Common Foundations 2018 - uniSTem: 6th Congress of Young Researchers in the Field of Civil Engineering and Related Sciences, Sep 25, 2018
Bukva je rijetko korištena kao građevinski materijal. U posljednje se vrijeme razmatra učestalije... more Bukva je rijetko korištena kao građevinski materijal. U posljednje se vrijeme razmatra učestalije korištenje u građevinarstvu budući da ima visoka mehanička svojstva i da je zabilježen porast zaliha-posebno u srednjoj i jugoistočnoj Europi. U radu su uspoređeni njemački, francuski i britanski standardi za vizualno ocjenjivanje skupa uzoraka iz lokalne pilane. Prema njima, relativno mali udio dasaka je ocijenjen najvišom ocjenom, a većina je dasaka negativno ocijenjena. Nakon provedenog vlačnog testa nad istim skupom dasaka, otkriveno je da daske imaju visoku vlačnu čvrstoću. Kako bi se poboljšao sustav vizualnog ocjenjivanja, korištena je metoda stabla odlučivanja. Novi sustav ocjenjivanja povoljnije je ocijenio daske nego opisane nacionalne norme.
Computer Methods in Applied Mechanics and Engineering, May 1, 1997
A finite element, large displacement formulation of static elasticplastic analysis of slender arb... more A finite element, large displacement formulation of static elasticplastic analysis of slender arbitrarily curved planar beams is presented. Nonconservative and dynamic loads are at present not included. The Bernoulli hy
Process capability estimation depends on the underlying data distribution. If data is not normall... more Process capability estimation depends on the underlying data distribution. If data is not normally distributed, other techniques for capability estimation should be taken into consideration. In this paper, we propose modified power transformation method for non-normal process capability estimation. Proposed method is compared to Box-Cox, Johnson and Abbasi-Niaki transformation method using simulation studies. In terms of transformed data and capability estimation, proposed transformation method showed better performance than Box-Cox and Abbasi-Niaki method.
The circular use of construction materials is an essential step in the drive to reduce the enviro... more The circular use of construction materials is an essential step in the drive to reduce the environmental impact of the construction sector. One of the factors that currently limits the ability to reuse timber recovered from demolition in structural applications is the lack of data relating to its structural performance, which would allow for the certification of its characteristics and the development of design guidelines. This paper presents a study on the embedment performance of recovered timber by determining the embedment strength of spruce and oak specimens recovered from demolition sites in Ireland and Slovenia. Tests were carried out in the parallel and in the perpendicular to the grain directions using three different dowel diameters. The results were comparable with mean values reported in the literature and with the empirical Eurocode 5 predictions. Based on these findings, it can be concluded that the embedment performance of the recovered spruce and oak is equivalent to that of new timber. Further studies on recovered timber of different origin, species, ages and history of use are needed to confirm these findings.
Klasifikacija prispevka po COBISS-u: 1.01 KLJUČNE BESEDE scientific publications, civil engineeri... more Klasifikacija prispevka po COBISS-u: 1.01 KLJUČNE BESEDE scientific publications, civil engineering, geodesy, citations of publications, open access, green road of open access znanstvene objave, gradbeništvo, geodezija, citiranost objav, odprti dostop, zelena pot odprtega dostopa
The Comparison Between Wheel Tracking and Triaxial Cyclic Compress Ion Test on Different Asp Halt Mixtures
Proceedings of the International Conference on Road and Rail Infrastructure CETRA, May 1, 2012
Road structural materials should have satisfactory behaviour that enables a proper load carrying ... more Road structural materials should have satisfactory behaviour that enables a proper load carrying capacity. Asphalt mixtures used in road construction, must have properties that prevent formation of permanent deformations and cracking caused by temperature changes and fatigue. Road damages caused by the impact of different factors don't have equal impact on all sections of carriageway and have manifested in various forms. To determine resistance to permanent deformations at high temperatures of asphalt specimens, triaxial cyclic compression and wheel tracking tests are used. We have made wheel tracking tests according to standard SIST EN 12697-22and triaxial cyclic compression test according to standard SIST EN 12697-25 methodB. Experiments were done for all principal asphalt mixtures: AC, SMA, MA and PA to obtain an extensive model of asphalt behaviour for mixtures which contain the most and the least air voids. Mastic asphalt dictated the use of bitumen B20/30 in all mixtures with the intention to compare results of wheel tracking test and cyclic compression test for four asphalt mixtures. The cylindrical specimen in triaxial test is subjected to a confining stress and a cyclic axial stress at elevated conditioning temperature and vertical plastic deformation is measured. The results will be interpreted with a statistical model.
A finite element, large displacement formulation of static elasticplastic analysis of slender arb... more A finite element, large displacement formulation of static elasticplastic analysis of slender arbitrarily curved planar beams is presented. Nonconservative and dynamic loads are at present not included. The Bernoulli hy
The geoid heights are needed for determining the orthometric heights from the Global Positioning ... more The geoid heights are needed for determining the orthometric heights from the Global Positioning System (GPS) ellipsoidal heights. There are several methods for geoid height determination. The paper presents a method employing the Artificial Neural Network (ANN) approximation together with the Least Squares Collocation (LSC). The surface obtained by the ANN approximation is used as a trend surface in the least squares collocation. In numerical examples four surfaces were compared: the global geopotential model (EGM96), the European gravimetric quasigeoid 1997 (EGG97), the surface approximated with minimum curvature splines in tension algorithm and the ANN surface approximation. The effectiveness of the ANN surface approximation depends on the number of control points. If the number of well distributed control points is sufficiently large, the results are better than those obtained by the minimum curvature algorithm and comparable to those obtained by the EGG97 model.
Structural Engineering and Mechanics, Dec 25, 2003
The non-linear structural analysis of reinforced concrete beams in fire consists of three separat... more The non-linear structural analysis of reinforced concrete beams in fire consists of three separate steps: (i) The estimation of the rise of surrounding air temperature due to fire; (ii) the determination of the distribution of the temperature within the beam during fire; (iii) the evaluation of the mechanical response due to simultaneous time-dependent thermal and mechanical loads. Steps (ii) and (iii) are dealt with in the present paper. We present a two-step computational procedure where a 2D transient thermal analysis over the cross-sections of beams are made first, followed by mechanical analysis of the structure. Fundamental to the accuracy of the mechanical analysis is a new planar beam finite element. The effects of plasticity in concrete, and plasticity and viscous creep in steel are taken into consideration. The properties of concrete and steel along with the values of their thermal and mechanical parameters are taken according to the European standard ENV 1992-1-2 (1995). The comparison of our numerical and full-scale experimental results shows that the proposed mechanical and 2D thermal computational procedure is capable to describe the actual response of reinforced concrete beam structures to fire.
VTT PUBLICATIONS 568 Potential of strength grading of timber with combined measurement techniques
This report documents the results of the first part of "Combigrade"project. 100 pieces... more This report documents the results of the first part of "Combigrade"project. 100 pieces of both spruce (Picea abies) logs and pine (Pinus sylvestris) logs were sampled and sawn timber produced. Nondestructive measurements of logs and sawn timber were made by 15 organisations producing 40 different measured quantities for each test piece. Finally, test material was loaded to failure in bending, and grade determining properties (modulus of elasticity, bending strength and density) were measured. Coefficients of determination were calculated between nondestructively measured indicators and grade determining properties. Also strength grading procedure determined by prEN 14081 was simulated numerically, and effectiveness of some potential grading methods was analysed. Part 1 of the project is planned to be followed by a larger testing programme enabling the determination of settings for new and combined grading methods in accordance with the upcoming European standard.
The paper presents an automatic procedure for the correction of bridge weigh-in-motion (B-WIM) me... more The paper presents an automatic procedure for the correction of bridge weigh-in-motion (B-WIM) measurements, which are used to determine the axle loads of heavy vehicles using instrumented bridges. According to the European Specifications for Weigh-in-Motion criteria, using this procedure the weighing results could be improved by up to one accuracy class. Whereas measurements performed on steel structures provide reliable information about the global behaviour of individual bridges, which is accounted for in the B-WIM algorithms, cracks that are present in concrete structures can, depending on their locations with respect to installed strain transducers, amplify or reduce the response. In the present work special care was taken to detect and calibrate any strain transducer which showed a disproportional response. The accuracy of the method was investigated numerically in relation to the extensive data which were available in the case of a reinforced concrete bridge (motorway underpass), located near Ljubljana, Slovenia, and then validated by a one-to-one comparison of the B-WIM weighing results and the statically weighed test vehicles.
Monitoring displacements of the object can be performed using geodetic methods by selecting refer... more Monitoring displacements of the object can be performed using geodetic methods by selecting reference points on the surrounding terrain and points on the object that discretely describe the object’s behavior. The measurements are repeated in several epochs. By analyzing the geodetic network we can determine the status of a single point, i.e., whether the point has moved or not. The article discusses the testing of congruence, the testing of transformation of a single triangle, and the calculation of other deformation parameters in 2D networks resulting from the changes of points coordinates between two epochs. This is essentially the content of the Munich deformation method presented by W.M. Welsch, which includes the X- and L-method. The article also proposes some corrections to the original Munich approach. Finally, the applicability of the method is shown on a well-known practical example.
Many heat-transfer problems involve a change of phase of material due to solidification or meltin... more Many heat-transfer problems involve a change of phase of material due to solidification or melting. Applications include: the safety studies of nuclear reactors (molten core concrete interaction), the drilling of high ice-content soil, the storage of thermal energy, etc. These problems are often called Stefan's or moving boundary value problems. Mathematically, the interface motion is expressed implicitly in an equation for the conservation of thermal energy at the interface (Stefan's conditions). This introduces a non-linear character to the system which treats each problem somewhat uniquely. The exact solution of phase change problems is limited exclusively to the cases in which e.g. the heat transfer regions are infinite or semiinfinite one dimensional-space. Therefore, solution is obtained either by approximate analytical solution or by numerical methods. Finite-difference methods and finite-element techniques have been used extensively for numerical solution of moving...
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