Structural Strengthening of Steel, Concrete, and Masonry Structures

Structural Strengthening of Steel, Concrete, and Masonry Structures: Definition, Advantages, Causes, and Methods According to International Standards

Definition:
Structural strengthening (retrofitting) refers to the process of improving the load-carrying capacity, ductility, durability, or overall performance of existing steel, concrete, or masonry structures. This is performed to ensure structures meet current safety, serviceability, and usage requirements, especially if they were not originally designed for such demands or have experienced deterioration.

Advantages:

Causes of Strengthening:

Methods (in accordance with international standards, e.g. ACI, EN, FEMA):

For Steel Structures:

For Concrete Structures:

For Masonry Structures:

References:

• • Enhances structural safety and prolongs service life
  • Restores or increases load capacity
  • Improves structural performance against earthquakes, wind, and other loads
  • Allows for change of use or upgrades without demolition
  • Increases resistance to environmental factors such as corrosion, moisture, or chemical attack
  • Cost-effective alternative to reconstruction
  • Minimizes disturbance to ongoing operations
  • Design or construction deficiencies in the original structure
  • Deterioration due to aging, corrosion, chemical attack, or fatigue
  • Changes in use or increased load requirements (e.g., new equipment, higher occupancy)
  • Damage from seismic events, impact, fire, or other disasters
  • Need for compliance with updated codes or standards
  • Improvements in structural integrity for insurance or risk management
  • Addition of steel plates, sections, or stiffeners (welding or bolting)
  • Replacement of damaged elements
  • Use of fiber-reinforced polymer (FRP) wraps
  • Section enlargement
  • Post-tensioning
  • Jacketing with steel or reinforced concrete
  • Application of FRP composites
  • Section enlargement with additional concrete
  • External pre-stressing or post-tensioning
  • Crack injection and repair
  • Cathodic protection against corrosion
  • Adding reinforced concrete or steel ties
  • Application of shotcrete or fiber-reinforced composites
  • Grout injection to fill voids and cracks
  • Installing new walls or columns for added support
  • Steel or FRP strip application
  • ACI 440.2R: Guide for the Design and Construction of Externally Bonded FRP Systems
  • EN 1504: Products and Systems for the Protection and Repair of Concrete Structures
  • FEMA 547: Techniques for the Seismic Rehabilitation of Existing Buildings