Horizontally Accelerating Free Surface

Consider a pool of water in the bed of your pickup truck. If you accelerate from rest, the water will slosh toward the rear, and you want to know how fast you can accelerate (ax) without spilling the water out of the back of the truck (see Fig. 4-4). That is, you must determine the slope (tan ) of the water surface as a function of the rate of acceleration (ax). Now at any point within the liquid there is a vertical pressure gradient due to gravity [Eq. (4-5)] and a horizontal pressure gradient due to the acceleration ax [Eq. (4-23)]. Thus at any location within the liquid the total differential pressure 

Since the surface of the water is open to the atmosphere, where P = constant (1 atm), 

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Example 2.19. A rectangular tank of orange juice on ja cart is moving in the x direction with a steady acceleration of 1 ft/s. See Fig. 2.21. What angle does its free surface make with the horizontal j... 

The seismic hazard at the location has been defined for return periods of 100,475 and 1,000 years with PGA values of 0.07g, 0.16g and 0.22g, respectively. The local soil was categorised as type B, based on the data available from geological and geotechnical investigations. A set of six horizontal histories of acceleration, meeting the ECS criteria, has been generated for the location. In accordance with the JUS standards, the numerical values of the seismicity factor Kc have been computed for the three return periods at the free surface of the terrain as 0.028,... 

The horizontal acceleration recorded at several locations is amplified towards the surface. The amplification ratio with respect to the base amplitude reduces with increased input motion amplitude due to the soil non-linear behavior. Moreover, the horizontal acceleration recorded at the roof slab of the tmmel is lower with respect to the acceleration at the same burial depth in free field. This difference increases with the increase of the input motion amplitude. 

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