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Optimized concepts for the deconstruction of natural draught cooling towers by blasting The deconstruction of natural draught cooling towers represents an essential part in the course of the conversion of old power plant sites. For monetary reasons in combination with reasons of sustainability, which are particularly reflected in the reusability of the site area and the recycling of the resource reinforced concrete, an immediate deconstruction of the natural draught cooling towers after the end of operation is recommended in most cases. In addition to the established state of the art, the article shows potentials for the further development of concepts for the deconstruction of natural draught cooling towers by blasting. Complex numerical simulations nowadays offer the possibility of precise simulations of both the structural stability for temporary, weakened construction stages and the collapse behaviour of reinforced concrete structures in the event of blasting. The key aspect is safety in various facets, which must also be considered and guaranteed for adjacent buildings in the immediate neighbourhood in particular. The new deconstruction concepts presented, for which no practical experience is available at this time, are compared with the established concepts with regard to the aspects of structural stability, collapse safety, vibration prognosis, necessary safety measures, effects on the environment, workload and costs. [ABSTRACT FROM AUTHOR]

Experiences with movable scaffolding systems in deconstruction of post‐tensioned viaducts The deconstruction of post‐tensioned viaducts with a movable scaffolding system is an established method where conventional and blasting deconstruction cannot be applied. The report describes the components of the deconstruction MSS, the special features of this deconstruction method and the boundary conditions for the use of movable scaffolding systems against and in the direction of construction of the structure to be demolished, as well as the possibility of reusing the movable scaffold for the new construction. Interfaces to the bridge structure are defined and advices are given on the planning of such dismantling projects. Using the example of the Onsbach viaduct, a description of the dismantling procedure is given. [ABSTRACT FROM AUTHOR]

The structural condition as challenge for the deconstruction planning Until now no mandatory guidelines for the structural planning of the deconstruction of existing concrete structures are introduced by the authorities, which assist the planning engineers in the evaluation of these existing or damage structures. Often complex structural states of deconstructions have to be calculated, which depend on the knowledge of the actual structural condition. Therefore the only source of information is given by the existing documents, which often don't represent the actual state. To reduce the risks and to increase the planning and tender security, diagnostic investigations offer a big potential. Because not all information, as e. g. the knowledge about the possibility of a subsequent anchorage of cut prestressed tendons can be evaluated in advance of a deconstruction, further experimental investigations are necessary. As yet no technical or contractual rules are defined. The paper gives an overview of practical experiences and possible potentials of these experimental investigations. [ABSTRACT FROM AUTHOR]

Structural engineering in dismantling of concrete bridges The deconstruction of viaducts in constricted valleys or in immediate vicinity of superstructures under traffic requires new engineer concept for the dismantling. Analog to new bridges the structural stability has to be proven for all states of deconstruction. This results in new challenges for civil engineers with innovative approaches and combined proofs with numerical and experimental investigations. [ABSTRACT FROM AUTHOR]

Deconstruction of prestressed concrete viaducts with movable scaffolding systems The central European highway-infrastructure of the 1960s and 1970s is characterized by increased overstraining. Often, repair tasks only allow further usage for a limited amount of time. Deconstruction and reconstruction, particularly in ecological sensible areas and ones with a high amount of intersections, call for a deconstruction system, which ensures that the interruption of traffic on the affected route section is minimalized. The deconstruction of viaducts with MSS represents a suitable approach, which meets the requirements to the buildings as well as the safety to traffic. The article describes the operational conditions for the deconstruction method, the functionality and the difference to the known reconstruction with MSS. In comparison to new building plans, here higher stress has to anticipated, as well as a certain vagueness of the expectant load from the existing structure and interphases to additionally involved parties, like the demolition companies. The requirements to planning, assembly and robustness of the construction are described on the basis of projects executed to date. Also the intersections to other involved parties, which are to be considered more before and during the deconstruction, are mentioned. [ABSTRACT FROM AUTHOR]