Petr Huňka

Assessment of Concrete Quality of Load-Bearing Structure of the Bridge Across Otava River No. 121-006 Near Zvikov after Fifty Years of Operation in Severe Environmental Conditions

This paper is introducing results of diagnostic survey of bridge no. 121-006 across Otava river near Zvikov [1], focusing on assessment of quality of concrete mix used for load-bearing structure of the bridge after more than 50 years of operation and assessment of reconstruction works (monolithic assembly of central joints of main fields) executed in 1994 [2]. Visual inspection of monolithic assembly joints, comparison of depth of concrete carbonation and thickness of top layer of reinforcement concrete and concrete compression strength are presented in this paper.

Dependence of Load Bearing Capacity on Homogeneity of Steel Fiber Distribution

Load-bearing capacity of fine grained cement-based composite materials UHPFRC depends on the homogeneity of the steel fiber distribution at cross section. The homogeneity of the steel fiber distribution has significant effect to the mechanical properties of UHPFRC elements, especially at tensile strength in bending. The load-bearing capacity depending on the homogeneity of steel fibers at the permanent formwork slabs made from UHPFRC is shown in this paper.

Investigation of the Bond Behavior of UHPC

Ultra High Performance Concrete - UHPC has become increasingly used. Its outstanding features are generally known. It is a fact that the bond of the reinfocement in UHPC is better than that in ordinary concrete, but this bond needs to be quantified .The aim of the experimental research was to determine the average bond stress between prestressing strands and different types of UHPC and to show very significant increase in the average shear stress in bond with UHPC compared to ordinary concrete. In order to determine the bond capacity, an experimental research was carried out. Experimental details of the models in real structures – parts of prestressed girders made from UHPC, were tested in the laboratory and the results were compared with specimens prepared according to standard. The influence of different material properties and different anchorage length of prestressing strands to bond behavior of UHPC was examined in pull out tests. Test results of bond test led to the conclusion that the application of UHPC can significantly reduce the anchorage length of reinforcement compared with the ordinary concrete.

Impact Resistance of Thin-Walled Shell Structures

Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Dynamic effects can be significant especially for thin-walled shell structures and barrier constructions. Impact loading of construction components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that reinforced concrete with fibers has a positive impact on increasing the resistance to impact loads. Results of impact load tests carried out on drop-weight test machine are presented in this paper. The results are supplemented by compression strength test.

Bridge Pavla Wonky in Pardubice. Diagnostics of Corrosion Condition of External Cables and Use of Special Materials for Proposal of Treatment

Annotation: Complete reconstruction of the reinforced prestressed bridge Pavla Wonky in Pardubice was carried out in 2006. During this reconstruction specialists of the Klokners Institute made complete revision of linear free external cables in bridge chambers, namely from the aspect of corrosion. Some of the findings obtained during this revision are presented in this article.

Adaptive Model of Cardiovascular System: Realization and Signal Database

The paper deals with a study of relationship between hemodynamic parameters and other various vital signs based on the modelling of hemodynamic parameters. The design of an adaptive mechanical model of cardiovascular system is presented in the paper. The connection between the modelling of cardiovascular system and smart homes and ambient assisted living applications is also discussed.