Eurocode

Regulations on which designers base their process of designing of any engineer structures should  include and combine mechanics, loads and dimensioning. It is not always the case as far as eurocodes are concerned. Ambiguities appear everywhere, which  sometimes leads to  incorrect understanding of a norm. The authors meticulously analysed  basic mechanical terms. Their digressions began with  the concepts of strain and deformation that have discrepant definitions in sources from other countries. The next part of article discusses the concept of „shear lag”. It is treated as an elementary concept in the eurocodes, although is has not been defined yet. Other sources define it as cooperating width and shear strain in the beam flanges or as stretching. Polish translation mentions the effect of „wide stripes”. The authors focused also on dynamics – especially while discussing first natural frequencies denoted as “n0”. They scrutinised  the norm EN 1991-2 in which dynamic problems of brid...

The primary purpose of this thesis is to investigate the plastic reserve of composite plate girder bridges. These structures are suitable for this due to the synergetic combination of the concrete and steel. The former provides the “cheap” stiffness and strength in compression while the steel in tension ensures the ductility. However, the theoretical and experimental aspects of plastic design are well established only in the US provisions are available for the designers.

The aim was to inquiry the plastic design in the framework of the Eurocode through an existing elastically designed bridge. In the first part of the study the necessary theoretical background is overviewed, the related literature is examined. The main emphasis is placed on the ultimate load bearing capacity, which is determined using various limit states, such as first hinge, incremental collapse and plastic collapse. The safety levels of these limit states were also investigated. To ensure the ductility of the pier-sections innovative structural solutions gathered and evaluated. The selected bridge is a composite, plate girder, continuous structure formed by three spans (30,0-40,0-30,0m). This was redesigned following plastic principles, the relevant provisions and the findings of the researchers.

The calculations showed that − for the original structure − the traffic load could be increased by ~30 and ~60% over the first yield in case of using first hinge and shakedown limit states, respectively. It was found that the safety levels of these limit states at least reach or exceed that of the first yield or first hinge. It should be noted that these results reflect only one example; nevertheless, they are in good agreement with the American results. The redesign yielded to a structure with cleaner lines with considerably less section transition and about 25% structural steel saving. Based on the calculations and international data the plastic design of girder bridges appears to be a promising way, at the same time more research required.

In past, hand calculations were the only way to design reinforced concrete sections. With the rapid development of computers, engineers are now able to perform more complex calculations faster and with greater precision, achieving more economical solutions. The goal of this thesis was to create an easy to use reinforced concrete section design tool with GUI. The result is a MATLAB program called ConcreteTool which can be used to design reinforced concrete beam sections (rectangular and T sections) subjected to bending, shear and torsion loads, according to Eurocode 2. Numerical example results obtained by ConcreteTool are compared against another commercial software called BETONexpress by RUNET.

U relativno bliskoj prošlosti, dimenzionisanje AB presjeka se vršilo isključivo ručno. Naglim razvojem računara, inženjeri su sada u mogućnosti da rješavaju mnogo kompleksnije probleme mnogo brže, preciznije i ekonomičnije. Cilj ovog rada bio je izrada jednostavnog programa sa grafičkim interfejsom za dimenzionisanje AB presjeka prema Evrokodu 2. Rezultat je MATLAB program pod nazivom ConcreteTool, koji se može koristiti za dimenzionisanje AB grednih presjeka izloženih uticajima momenta savijanja, transverzalne sile i momenta torzije. Rezultat proračuna brojnog primjera upoređen je sa drugim komercijalnim programom pod nazivom BETONexpress (RUNET).

Principi i procedure seta evropskih standarda-sistema tehničkih pravila za projektovanje zgrada i inženjerskih konstrukcija uključujući građevinske materijale i objedinjavanje metodologija konstrukterskog projektovanja (prvo izdanje) Sarajevo 2018

p. 2569-2576 The main part of a traditional silo is the cylindrical shell placed upon a limited number of support columns in order to facilitate emptying operations. These local supports lead to stress concentrations in the cylinder and can cause local instabilities of the shell. In order to prevent this failure phenomenon, the cylindrical shell can be reinforced by means of two longitudinal stiffeners of limited length above each support in combination with a ring stiffener above and below the vertical stiffeners. In this paper, the longitudinal stiffeners are assumed to be flexurally and axially rigid in order to prevent the stiffeners from buckling and to allow the study of the structural behaviour of the cylinder. The results of an initial numerical study with the finite element package ABAQUS are presented.

Ce rapport presente les resultats d’une recherche en deux parties sur le theme de la precontrainte exterieure des ponts routiers. Partie I – Comparaison avec la precontrainte interieure Une etude parametrique comparative a ete conduite sur deux ponts caisson, l’un precontraint interieurement, l’autre exterieurement (chapitres 2 & 3). Il s’agit dans les deux cas d’un mod-ele simplifie d’un pont autoroutier de cinq travees dont la precontrainte est choisie sur la base du critere de compensation des deformations. Cette etude montre qu’il n’est pas possible de donner une estimation quantitative simple et generale de la difference de quantite d’armature flexionnelle passive et precontrainte entre les deux types de precontrainte. On peut cependant dire en regle generale, et contrairement a ce que l’on entend parfois, que la difference est faible, ce qui implique que le choix du type de precontrainte doit etre base sur d’autres consi-derations, telles que la qualite, la methode de construc...

The choice of the different design approaches has a substantial effect on the limit state analysis of geotechnical structures. In particular, the soil-structure interaction behaviour is complicated in supported excavations, since the actions and resistances due to the earth pressure on the excavation walls are dependant on the deformations and has to be taken into consideration with different partial safety factors.
The limit state conditions of excavations had been investigated according to the German approach with consideration of the national annex to the EC 7-1 and the national recommendations for “Excavations” EAB (2006). The determination of the required embedment depth and the corresponding section forces are of special importance in the design of the retaining walls in the ultimate limit state (ULS) according to EC 7-1 and DIN 1054:2005. For a practical application, this has been illustrated in the paper on the basis of a numerical and analytical analysis of an idealized excavation. The results are compared with other alternative design approaches
of the EC 7-1.

This study describes numerically, the interdependency between several seismic acceleration parameters and diverse structural damage indices. Peak ground motion, spectral and energy parameters are used for characterising the seismic excitation. On the other hand both, structural and nonstructural damage is considered, expressed by the modified Park/Ang overall structural damage index (OSDI), the maximum interstory drift (ISD) and the maximum floor acceleration. After the numerical evaluation of several seismic parameters, nonlinear dynamic analyses are conducted to furnish the structural damage status. The degree of the interrelationship between the seismic parameters and the damage indices is provided by correlation coefficients. The investigation is carried out for a reinforced concrete plane frame system designed after Eurocodes 2 and 8 (EC2, EC8) and the aim is to determine the characteristics of the accelerograms that exhibit the strongest influence on structural and nonstructural damages. The numerical results have shown, that peak ground motion seismic parameters provide poor or fair correlation with the OSDI, whereas the spectral and energy parameters provide good correlation. Furthermore, the central period and the strong motion duration after Trifunac/Brady exhibit poor correlation with the OSDI. All these results give reason to recommend the spectra and energy related seismic intensity parameters as reliable descriptors of the seismic damage potential.

The performance of a structural system under seismic action can be evaluated by resorting to non-linear static analysis. This involves the estimation of the structural strength and available capacities and the comparison with the deformation demands at desired performance levels. Seismic evaluation of existing structures and of the proposed design for new structures can be done based on Non-linear Static Procedure popularly known as Pushover Analysis (PoA). The ‘Iterative Procedure (Optional)’ mentioned in Eurocode 8 (EC8) has been developed to an EC8 based Capacity Spectrum Method (CSM) procedure and is investigated here. Since commercial packages, including SAP2000 which was used for this investigation, has no facility for conducting an EC8 based CSM, a method was developed, and the procedure is programmed in VB-Script and embedded in MS-Excel. The paper also attempts to investigate the Consecutive Modal Pushover (CMP) analysis, using the EC8 based CSM procedure developed. Althoug...

To assess the fire resistance of historical buildings, information is needed about the applied materials, the construction details, etc. Starting from this information calculation models can be set up to determine the fire resistance of the total structure and its components. Assessing cast iron framed buildings is difficult because cast iron as well as the former construction techniques are no

The widespread brittle failure of welded beam-to-column connections caused by the 1994 Northridge and 1995 Kobe earthquakes highlighted the need for retrofitting measures effective in providing ductility to connections. Researchers presented the reduced beam section (RBS) as a viable option to prevent brittle failure at the connection weld. More recently, an alternative connection known as a reduced web section (RWS) has been developed as a potential replacement, and initial studies show ideal performance in terms of rotational capacity and ductility. This study performs a series of non-linear static pushover analyses using a modal load case on three steel moment-resisting frames (MRFs) of 4-storeys, 8-storeys and 16-storeys. The frames are studied with three different types of connections; fully-fixed moment connections, RBS connections and RWS connections, in order to compare the differences in capacity curves, inter-storey drifts and plastic hinge formation. The seismic-resistant...

This work presents preliminary design of the road bridge made of laminated timber. The supporting system of the main bearing elements is made of the laminated timber in the system of arch with three joints; the bridge slab is designed as continuous slab, made of nine equal fields; each pair is made as composite timber-concrete beam, where the road slab is made of concrete and the needle pieces are made of timber. Fundament is based on HW piles. All the elements are designed to Eurocode.