Earthquake-Resistant Design Philosophy & Building Configuration

Objectives of earthquake-resistant design; performance levels and performance-based design; strength, stiffness and ductility; capacity design and the strong column–weak beam principle; energy dissipation and response reduction; importance of building configuration — simplicity, symmetry, regularity, continuity of load path; common failures — soft and weak storeys, short column effect, torsion, pounding, floating columns, heavy overhangs, infill effects, non-structural damage, foundation and liquefaction failures; earthquake-resistant masonry buildings (IS 4326) — bands, vertical reinforcement, opening limits; seismic isolation and energy dissipation devices.

Earthquake-Resistant Design Philosophy & Building Configuration

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Last reviewed 16 Sept 2026 · 7 min read

Objectives of earthquake-resistant design

Designing a structure to remain elastic during the strongest possible earthquake is uneconomical. Earthquake-resistant design therefore aims at:

No damage under frequent minor shaking.
Repairable damage (mainly non-structural) under moderate shaking — the design basis earthquake (DBE).
No collapse (life safety) under rare major shaking — the maximum considered earthquake (MCE).

The structure is allowed to yield and dissipate energy in controlled locations during strong shaking — "earthquake-resistant", not "earthquake-proof".

Performance levels (performance-based design)

Level	Description
Operational / Immediate occupancy	Negligible damage; building usable immediately
Life safety	Significant damage but adequate margin against collapse; occupants safe
Collapse prevention	Severe damage; structure just stands

Performance-based seismic design targets specified performance levels for given hazard levels, verified by nonlinear analyses (e.g. pushover analysis, nonlinear time history).

Key structural properties

Property	Role
Strength	Resist lateral forces without failure
Stiffness	Limit deformations/drift to control damage to non-structural elements and P-Δ effects
Ductility	Ability to deform inelastically without significant loss of strength — dissipates energy; allows design for reduced forces
Redundancy	Multiple load paths — failure of one element does not cause collapse
Overstrength	Actual strength greater than design strength
Damping	Energy dissipation

FormulaDuctility factor

μ = \frac{Δ _{u}}{Δ _{y}}

$Δ_{u}$ = ultimate displacement; $Δ_{y}$ = yield displacement. The response reduction factor R in codes reflects ductility, overstrength and redundancy.

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