Volume 20 (2012): Issue 4 (December 2012)

The article introduces the concept and content of facilities management (FM) services. Thepaper presents the concept of customer satisfaction and discusses the key factors whichinfluence the opinions of customers and their satisfaction or dissatisfaction with theservices provided. The article presents two studies: a brief survey of several FM serviceproviders and a survey of customer satisfaction with FM services in Lithuania. Theconclusions are given at the end of the article.

Damping effects are of great interest for structural analysis and evaluations. Structuralmodal damping characteristics can be obtained from experiments. This paper introducesnew possibilities for the modelling of the damping of a dynamic system with classical normalmodes and provides an overview of the known methods for formulating a damping matrixbase with experimental modal damping values. The proposed method offers an opportunityto extrapolate modal damping values for unmeasured modes by a regression method basedon the measured modal properties. The points of view on the choice of an analytical formfor damping regression functions are examined. An analytical form of regression functionscan be chosen as the modal decay rate versus the square of the frequency or the modaldamping ratio versus the frequency. Damping regressions can be performed based ona group of typical vibration modes, such as bending, torsion and lateral, symmetrical oranti-symmetrical modes. The regression data obtained for the damping constants can thenbe applied in a finite element model for further structural analysis.

The paper deals with the theoretical foundations of laminar and turbulent fluid flows ina boundary layer and the effects of wind on constructions. The application sectiondescribes the flow of compressible Newtonian fluid as a system of partial differentialequations (the Navier-Stokes equation) and solves these equations using FEM at each timestep. Simplifying a 3D task to a plane problem and ignoring vorticity allows for theformulation of a wind flow on an open terrain and the effects of wind on a barrier. Twoapproaches to the numerical solution of wind flows are presented: one involves the Fluentcommercial program to obtain the velocity field and pressure at a constant wind speed inan inlet region, and the other approach involves the development of the SIXIS specificsoftware program for the purpose of this thesis, which modifies the wind velocity profileaccording to EN 1994-1-4. The results obtained - velocity fields around obstacles and thewind pressure coefficients on a barrier are processed and compared in a table.

Most of the studies that assess the performance of various calibration techniques have todeal with a certain amount of uncertainty in the calibration data. In this study we testedHBV model calibration procedures in hypothetically ideal conditions under the assumptionof no errors in the measured data. This was achieved by creating an artificial time seriesof the flows created by the HBV model using the parameters obtained from calibrating themeasured flows. The artificial flows were then used to replace the original flows in thecalibration data, which was then used for testing how calibration procedures can reproduceknown model parameters. The results showed that in performing one hundred independentcalibration runs of the HBV model, we did not manage to obtain parameters that werealmost identical to those used to create the artificial flow data without a certain degree ofuncertainty. Although the calibration procedure of the model works properly froma practical point of view, it can be regarded as a demonstration of the equifinality principle,since several parameter sets were obtained which led to equally acceptable or behaviouralrepresentations of the observed flows. The study demonstrated that this concept forassessing how uncertain hydrological predictions can be applied in the further developmentof a model or the choice of calibration method using artificially generated data.

Newly-designed structures and landscaping elements are often used for flood protection.This article assesses the use of existing sunken lanes for retaining water in a landscape andthe sedimentation of washed-off soil. The article also describes ways how to preserve or, atleast minimally disrupt, existing biotopes and landscape segments. Geodetic data from onespecific sunken lane in South Moravia in the Czech Republic were transferred to a digitalterrain model; 9 models were subsequently generated, each with a different longitudinalsunken lane bed slope. Retention dams consisting of gabions were placed in them. Thenumber of dams, the volume of structures made of steel gabions, and the retention areavolume behind the dams were determined for each model specifically. It was determinedthat the number of dams, as well as their total volume, increased with the averagelongitudinal slope of the sunken lane bed. It was also discovered that the retention volumeremained almost the same, as it only very slightly decreases with an increasing longitudinalslope.

Unsteady flows in channels and rivers combine a number of very complex naturalphenomena, particularly phenomena related to the wave propagation caused by gravity orfloods. The free surface flows relative to flows are regulated by the dynamic equilibrium ofthe forces of gravity, inertia and friction (Hervouet, 2003).In this present research study thefocus is primarily on the dynamic behavior of flows in an open channel, which occurs afterthe opening of a partition in the case of an enlargement and finally an abrupt drop. Thenumerical integration of the governing hyperbolic partial differential equations allowed usto better understand the phenomenon studied in the three cases cited above. Solving theseequations could be realized by using a FORTRAN calculation program that we developed.