Civil Engineer in South Africa - Volume 26, Issue 4, 1984
Volume 26, Issue 4, 1984
Source: Civil Engineer in South Africa 26, pp 141 –153 (1984)More Less
This serves as an introduction to the accompanying papers on the Tsitsikama bridges. A brief history is given of the evolution of bridges, with special reference to arches. Modern understanding of the design process and design criteria for bridges are discussed in the list of developments in the philosophy of structural engineering. The Gouritz river bridge which, together with the Storms river and Van Staden's gorge bridges, was a forerunner of the above bridges, is described in outline and the influence of 'secondary' effects on the results of the analysis is explained.
Hierdie dien as inleiding tot die referate oor die Tsitsikama-brûe. 'n Kort geskiedenis van die ontwikkeling van brûe, met spesifieke verwysing na boogbrûe, word gegee. Die hedendaagse begrip van die ontwerpproses en ontwerpskriteria word bespreek in die lig van ontwikkelings in die filosofie van struktuuringenieurswese. Die Gouritzrivierbrug, wat tesame met die Stormsrivier- en Van Stadens-kloofbrûe, 'n voorloper was van bogenoemde brûe , word in breë trekke beskryf en die invloed van 'sekondêre' effekte op die ontleding word beskryf.
Author J.J. SmitSource: Civil Engineer in South Africa 26, pp 155 –157 (1984)More Less
This paper gives a resumé of the National Commission's involvement in the planning, design and construction of a section of national road N2 in the Tsitsikamma. More specifically attention is devoted to the alternative routes investigated and in particular the topographical, geological and ecological problems encountered in crossing the Bobbejaans River, Groot River and Bloukrans River flowing in very deep gorges. Design criteria is given and the tender procedure adopted is discussed. A description of the philosophy followed by the Department of Transport to ensure sound site relations is given together with a summary of the final costs and some comparative cost factors.
Source: Civil Engineer in South Africa 26, pp 159 –172 (1984)More Less
The Bloukrans Bridge is the largest of three major arch bridges recently constructed on the Garden Route in the Southern Cape. This paper briefly describes the procedures followed in the development of the final structural configuration, the main design considerations, investigations, surveys, the geological evaluation of the site and foundation conditions. Details of the bridge are described and the application and analysis of the main actions and effects for which it was designed are discussed. These include stage-by-stage analysis of the long term effects, non linear analyses under abnormal traffic loading, the application of equivalent static wind loading and dynamic analysis of earthquake action.
Die Bloukransbrug is die grootste van drie vername boogbrüe wat onlangs op die Tuinroete in Suid-Kaapland gebou is. Hierdie referaat beskryf kortliks die prosedures wat gevolg is in die ontwikkeling van die finale strukturele vorm, die hoof ontwerp oorwegings, ondersoeke, opmetings, die geologiese evaluasie van die terrein en fondasietoestande. Besonderhede van die brug word beskryf en die toepassing en ontleding van die hoof belastingsgevalle waarvoor die brug ontwerp is, word bespreek. Dit sluit in die stadiumsgewys ontleding van die langtermyn effekte, die nie-liniêre ontleding van abnormale verkeembelastings, die toepassing van die ekwivalent-statiese windbelasting en dinamiese ontleding van aardbewingsaksie.
Source: Civil Engineer in South Africa 26, pp 175 –182 (1984)More Less
The paper describes the Groot River Bridge and the site in which it is situated. A brief history of the development of the design of the bridge is given, together with some aspects of the final design. Construction problems peculiar to the site are discussed and construction methods used only on the Groot River Bridge, such as the casting of columns to full height in one continuous operation, are described. The methods used to control the arch profile during its construction and also the procedure for closing the arch are given. Mention is made of precautions taken against alkali-aggregate reaction and a break-down of costs is shown.
Hierdie referaat beskryf die Grootrivier-brug en die terrein waarop dit geleë is. 'n Kort geskiedenis van die ontwerpontwikkeling van die brug tesame met 'n paar aspekte van die finale ontwerp word bespreek. Konstruksieprobleme wat enig was tot dié terrein, word bespreek, asook konstruksiemetodes wat net by hierdie brug gebruik is, soos bv die giet van kolomme tot hul volle lengtes in een ononderbroke proses. Die metodes wat gebruik is om die boogprofiel gedurende konstruksie te behou en ook die prosedure om die boog te voltooi word beskryf. Melding word gemaak van die voorsorgmaatreëls wat teen alkali-aggregaatreaksie geneem is, en 'n opsomming van kostes word ook verskaf.
Source: Civil Engineer in South Africa 26, pp 183 –188 (1984)More Less
A description is given of the steps taken during the development of the design of a large arch bridge, of its analysis and of the structure as it was presented to tenderers and subsequently built.
'n Beskrywing word gegee van stappe gedoen gedurende die ontwikkeling van die ontwerp van 'n groot boogbrug, van die ontleding daarvan, asook van die struktuur soos dit voorgelê was aan tenderaars, en uiteindelik gebou is.
Source: Civil Engineer in South Africa 26, pp 189 –204 (1984)More Less
Whereas the construction of large concrete arches had become uneconomical in comparison with structures such as cable-stayed girder bridges, the successful application of sophisticated construction techniques such as the suspended cantilever and related methods has since the late 1960's led to the design and construction of various large span concrete arch bridge. Due to the nature of the interaction between the permanent structure and temporary erection and bracing structures these techniques require a greater degree of expertise than the conventional forms of construction such as formwork supported by centering from the ground. The associated savings in the cost of temporary works and labour are such that for sites with suitable founding conditions the large span concrete arch has again become competitive with other structural configurations in bridge construction.
Source: Civil Engineer in South Africa 26, pp 205 –215 (1984)More Less
The simultaneous construction of 3 large concrete arch bridges, of which the one over the Bloukrans Gorge ranks as the 4th largest of its kind in the world, required the development of some sophisticated construction techniques and equipment; the mobilization and commissioning of no less than 5 cable cranes; and the appointment of sufficient and competent construction personnel, capable of achieving the relatively tight programme safely, profitably and to a high standard of quality and workmanship. The completion of all three bridges ahead of their tendered schedules and the subsequent accolades bestowed upon the Bloukrans Bridge in particular are evidence not only of the success of the construction process, but also of the unique relationships which developed between contractor and consultants and which had such marked effects on the end result.