Analysis of material non-linearity of steel girders subjected to patch loading

U radu se daje analiza ponašanja limenih nosača (nosači od zavarenog čelika I) pod lokalnim opterećenjem. Koncentrirano ili jednoliko raspoređeno opterećenje na maloj udaljenosti od prirubnice i u ravnini mreže, poznato je kao lokalno opterećenje (patch loading). Analiziralo se ponašanje nosača u nelinearnom području kao i učinak kritičnog opterećenja, koji se manifestira izvijanjem. Za modeliranje nosača primijenjen je softver ANSYS Workbench 15 [1]. U skladu s važećim propisima EN 1993-1-5 [2] i BSK 07 [3], tijekom numeričke analize korišteno je šest različitih modela materijala. Dobiveni rezultati uspoređeni su s eksperimentalno dobivenim rezultatima.The paper presents an analysis of behaviour of plate girders (welded steel I girders) under patch loading. Concentrated or uniformly distributed loading on a short length of the flange, and in the plane of web is known as patch loading. Behaviour of the girder in non-linear area, as well as the ultimate load capacity, which is manifested by buckling in the loaded zone were analysed. Girder modelling was performed in ANSYS Workbench 15 software [1]. In accordance with the standing regulations EN 1993-1-5 [2] and BSK 07 [3], in the course of the numerical analysis, six different material models were employed. The obtained results were compared to the experimentally obtained results

Stress Analysis of Steel Plate Girders Subjected to Patch Loading in Elastoplastic Domain

This paper considers the stress analysis of steel I girders subjected to patch loading for different lengths of load. Behavior of the girders under the patch loading or uniformly distributed load on the flange and in the plane of web represents complex stability and elastic-plastic problem. The geometric and material non-linearities that exist, also affect the behavior of the girder. A better knowledge of girder behavior is important in order to achieve a more economical and a safer design. In addition to the limit load analysis, the stress analysis is of particular interest. The results from the experiment were used and were compared with the results obtained by modeling the girders in the ANSYS software

On the Optimal Design of Steel Shells with Technological Constraints

This paper is concerned with determining the optimum conditions of steel cylindrical shells with technological limitations and one behavioral constraint, related to a specific constitutive law for limiting load-carrying capacity. The optimum structural design in the plastic range of circular cylindrical full shells composed of rings of variable thickness is given. A numerical procedure for determining the optimal dimensions of shell rings is given. A shell collapse mechanism is assumed in the kinematic part, which satisfies requirements. Within the optimum conditions, the power of the dissipation energy of rings assuming the hexagon Hodge condition of plasticity are derived. A series of numerical solutions and results of optimal structural designs for a shell that is simply supported at the ends are presented. In one example of optimally calculated shells, the length X1 of one ring was varied

On the Optimal Design of Steel Shells with Technological Constraints

This paper is concerned with determining the optimum conditions of steel cylindrical shells with technological limitations and one behavioral constraint, related to a specific constitutive law for limiting load-carrying capacity. The optimum structural design in the plastic range of circular cylindrical full shells composed of rings of variable thickness is given. A numerical procedure for determining the optimal dimensions of shell rings is given. A shell collapse mechanism is assumed in the kinematic part, which satisfies requirements. Within the optimum conditions, the power of the dissipation energy of rings assuming the hexagon Hodge condition of plasticity are derived. A series of numerical solutions and results of optimal structural designs for a shell that is simply supported at the ends are presented. In one example of optimally calculated shells, the length X1 of one ring was varied

Design of a System for Monitoring Reliability of Structures and Constructions in Civil Engineering

Monitoring of civil engineering structures and constructions requires techniques which can produce high precision and accuracy, reliable measurements and fast processing speed. The development of information and communication systems as well as of microprocessor controllers has enabled a creation of monitoring systems that can be used for tracking reliability of structures and constructions in civil engineering, with described key features. This paper describes in detail the architecture of the Civil Engineering Structures Reliability Monitoring (CERM) system. The system has been designed for the purposes of the Technical Mechanics and Theory of Constructions Department at the Faculty of Civil Engineering and Architecture, University of Nis. Unlike general commercial monitoring systems, the CERM system has been specially designed for the purpose of reliability monitoring, and its potential will be further exploited in this paper. It is based on usage of universal microprocessor controllers Integraf of series 10X, along with specially designed software package. This system provides real time acquisition of measurements for observed civil engineering structures and analysis of received values based on developed mathematical models

Design of a System for Monitoring Reliability of Structures and Constructions in Civil Engineering

<span style="font-family: "Times New Roman"; font-size: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-US">Monitoring of civil engineering structures and constructions requires techniques which can produce high precision and accuracy, reliable measurements and fast processing speed. The development of information and communication systems as well as of microprocessor controllers has enabled a creation of monitoring systems that can be used for tracking reliability of structures and constructions in civil engineering, with described key features. This paper describes in detail the architecture of the Civil Engineering Structures Reliability Monitoring (CERM) system. The system has been designed for the purposes of the Technical Mechanics and Theory of Constructions Department at the Faculty of Civil Engineering and Architecture, University of Nis. Unlike general commercial monitoring systems, the CERM system has been specially designed for the purpose of reliability monitoring, and its potential will be further exploited in this paper. It is based on usage of universal microprocessor controllers Integraf of series 10X, along with specially designed software package. This system provides real time acquisition of measurements for observed civil engineering structures and analysis of received values based on developed mathematical models.</span&gt

REDISTRIBUTION OF THE INFLUENCES IN SYSTEMS WITH SEMI-RIGID JOINTS ON ELASTIC FOUNDATIONS

Abstract. Most often, in the case of typefied prefabricated systems, foundations are designed and constructed as prefabricated elements as well. When the structure is exposed to high intensity loading and founded on a weak soil, beam foundations are often used instead of pad foundations. Beam foundations, stiffening girders, as well as beams which support the façade elements or partition walls, are treated as beams on elastic foundations, while joint of these girders to pad foundations or vertical support elements of a precast structure can be treated as semi-rigid. Modeling of systems with semi-rigid joints on elastic foundations, for different levels of rigidity of connections, is illustrated by an example of a frame under static loading. On the basis of the results of the calculation carried out in this paper, it is evident that taking into account the elastic foundations of the member and the corresponding degree of fixation of the member on this foundations significantly affects the magnitude of the forces in the cross-sections of the member, and on the redistribution of influences in the entire structure. Yet, the foundations-and-soil interaction exerted the highest influence on the magnitude of the stress in the foundation structure itself. Key words: precast structure, semi-rigid connection, redistribution of influences. 1

SYSTEM IDENTIFICATION APPROACH APPLICATION FOR EVALUATION OF SYSTEM PROPERTIES DEGRADATION UDC 624.01:624.042.8(045)=20

Abstract. In respect to the subspace identification method as one of the possible variants of inverse dynamic analyses, behavior of real structural systems with real load and real noise contaminated input/output data was investigated in this work. A useful and non-destructive dynamic parameters evaluation tool- vibration monitoring of the structure- is proposed. The report of original investigation on real models excited by an impulse load in laboratory is also presented. A special contribution is a software program for experiment monitoring and for determination of relevant mechanical characteristics as well as of the location of a possible structural damage. 1

PRIMENA OBRADE ABRAZIVNIM VODENIM MLAZOM U GRAĐEVINARSTVU (GRAĐEVINSKOM INŽENJERSTVU)

Water jet processing techniques can be successfully applied in many fields of civil engineering, such as: structural engineering, structural reconstruction, renovation, demolition and recycling. The problem of cutting difficult-to-machine materials led to the development and application of today the most attractive method for contour cutting - Abrasive Water Jet Cutting (AWJC). It is a high-tech technique that provides unique capabilities compared to conventional machining processes. This paper, along the theoretical derivations, provides a study on use of water jet in construction and civil engineering. The particular part of this paper deals with the results of the original experimental research on granite and aluminum cutting.Tehnika obrade vodenim mlazom može se uspešno primenjivati u mnogim oblastima građevinskog inženjerstva, kao što su: strukturalno inženjerstvo, rekonstrukcija konstrukcija, renovirenje, rušenje i u potupcima reciklaže. Problem sečenja teško obradivih materijala doveo je do razvoja i primene, danas naj atraktivnije metode za konturno sečenje materijala abrazivnim vodenim mlazom. To je visoko tehnološki postupak koji poseduje jedinstvene karakteristike u odnosu na uobičajene postupke obrade materijala. U ovom radu su, pored teorijskog osvrta, predstavljene mogućnosti primene ove tehnike u građevinskom inženjerstvu, dok su u delu rada predstavljeni rezultata ispitivanja na uzorcima od granita i aluminijuma

A BEARING STRUCTURE AND FINISHED CONSTRUCTION BEHAVIOR ANALYSIS BASED ON THE FULL-SCALE

Abstract. The paper deals with a brief presentation of a part of the performed experimental tests of the prefabricated reinforced concrete structural system "AMONT"for construction of various types of modern industrial halls. The test results are analyzed for two industrial halls both constructed according to this structural system but in the different phases of construction, tested in the full scale by application of AMBIENT vibration method. From the obtained Fourier spectra for measured ambient vibrations in two orthogonal direction for the structure without walls and the other with façade and filling walls, a significant discrepancy in their natural frequencies has been observed, and some conclusions about the influence of panel walls on dynamic characteristic the frame structure have been drawn out. The paper used some data of the research after the earthquake in Montenegro which took place on 15 th of April 1979