ENG 333 Communication for Science and Research

Problem

• P - What deformation and loads can columns sustain
• P - How can we strengthen columns efficiently
• P - If global stiffening elements are used, how can elements be added to columns to achieve the effect
• P - Need to understand effectiveness of steel bracing elements for retrofitting existing structures
• P - Need to understand behavior or retrofit on shaking structures
• P - Column failures due to lateral and vertical load

Background

• B - Structural frames prior to 1970 are inadequate
• B - Columns on structure are bad
• B - Structures
  • Pre-seismic code building with no lateral force resisting system
  • Pre-seismic code building with effective lateral force resisting system
  • Moment frame buildings designed for lateral forces with weak columns
  • Shear wall buildings with inadequate strength
• B - Loma Prieta earthquake illustrates problem especially in elevated structures
  • Examples: Cypress Viaduct, Central Freeway, Southern Freeway
  • Hospital in Palo Alto
  • Hotel in downtown Santa Cruz
• B - Structures typical of this problem prevalent in state
  • High occupancy in these structures

Present Conditions

• C - To strengthen existing columns now
  • Concrete infills or external buttresses
  • Heavy and difficult installation
  • Steel bracings

Experiment

• E - Project experimental
• E - 5 years
• E - Review literature and experience on similar problems
• E - Test isolated columns
• E - Static test of structures
• E - Dynamic test of structures
• E - Use researchers from university and professional practice together since research is applied