Development of an updated fundamental basic wind speed map for SANS 10160-3

This paper evaluates the need for updating the strong wind climate stipulations of South Africa for the design of structures in accordance with SANS 10160-3:2010, as based on the latest information presented by Kruger et al (2013a; 2013b). The primary objective is to provide the geographic distribution of the characteristic gust wind speed by means of the fundamental value of the basic wind speed, stipulated as vb,0 in SANS 10160-3. A reassessment of previously published information is made to incorporate additional wind speed modelling results and to investigate identified anomalies. The format of presentation, based on local municipal districts, is subsequently motivated, assessed and implemented. In order to provide for situations requiring the consideration of the dynamic effects of wind loading, similar information on characteristic hourly mean wind speed is provided. It is concluded that the presentation of wind speed on a district basis provides an effective balance between the spatial resolution of the available information and its use in operational standardised design.http://www.journals.co.za/ej/ejour_civileng.htmlam2018Geography, Geoinformatics and Meteorolog

Principles and application of structural design code development in South Africa

Structural design codes reflect the customs in construction, available materials, training and other characteristics of the regions from where they originate. However, owing to globalisation, and a worldwide trend in which structural design codes are being harmonised, the application of international codes locally requires a proper framework and guidelines in order to match the implicit basis of these codes to local conditions and requirements. South Africa is in the process of revising their suite of structural design codes, and has opted to use the Eurocode suite of codes as reference material for this process. Inherent differences between the environment in which Eurocode and such transferred codes will operate makes it imperative that local implementation be based on a fundamental approach of code development. The paper presents a scheme that can serve as guidelines for code development, based on a set of attributes serving as the driving potential for the process, within the context of the technical nature of structural design codes, some meta- technical characteristics and organisational relationships. The application of the scheme is demonstrated by showing examples of how selected Eurocode standards are applied as South African codes

Towards a reliability based development program for SHCC design procedures

Principles of structural reliability are used mainly to provide a rational basis for improving the safety and economy of design practice with an extensive experience base. Execution of a development program for design procedures for innovative materials and applications on the basis of structural reliability ensures that the outcome readily conforms to existing practice. Other advantages are that reliability techniques could be applied to identify important sources of uncertainty on which subsequent testing and modelling investigations could focus. The use of Bayesian updating techniques allows optimal utilisation of existing information. This could compensate for the lack of an established experience base and extensive information. The development of a reliability based design model and procedure can highlight the advantages of the innovation. The objective of the paper is to outline the way in which the development of the application of an advanced concrete material such as SHCC should be approached. © 2010 Taylor & Francis Group, London

Reliability basis for adopting Eurocodes as South African standards

The merit of accepting Eurocode as reference for the next generation of South African standards for structural design is generally accepted locally. Due to wide differences in construction, environmental and institutional conditions, such implementation of Eurocode requirements and procedures into South African standards is not a straightforward process. The only rational manner in which standards from elsewhere could be adopted, adapted and calibrated for a specific set of conditions is to base the process on the principles of structural reliability. The paper describes the way in which calibration procedures are used to assess action combinations schemes and associated partial factors, and for structural resistance procedures with special reference to geotechnical design, concrete and water retaining structures. © 2011 Taylor & Francis Group, London

Review of climatic input data for wind load design in accordance with SANS 10160-3

With the publication of Part 3 Wind Actions of the South African Loading Code SANS 10160:2010, several issues concerning adjustments from the reference standard Eurocode EN 1991-1-4:2004 could not be resolved due to lack of sufficient updated background information on South African conditions. The need for updating the map for the free field wind speed is related also to the improved representation of the mixed and complex strong wind climate of the country. Furthermore, strong wind probability models are used for the reliability assessment and calibration of wind design procedures. Updating of the reliability provisions for the revised wind loading process was a further need identified at the time. This paper provides a review of the historical development of the representation of the free field wind, used as input to design wind loading procedures for South Africa. The review considers: (i) the historical representations of the geographic distribution of free field wind, (ii) the climatic influences considered, and (iii) the probabilistic bases for the stipulated wind speed for the reliability provisions for design wind loads. On this basis, the background and motivation are provided for updating SANS 10160-3:2010.http://www.journals.co.za/ej/ejour_civileng.htmlam2018Geography, Geoinformatics and Meteorolog

Clustering of extreme winds in the mixed climate of South Africa

A substantial part of South Africa is subject to more than one strong wind source. The effect of that on extreme winds is that higher quantiles are usually estimated with a mixed strong wind climate estimation method, compared to the traditional Gumbel approach based on a single population. The differences in the estimated quantiles between the two methods depend on the values of the Gumbel distribution parameters for the different strong wind mechanisms involved. Cluster analysis of the distribution parameters provides a characterization of the effect of the relative differences in their values, and therefore the dominance of the different strong wind mechanisms. For gusts, cold fronts tend to dominate over the coastal and high-lying areas, while other mechanisms, especially thunderstorms, are dominant over the lower-lying areas in the interior. For the hourly mean wind speeds cold fronts are dominant in the south-west, south and east of the country. On the West Coast the ridging of the Atlantic Ocean high-pressure system dominate in the south, while the presence of a deep trough or coastal low pressure system is the main strong wind mechanism in the north. In the central interior cold fronts tend to share their influence almost equally with other synoptic-scale mechanisms

Characterization of model uncertainty in the static pile design formula

10.1061/(ASCE)GT.1943-5606.0000401Journal of Geotechnical and Geoenvironmental Engineering137170-8