Repair and Reinforcement of Building Structures
Masonry and Concrete Constructions
Causes of Cracks in Masonry and Concrete
Cracks in masonry load-bearing walls and concrete constructions can result from:
- Structural causes: Overloading, differential settlements, dynamic vibrations, and out-of-plane deformations.
- Non-structural causes: Moisture changes, thermal movements, elastic deformations, creep, chemical reactions, foundation movement, and vegetation.
Temporary Repair Technologies for Cracks
- Structural support: Use of temporary support elements like timber or steel to prevent collapse.
- Simple temporary methods: Sealing with plaster or flexible materials to prevent water ingress or further deterioration.
Permanent Repair Technologies for Cracks
- Epoxy injection: Fills fine cracks to restore strength and stop leaks.
- Crack stitching: Insertion of helical bars into cracks to reinforce and stabilize.
- Shotcrete (sprayed concrete): Reinforcement of large areas with pneumatically applied concrete.
- Post-tensioning: Application of compressive forces through steel cables to close cracks and strengthen structures.
Timber Constructions
Causes of Failures in Timber Structures
- Biological degradation: Attack by fungi and termites.
- Moisture: Swelling and weakening due to excess water.
- Structural overloading: Impacts or loads exceeding the design capacity.
Technologies for Timber Structure Repairs
- Replacement: Substitution of damaged sections with similar quality wood.
- Reinforcement: Use of epoxy resins and metal plates.
- Strengthening: Addition of fiber-reinforced polymer (FRP) strips and steel cables.
Foundations
Causes of Foundation Failures
- Differential settlements: Variations in the soil’s bearing capacity.
- Soil erosion: Loss of supporting material due to water.
- Poor design: Lack of horizontal stiffness or incorrect dimensioning.
Technologies for Foundation Rehabilitation
- Foundation expansion: Addition of reinforced concrete footings to increase the bearing area.
- Foundation deepening: Use of micropiles or grout injections for stabilization.
Dampness Problems in Constructions
Causes of Dampness Problems in Buildings
- Capillary action: Water rising through walls due to the absence of waterproof barriers.
- Poor drainage: Accumulation of surface water or defective drainage systems.
- Condensation: Lack of adequate ventilation.
- Leaks: Leaking pipes or roofs.
Defects in Masonry and Concrete
- Pathology and Diagnostics: Identifying causes of failures (moisture, excessive loads, defective materials).
- Reconstruction and Reinforcement: Techniques to reinforce and repair structures, including modern materials and crack repair methods.
Defects in Timber Constructions
- Pathology and Diagnostics: Common causes of failures (moisture, insects, aging).
- Reconstruction and Reinforcement: Replacing damaged elements and reinforcing using new materials or treatments.
Moisture Problems in Buildings
- Typical Sources of Moisture: Water leaks, capillary action (rising damp), condensation.
- Technologies for Repairing Moisture Problems:
- Rising Damp: Using vapor barriers, injections of waterproofing products.
- High Humidity: Improving ventilation, using dehumidifiers, treating affected masonry.
Foundation Failures
- Pathology and Diagnostics: Causes of failures (differential settlement, unsuitable materials, vibrations, overloading).
- Reconstruction and Reinforcement: Using micropiles, resin injections, or steel structures to stabilize the foundation.