Experience, and load testing of rock sockets (drilled shafts in rock) tells us that traditional socket design is notoriously conservative. Prof. Schmertmann and Mr. Jack Hayes in their technical paper The Osterberg Cell and Bored Pile Testing - A Symbiosis* state that Our experience shows that generally the stronger the supporting material, the larger the ratio between the measured shaft capacity and the prior engineering estimate of capacity. This ratio often exceeds 10 in rock sockets!
Our experience with Rocket is similar. Use of the Rocket program allows these prior engineering estimates to be much closer to measured performance. It also allows engineers to test the sensitivity of the solution to changes in construction practices, pile diameter and ground conditions strength and mass stiffness which is affected by jointing.
Rocket is a practical design tool, and the Rocket approach has been built into add-on solutions by Foundation QA and Golder Associates to provide a real-time design approach allowing socket lengths to be adjusted during construction based on the logged rock conditions.
The following pages showcase some projects which have utilized Rocket for foundation design.
* Presented at the Third International Geotechnical Engineering Conference, 5 - 8 January, 1997, Cairo, Egypt