Inter-story drift

Definition

Inter-story drift is the relative displacement between two adjacent floors of a building during seismic events, which is a crucial factor in assessing the performance and safety of structures. This term is essential for understanding how buildings respond to earthquakes, particularly in terms of lateral stability and the potential for structural damage. Monitoring inter-story drift helps engineers evaluate if a building can withstand seismic forces without suffering excessive deformations or failure.

5 Must Know Facts For Your Next Test

1. Inter-story drift is often quantified as a percentage of the floor-to-floor height, and exceeding specified limits can indicate potential structural problems.
2. Design codes usually define acceptable drift limits to ensure that buildings perform well under seismic loads while maintaining life safety and minimizing damage.
3. Large inter-story drifts can lead to non-structural damage, such as cracking of walls and breaking of windows, which may pose hazards to occupants.
4. The assessment of inter-story drift is essential in incremental dynamic analysis, as it provides insights into how buildings behave under varying seismic intensities.
5. Effective lateral load-resisting systems are key to minimizing inter-story drift and enhancing the overall seismic performance of structures.

Review Questions

• How does inter-story drift influence the design of seismic-resistant structures?
  • Inter-story drift plays a critical role in the design of seismic-resistant structures because it directly affects how a building responds to lateral forces during an earthquake. Engineers must account for the potential relative displacements between floors when designing structural components to ensure they can accommodate expected movements without leading to structural failure or excessive damage. This consideration is essential for meeting code requirements and ensuring occupant safety.
• Discuss the relationship between inter-story drift and structural performance during seismic events.
  • Inter-story drift is closely tied to structural performance during seismic events because it reflects how well a building can maintain its integrity under lateral loads. Excessive drift can result in significant stress concentrations, leading to both structural and non-structural damage. Therefore, controlling inter-story drift is vital for ensuring that buildings not only survive earthquakes but also provide a safe environment for occupants by limiting damage to crucial elements.
• Evaluate the effectiveness of current design codes regarding inter-story drift in improving the resilience of seismically designed structures.
  • Current design codes have made significant advancements in addressing inter-story drift by incorporating stringent drift limits and guidelines aimed at enhancing the resilience of seismically designed structures. By setting clear standards for acceptable levels of drift, these codes help engineers create buildings that can better withstand seismic forces while minimizing risks associated with structural failure. The effectiveness of these codes has been demonstrated in recent seismic events, where well-designed structures have shown improved performance, resulting in fewer casualties and reduced economic losses.

Related terms

Seismic Response: The reaction of a structure to ground shaking during an earthquake, including displacement, acceleration, and stress experienced by the building.

Drift Limits: Specified thresholds for allowable lateral displacement between floors in a building, designed to prevent structural damage and ensure occupant safety.

Base Shear: The total horizontal force that acts at the base of a structure due to seismic activity, critical for determining design requirements and overall stability.