During design for the proposed Academic Building and Parking Deck, the A/E hired a geotechnical firm to test the site subsurface to evaluate site conditions and determine what type of foundations the buildings should have. During this study, extremely dense subsurface conditions were encountered at various locations and depths below the existing surface within both building footprints. As a result of the extremely dense conditions encountered, an allowance for rock excavation was provided for in the contract documents. Rock is generally defined as any material that is not able to be excavated using normal excavation methods and equipment.
No rock was encounterd within the building footprint for the Academic Building. However, during site excavation for the Parking Deck, this dense material (rock) was encountered closer to the surface and over a larger area than originally anticipated. As the result of this, several alternates were studied to evaluate the best method with the best cost value to address the problem. Originally, the cost to remove all of the rock to obtain the proper building grades would have cost a very large amount of money. After much evaluation, it was determined that the best value solution was to raise the Parking Deck 10ft. and re-grade the utilities and approaches to the deck. This would require substantially less blasting of rock than was originally calculated.
Blasting began on Thursday, December 4, and will continue until completed, approximately 10 days. Blasting has very specific regulatory controls, which include licensed blasters, general and specific notifications, monitoring and observation. The blaster will drill into the rock to a specific depth and will only drill an area each day that he can detonated that same day. The drill holes cannot be left open overnight and all charges that are set must be discharged the day they are set. Blasting cannot be performed during inclement weather. Once the charges are set, the blaster sets a blast mat over the charge site to eliminate flying debris and minimize disturbance to surrounding areas. Clearing of the blast area and a horn notification immediately prior to detonation are performed. An all clear notification is given after successful detonation of all placed charges. Full detonation does not always happen, though it is rare.
Upon completion of the blasting, grading of the Parking Deck and approaches to the deck will be completed. Soon after, foundations will begin and pre-cast concrete panels will begin arriving on site, and erection of those panels will commence.