Betoninstandsetzung – quo vadis?

Concrete restoration – quo vadis? This article describes the mechanism of the corrosion process for reinforcing steel in concrete which is not under strain by chlorides. Concluding from that the principles of protection following the guidelines of the German Committee for Reinforced Concrete will be presented. The protection principle “W” will be addressed in particular which simplistically means that thermal insulating measures resp. coatings on concrete surfaces already damaged by corrosion result in a protection against further corrosion. The limits of efficacy of coatings will be referred to.     

Schubert und Reuleaux – ein verpasster Paradigmenwechsel? – zum 200. Geburtstag von Johann Andreas Schubert (1808–1870)

Schubert and Reuleaux – missed chance for a paradigm change? – On the 200th anniversary of the birth of Johann Andreas Schubert (1808–1870). The appeal of the life and work of Johann Andreas Schubert is to be found in its outstanding universality and the diversity of the methods. What is most impressive is the broadness of Schubert's work at the Royal Polytechnic School in Dresden, where he remained for many years; it extends from mathematics and applied mechanics to mechanical engineering, from building roads and canals to building railways and bridges. Influenced by his successful contribution to the Commission's designs for the great Vogtland railway viaducts, Schubert switched to teaching construction engineering around 1850, a subject to which he remained dedicated for the rest of his life. Less well known is the fact that Franz Reuleaux, without doubt the best‐known and most controversial mechanical engineering theorist in Germany at the close of the 19th century, applied for the post of professor of mechanical engineering left vacant by Schubert. Questions regarding the paradigm change in the engineering sciences plus the interaction between theory of structures and mechanics of machines are investigated here by means of the complex appointment process.     

Agriculture: Sustainable Business – Sustainable Environment?

Irrigation is a small but important part of UK agriculture, accounting for about 150 000 ha of land and 160 000 Ml of water in a 'dry'year. By the year 2021, the irrigated area is predicted to increase by 14% and the volume applied by 50%. Irrigation is of significant economic importance to (a) farmers, (b) growers, (c) the food industry – improving crop yields, quality, consistency and reliability.
The environmental impacts of irrigation on river flows and wetland biodiversity are now receiving more attention. Irrigators are given advice on environmental impacts, voluntary agreements are secured between groups of irrigators and the Environment Agency, and on-farm reservoirs are constructed to reduce summer abstraction and provide more secure and flexible supplies. Better long-term planning and short-term management are essential.     

Stahl im Hochbau – ein nachhaltiger Werkstoff?

Steel for building constructions – a sustainable material? Since the Brundtland Report [12] “Our Common Future” 1985 and the Earth Summit of Rio 1992 “Sustainable Development” is omnipresent in our society: “Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs“. The transmission of this concept into the building sector is called “Sustainable Construction“. Sustainable construction means to design and construct buildings with a holistic approach considering ecological, economical and sociocultural aspects ‐ a paradigm shift for the entire building sector. The “Austrian Steel Association” has commissioned the first mentioned author to point out in a pre‐feasibility study a SWOT‐analysis (strengths, weaknesses, opportunities and threats) of steel for constructions as well as to identify a future call for action for the steel construction industry. Three office buildings with load bearings systems made of steel, timber and reinforced concrete were compared. For the ecological assessment a life cycle analysis (LCA) on the basis of the ÖNORM EN ISO 14040 [25] was undertaken. Recycling or dismantling can not be depicted by life cycle assessments based on recent ISO draft standards. Within this work the ecological datasets for EAF‐steel (electric arc furnace) could be substantially improved.     

Robustheit von Tragwerken – ein vergessenes Entwurfsziel?

Robustness of structures – a forgotten design target? Engineering structures may react on high or unplanned load scenarios in considerably different manner: Some remain nearly free of damage, others are affected by loss of their load‐bearing capacity. The property of structural survival with rather limited damage is called structural robustness, defined with respect to a specific action. However and in opposition to classical structural properties, like redundancy or ductility, for robustness neither exists an exact definition nor any quantification, up to now. The present contribution attempts both in engineering‐like manner; it explains the gained derivations by example of several structural responses, and draws attention to catalogues and procedures for enhancement of structural robustness.