Browsing by Author "Vianney, Ntibaziyaremye"
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- ItemSeismic performance of steel framed water tower structures(Stellenbosch : Stellenbosch University, 2016-12) Vianney, Ntibaziyaremye; Strasheim, J. A. v. B.; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.ENGLISH ABSTRACT: From the year 1620 until June, 2008, more than 27000 earthquakes of magnitude ranging from 0.2 to 6.3 have been recorded by the South African National Seismological Database (SANSD). The most affected regions are Cape Town, Ceres, Koffiefontein, Lesotho and the Witwatersrand Basin. The historical record showed that the earthquake with the longest time duration was felt in South Africa on 4 December 1809. It caused small damages to buildings in Cape Town and caused liquefaction and cracks in the soil in the region of Blauwberg. However, the 29 September 1969 earthquake was the strongest and the most damaging in South African earthquake history. It was felt across Western Cape as far as Ceres, Tulbagh and Wolseley. It was of magnitude 6.3 on the Richter scale. Many building structures were seriously damaged, a few people were killed and others were injured. Old and poorly constructed buildings were completely destroyed. The total cost of the damaged infrastructure was estimated at U.S. $24million. Given this history, South African is classified as being at risk of moderate intensity earthquakes. The first version of seismic design code was released in 1980. It was updated in 1989 and 2010, but the updated code does not include all factors influencing the seismic response of the structures (e.g. soil foundation interaction). In addition, structures like dams, water towers, bridges, silos, pipelines, masts and chimneys were not covered. The new code limited its consideration to building structures. The concern is to know whether old structures or newer structures which are not covered by the new seismic designed code will be susceptible to damage by the seismic intensity assigned to the region of their location. Therefore, a methodology for seismic performance assessment of steel framed structures was presented from various publications and was applied to a typical water tower located in a high risk seismic zone of South Africa. The Winelands Engen 1-Stop water tower met the above criteria and was checked for its susceptibility to a seismic event. The results showed that the Engen 1-Stop water tower is vulnerable to the seismic risk attributed to its location. The seismic demand on the tower far exceeds its seismic capacity, which causes concern over whether the Engen 1-Stop water tower was designed to meet any seismic hazard.