Analysis of Earthquake Incidents in Concrete Buildings: Lessons from Iran and Around the World

Introduction

Concrete structures are among the most widely used structural systems in the world. However, the painful experiences of earthquakes in Iran and many other countries have shown that if the design and construction of concrete buildings are not carried out according to proper engineering principles, they can become highly vulnerable to seismic forces. This article examines examples of destructive earthquakes involving concrete buildings and analyzes the key reasons behind their failures.

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Why Concrete Structures Become Vulnerable During Earthquakes

• The high weight of concrete increases the inertial forces during seismic motion

• The inherently brittle behavior of concrete under tension and bending without proper reinforcement

• Insufficient ductility in joints—especially in columns and beams

• Poor construction quality in concrete placement, reinforcement detailing, and connections

• Deficiencies in seismic design or lack of compliance with building codes

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Examples of Earthquake Incidents in Iran

Bam Earthquake (2003) – Magnitude 6.6

• Over 85% destruction of concrete and masonry buildings

• Widespread use of non-engineered, unreinforced concrete structures

• Severe lack of confinement reinforcement (stirrups) in columns

• Poor connection between walls and the structural frame

• More than 30,000 fatalities

Kermanshah Earthquake (2017) – Magnitude 7.3

• Extensive damage to newly built reinforced-concrete buildings

• Column failures due to improper reinforcement detailing

• Lack of ductile detailing in joints and neglect of Iran’s seismic codes (Sections 9 & 10)

• Collapse of some buildings that had valid construction permits

Manjil–Rudbar Earthquake (1990) – Magnitude 7.4

• Destruction of many improperly designed concrete homes

• Weak columns, poor foundations, and absence of seismic gaps

• About 35,000 casualties

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Global Examples of Earthquake Damage in Concrete Structures

Haiti Earthquake (2010) – Magnitude 7.0

• Collapse of hundreds of concrete buildings

• Use of poor-quality concrete and undersized rebar

• Improper connections and extremely weak confinement

• Over 200,000 deaths

Nepal Earthquake (2015) – Magnitude 7.8

• Widespread collapse of reinforced-concrete structures in Kathmandu

• Weak column design and inadequate reinforcement

• Poor implementation of seismic design standards

Turkey Earthquake (2023) – Magnitude 7.8

• Thousands of concrete buildings, including high-rises, collapsed

• Violation of construction standards, corruption, and low-quality materials

• A major wake-up call for modern engineering and urban regulations

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Key Factors Leading to the Collapse of Concrete Buildings During Earthquakes

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Solutions for Prevention and Seismic Strengthening

• Designing structures according to seismic codes (e.g., Iran’s Standard 2800)

• Proper reinforcement detailing, especially in critical joints and columns

• Increasing ductility using closely spaced stirrups in plastic hinge regions

• Ensuring high-quality concrete placement and continuous engineering supervision

• Retrofitting older buildings using FRP, concrete jacketing, or steel bracing

• Using base isolators in special or essential structures

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Conclusion

Earthquakes are the ultimate test of a country’s construction quality. Iranian and global experiences have proven that concrete structures are safe only when design, construction, and supervision strictly follow engineering standards. Proper execution of concrete placement, reinforcement detailing, and joint design saves lives and prevents recurring tragedies.