Question

A 4 m high noise barrier is to be installed at the side of a major road, and concern is raised about its stability in high winds. It is supported by concrete posts every 20 m, and the maximum base shear force that each post can withstand is 75 kN. Wind tunnel tests reveal that the maximum pressure coefficient, based on the mean wind velocity at the top of the barrier, on the windward face of the barrier is 1.5, and on the leeward face of the barrier is -0.4. If the barrier is in country terrain with zero displacement height and a roughness length of 0.03 m, and the mode and dispersion of the extreme value distribution of the wind 10 m above ground level are 25 m/s and 0.4 s/m respectively, find the return period of the wind speed that will cause the design load on the posts to be exceeded The Gumbel extreme value formula is given by where P is the probability that a velocity V will be exceeded in any one year, a is the dispersion and u is the mode. The density of air may be taken as 1.2 kg/m

Answer 1

Ame Maa Am liS20xV Sooo N 0.4 e (xhrsh) 0.44 0.9914 .CDF tatim 4414