San Diego Central Library Dome: Quick Factsheet

psithurismaccountantUrban and Civil

Nov 29, 2013 (3 years and 8 months ago)


San Diego Central Library Dome:
Quick Fact

Source: Brandon E. Talbot, SME Steel Contractors


275 tons: ribs, sails, diagonal braces, compression ring and rails.

2825 shop drawings (includes sub drawings)

3130 part sheets

Ribs and sails:

Each of the eight ribs has a depth that varies depending on its location. The
maximum elevation distance between the highest and lowest rib base is 41’

Each rib is comprised of an upper and lower section. While each upper section is
roughly 72

long, the longest lower sections are 73

feet 6 inches

and the
shortest bottom section is roughly 39

feet 6 inches


Maximum Rib depth: 9



Each rib tapers to a point at the compression ring, a singular HSS [hollow
structure section] pipe

(elevation of 255

feet 6 inches
) in which all ribs will
connect to.

The arcs in the rib are compound and vary depending on the overall shape
requirements of the structure.

Rib Weights
Sequence 7: upper

8.9 tons

9.6 tons; total: 18.5 tons


of the eight sails spans from the top chord of one rib to the lower chord of
another rib. Each rib consists of a pipe grid, upper and lower trusses,
spreaders, cable net and rod and clevis bracing systems. The pipe grid is
created using rolled HSS piece
s vertically and horizontally to match the shape of
the ribs, with the crossing clevis and rod system in each bay. The horizontal
rows of the pipe grid slope down incrementally as the depth of the sail grows.
The upper and lower trusses, along with the ca
ble net spreaders, set the cable
net into place. The cable net consists of 1
foot cables, passed through
the ends of each spreader and attaching to the ribs and upper and lower trusses.
The cable net will be tensioned to evenly distribute the load
throughout each
sail connection.

Sail weights: vary from 12.5 tons (on the northwest corner) to 25.5 tons (on the
south). The south sail has a total of five trusses instead of the typical two


a total of 785 stainless steel rod and clevis braces

for the entire
a total of 1
570 clevis
es. (A clevis is a faster through which a pin or
bolt is inserted.)

152 total spreaders, 608 total stainless steel plates clamping the cable net.

The deepest sails, (
south and southeast
) will be roughly

93 fe
deep, once in

Sail shapes vary at each location (no two sails are the same)

The width of the
south sail at the bottom, along its bottom chord

is 75

feet 6 inches

long, while
only 10

feet 8 inches

at the top of the sail.

The arcs in the sails

are compound and vary depending on each sails geometry and
individual requirements.

The depth of the dome structure once in position, from top of the compression
ring to the bottom of the de
epest ribs bases is roughly 114 feet