Crane Runway Research Articles

Failure analysis concerning causes of wear for bridge crane rails and wheels

Wear of the guiding structures is an undesirable phenomenon, which is occurring very often in the technical practice. This negative phenomenon also reduces reliability level of the hoisting machines and machinery. Taking into consideration the practical point of view it is possible to specify that wear of the crane guiding structures means wear of the crane rails and crane wheels. The guiding structure is defined in this case as a cinematic couple “wheel-rail”. There is presented in the article an experimental and calculation analysis, which was performed in order to investigate an excessive wear of the crane guiding structure, namely in the case of the hoisting equipment utilised in a real operation. There were experimentally researched two bridge slab tong cranes with the loading capacity 50 t and also their crane runways. It was determined, according to the performed analyses that in the case of one crane the geometry of its undercarriage is incorrect. The experimental measurements confirmed a fact that the real value of the horizontal force was approximately 3.8-times higher in comparison with the assumed force value obtained from a calculation. Another finding was that also the crane runway geometry exceeded values of the permitted deviations with regard to the valid technical standard. There is described in the chapter Conclusion a proposed short-term solution, which is able to eliminate wear of the crane rails and crane wheel flanges, however without prevention of the crane skewing.

Dynamical Model for Calculation Transverse Forces between Overhead Bridge Crane and Crane Runway

Horizontal forces between the crane and the crane runway girder occur during a motion of an overhead travelling crane on the crane runway. There are several methods for calculation of these forces. The most significant load caused by motion of crane is the skewing and the acceleration of the crane and of the crab. This paper deals with the acceleration of the crane and with the skewing of the crane. In present the skewing of crane is defined as the motion of the overhead bridge crane with the constant velocity but with the angle relative to the crane runway. The transverse forces caused by acceleration of the crane are calculated separately. But the skewing of the crane can occur also during the accelerating of the crane. Present standards don’t take this situation into account. A dynamical model presented in this paper describes motion of the overhead double bridge crane during its acceleration. The basic assumption of this model is that there the contact between the rim of the firs crane wheel and the rail of the crane runway.

Integrity analysis on existing crane runway girders with defects using constraint-based R6 criterion

Integrity analysis on existing crane runway girders with defects using constraint-based R6 criterion

GEOMATIC TECHNIQUES FOR MONITORING AND VERIFYING OF THE WEAR CONDITION OF THE RUNWAYS OF THE BRIDGE CRANES

Abstract. Monitoring and diagnostics of the lifting systems in the field of rail transport play a fundamental role in order to enable it to function safely providing any deviations from the expected behaviour of the regular conditions. The transit of heavy convoys naturally tends to worsen the geometrical position and, of consequence, it is necessary to identify some monitoring techniques that allow to establish the maintenance of infrastructure in accordance with the standards UNI ISO 9927-1 and in according to ISO 12488-1 must be verify the tolerance for wheels and travel and traversing tracks; for a crane runway these are for example the span, the position and height of the rails.. Especially the ground infrastructure related to the bridge crane requires periodic checks. The purpose of this paper is to identify suitable geomatics techniques for monitoring of the runways of the bridge cranes. To achieve this aim, the paper is divided in more sections. In the first part, the paper describes the area involved in the monitoring and standards in the field of monitoring the wear of the rails. In the second part, the paper describes the criteria and regulations for checking the wear of the bridge cranes using several geomatics techniques, tool and software.

Influence of corrosion on fatigue behaviour of old crane runway steel

Experimental measurements of fatigue properties of old steel used for a crane runway were performed to capture the influence of corrosion on fatigue life of the material. Basquin’s law was used to quantify the fatigue properties of old steel with different cross sections and with different surface of specimens (polished and corroded). The finite element model was prepared to assess and quantify the various stress distribution in specimens with circular and rectangular cross sections. Fracture surfaces of the three kinds of specimens (circular polished, rectangular polished and rectangular corroded) were studied and they showed the surface crack initiation. The following fatigue cracks developed from the surface and expanded into specimen with radiation pattern. Observed crack initiation areas confirmed the ones expected according to stress concentrations.

Dynamical Model for Determination of Horizontal Forces on Crane Runway during Motion of the Crane

During a motion of an overhead travelling crane on the crane runway, horizontal forces between the crane and the crane runway girder occur. The reason of these forces can be the acceleration or deceleration of the crane and then most significant part of these horizontal forces is skewing of the crane. There are several methods for calculation of these forces. These methods depend mainly on the chosen computational model. Some comparison of these methods was made in a past conference by the author of this article. The most significant load caused by motion of crane is the skewing. In the past, the cause of the skewing was considered to be caused by different speeds of the end-carriages of the crane which result to the horizontal transverse loads of the crane runway. In the present, the skewing of crane is defined as the motion of the overhead bridge crane with the constant velocity, but with the angle relative to the crane runway. It means that the overhead bridge crane is angled relative to the crane runway and moves with constant velocity. During this motion, the crane wheels are angled relative to the rail of the crane runway and the transverse forces occur on crane wheels. But this situation can occur also during the acceleration or deceleration of the crane. Present standards do not take into account this situation. A dynamical model is presented in this paper, describing the motion of the overhead double bridge crane during its acceleration. The dynamical model includes things which can influence the motion of the crane, the forces acting on crane wheels. The model thus describes the behaviour of the crane during acceleration in general and enables to determinate the horizontal transverse forces. The basic assumption of this model is that there is no contact between the rim of the crane wheel and the rail of the crane runway.

Fatigue Failure of runway beams due to wheel loads

ABSTRACTThe introduction of the Eurocode 3 led to a significantly stricter fatigue classification, especially for flange to web connections of runway beams of heavy duty cranes compared to former national design rules like DIN 4132. At present, this leads to a doubling of the cross‐sectional thicknesses, which e.g. can result into web plates with extreme thicknesses of 80 mm. Execution as well as monitoring of such flange to web connections using full penetration tee‐butt welds are quite critical and thus no longer to be realized reasonably.On this account new fatigue strengths for the runway beam specific fatigue detail “Top flange to web junction of runway beams” in EC3‐1‐9 Table 8.10 have been established within the FOSTA‐research project “Fatigue failure of runway beams due to wheel loads in heavy smeltery cranes” as recommendations for an eventually modification or even extension of the current codes. In Particular, the detail executed using full penetration tee‐butt welds has been investigated in the framework of this research project.The essential core of the methodical approach is that real existing crane runway girders have been examined, documented and evaluated in regard of fatigue failure of the flange to web connection. In this way, a direct quantitative assessment of safety against fatigue failure for the investigated detail could be derived. In addition, synthetic notch cases have been investigated numerically. The results of both methodologies have been prepared for a proposal of amendment of the current codes. This paper provides an insight into the methodological approaches and the main results achieved.

Laboratory tests on a real crane runway girder with welded box section and eccentric wheel loading

ABSTRACTThe design of crane runway girders is strongly affected by the local stresses at the web top due to wheel loads (mainly fatigue design, but also web buckling). A realistic approach of these local stresses due to centric and eccentric wheel loading is very important for economic design.In this paper, experimental tests on a real crane runway girder with welded box section are presented. Centric as well as eccentric wheel loading is investigated. The tests have been conducted with and without longitudinal stiffeners in the web under the crane rail. Therefore, the influence of these stiffeners on the local vertical stresses can be highlighted.For all tests, additional comprehensive finite element analyses have been conducted. The results of the numerical calculations are compared with the test results and with the predictions of a sophisticated engineering model that takes into account the typical load carrying behaviour of welded box sections.

Laboratory and numerical tests on real crane runway girder with box section

This paper investigates the local stresses in crane runway girders with welded box section due to wheel loading. The effects of load eccentricity are studied in detail for webs with and without longitudinal stiffeners. Since current design codes only give stress formulae for I-sections, a new analytical model is presented in this paper. This extended analytical model for eccentric loads allows for consideration of the stiffness contribution of the upper flange and of the additional web supporting effect of longitudinal stiffeners, if present.Additionally, laboratory tests on a full scale crane runway girder with welded box section and corresponding finite element calculations are presented. The local stresses of both are compared with the new analytical model and with code predictions. Concentric wheel loading as well as eccentric loading is studied. Three different load positions are investigated: LP I with longitudinal web stiffeners, LP III without stiffeners and LP II directly at a diaphragm. Moreover, additional fatigue tests due to cyclic wheel loading are presented for all three load positions.

Dismantling and decontamination of large-sized radiation-contaminated equipment during Research Building B decommissioning at the Bochvar Institute site

The article presents the results of work on dismantling the large installation equipment of Research Building B at the Bochvar High-technology Research Institute of Inorganic Materials (Bochvar Institute). The works were carried out as part of Building B preparation for decommissioning. The purpose of dismantling the large-sized capacitive equipment was to reconstruct the large installation site for managing radioactive waste generated during Building B decommissioning. The works on decommissioning a radioactively contaminated building within a densely populated district of megalopolis were carried out for the first time. The characteristics of the large-sized capacitive equipment are presented. Radioactive contamination of the capacitive equipment is determined by long-lived a-emitting isotopes: 235U, 238U, 239Pu. The sequence of works on dismantling the radiation-contaminated capacitive equipment includes preparatory work, dismantling the tank piping, localizing radioactive contamination of the external surface of the equipment as well as dismantling and moving it into a transport container. Dismantling and decontamination of the large-sized capacitive equipment was carried out by the Bochvar Institute Decommissioning Department. The following tools were used during the works: (1) a mobile foam decontamination facility to perform decontamination works and (2) a mobile high pressure facility to apply localizing and decontaminating film coatings. The tanks were dismantled by means of low-spark tools, i.e., reciprocating saws. Crane runways were made in order to move the dismantled equipment into transport containers: the movement was carried out with the help of a winch. The main results of dismantling and decontaminating the radioactively contaminated tanks are the dismantling of four units of long-length column-type equipment with heights from 4.2 to 6.4 m and 26 units of capacitive equipment (maximum capacity = 8 m3) as well as decontamination of the internal surfaces of radiation-contaminated equipment (decontamination factor = 25–70). As a result, the activity of the accumulated radioactive waste was reduced (the RW class was changed from 3 to 4). The main conclusion regarding the managment of large-sized radiation-contaminated tanks during Building B decommissioning is as follows: the works were organized and carried out at a high technical level, using modern decontamination and dismantling equipment and modern methods to ensure work safety at the Bochvar Institute site in the city of Moscow.

Analisis Kekuatan Struktur Penopang Overhead Crane Kapasitas 2 x 20 Ton

<em>This research investigated the design of the overhead crane supports with capacity of 2 x 20 ton. The crane design was modeled using both solids and surfaces, and the analysis was performed with finite element method. The results from the analysis verified the stress level, deflection level from crane column and runway beam, and the critical load of buckling for crane column to prevent the structure failure. The stress level result was compared to the material yield strength to find out whether or not the design is safe. It is concluded that the stresses arising from the rail beam and column are still within the permissible limits so that the design is safe to use. </em>

Multi-scale fatigue damage model for steel structures working under high temperature

In order to better understand the fatigue mechanisms of steel structures working under high temperature, a multi-scale fatigue damage model at high temperature is developed. In the developed model, the macroscopic fatigue damage of metallic materials due to the collective behavior of micro-cracks is quantified by using the generalized self-consistent method. The influence of temperature on fatigue damage of steel structures is quantified by using the previous creep damage model. In addition, the fatigue damage at room temperature and creep damage is coupled in the multi-scale fatigue damage model. The validity of the developed multi-scale damage model is verified by comparing the predicted damage evolution curve with the experimental data. It shows that the developed model is effectiveness. Finally, the fatigue analysis on steel crane runway girders (CRGs) of industrial steel melt shop is performed based on the developed model.

Horizontal Forces on Crane Runway Caused by Skewing of the Crane

Horizontal forces between the crane and the crane runway girder occur during a motion of an overhead travelling crane on the crane runway. These forces can be caused by skewing, acceleration or braking of the crane. As a result of these forces wear of wheel rims can occur and drive ability of overhead crane can get worse. There are several procedures for determination of these horizontal loads varying both in physical model and magnitude of forces. Historically, these procedures have been developed. The first methods were based on empirical bases and experiences. The main problem of determining of these forces is a large number of factors which affect a magnitude of these horizontal forces. These factors are in addition difficult to describe, to measure etc. However, with the increasing possibilities of science and technology some methods based on a scientific and experimental basis were developed. This paper summarizes some of the methods used in past and in present and also show possibility to calculate the horizontal forces between crane runway and the overhead crane by dynamic model.

Computational Model for Calculation Horizontal Forces on Crane Runway

During a motion of an overhead bridge crane horizontal forces between wheels of the crane and the crane runway occur. These forces can be caused by skewing, acceleration or braking of the crane. There are several procedures for determination of these forces. These procedures can be found in professional literature and also in present standards for check and designing of crane structures. However, when there is made a comparison of computational models presented in the literature and present standards, it turns out that the computational models are different even if they describe the same physical situation – for example skewing of the crane or the acceleration or braking of the crane. The aim of this paper is to create computational model which would describe real behaviour of the crane during its motion on the crane runway and which would also enable to calculate the horizontal transverse forces between the crane wheels and the crane runway. This model will be created by modifying of the model already created by another author by taking account influences affecting the crane motion on the crane runway.

Failure of the overhead crane runway

The paper reports a failure of the overhead crane runway. Failures of this type often occur in industrial buildings that have been in operation for a long period of time. The reasons are dynamic, fatigue-related phenomena in crane operations, and also design and structural errors. An important issue is also the presence of geometric notches, which promote the formation of fatigue cracks, accelerating the process of degradation of the structure. Visual inspection of the overhead crane runways revealed loosening and failure of rail – beam connections, and also substantial horizontal and vertical displacements of the rails. Additionally, geodetic measurements of rail arrangement were taken. They indicated the exceeding of permissible deviations for rails spacing and vertical arrangement stated in the relevant standards. The runway damages resulted from dynamic character of the loads applied. In some cases, high crane travel speed and acceleration produced impact forces that affected the runway structure. Vertical and horizontal deformation of rails was an additional source of impact in the crane runs. Another contributing factor was inappropriate design of rails and beams fastening, and also insufficient number of rail dilatations. A repair program was proposed which involved the use of additional rail fastenings and dilatations.

Revisiting the bearing stresses in webs of crane runway girders under wheel loads

This article revisited the problem of local bearing stress in webs of I-section girders supporting overhead cranes. Finite element analysis was carried out to determine the equivalent bearing length. It was found that the moment of inertia of the rail and the web thickness of the girder are the two predominant factors. The equivalent bearing lengths by the finite element analysis were found to be significantly smaller than that predicted by the formula in various codes. Analysis revealed that the differences come from the shear deformation in the rail and the load position on the rail. Closed-form solutions for a Timoshenko’s beam on a semi-infinite plane subjected to a concentrated or distributed load were presented in which the Fourier transform is used. After the shear deformation was considered and a widened load distribution length on the centroid axis of the rail, which considered the load dispersion in an angle of 35°–40° from the top of the rail to the centroid axis, are adopted in the Fourier transform solution, the analytical results are in good agreement with finite element analysis. Formulas of equivalent bearing lengths for two types of rails used in China are recommended for practical use.

End stop for overhead cranes stopping

There are accidents through the low reliability of protective systems of overhead cranes in the end of crane runway. The construction of the dead stop for increasing of the protective systems reliability and ensuring of the safety operation of overhead cranes was suggested. The end stop consists of the fixed frame, curvilinear stop, dismountable side plates, rod with rack bar, that coupled with wheel gear and goes through the frame coupled with compression spring, pegged to the back wall of the curvilinear stop. Suggested construction of dead stop must increase a reliability of protective systems of overhead cranes in the end of crane runway. Operation of this device allows reliably and safely to stop hoist cranes during the accidents.

Eksperymentalne wyznaczanie sił poprzecznych wywołanych skrętem suwnicy podczas jazdy

Crane condition depends on the large number of variables randomly changing in time. Due to the large number of parameters, skewing forces have stochastic character. Though in standards treated as occasional loads, their dynamic action in certain cases can cause fatigue damage of the crane travelling mechanisms, structure and runway components. Current European Norms have left the question of skewing forces influence upon the fatigue damage occurrence unresolved. The paper presents an experimental determination of lateral forces acting on the vertical wheels of a bridge crane using two different solutions of transducers for the direct measurement on the wheels of the cranes in operation, without changing the way of lateral guiding. As an illustration, few records of the measured wheel lateral force vs. time are shown. Presentation of such records in the form of a loading spectrum (e.g. using the software nCode), obtained during long-lasting or continuous monitoring of cranes in operation, is the first step in finding the relevant answer to the previously unresolved question

크레인의 이동 및 권상 시 주행거더 충격계수 분석

크레인의 이동 및 권상 시 주행거더 충격계수 분석

Local stresses in webs of crane runway girders: Tests and numerical calculations

The design of crane runway girders is strongly affected by the local stresses due to wheel loads (mainly fatigue design, but also web buckling). A realistic approach of these local stresses, particularly the vertical direct stresses σz at the web top, is very important for economic design.In this paper firstly a summary of formulae in literature and in relevant international design standards is given. These formulae are based on very limited tests in the past, which are also mentioned.In the main part of this paper new test results for local stresses in webs due to vertical wheel loads for crane runway girders with I-section and box section are given, also including different connections with the crane rails (with/without welds between rail and girder flange and cases with no rail). Centric loading was tested, but also eccentric loading with different eccentricities, leading to additional web bending out of plane.For all tests, accompanying comprehensive Finite Element analyses were conducted. These FE-models are also presented and their results are compared with the test results and with the predictions of design formulae, used in practice. Finally, additional numerical investigations are presented, dealing with the effects of different contact properties between rail and girder flange.