Romualdas Kliukas

Probabilistic durability prediction of existing building elements

Abstract An effect of service and proof actions on probabilistic reliability (serviceability, safety and durability) of building elements (components and members) of existing enclosure and bearing structures is under consideration. Time‐dependent models for reliability assessment of elements under sustained variable and multicycle actions are presented. Revised reliability indices of existing elements exposed to service permanent and variable actions are discussed. It is recommended to assess the long‐term reliability index of elements taking into account the effect of latent defects. Truncated probability distributions of physical‐mechanical resistances of elements and an effect of their latent defects on reliability index assessment are taken into account. Methodological peculiarities of durability prediction of elements and avoiding unfounded premature repairs or replacements are analysed. The applied illustration of the presented method on the probabilistic reliability prediction of deteriorating conc...

A monument of historical heritage ‐ Vilnius archcathedral belfry: The dynamic investigation

Abstract The dynamic investigation of a monument of historical heritage ‐ Vilnius Archcathedral Belfry ‐ is investigated. In 2002 six new bells were installed in Vilnius Archcathedral Belfry according to a modern location scheme and their ringing order was changed. Evidently, they caused different dynamic loads which were not completely controlled and their effect on historical buildings of the Old Town of Vilnius could hardly be predictable. The paper presents the results of dynamic investigation of the Archcathedral Belfry, subject to the influence of the bell system operation. The dynamic impact was evaluated by measuring the acceleration history under the conditions, when different combinations of bells were used. A contribution of the dynamic effects was assessed in terms of response spectra. The obtained results have been thoroughly analysed and the appropriate findings and conclusions provided.

Investigation of Traffic-Induced Vibration in Vilnius Arch-Cathedral Belfry

Abstract The influence of city traffic‐induced vibration on Vilnius Arch‐Cathedral Belfry is investigated. Two sources of dynamic excitation are studied. Conventional city traffic is considered to be a natural source of excitation while excitation imposed artificially by moving a heavily loaded truck is considered to be the source of increased risk excitation. The influence of induced vibrations is recorded by accelerometers located in various positions of the Belfrys structures and shown by accelerograms. Dynamic effects are evaluated by considering acceleration magnitudes and response spectra. A comparative analysis of both effects is presented and conclusions and recommendations are provided.

The limit state design of spun concrete columns using load combinations recommended by EN 1990 and ASCE/SEI 7–05

Abstract The expediency of using precast spun concrete columns of annular cross‐sections reinforced by high‐strength steel bars is discussed. Test material properties, efficiency factors and resisting compressive stresses of plain and reinforced spun concretes are presented. Modelling a bearing capacity of eccentrically loaded members of annular cross‐sections is based on the concepts of compression with a bending moment and bending with a concentrical force. The comparison of test and modelling data of concentrically and eccentrically loaded members is analysed. The expediency to use in design practice the approaches of current methods of partial safety factors design (PSFD) legitimated in Europe and load and resistance factors design (LRFD) suggested in the USA and other countries is considered and illustrated by a numerical example.

Transport management: The popularity of study programmes among the applicants to Lithuanian universities evaluating the qualifications of graduates in the labour‐market

Abstract The accession of Lithuania to the European Union made transport one of the most important branches of national economy. Presently, economic development is hardly possible without an efficient transport system (providing both local and international transportation). The operation of industrial, construction and agricultural enterprises as well as work efficiency and a public opinion largely depend on the reliability and effective performance of transport systems which is not possible without qualified transport managers. The paper presents requirements raised for controlling the abilities and level of educating specialists in Transport Management and introduces employee assesment at student skills. Specialists in Transport Management are trained at vocational and higher schools of Lithuania. Experts in the field of Transport Management are trained at two university‐level higher schools in Lithuania (Bachelors, Masters and Doctors) including Vilnius Gediminas Technical University and The General Jo...

QUALITATIVE ANALYSIS OF THE KNOWLEDGE OF APPLICANTS TO TRANSPORT ENGINEERING COURSES OF STUDY

The problems of selecting applicants to the Lithuanian universities and the level of knowledge of the applicants to transport engineering specialities will be discussed in this paper. A brief analysis of courses of studies in transport engineering at theLithuanian univitersities is presented. Some statistical data reflecting the results of joint applicants admission to the Lithuanian higher schools are presented. The selection of applicants to study transport engineering courses at the Lithuanian universities is analyzed.

ON DESIGN FEATURES OF PROPPED AND UNPROPPED HYPERSTATIC STRUCTURES

Abstract An effect of structural and technological features on the design methodology of hyperstatic precast reinforced concrete and composite steel‐concrete structures is discussed. Permanent and variable service, snow and wind loads of buildings and their extreme values are analysed. Two loading cases of precast reinforced concrete and composite steel‐concrete continuous and sway frame beams as propped and unpropped members are considered. A redistribution of bending moments for the ultimate limit state of beams is investigated. A limit state verification of hyperstatic beams by the partial factor and probability‐based methods is presented. It is recommended to calculate a long‐term survival probability of beams by the analytical method of transformed conditional probabilities.

Efficient technique for constitutive analysis of reinforced concrete flexural members

Abstract One of the most difficult issues in the theory of reinforced concrete (RC) is an adequate modelling of deformation behaviour, cracking and, particularly, post-cracking behaviour, as one of the major sources of non-linearity. Applying the concept of average cracking and average strains, deformation behaviour of RC can be modelled by stress–strain tension–stiffening relationships. The authors proposed an innovative inverse technique for constitutive modelling of flexural RC elements. The technique is based on the smeared crack approach and layer model of RC section. The inverse technique aims at deriving tension–stiffening constitutive models from experimental moment–curvature diagrams. The present analysis takes into account the shrinkage effect that is often neglected in other studies. Based on the inverse technique, free-of-shrinkage tension–stiffening relationships are derived using test data of shrunk RC beams. Examples of the application for the analysis of the experimental data obtained by the authors are presented to illustrate the calculation efficiency of the proposed technique.

Sustainability assessment for recreational buildings

ABSTRACT A large amount of natural resources and energy is wasted during and after the building construction process which might cause environmental problems such as climate changes. In order to achieve higher standards of environmental protection a range of building assessment systems has been established. However, they are mostly connected with the efficiency of an environmental protection and consumption of resources. Only few of them have limited possibilities to assess social and economic sustainability. A sustainable building includes aspects of environment, economy and society and therefore requirements to its assessment systems should be complex. We suggest that sustainability principles, that is, environmental, social and economic sustainability, should be estimated in the same equal weightings. The authors of this article created a model for assessing the sustainability for recreational buildings. Our model was created, in collaboration with experts, using breakdown, compensation and the analytic hierarchy process methods. The sustainability of Druskininkai Snow Arena (Lithuania) was assessed using a sustainability assessment system based on the proposed model.

Experimental Investigation of Tension Stiffening in RC Ties

The increasing application of high-performance materials in civil engineering led to the development of reinforced concrete (RC) structures with reduced cross sections and increased spans. In such structures serviceability limit state often becomes the governing condition of the design. Present study investigates the deformation behaviour of high-strength RC ties reinforced with high-grade bars. Experimental investigation was carried out measuring the postcracking stiffness of the specimens at high strain levels. It was found that, despite the reduction in stiffness, a considerable part of the average tensile stresses were carried by the concrete at the advanced loading stages, thus effectively stiffening the RC member.