Další odborné publikace
Sanace 2006 (24. – 25. května 2006, Brno)
sanace06.pdf – Ověřování existujících konstrukcí podle ISO 13822
Zavedením normy ČSN ISO 13822 do soustavy našich předpisů se umožňuje hodnotit existující konstrukce jak metodou dílčích součinitelů, tak také pravděpodobnostními postupy. Zpracované národní přílohy vysvětlují vybraná ustanovení ISO 13822 a uvádějí doplňující informace o existujících konstrukcích a materiálech, které se v ČR v minulosti uplatňovaly při výstavbě. Očekává se, že norma ČSN ISO 13822 usnadní ověřování existujících konstrukcí a navrhování jejich obnov.
STREMAH 2007 – Tenth International Conference on Studies, Repairs and Maintenance of Heritage Architecture (4. – 6. července 2007, Praha)
stremah07.pdf – Durability assessment of heritage architecture (Hodnocení trvanlivosti historických objektů – v angličtině)
General principles on durability assessment are provided in a newly developing international standard ISO “General Principles on the Design of Structures for Durability” prepared by a international working group of experts. It is expected that the document will be soon completed and then implemented into the systems of national standards in many countries. The document can be used in durability assessment of any building including heritage architecture. However, the operational use of the new procedures in practice would require additional studies focussed primarily on durability criteria, physical models of material deteriorations, and theoretical models of basic variables. It appears that the probabilistic methods may provide valuable background information facilitating specification of appropriate durability criteria.
ENGINEERING NATURE 2007 (11. – 13. července 2007, The New Forest, UK)
eng_nature07.pdf – Safety design of lightweight roofs exposed to snow load (Hodnocení bezpečnosti lehkých střech vystavených zatížení sněhem – v angličtině)
The collapse of a number of lightweight roofs during the winter period 2005/2006 initiated an international discussion concerning the reliability of roofs exposed to permanent and snow load. In some countries, all available measurements of snow loads have been newly evaluated and relevant standards have been promptly revised. Newly developed maps of snow loads are based on the principles of the European standards specifying the characteristic value of snow load on the ground as the 98 fractile of annual extremes (50 years´ return period). The submitted paper provides a critical analysis of presently accepted design procedures taking into account available data of snow load. In the reliability analysis permanent load is described by normal distribution, snow load by Gumbel distribution and resistance by lognormal distribution. It appears that the partial factor design method provided in the present European standards may not guarantee an adequate reliability level of lightweight roofs. An alternative procedure for the safety design of roofs exposed to self weight and snow load only is, therefore, proposed.
ICASP10 – Applications of Statistics and Probability in Civil Engineering 2007 (31. července – 3. srpna 2007, Tokio)
icasp07.pdf – Probabilistic verification and optimization of structural durability (Pravděpodobnostní hodnocení a optimalizace trvanlivosti konstrukcí – v angličtině)
Principles of the probabilistic approach to structural durability will be soon provided in a newly developing international standard ISO General Principles on the Design of Structures for Durability. It is expected that after its completion the document will be implemented into the system of national standards in many countries. It appears, however, that the operational use of the new procedures in practice would require additional studies focussed on durability criteria, physical models of material deterioration, and theoretical models of basic variables. An example of the durability limit state concerning reinforced concrete members illustrates the general procedures. It is shown that the predicted service life is significantly dependent on the theoretical models of basic variables and the required reliability level. The optimum thickness of the concrete cover and the corresponding reliability level increases with increasing the cost of consequences and increasing the design service life, decreases with increasing the discount rate.
Zkoušení a jakost ve stavebnictví 2007 (26.-27. září 2007, Praha)
en13791.pdf – Statistické hodnocení zkoušek materiálových vlastností
Využití zkoušek je důležitou součástí ověřování spolehlivosti existujících železobetonových konstrukcí. Při odhadu charakteristické hodnoty materiálových vlastností se uplatní statistické metody uvedené v příloze D normy ČSN EN 1990 a také v novém evropském dokumentu EN 13791. Postupy podle obou dokumentů se však navzájem liší a mohou vést k rozdílným odhadům charakteristické hodnoty. Empirické vztahy uvedené v předpisu EN 13791 zpravidla vedou k vyšším hodnotám charakteristické pevnosti.
International RILEM Workshop on Integral Service Life Modelling of Concrete Structures (5. – 6. listopadu 2007, Guimaraes, Portugalsko)
rilem.pdf – Optimization of structural durability (Optimalizace trvanlivosti stavebních konstrukcí – v angličtině)
Principles of the probabilistic approach to structural durability will be soon provided in a newly developing international standard ISO ?General Principles on the Design of Structures for Durability?. It is expected that after its completion the document will be implemented into the system of national standards in many countries. The operational use of the new procedures in practice would require additional studies focused on durability criteria, required reliability level, physical models of material deterioration, and theoretical models of basic variables.
An example of the durability limit state concerning reinforced concrete members illustrates the general optimization procedures. It appears that the optimum thickness of the concrete cover and the corresponding reliability level increases with the increasing cost of failure consequences and decreases with the increasing discount rate.
Further research into the target reliability levels considered in the limit states of structural durability should be based on advanced optimisation models, relevant economic data, physical models of material deterioration, and on theoretical models of basic variables.
