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As part of the search for safe and economic design criterion to line slabs of stilling basins, the present study is one of the first to calculate the center of pressure, uplift forces, and momenta from a spatiotemporal analysis of the pressures measured above and below instrumented slabs in a physical model. Controlled release of the waterstops, and variation in the dimensions of expansion joints and in the gap between foundation and the lining slab were carried out in order to consider their effects on the magnitudes of uplift forces and momenta. An offset of the center of pressure from the slab’s center of gravity was identified. The objective of this work was to consider the failure mechanism induced by momentum in the slab’s design. Design criterion to make the lining slab’s thickness to length between 6 and 12 times the incident flow depth, is proposed, and this is compared to other design criteria.

As part of the search for safe and economic design criterion to line slabs of stilling basins, the present study is one of the first to calculate the center of pressure, uplift forces, and momenta from a spatiotemporal analysis of the pressures measured above and below instrumented slabs in a physical model. Controlled release of the waterstops, and variation in the dimensions of expansion joints and in the gap between foundation and the lining slab were carried out in order to consider their effects on the magnitudes of uplift forces and momenta. An offset of the center of pressure from the slab's center of gravity was identified. The objective of this work was to consider the failure mechanism induced by momentum in the slab's design. Design criterion to make the lining slab's thickness to length between 6 and 12 times the incident flow depth, is proposed, and this is compared to other design criteria. [ABSTRACT FROM AUTHOR]

Analyses of measured pressures using multiple sensors above and below a slab subject to supercritical flow and hydraulic jump are presented. Pressures were measured in a physical model constructed in the Hydraulic Laboratory of the Universidad del Valle in Cali, Colombia. Details such as expansion joints, waterstops, slab thickness, and soil-slab separation were simulated. Inflow was full and partially developed, with Froude numbers ranging from 2.84 to 11.6. The role of the expansion joints and waterstops in the generation of uplift pressure and hydraulic gradient below the slab were identified using pressure fields above and below the slab, in multiple tests. The results of this research are critical for the design of bottom slabs in hydraulic structures, which are required to withstand uplift forces and prevent internal erosion problems. [ABSTRACT FROM AUTHOR]