Cooper B-Line Seismic Restraints - Dixie Construction Products

Example One, Deeply Embedded Anchors:
Cable tray system is suspended on the 1st floor of a 40-foot tall, 2-story surgical center in California.
The cable tray is actually suspended from the bottom of the 2nd floor, which has an elevation of 20
feet above grade. Location of the surgical center is in seismic zone 4 with a rock soil profile.
F p = a pC a I p
(1 + 3 • hx )W p
R p
h r
a p = 1.0 from Table 16-O
C a = .40Na from Table 16A-Q, which is combination of Seismic Zone factor and Soil
profile type
Where,
Z = .40 for seismic zone 4 applications (Table 16-I)
Soil Profile Type = S B for rock sediment (Table 16-J)
Seismic Source Type = B for faults other than Type A & C (Table 16-U)
Na = 1.0, for 5 km from known seismic source (Table 16-S)
I p
= (1.5) for an essential surgery and emergency treatment area (Table 16-K)
R p = (3.0) for cable trays supported with deep embedded anchors (Table 16-O)
h x = 20 feet, for the elevation of the floor used to support the cable tray
h r
= 40 feet, for the elevation of the structure roof
Check if value falls within limits:
F p = (1.0)((0.40(1.0))(1.5) (1 + 3 • 20 )W p = 0.50W p = 0.50g
3.0 40
F p shall not be taken less than, 0.7C a I p W p = 0.7(.40)(1.5)W p = .42g
F p shall not be greater than, 4.0C a I p W p = 4.0(.40)(1.5)W p = 2.4g
2.4g > .5 > 0.42g Therefore allowing the use of 0.50g
To convert this F p from a strength design, as just determined from the building code, to an
Allowable Stress Design (ASD) used in the Cooper B-Line Seismic Restraints Manual divide by 1.4.
F p = 0.50g = 0.36g (ASD)
1.4
0.36g is the Allowable Stress Design Seismic Load Factor determined from 1997 Uniform
Building Code.
Special Note: Installations using concrete anchors installed with an embedment length-to-diameter
ratio of less than 8, also referred as shallow embedment anchors, have an adjusted Component
Response Factor being R p = 1.5.
COOPER B-Line
509 West Monroe Street
Highland, Illinois 62249
Phone: 800-851-7415
Fax: 618-654-1917
Date:
Page No.
Sheet Number:
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153
of
Raafat S. Aboulhosn
Structural Engineer S 3913