Search

Stiffened slabs-on-grade are one of the most efficient and inexpensive foundation solutions for lightweight structures on shrinkswell soils. The Ellison Office Building (EOB) is a 1-story steel-framed building founded on a clay formation of high shrink-swell potential. The foundation system of the EOB is composed of a rectangular stiffened slab-on-grade with approximate dimensions of 18.3 by 38.1 m. The slab thickness is 0.1 m, and the depth of all stiffening beams is 1.05 m. Beam spacing distances, center to center, are 3.05 and 3.81 m in the short and long directions, respectively. Exploration of subsurface soil conditions at the EOB site took place to determine soil index properties as well as unsaturated moisture diffusion and volume change characteristics for unsaturated soils. Monitoring the movements of both the slab-on-grade and the 4.5 m soil underneath continued for 2 years after foundation construction, since September 2004. Investigating the EOB foundation performance in light of the soil-structure interaction characteristics of the foundation showed two main distinct slab movement patterns: continuous global heave and localized fluctuating slab edge heave and drop movements. [ABSTRACT FROM AUTHOR]

The San Jacinto Monument was built in 1936 to commemorate the 100-year anniversary of the victory of the Texan army over the Mexican army. The victory at the battle of San Jacinto followed the defeat at the battle of the Alamo and secured the independence of Texas, as well as several other states along the Mexican border. The monument consists of a 176.5-m-high column resting on a large square mat with each side=37.8 m. The mat foundation was designed by Raymond Dawson who chose an average pressure of 223.8 kPa under the mat. Dawson had settlement points placed on the mat foundation together with benchmarks away from the monument. The settlement of the monument has been recorded over the last 70 years and shows a total settlement to date of 0.329 m. The settlement appears to be almost complete. This remarkable case history is used to evaluate current practice of calculating consolidation settlement and a best approach is suggested for such structures. Other issues addressed include the depth of influence, the time rate of settlement, the elastic-modulus approach, and the ultimate bearing capacity. [ABSTRACT FROM AUTHOR]

Channel centreline migration rates were derived from a set of large-scale laboratory experiments. The channel radius of curvature, bend angle, and discharge were varied to evaluate correlations between the channel centreline migration rate and the controlling geometry and hydraulic conditions. An excessive Froude number was adopted to account for soil resistance strength. The intersection of the channel centreline between two consecutive time steps was identified. A phase lag of angle to channel curvature exists in both channel plan form and the onset of cross-section scour. The migration rate between two successive inflection points of migration exhibits a growth and decay pattern and is modelled using a sine function related to the channel geometry, the flow condition, and the soil property. A three-equation prediction method was developed and applied to a natural river in Texas. [ABSTRACT FROM PUBLISHER]