Civil Engineer in South Africa - Volume 21, Issue 12, 1979
Volume 21, Issue 12, 1979
Source: Civil Engineer in South Africa 21, pp 287 –294 (1979)More Less
The paper describes the design and construction of the 300 m high multi-flue chimney at Duvha Power Station in the Eastern Transvaal. This is the first of a number of chimneys of comparable height to be constructed at Escom's new powerstations to meet strict pollution control requirements. The paper deals with the reasons for the choice of a multi-flue configuration and covers those aspects of the design and construction in which special problems had to be overcome. Special attention is paid to the choice of suitable lining materials to meet the corrosive environment inside the flues and the design approach to resist wind loads and particularly the aerodynamic interaction between structure and wind. Proposals to instrument the chimney to obtain data about flue gas composition and corrosion and new information about dynamic wind pressures and response are described.
Author J.M. RolfeSource: Civil Engineer in South Africa 21, pp 295 –302 (1979)More Less
Design of slabs and shallow beams frequently reduces to ensuring simultaneous compliance with the strength and deflection limit states or, in effect, assessing correctly the modification factor that will emerge from Table 10 of CP110 after determination of the proportion of reinforcement. This Table is awkward to use, particularly if the service stress differs from the tabulated values, since it involves non-linear interpolation between values of two variables which are mutually dependent. The result of an incorrect first assumption gives insufficient guidance for the next approximation, which can result in an unstable convergence to the limiting design. The equations involved are transcendental, preventing the use of direct solutions.
Five charts are presented which simplify the use of Table 10, permit an accurate prediction of the limiting factor from this Table for any given loading and enable accurate prediction of any subsequent modification of effective depth or service stress that may be necessary. The use of charts is illustrated by examples which include cases not explicitly covered by the Code.
Source: Civil Engineer in South Africa 21 (1979)More Less
A combined research report and manual entitled The development of the concept of the runhydrograph in the analysis of flood hydrographs, carried out by the Department of Civil Engineering of the Natal University, under contract of the Water Research Commission, has now become available.
Proceedings from the March 25 to 30 IAWPR Water Reuse Symposium in Washington DC are available.