A theory is presented for determining the ultimate load capacity of steel I-beams containing two or more closely-spaced web openings. The proposed method may be used to predict the load at which a plastic mechanism forms and also the load at which actual physical collapse occurs.
Vehicle speeds at six sites on Transvaal rural roads between 1973 and 1987 are descriptionbed. The mean speed of light vehicles at the end of the period is 5 km/h higher than it was at the beginning of 1973; heavy vehicles were travelling 17 km/h faster. Between 1985 and 1988 the mean speed of cars increased by 1,2 km/h per year on freeways and by 4.8 km/h per year on non freeway roads. At the end of 1987 30 per cent of car drivers on freeways and 15 per cent on non-freeway roads were exceeding 120 km/h.