Information for Strong-Motion Station
Los Angeles - 73-story Office/Resid Bldg
CGS - CSMIP Station 24660
Earthquakes recorded by this station
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 34.0503 N
Longitude 118.2601 W
Elevation (m) 91
Site Geology Shallow alluvium over rock (sedimentary)
Vs30 (m/sec) 500 (measured)
Site Class C
Remarks/Notes Site information sources
No. of Stories above/below ground73/5
Plan ShapeRectangular with irregularities
Base Dimensions408 x 339 ft
Typical Floor Dimensions244 x 112 ft
Design Date2014
Instrumentation2017, 36 accelerometers on 11 levels.
Vertical Load Carrying SystemConcrete beams and slabs inside the core walls. Outside the core walls: lightweight concrete over metal deck supported by steel beams, perimeter steel box columns filled with concrete, and concrete core walls. Concrete flat slabs at the First Floor and below). At the top of the building is a glazed steel braced frame structure (sail) standing 97 feet above the main roof at Level 73. The 295 feet long tubular steel cantilever spire extends above the roof. A low-rise podium is adjacent to the
Lateral Force Resisting SystemConcrete core shear walls (4 feet thick at the base tapering to 2 feet at the top) with outriggers and belt trusses. In transverse direction, the outriggers with buckling restrained braces (BRBs) are placed at three locations along the height of the structure (Levels 28 to 31, Levels 53 to 59, and Levels 70 to 73). Two three-story tall belt trusses are around the perimeter at the lower and pper outrigger levels.
Foundation TypeThe Tower is supported on 18-ft thick concrete mat foundation. The foundation is supported on bedrock.
RemarksStructural design was based on performance-based seismic design and the 2011 City of LA Building Code (2010 CBC). Extensive Instrumentation was required by the City of Los Angeles. Funding for the instrumentation was provided by the owner. CSMIP provided assistance in instrumentation. With the spire, this is the tallest building in California with a height of 1100 feet.