Large Scale Load Test and Data Base of Spread Footings on Sand





1.1 GOALS

In most cases shallow foundations are less expensive than deep foundations (Briaud, 1992). The FHWA is therefore making efforts to ensure that spread footings are considered as a viable alternative for all bridges. Part of this effort is in the form of research on spread footings to improve the reliability of the design rules thereby increasing the confidence of engineers across the country in this economical solution,

There are approximately 600,000 bridges in the country. If those bridges had to be replaced today by new bridges it would cost approximately $300 billion. Therefore the average cost of a bridge is $500,000. About 50% of that cost is in the foundation. For such an average bridge the difference in cost between shallow foundations and deep foundations is $90,000 (Briaud, 1993).

Each year 6,000 new bridges are built for a yearly national bridge budget of $3 billion. Approximately 85% of the existing 600,000 bridges in the inventory are over water. This percentage is probably more like 50% when considering the bridges built in the last few years. If one assumes that all 6,000 bridges built yearly are on deep foundations and if one further assumes that all bridges that are not over water can be placed on shallow foundations, the numbers above indicate a yearly saving to taxpayers of 90,000 x 6000 x 0.5 = $270 million. Even if the saving is only a fraction of this number, say 100 million, the potential saving is significant.



Download
*