing their performance. Using a model MR fluid, accelerated testing was performed to analyze the consequences of idle time

TSUNAMI INFORMATION SOURCES PART 2

Tsunami Information Sources (Robert L. Wiegel, University of California, Berkeley, CA, UCB/HEL 2005-1, 14 December 2005, 115 pages), is available in printed format, and on a diskette. It is also available in electronic format at the Water Resources Center Archives, University of California, Berkeley, CA http:www.lib.berkeley.edu/WRCA/tsunamis.htmland in the International Journal of The Tsunami Society, Science of Tsunami Hazards (Vol. 24, No. 2, 2006, pp 58-171) at http://www.sthjournal.org/sth6.htm.This is Part 2 of the report. It has two components. They are: 1.(Sections A and B). Sources added since the first report, and corrections to a few listed in the first report. 2.(Sections C and D). References from both the first report and this report, listed in two categories:Section C. Planning and engineering design for tsunami mitigation/protection; adjustments to the hazard; damage to structures and infrastructureSection D. Tsunami propagation nearshore; induced oscillations; runup/inundation (flooding) and drawdown

Multiscale Modelling of Tunnel Ventilation Flows and Fires

F Colella, Multiscale analysis of tunnel ventilation flows and fires, PhD Thesis, Politecnico di Torino, Dipartimento di Energetica. May 2010Tunnels represent a key part of world transportation system with a role both in people and freight transport. Past events show that fire poses a severe threat to safety in tunnels. Indeed in the past decades over four hundred people worldwide have died as a result of fires in road, rail and metro tunnels. In Europe alone, fires in tunnels have brought vital parts of the road network to a standstill and have cost the European economy billions of euros. Disasters like Mont Blanc tunnel (Italy, 1999) and the more recent three Channel Tunnel fires (2008, 2006 and 1996) show that tunnel fire emergencies must be managed by a global safety system and strategies capable of integrating detection, ventilation, evacuation and fire fighting response, keeping as low as possible damage to occupants, rescue teams and structures. Within this safety strategy, the ventilation system plays a crucial role because it takes charge of maintaining tenable conditions to allow safe evacuation and rescue procedures as well as fire fighting. The response of the ventilation system during a fire is a complex problem. The resulting air flow within a tunnel is dependent on the combination of the fire-induced flows and the active ventilation devices (jet fans, axial fans), tunnel layout, atmospheric conditions at the portals and the presence of vehicles. The calculation of tunnel ventilation flows and fires is more economical and time efficient when done using numerical models but physical accuracy is an issue. Different modelling approaches can be used depending on the accuracy required and the resources available. If details of the flow field are needed, 2D or 3D computational fluid dynamics (CFD) tools can be used providing details of the flow behaviour around walls, flames, ventilation devices and obstructions. The computational cost of CFD is very high, even for medium size tunnels (few hundreds meters). If the analysis requires only bulk flow velocities, 1D models can be adopted. Their low computational cost favours large number of parametric studies involving broad range ventilation scenarios, portal conditions and fire sizes/locations.Another class of methods, called multiscale methods, adopts different levels of complexity in the numerical representation of the system. Regions of interest are described using more detailed models (i.e. CFD models), while the rest of the system XIX can be represented using a simpler approach (i.e. 1D models). Multiscale methods are characterized by low computational complexity compared to full CFD models but provide the same accuracy. The much lower computational cost is of great engineering value, especially for parametric and sensitivity studies required in the design or assessment of ventilation and fire safety systems. Multiscale techniques are used here for the first time to model tunnel ventilation flows and fires.This thesis provides in Chapter 1 a general introduction on the fundamentals of tunnel ventilation flows and fires. Chapter 2 contains a description of 1D models, and a case study on the Frejus tunnel (IT) involving some comparisons to experimental data. Chapter 3 discusses CFD techniques with an extensive review of the literature in the last 30 years. The chapter provides also two model validations for cold ventilation flows in the Norfolk Tunnels (AU) and fire induced flows in a small scale tunnel. Chapter 4 introduces multiscale methods and addresses the typical 1D-CFD coupling strategies. Chapter 5 applies multiscale modelling for cold flow steady-state scenarios in the Dartford Tunnels (UK) where a further validation against experimental data has been introduced. Chapter 6 present the calculations from coupling fire and ventilation flows in realistic modern tunnel layout and investigates the accuracy of the multiscale predictions as compared to full CFD. Chapter 7 represents application of multiscale computing techniques to transient problems involving the dynamic response of the ventilation system. The multiscale model has been demonstrated to be a valid technique for the simulation of complex tunnel ventilation systems both in steady-state and timedependent problems. It is as accurate as full CFD models and it can be successfully adopted to conduct parametric and sensitivity studies in long tunnels, to design ventilation systems, to assess system redundancy and the performance under different hazards conditions. Time-dependent simulations allow determining the evolution of hazardous zones in the tunnel domain or to determine the correct timing for the activation of fixed fire fighting systems. Another significant advantage is that it allows for full coupling of the fire and the whole tunnel domain including the ventilation devices. This allows for an accurate assessment of the fire throttling effect that is shown here to be significant and for a prediction of the minimum number of jet fans needed to cope with a certain fire size. Furthermore, it is firmly believed that the multiscale methodology represents the only feasible tool to conduct accurate simulations in tunnels longer than few kilometres, when the limitation of the computational cost becomes too restrictive

The Suitability of Double-Layer Space Structures for Super-Tall Buildings: A Study from Structural and Building Systems Integration Perspectives

As buildings rise higher, designers face two major issues. Firstly, how to design efficient structures to resist the lateral loads that impact so greatly on tall buildings. Secondly, how to effectively integrate building systems, which often consume large amounts of space in taller buildings and potentially detract from the building aesthetics. Double‐layer space structures have the potential to address these issues due to several beneficial design characteristics. As three‐dimensional structures, double‐layer space structures are rigid and structurally efficient. They can also integrate with other building systems by using the inherent structural cavities to accommodate services components and contribute a particular architectural aesthetic if their regular pattern is exposed. Double‐layer space structures have been used in long‐span structure buildings, but have yet to be applied as vertical structures for super‐tall buildings. Only two projects, proposed by Kahn and Tying, and Swenson, have applied double‐layer space structures as vertical structures in high‐rise buildings. However, they have not yet been executed and no literature has discussed the feasibility of the application of this structural system to supertall buildings. This situation leads to the research question; “Are double‐layer space structures suitable for super‐tall buildings?” To answer this question, a long‐term study with multidisciplinary knowledge, involving surveys of public opinion, and possibly real pilot projects would be required. This research focuses only on structural efficiency and systems integration as the initial step of the study of vertical double‐layer space structures in super‐tall buildings. The main objective of this research is to analyse the efficiency of this structural system, especially compared to other current tall structural systems. The second objective is to investigate to what extent these structures can integrate with other building systems as well as a discussion on advantages and disadvantages of the integration. The significance of this research is to provide initial scientific information for designers about the possibility of using double‐layer space structures as a structural system of super‐tall building. A research methodology including both quantitative and qualitative approaches is employed to measure the structural efficiency of vertical double‐layer space structures and to assess their potential to integrate with other building systems. This research covers structural aspects, building services systems including fire safety and approaches to energy efficiency, architectural integration, and construction. A quantitative approach by structural design and analysis, and comparison of double‐layer space structures with other structural systems is used to analyse structural efficiency. Case studies using the structural models of two 100‐storey double‐layer space structure buildings with different values of slenderness are designed and analysed using the computer software, ETABS. Other currently used structural systems, a bundled‐tube, a braced‐tube and a diagrid, are also designed using the same configuration and their structural analysis findings are compared to those of double‐layer space structures. Services systems, including HVAC, stairs and elevators, are also designed and integrated with the structure. The systems integration aspect of this research in double‐layer space structure buildings is analysed using a qualitative approach in three main steps. The first step is a review of relevant literature covering systems integration and current technologies in tall buildings. Based on this review, systems integration in double‐layer space structure buildings in general and the 100‐storey case study buildings in particular are explored using computer models. As the final step, the advantages and disadvantages of the systems integration in the designed case studies are discussed. These case studies are designed in order to represent current super‐tall buildings and recent technologies in high‐rise buildings. The structural models of 100‐storey buildings are relevant for buildings in the approximate range of 75 to 125 storeys or 300 to 500 metres high; the majority of current super‐tall buildings have been built in that range of heights. Recent technologies that are commonly used in super‐tall buildings, for example Centralised Air Handling and Localised Air Handling for HVAC system, double‐decking and sky lobbies for elevator system, and various façade systems, are adopted in these case studies. The aim is The Suitability of Double‐layer Space Structures for Super‐tall Buildings to investigate if double‐layer space structures can accommodate building components of current technologies. The results of this research show that double‐layer space structures are efficient where applied in super‐tall buildings when compared to other existing structural systems. Doublelayer space structures can also integrate with services components. The case study design shows how larger usable floor areas than those in typical tall buildings can be provided by positioning the majority of services and structural components within the space structure on the perimeter of the building. In terms of fire safety, positioning fire safety and egress systems in two different locations far apart, as proposed in this research, increases their reliability. Double‐layer space structures are highly redundant structures that enable loads to be transferred through other structural members if several structural members collapse. This advantage minimises the possibility of progressive collapse. The ability of double‐layer space structures to visually and physically integrate with architectural components and aspects like façade, interior space and building geometry in various ways is also explored. In terms of construction, simple connections and construction methods can be applied to double‐layer space structures leading to competitive construction costs. The research concludes by discussing the advantages and disadvantages of double‐layer space structures for super‐tall buildings and concludes that double‐layer space structures are indeed suitable for this application within the scope of this research. However, the study also recommends future research to address issues that are not covered in this research

Progress in Landslide Research and Technology, Volume 1 Issue 1, 2022

This open access book provides an overview of the progress in landslide research and technology and is part of a book series of the International Consortium on Landslides (ICL). The book provides a common platform for the publication of recent progress in landslide research and technology for practical applications and the benefit for the society contributing to the Kyoto Landslide Commitment 2020, which is expected to continue up to 2030 and even beyond to globally promote the understanding and reduction of landslide disaster risk, as well as to address the 2030 Agenda Sustainable Development Goals