**Problem 8.75**A model of a high-rise office building at 1/550 scale is tested in a wind tunnel to estimate the pressures and forces on the full-scale structure. The wind-tunnel air speed is 20 m/s at 20°C and atmospheric pressure, and the full-scale structure is expected to withstand winds of 200 km/h (10°C). If the extreme values of the pressure coefficient are found to be 1.0, -2.7, and -0.8 on the windward wall, side wall, and leeward wall of the model, respectively, what corresponding pressures could be expected to act on the prototype? If the lateral wind force (wind force on building normal to wind direction) was measured as 20 N in the model, what lateral force might be expected in the prototype in the 200 km/h wind?

Introduction- Atmospheric pressure, denoted by P, is the weight of air per unit surface area of the globe . Atmospheric pressure is inversely related to height, with a standard value of 760 mm Hg. Absolute Pressure: When pressure is measured in relation to absolute zero, it is referred to as absolute pressure.The pressure exerted at the surface of a body by a column of air in an atmosphere is known as atmospheric pressure. The pressure fluctuates with altitude as well as weather patterns. The standard is defined as one atmosphere on Earth and represents an average atmospheric pressure at sea level.The relation between pressure and wind speed, Pressure=12×density of air ×wind speed2 ×shape factor The windward wall pressure, Pwind ward=137500 Pa The wind pressure or leeward wall, Pleeward=137500×-8Pleeward=-110000Pa The wind pressure on the side wall, Pside wall=137500×-2.7Pside wall=-371250Pa The force on the wall will be a factor of 550. 550×20=11000 N on wind wall. 550×2.7=1485 N on the side wall. 550×0.8=440 N leeward wall