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| Los Angeles City Hall Seismic Rehabilitation Project - Emergency Tenant Reallocations |
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In the aftermath of the Northridge Earthquake of January 17, 1994, City Hall was found to have suffered damage to its tower sufficient to require immediate evacuation of its top floors, 25 through 27, temporary bracing and a shroud or net suspended around this area to literally prevent debris from the building from falling into public areas below.
A second issue arose on the floors between 5 and 24 (the red area in the drawing at right). This issue involves the nature of the exit routes people in the tour would take to evacuate in the event of another earthquake similar to the Northridge event. Evacuation routes from the tower had been compromised and held the potential of becoming impassable should the building be jolted by another large seismic event.
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| These exit routes consisted of the elevators which would become inoperable in an earthquake and one stairwell from 26 to 10; and two stairwells from 10 down to 4. Those stairwells, constructed to 1927 standards, however, had a high probability of becoming impassable should another earthquake occur. |
| Construction methods used in 1927 provided fire protection within City Hall's stairwells by encasing the stairwells in a fire resistant but unreinforced masonry and hollow clay tile structure that was hidden behind plaster walls. This hollow clay tile can be seen in the photo, right, with a section of the plaster wall removed. This unreinforced masonry housing could easily collapse and fall into the stairwell during a seismic event, making the stairwell impassable, and stranding the occupants. It became imperative to relocate all of the tenants on the floors to alternative office sites and close those floors to the public. |
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| The emergency relocation of 1,135 people from floors 5 through 27 commenced in September of 1994 and was completed by March, 1995. Structural bracing of the earthquake damaged tower was completed in July, 1995 while floors 1 through 4 remained occupied during the period it required to redesign the seismic rehabilitation plans of City Hall to incorporate lessons learned from the Northridge Earthquake. By March 1998, the remaining 1,250 people on floors 1 through 4 were relocated to the historic corridor along Spring Street, to 201 North Figueroa Street and to several other locations within the Civic Center. |
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