San Francisco Earthquake Fire Disaster By Purushotham P

Outline Introduction Causes of Fire Affected areas Behavior of Important buildings of San Francisco Lessons to be learnt Conclusions

Introduction Major disaster in the world’s history Simultaneous occurrence of two natural calamities April 18,1906. Magnitude of 7.8 90% of total destruction by fires

Causes of Fire Natural gas mains broken due to earthquake Arson, campfires set by evacuees Untrained use of dynamite to create firebreaks (> 50% would have survived) 3 days 2 nights

Affected Areas

Fire Spread

Important Buildings (City Hall) 3 storied building Floors supported by steel girder & beams Wood stud and wood lath partitions use to divide floor space into small rooms Initial damage by EQ followed by fire Floor beams badly deflected due to wood work in floor finish(10” -15”) Absence of filling between concrete arch and wood flooring Little damage to stairways

Call Building Nineteen storied Metal frame is of steel skeleton type, resting on grillage foundations Beams (bottom side) protected by plaster flush with concrete Elevator shaft drew fire to top floor and the building burned from top to bottom Window openings are completely spalled Steel work was never finished (19th) Stairways are completely wrecked Elevators are completely distorted and bulged, framing in the shaft is deflected

Parrott Building Seven storied building occupied as a department store and office building 3 lower stories are fire-proof and upper stories were of wood Building was of steel frame construction Hollow tiled blocks laid in the form of segmental arch (3 lower stories FP) Nothing remained above 3rd floor, huge sections collapsed from roof to the basement (1/3 of entire floor area) Department store  Large amount of combustibles, fire of considerable duration and intensity Overall collapse due to collapsed sections due to column failures

Sectional Elevation

Chronicle Building None-story building occupied by San Francisco Chronicle Special reference to fire-resisting qualities Metal frame consisted of cast-iron columns with steel beams and girders Floors are fire-proof made up of hard burned, hollow tile, single cell blocks Roof was of wood construction, supported by steel beams Subjected to normal fire only Burning of wood roof increased duration and intensity of fire Collapse also due to heavy machinery located on the top floor

Lessons to be learnt Roofs, roof appurtenances, and skylights should be given ample protection against fires. A great excess of fire hose and apparatus, beyond ordinary needs, should be available. A strong bond for fireproof tiling etc for both girder and column protection is essential Protection for front windows, as well as for side and rear ones, is very important. Openings of the outside walls should be protected against Exterior Fire Hazard. Columns and other important structural members should be should be protected in proportion to the requirements. Refractory materials should be used for facades. Concrete floor construction should be selected in such a way that it should have sufficient strength and fire resistance. Reinforced Concrete should be adopted for partitions. Avoid pipes inside of column protections. Metal Treads should be provided for staircases. Sufficient arrangements should be provided for expansion of steel lintels and mullions. Filling between fire proof floor arches and the underside of the finished floor should never be ignored. Lights supports, Plaster ceiling construction should be avoided.

Conclusions Initial damage by EQ followed by fire Water mains were damaged due to EQ  hard to control fire in initial stages Exteriors of all buildings were damaged Damage also caused due to interior flames, spalling of windows etc Need for highly protected windows Strong bond between fire proof tiling and columns, girders is necessary Interiors of buildings should be provided with sprinklers, heat detectors etc