Dissertation (PhD)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (MScIng)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (PhD (Civil Engineering))--University of Stellenbosch, 2007. / The current codes of practice for the design of structures which were studied during this investigation do not explicitly account for the flexibilities and interactions of the Electric Overhead Travelling Crane (EOHTC) and the crane support structure. This leads to analysing the EOHTC and the gantry structure as a decoupled system for ease of computation. Thus, the interaction of the various components of the EOHTC and gantry structure is ignored, which may result in an incorrect assessment of the forces computed in the gantry structure’s members. This led to a study to determine the effects of a EOHTC on the gantry structure. The research was conducted through a series of limited experimental tests and extensive advanced Finite Element Analysis (FEA) simulations. This resulted in developing a computationally efficient FEA model of the full scale experimental EOHTC testing facility in the structural engineering laboratory at Stellenbosch University. The FEA model was developed to conduct simulations for the various load models, namely, vertical wheel load, horizontal longitudinal load and the horizontal lateral load models, as prescribed by the various codes. The research was then focussed at determining the maximum end buffer impact force responses when the crane runs into the end stops. The other load models were investigated by another researcher using the same FEA model. The results from the experimental tests were used to calibrate the FEA simulations. This proved exceptionally challenging due to the various structural response phenomena which occur during the impact of the crane against the end stops. A good correlation between the experimental values and the values predicted by the FEA simulations was achieved for the first impact. Modal analysis and modal superposition methods of analysis were used to determine the effect of the modes of vibration on the structural response to the end buffer impact. A FEA sensitivity analysis was conducted on a set of identified parameters which have a significant effect on the structural response to the end buffer impact. The maximum end buffer impact force was determined for a chosen level of reliability based on the responses from the sensitivity analysis using the Lagrange Multiplier method. These maximum end buffer impact forces are then compared with the forces prescribed by the codes. SABS 0160 slightly underestimates, while SANS 10160 severely overestimates the end buffer impact force obtained from the constraint optimization technique for a target level of reliability of β =3.

Thesis (MEng (Civil Engineering))--University of Stellenbosch, 2007. / The failure rate of electric overhead travelling crane supporting structures across the world is unacceptably high. Failures occur even when the supporting structures are designed within the relevant design codes. This demonstrates a lack of understanding of the dynamic behaviour of cranes in many design codes. The current South African loading code is simplistic with respect to crane supporting structure design, relying on empirical factors to determine the correct loads. While these factors lead to predicted forces in the correct range of values, the Eurocode’s methods are more scientifically based. In recognition of this the draft South African code predominantly incorporates the methods used by the Eurocode to calculate design forces for crane supporting structures. The purpose of this thesis was to use an existing numerical model to determine the wheel loads induced by a crane into the crane supporting structure through hoisting, normal longitudinal travel, skewing and rail misalignment. The numerically obtained forces were then compared with the design forces estimated in the current South African code and the Eurocode, in order to determine whether the factors and methods used in the codes are accurate. The current empirically based South African code was found to be highly conservative. In contrast the scientifically based design forces from the Eurocode were close to the numerically calculated forces, only failing to predict the behaviour of the crane in the case of skewing. Further work needs to be completed in the estimation of forces induced during this load case. Once this is achieved it is hoped that the better understanding of the crane forces adapted from the Eurocode into the draft South African code will lead to a reduction in failures of electric overhead travelling crane supporting structures.

Thesis (M.S.)--Mississippi State University. Department of Industrial and Systems Engineering. / Title from title screen. Includes bibliographical references.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Electric driven overhead travelling bridge cranes (EOHTC) form a vital part of industrial plants where heavy objects require moving. Overhead travelling cranes aid in production by allowing an uninterrupted work process on the ground while heavy loads are moved to their required locations. Various factors need consideration in determining the loads induced by an EOHTC on its support structure. In order to design such a support structure, the designer must understand and take into account the various loads that the support structure will be subject to during its lifetime. The procedure for determining the loads induced by the EOHTC on its support structure is laid out in the SANS 10160-6:2010 code of practice. This document was published in June 2010 and as a result very few worked examples exist to test the coherence of the procedure. This thesis presents an investigation into the procedure for determining the actions induced by overhead travelling bridge cranes adopted in the SANS 10160-6:2010 code of practice. The investigation was conducted by developing a software application to automatically determine the necessary crane actions needed for the design of the crane support structure, given certain input parameters. The motivation behind this was to have a tool that can calculate the crane induced loads automatically. And by developing such a tool the procedure given in the code of practice is better understood. The Java programming language was used to code the calculations with an object oriented programming approach (OOP). NetBeans, the integrated development environment for developing with Java was used to generate the required graphical user interface of the application. In addition, a Microsoft Excel calculation sheet was also developed for the purpose of comparison and verification. Whilst developing the software application, it was found that the model for the acceleration or deceleration of the crane was specific for four wheel cranes only. This model was then extended to accommodate eight and sixteen wheel cranes and incorporated into the algorithm architecture of the application. The application was successfully completed and verified using benchmarked examples. / AFRIKAANSE OPSOMMING: Elektriese oorhoofse brugkrane vorm ‘n belangrike deel van baie nywerheidsprosesse, waar dit gebruik word om swaar laste in die nywerheidsaanleg te verskuif. Oorhoofse brugkrane voeg waarde by die produksie lyn deur te sorg dat die werksproses op die grond onversteurd voortgaan terwyl swaar laste na hul vereiste posisies verskuif word. Verskillende faktore moet in ag geneem word om die nodige kraanlaste te bepaal. Hierdie laste word benodig om die kraan se ondersteuningstruktuur te ontwerp. Die ontwerper moet die nodige kundigheid hê en moet ook die verskeie laste in ag neem wat die ondersteuningstruktuur gedurende sy leeftyd sal dra. SANS 10160-6:2010 verskaf riglyne vir die bepaling van die laste wat deur oorhoofse brugkrane uitgeoefen word. Hierdie dokument is in Junie 2010 gepubliseer dus bestaan daar min uitgewerkte voorbeelde om die korrektheid van die riglyne te toets en toepassing te demonstreer. Hierdie proefskrif ondersoek die riglyne vir die bepaling van oorhoofse brugkraan aksies soos uiteengesit in die SANS 10160-6:2010. Die navorsing is uitgevoer deur middel van die ontwikkeling van ‘n sagteware toepassing wat die nodige oorhoofse brugkraanlaste automaties bepaal, gegee sekere invoer waardes. Die rede hiervoor was om ‘n hulpmiddel te ontwikkel vir die outomatiese bepaling van oorhoofse brugkraan. Deur die bogenoemde hulpmiddel te ontwikkel word die riglyne, soos gegee in die kode beter verstaan. Java is gebruik as programmeringstaal waar die objek geörienteerde programeringstyl toegepas was. Die geintegreerde ontwikkelingsomgewing vir ontwikkeling met Java, naamlik NetBeans is gebruik om die nodige gebruikers koppelvlak op te bou. ‘n Microsoft Excel sigblad is ook ontwikkel vir kontrolerings doeleindes. Gedurende die ontwikkeling van die sagtewarepakket is dit bevind dat die lasmodel vir die versnelling of vertraging van die oorhoofse brugkraan slegs op vierwiel krane van toepasing is. Hierdie lasmodel is dus uitgebrei om agt- en sestienwiel krane ook te bevat. Die lasmodel aanpassing is dan ook in die program se algoritme-argitektuur ingebou. Die sagteware toepassing is suksesvol ontwikkel en gekontroleer met ‘n maatstaf voorbeeld.