The Van Nuys Holiday Inn is a 7-story concrete frame building built in 1966 with consistent plan dimensions of approximately 63 feet by 151 feet. The building is mostly symmetrical in plan and has three bays in the transverse direction and eight bays in t...

Prepared By: Quinn Peck
Occupancy: Hotel
Year Built: 1966
Height: 65 ft
Number of stories: 7
Stories below ground: 0
Size: 93000 gsf
Original Code: 1964 Los Angeles City Code
Modification: Retrofit
Year Modified: 1971
Code of Modification:
Lateral Load System: MomentFrame
Other Load System:
Vertical Load System: Slabl_Beams_Columns
Other Vertical Load System:
Foundation : Piles or Piers
Other Foundation :
Country: United States
State: California
City: Van Nuys
Street: 8244 Orion Avenue
Latitude: 34.2201
Longitude: -118.471


 

Holiday Inn

Earthquake Information

 

 

Earthquake Date 1/17/1994
Moment Magnitude 6.7
Epicentral Distance 7
Local Intensity VIII MMI
Site Description "Geologic source data indicate that the site lies on recent alluvium. The underlaying soil was identified to be primarily fine sandy silts and silty fine sands. This suggests a site factor coefficient of S2 or greater." (SSC, 1994)
PGA Lateral None (g)
PGA Vertical None (g)
SaT
Ground motion recording stations CSMIP Station No. 24386
Distance to station 0
Station Latitude 34.2201
Station Longitude -118.471
Ground Motion Summary The earthquake occurred along the Pico thrust fault, a previously undiscovered Northridge blind thrust fault, and produced some of the strongest ground motions ever recorded in North America. The earthquake started at the down-dip, southeastern corner of the Pico fault plane and ruptured up northwest approximately 15 km, with no evidence of slip above 7 km below the earth's surface. The hypocenter is believed to lie at a depth of about 19 km km at a location of 34.213, -118.537. An overall maximum horizontal ground acceleration of 1.93g was recorded at Tarzana, about 11.2 km from the epicenter. The Van Nuys Holiday Inn had a total of sixteen ground motion sensors located throughout the building, including 10 measuring north-south motion, 5 measuring east-west motion, and one measuring vertical motion.

 

Damage Information

 

 

Performance summary

The Holiday Inn experienced extensive structural damage during the Northridge earthquake and was "red tagged" and remained unoccupied until renovation and retrofit measures were completed.

Damage state description

Structural damage from the Northridge Earthquake was predominantly restricted to the longitudinal perimeter frames. Damage was most extreme on the south face of the building between the fourth and fifth floors, including severe X-pattern shear failures in the columns and subsequent buckling of the vertical reinforcing. Minor to moderate cracking occured in the beam-columns joints below the fifth floor, with damage most extensive along the south face. Some minor flexural cracking occured in the bottoms of several spandrel beams suggesting possible yielding of the borrom reinforcing steel. The transverse perimeter frames only exhibited minor flexural cracks in the end bays. The nonstructural brick infill in the northeastern corner of the first floor exhibited cracking at the corners of each panel, suggesting they participated in the seismic response of the structure.

Summary of causes of damage

1. The presence of brick infill solely on the north face of the building in the eastermost bays introduced assymetry in the longitudinal direction of the building, likely resulting in a torsional eccentricity. The concentration of damage in the spandrel beam-column framing on the south face of the structure would appear to corroborate this hypothesis. 2. The concentration of damage between the fourth and fifth floors suggest that building's second mode of vibration played a signficant role during the earthquake. The recorded story shears appear to confirm this, as the shear demand between the fourth and fifth floor is nearly the maximum experienced by the structure. This fact, along with the lower shear capacity at this story largely explains the damage at this location. 3. The larger displacement demand caused by a combination of the unexpectedly large shear forces and the plan asymmetry resulted in significant forces along south face between the fourth and fifth floors, resulting in significant shear failures in five of the nine columns. Widely spaced or entirely absent transverse reinforcing in the beam-column joints contributed to the extensive failure along this face of the building.

Observed Design and Construction Characteristics

 

Construction Quality

MaterialsNotesContribution to Damage
Concrete
Reinforcing steel

ExecutionNotesContribution to Damage
Conveyance/placement of concrete
Rebar
Field variance with design documents
OtherNotesContribution to Damage
Other Factors Construction Quality

Configuration

Plan IrregularitiesNotesContribution to Damage
Torsion
Perimeter boundary
Diaphragm
Out-of-plane offsets in lateral resisting system
Non-orthogonal systems

Vertical IrregularitiesNotesContribution to Damage
Soft story
Weak story
Geometric variablility of lateral resisting system
In-plane discontinuity of lateral resisting system
Mass distribution
Setback
Change in stiffness

OtherNotesContribution to Damage
Other Factors Configuration

Lateral Load Resisting System‐General

StrengthNotesContribution to Damage
Overall lack of strength Strength in the upper stories was insufficient for the applied forces, but only because the second mode of vibration was significant.

StiffnessNotesContribution to Damage
Extreme Flexibility

Load PathNotesContribution to Damage
Collectors/Struts
Anchorage of nonstructural elements
Out-of-plane capacity of walls
Diaphragm chords
Diaphragm openings

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-General

Lateral Load Resisting System‐Frames

ColumnsNotesContribution to Damage
Shear strength
Flexural strength
Axial load ratio
Vertical load columns drift capacity
Interference of frame action by infill

BeamsNotesContribution to Damage
Strength relative to columns
Shear controlled behavior
Continuity of longitudinal reinforcing
Loss of vertical capacity
Interference of frame action by infill beams

JointsNotesContribution to Damage
Interior
Exterior
Corner

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-Frames

Lateral Load Resisting System‐Shear Walls

ShearNotesContribution to Damage
Diagonal tension/compression
Sliding Shear
Flexure/shear

FlexureNotesContribution to Damage
Compression zone buckling capacity
Discontinuity of wall
Boundary reinforcing fracture/buckling
Boundary Reinforcing at openings

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-Shear Walls

Lateral Load Resisting System‐Infills

InfillsNotesContribution to Damage
Unreinforced
Interference with frame action
Out of plane
Attachment to framing

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting Systems-Infills

Lateral Load Resisting System‐Other

FoundationsNotesContribution to Damage
Liquefaction
Pounding
Surface Rupture

OtherNotesContribution to Damage
Pile/Pier tension capacity

MiscellaneousNotesContribution to Damage
Spread footing capacity
Other Factors Lateral Load Resisting Systems-Other-Foundations

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting Systems-Other-Misc

Repair and Retrofit Information

 

Type of Retrofit or Repair

Improved Performance

Other Retrofit or Repair

Performance Level

Unknown

Hazard Level

Unknown

Retrofit or Repair Code

Unknown

Other Retrofit or Repair Code

Lateral Analysis

Unknown

Other Lateral Analysis

Design Strategy

New reinforced concrete shear walls were introduced to strength the lateral force-resisting system.

Retrofit Summary

References

 

http://www.seismic.ca.gov/pub.html
Seismic Safety Commission (SSC), 1994. Holiday Inn. Northridge Building Case Studies Project. M. Saiful Islam, Englekirk & Sabol Consulting Engineers for the California Seismic Safety Commission. Second Draft, September 26.


http://db.concretecoalition.org/static/data/6-references/USA001_Reference_2.pdf
Earthquake Engineering Field Investigation Team (EEFIT), 1994. The Northridge, California Earthquake of 17 January 1994: A Field Report by EEFIT. EEFIT, Institute of Structural Engineers.


http://nisee.berkeley.edu/elibrary/Image/NR212
Clark, Peter W., 1994. "Van Nuys Holiday Inn." Photo. Courtesy of the National Information Service for Earthquake Engineering, EERC, University of California, Berkeley.http://nisee.berkeley.edu/elibrary/Image/NR212 (9 July 2012).


http://db.concretecoalition.org/static/data/6-references/USA001_Reference_4.pdf
Comartin, Craig, Kenneth Elwood, and Heidi Faison, 2004. "Reinforced Concrete Moment Frame Building without Seismic Details." World Housing Encyclopedia.http://www.world-housing.net/WHEReports/wh100108.pdf ( 9 July 2012).


http://db.concretecoalition.org/static/data/3-additional-ground-motion/USA001_Ground_Motion_1.jpeg
United States Geological Survey (USGS), 2009.CISN ShakeMap for Northridge Earthquake,http://earthquake.usgs.gov/earthquakes/shakemap/sc/shake/Northridge/ (9 July 2012).


http://eqs.eeri.org/resource/1/easpef/v12/iS1/p49_s1
Osteraas, John, and Peter Somers, 1996. Reinforced Concrete Structures.Earthquake Spectra,11, Supplement C, Vol. 2, 5961.


http://eqs.eeri.org/resource/1/easpef/v11/iS2/p13_s1
Huang, M.J., and A. F. Shakal, 1995. Recorded ground and structure motions.Earthquake Spectra,11, Supplement C, Vol. 1,1396.


http://eqs.eeri.org/resource/1/easpef/v14/i2/p265_s1?isAuthorized=no
Jirsa, James O., and Y. Roger Li, 1998. Nonlinear analyses of an instrumented structure damaged in the 1994 Northridge earthquake,Earthquake Spectra,14, 265283.


https://www.atcouncil.org/Rehabilitation-of-Engineered-Buildings/Seismic-Evaluation-and-Retrofit-of-Concrete-Buildings/flypage.tpl.html?keyword=atc-40
Applied Technology Council (ATC), 1996.Seismic Evaluation and Retrofit of Concrete Buildings, Vol. 2,Report No. ATC-40, Redwood City, CA.