Lessons Learned: Structural Upgrade of Sutro Tower

December 30, 2005
Publication: Structure Magazine p. 8-10
Author(s): Ronald Hamburger

Sutro Tower, in San Francisco, California is a 770-foot high, freestanding steel broadcast tower supporting three main, 215-foot high antenna structures and numerous ancillary broadcast equipment. It is owned and operated by a consortium of the three major broadcast networks, and provides television, radio, and emergency services communication transmission throughout the San Francisco Bay area. The tower was designed and constructed in the mid-1970s. In 1998, digital television transmission equipment was added. This equipment consisted of a large mast antenna, suspended at the center of the tower, near its top. Addition of the antenna equipment resulted in signifi cant wind load increase, but only relatively minor additional seismic loading. A structural strengthening project was undertaken to reinforce the tower for the additional wind loading.