Civil Engineer in South Africa - Volume 33, Issue 10, 1991
Volume 33, Issue 10, 1991
Bepaling van die ballasonderstoppingsiklus vir spoorbane met behulp van die meganistiese ontwerpbenadering : technical paperSource: Civil Engineer in South Africa 33, pp 379 –384 (1991)More Less
'n Metode om die ballasonderstoppingsiklus van spoorbane te bereken deur van die meganistiese ontwerpmetode gebruik te maak, word voorgestel. Die onderstoppingsiklus wat so bepaal word, is 'n funksie van die tipe spoorstaaf,die dwarsleerspasiering, die plaveiselmateriale en die verkeer. Die toepaslikheid is evalueer deur die metode op die steenkoollyn tussen Paulpietersburg en Piet Retief te toets.
Die elastiese eienskappe van die plaveiselmateriale is met behulp van multidiepte deflektometerontledings, sikliese drie-assige druk- en indirekte trektoetse bepaal. Die akummulatiewe skade deur die verkeer veroorsaak, is met behulp van Miner se hipotese in 'n onderstoppingsiklus omgeskakel. Hierdie onderstoppingsiklus is baie na aan die waarde vir die teoretiese siklus wat bereken is met behulp van die formule 48/ T waar T die bruto jaarlikse tonnemaat in miljoene tonne is.
Vervolgens is die invloed van verskillende plaveiselstrukture op die onderstoppingsiklus bepaal. Daar is gevind dat stywe en dik ballaslae neig om die siklus te verleng.
The paper proposes a method for calculating the ballast tamping cycle of railway lines using the mechanistic design procedure. The tamping cycle determined in this way is a function of rail type, tie spacing, pavement materials and traffic. The applicability of the method was evaluated on the coal line between Paulpietersburg and Piet Retief.
The elastic parameters of the pavement materials were determined from multi-depth deflectometer analyses and cyclic triaxial and indirect tensile testing. A tamping cycle was calculated by applying Miner's hypothesis to the accumulative damage caused by traffic on the railway line. The tamping cycle thus calculated corresponds well with the theoretical tamping cycle calculated with the formula 48/ T, where T is the annual gross tonnage in million tonnes.
The influence of different pavement structures on the tamping cycle is discussed in conclusion. It was found that stiff and thick ballast layers tend to lengthen the tamping cycle.
Author D M MacKenzieSource: Civil Engineer in South Africa 33, pp 391 –392 (1991)More Less
Continuing education throughout their careers is becoming an increasingly important requirement for civil engineers. However, who will provide this 'education' and what will they provide? This paper describes the author's recent experience at Paisley College of Technology, Scotland, in connection with the development of a college-based training unit called Construction Education-Macdata. One short course in particular is discussed.
The benefits of game playing and learning by doing in the development of construction management techniques are highlighted by the discussion of a game based on a mock negotiation meeting. The game is part of a two-day short course entitled 'Negotiation Skills' and is designed for project managers and senior engineers. Use is made of TV video-taping for playback and analysis of the various negotiating styles.