Rehabilitation of Existing Cultural Heritage Buildings_Strengthening Masonry Brick Walls Using Helical Stainless-Steel Bars

15000

Many existing masonry buildings, particularly those constructed before modern building codes were established, exhibit significant structural deficiencies. These deficiencies are a major safety concern, as they can lead to severe damage or collapse during events such as earthquakes, high winds, or even due to the aging of materials. Masonry walls, typically comprising bricks and mortar, are particularly susceptible to shear and bending stresses, leading to cracks and potential failure.

Effective strengthening methods are crucial for these structures. Traditional reinforcement techniques, while effective, often involve invasive procedures that can alter the appearance of the buildings, making them less suitable for historical or architecturally significant structures. Additionally, some traditional methods may not provide the necessary levels of performance or may be difficult to implement in certain scenarios.

An innovative solution involves helical stainless-steel bars embedded in horizontal mortar joints. These bars are designed with a helical shape, resembling a twisted screw, which provides several mechanical and adhesion benefits. The helical geometry ensures that when the bars are embedded in the mortar, they achieve a high level of mechanical interlock and chemical adhesion with the surrounding materials. This is particularly important as it enhances the load-bearing capacity and overall stability of the masonry wall.

The bars are typically made from high-grade stainless steel, which offers excellent corrosion resistance and long-term durability. This makes them suitable for use in a variety of environments, including those with high humidity or exposure to pollutants.

Helical bars can be used in several applications:
• Shear and Bending Strengthening of Brick Walls: By embedding the bars in the mortar joints, the walls’ resistance to shear forces and bending moments is significantly improved. This helps prevent the formation and propagation of cracks, maintaining the structural integrity of the wall.
• Repair of Disconnected or Damaged Portions of Masonry Walls: In cases where portions of the wall have become disconnected or damaged, helical bars can be used to re-establish the structural connection and reinforce the compromised areas. This method is particularly useful for repairing historical buildings where maintaining the original materials and appearance is important.
• Surface Consolidation of Outer Walls: For buildings where aesthetics are a concern, helical bars can be used for surface consolidation. This involves embedding the bars in the outer layers of the wall, providing reinforcement without altering the visible appearance of the structure. This makes it an ideal solution for heritage buildings and structures with architectural significance.

The introduction of helical bars for masonry strengthening presents several advantages over traditional methods. The non-invasive nature of the installation process means that the structural integrity of the existing wall is preserved, and the aesthetic appearance remains unchanged. Furthermore, the high mechanical performance of the bars, combined with their excellent adhesion properties, ensures long-lasting and reliable reinforcement.

This project aims to explore the effectiveness of this method, focusing on its application, also in combination with fibre-reinforced plaster as additional reinforcement, through a series of experimental tests and analyses, which will shed light on the performance of helical bars in masonry strengthening applications.