Unreinforced Masonry Buildings

By: Erica and Laura Garcia

Abstract

• The affect of earthquakes on un-reinforced masonry buildings and solutions to reduce the damage of future earthquakes.

What is an Un-reinforced Masonry Building?

• Brick and mortar

• No Reinforcement (steel re-bars)

• An earthquake will Push and Pull on the bricks and so it causes the bricks to crack.

Experiment

• Sugar Cubes (brick)• Peanut Butter

(mortar)

Failure of Masonry Structures

• Typical failures occur in: • Walls• Windows, doors• Unsymmetrical plan of building

Failure Modes

• Shear

• Sliding shear

• Bending

Un-reinforced Masonry

Shear

Examples

• Wall Failure

Shear Failure

Bending

What is retrofit?

• Retrofitting is the way that many buildings are reinforced to better withstand the shaking of an earthquake.

Ways to retrofit

• Fiber reinforced polymers

• Steel reinforcement

• Dampers (shock absorbers)

• Connection of walls properly to roof and floor, windows and doors

• Increasing shear strength

Retrofitted Sugarhouse

Steel Bolts

Steel Braces

Laws Passed

• After each major earthquake the state of California has established new laws to improve seismic safety

• The Field Act (1933) and Garrison Act (1939)• Hospital Seismic Safety Act (1972) • The Hospital Facilities Seismic Safety Act

(1994) • Un-reinforced Masonry Building Law (1986)

Conclusion

After experimenting with our model and researching the topic of masonry buildings we conclude that the un-reinforced masonry structures are more vulnerable to damage than the reinforced structure during an earthquake. The reinforced structure can withstand greater magnitudes of earthquakes and more earthquakes than the un-reinforced structures.

Works Cited

• http://www.sandiego.gov/development-services/industry/urmexamples.shtml

• http://www.staff.city.ac.uk/earthquakes/MasonryBrick/PlainBrickMasonry.htm

• http://images.google.com/imgres?imgurl=http://www.ngdc.noaa.gov/seg/hazard/icons/thumb/14/14_288.jpg&imgrefurl=http://www.ngdc.noaa.gov/seg/hazard/slideset/14/14_thumbs.shtml&h=58&w=87&sz=2&hl=en&start=11&tbnid=RaCiWVL7Ng2ADM:&tbnh=51&tbnw=77&prev=/images%3Fq%3Dunreinforced%2Band%2Breinforced%2Bmasonry%2Bbuildings%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN

• http://pasadena.wr.usgs.gov/office/ganderson/es10/lectures/lecture18/lecture18.html

ACKNOWLEDGEMENTS

Thanks to Andreas Stavridis

Jonathan DeckProfessor Benson Shing

Jerry LedermanBridget SmithAllison Jacobs