Key words: earthquake, seismic, Northridge, nonstructural, codes, reconnaissance.

1. Presented by
Vishva R. Patel
(12CLD044)

2. contant
 Introduction
 Location Map
 Commercial facilities and library at
Northridge Mall
 Stores at Northridge Fashion Mall
 Holy Cross Medical Centre
 Sylmar substation
 Rinaldi substation
 Code provisions
 Conclusions

3. Introduction
 Following the magnitude 6.6 Northridge earthquake,
which occurred at 4:31 a.m. on January 17, 1994, groups
of Canadian engineers visited the damaged areas to
assist with damage assessment and for general damage
reconnaissance.
 This paper presents the observations of nonstructural
damage to facilities in the Northridge area caused by
theearthquake.

4. Location Map
 The locations of the facilities discussed in this paper are shown
on a map of the Northridge area in map.
 Location Key
 A - Anheuser-Busch Breweries
 F - Northridge Fashion Mall
 H - Holy Cross Medical Centre
 M- North ridge Mall
(Reseda & Nordhoff)
 N - Northridge Campus
 R - Rinaldi Substation
 S - Sylmar Substation
 V - Veteran’s Administration
Hospital

5. Commercial facilities and library at
Northridge Mall
 The mall is 3 km from the epicenter and experienced a
horizontal ground acceleration of 0.8g and a vertical
acceleration of 0.5g.
 The Northridge branch of the Los Angeles Public
Library is a single storey building with masonry walls
and timber roof.
 The only observed structural damage was local to a
canopy on the east side of the building.
 Ceiling damage was extensive with failure of lighting,
diffusers, and suspended ceiling system. (fig-A)

6. (Fig-A) Ceiling damage and contents of shelves
scattered at Northridge Branch library.

7. Stores at Northridge Fashion Mall
 The mall is 5 km from the epicenter and experienced a
horizontal ground acceleration of approximately 0.6g and a
vertical acceleration of approximately 0.5g.
 The parking structure failures and other structural failures
in this shopping mall have been widely reported.
 However, several single-storey structures survived the
earthquake with little or no structural damage.
 In these buildings nonstructural damage was extensive.
 The damage was predominantly associated with ceiling
systems.
 In some cases damage to shelving and racking was
observed.

8. Holy Cross Medical Centre
 The Holy Cross Medical Centre, located in the Mission
Hills district, is approximately 8 km from the epicenter
and experienced a horizontal ground acceleration of
approximately 1.0g and a vertical ground acceleration
of approximately 0.5g.
 lt is a two-storey reinforced concrete structure with a
large light steel framed mechanical penthouse situated
on its roof.

9. Sylmar substation
 The Sylmar substation is 13 km from the epicenter and
experienced a horizontal ground acceleration of
approximately 0.8g and a vertical ground acceleration
of approximately 0.5g.
 The thyristor valves suspended from the roof of the
valve building sustained only minor damage one of the
suspension insulators between valve groups failed (Fig.
23).

10. (Fig - B)
Sylmar east - thyristor valves
sustained only minor damage during
earthquake.
(Fig - C)
Sylmar east - failed 500 kV surge
arrester

11. Rinaldi substation
 The Rinaldi substation is 8 km from the epicenter and
experienced a horizontal ground acceleration of
approximately 0.85g and a vertical ground acceleration
of approximately 0.5g.
 Failure of the nearby Los Angeles Aqueduct flooded
the control building and locally deposited materials in
the Rinaldi switch yard, but'did not appear to have
significantly affected the operability of the yard.
 Damage to this 500/230 kV substation during the
earthquake was reported as being extensive.

12. Code provisions
 The majority of nonstructural damage occurred to
components that had inadequate restraint provisions.
 It was observed that the majority of components with
restraints designed to current code requirements (i.e.,
0.4g peak horizontal acceleration for UBC zone 4)
performed well, in spite of measured ground
accelerations of twice the design value.
 In the several situations where damage did occur to
components in facilities designed to current code
provisions, the failure can be attributed to poor design
details.

13. Conclusions
 Observations made following the Northridge
earthquake show the significance of nonstructural
damage in buildings and facilities where there is little
or no structural damage.
 The lessons of this earthquake show the high potential
for loss of life, personal injury, and considerable
economic cost due to nonstructural damage.