A BIG thank you to Kirk Ellison, Andrew Yeskoo and Adrian Crowther of ARUP for the excellent field tour on Friday January 31st. We visited the deep excavation of Salesforce Tower where we heard about the project from both ARUP and the contractor, Clark Construction. We discussed, in depth, the innovative barrette foundation elements being used to support the building core. Next, we visited the Park Tower site in the early phases of pile installation. Fresh samples of Franciscan Bedrock were passed around as we discussed the challenges it posed for design. Finally, the we were treated to a lesson in seismic structural design when we toured the under construction, 181 Fremont Tower. We witnessed the mega-column support system in the buildingâs lobby before going to the 10th floor for a discussion on the structural damping system and some excellent views of the under construction Transbay Transit Center. Here are few photos highlighting the tour.