The Student Union Building needed to upgrade the existing foundations in order to support the loads from the renovation and new lateral force resisting system. The existing caissons turned out to not be sufficient. They were re-used by using micropiles on either side, constructing a reinforcing cage, and casting a cap that encompased the existing and new foundation elements. This was completed on most of the foundations when we toured.
The site also had a lot of existing utilities to work around. The utility line on the left needed to be supported by a steel beam during construction to span the trench. Other utilities and the trench box used for excavations are also shown. Trench boxes are essential on excavations that have near vertical walls. If unsupported the walls could collapse and cause injury or death to workers.
Other features of the tour were: