Masonry and brick construction has been used throughout the world for thousands of years even in remote parts of the world where there have been no interchange or exchange between various disparate peoples. The occurrence of science or technology being invented by people with no cross pollination between them is a phenomenon known as multiple invention or parallel invention. This phenomenon has happened many times in the history of human existence, but few occurrences of multiple invention have propelled civilization forward as mush as brick masonry. Brick masonry has allowed humans to build structures and stable, safe housing in close proximity in cities throughout the world over millennia. Steel hasn’t always been used as a component in brick masonry, but in contemporary structures and in the late historic structures still found in our modern cities, steel has allowed openings for doors, windows gated and even carports and roadways. Today we will discuss halow steel lintels are used to support brick opening headers. The overall outline of a two-part perishes on the topic follows below. The items highlighted below will be discussed in today’s article and then the items below that will be discussed in the article this coming week. This week’s topics:
Topics covered in the next article:
Supporting Masonry with a HeaderMasonry construction, particularly in historic buildings, requires careful consideration of structural support systems to ensure the longevity and stability of the structure. One crucial element in this regard is the use of structural headers above openings such as doors, windows, and arches. A header, in the context of masonry construction, refers to a structural member that spans across an opening and supports the weight of the masonry above it. Without a proper header in place, the weight of the masonry would cause the opening to collapse inward, compromising the structural integrity of the entire wall assembly. The need for structural headers arises from the inherent nature of masonry materials like bricks or stone blocks. While these materials possess excellent compressive strength, their tensile strength (resistance to being pulled apart) is relatively low. When an opening is introduced in a masonry wall, the weight of the masonry above the opening creates tensile forces that the bricks or stones alone cannot effectively resist. Structural headers are designed to bridge the opening and transfer the weight of the masonry above to the adjacent wall sections or support structures. By distributing the load evenly, headers prevent the masonry from failing under its own weight and maintain the structural stability of the wall assembly. (The picture above shows a common horizontal steel lintel set on top of a brick wall at the side of an opening.) In historic masonry construction, headers were often made of materials such as wood beams or steel lintels. These structural elements were carefully integrated into the masonry during the construction process, ensuring that they were properly supported and capable of bearing the imposed loads. Over time, as construction techniques evolved and the understanding of structural engineering advanced, various types of headers were introduced to meet the demands of different building styles and load requirements. Modern masonry construction often employs steel lintels, reinforced concrete beams, or pre-engineered structural components as headers, offering enhanced strength and durability. Regardless of the specific material used, the proper installation and maintenance of structural headers are crucial in preserving the integrity of historic masonry structures. Failure or deterioration of these crucial elements can lead to cracking, bulging, or even collapse of the masonry above the opening, posing significant safety risks and potential damage to the building. (In the picture above you can see that the steel lintel supports the brick above by transferring the load to the side walls.) Historic Arches used TodayBrick masonry, while known for its durability and compressive strength, is inherently weak in resisting tensile forces. When an opening, such as a door or window, is introduced in a brick wall, the weight of the masonry above the opening creates horizontal tensile forces that the bricks alone cannot withstand effectively. Without a proper structural support system, such as an arch or a horizontal lintel header, the bricks above the opening will eventually succumb to these tensile forces, leading to collapse and failure. The reason for this vulnerability lies in the nature of brick construction itself. Bricks are laid in a staggered pattern, with each brick overlapping the one below it and held together by mortar. While this arrangement provides excellent compressive strength, allowing the bricks to transfer the load vertically, it lacks the ability to resist horizontal tensile forces effectively. When an opening is present, the bricks above it no longer have continuous vertical support, creating a gap or discontinuity in the load transfer path. As gravity acts on the weight of the masonry above the opening, it generates horizontal tensile forces that pull the bricks outward and downward. Without a supporting structure to resist these forces, the bricks will eventually separate from one another, leading to cracking, bulging, and ultimately, collapse. (The steel lintel is connected to a vertical steel support but that still support actually was originally built as a frame for a roll-up door, not an original structural element.) An arch is a structural element that addresses this issue by transferring the weight of the masonry above the opening through a curved, self-supporting configuration. The bricks in an arch are arranged in a semicircular or segmental pattern, with each brick partially supporting the ones above it through compressive forces. This arrangement allows the weight of the masonry to be distributed evenly along the curve of the arch, effectively transferring the load to the adjacent wall sections or support structures. However, in situations where an arch is not feasible or desired, a horizontal lintel header becomes the primary support system for the masonry above the opening. A lintel header is a structural beam, typically made of steel, reinforced concrete, or wood, that spans across the opening and transfers the weight of the masonry above it to the adjacent wall sections or support structures. The lintel header functions by resisting the horizontal tensile forces generated by the weight of the masonry above the opening. Its strength and rigidity allow it to span the opening without deflecting or sagging, effectively distributing the load evenly to the supporting wall sections. Without a lintel header in place, the bricks above the opening would eventually succumb to the tensile forces, leading to cracking, bulging, and potentially catastrophic collapse. (The abandoned steel roll up door is now defunct but left in place and replaced with corrugated panels as a makeshift cheap alternative. This is a lot about the changing economic values of urban industrial space.) The Advent of Structural Steel and Steel HeadersThe advent of structural steel and the introduction of steel headers revolutionized the way masonry structures were built, allowing for greater spans, taller constructions, and more flexible designs. Although iron and steel have been around for centuries, their widespread use in construction as structural members is a relatively recent development. It wasn’t until the late 18th and early 19th centuries that the mass production of wrought iron and, later, steel became feasible. The Industrial Revolution and the advancement of manufacturing processes, such as the Bessemer process for steel production, paved the way for the widespread availability of these materials. Prior to the mass production of structural steel, masonry openings were primarily supported by wooden lintels or arched configurations. While these traditional methods were effective for smaller openings and lower loads, they imposed limitations on the size and design of buildings. Wooden lintels had limited span capabilities, and arches required specific structural configurations that could be limiting in certain architectural styles. The introduction of steel angles and I-beams as headers in masonry construction marked a significant turning point. These structural members could be mass-produced with consistent quality and strength, making them readily available for construction projects. Steel’s high strength-to-weight ratio and ductility allowed for longer spans and the ability to support greater loads compared to traditional materials like wood or cast iron. (Overall, the opening is very wide, a total span that would have been very difficult to accomplish with historic brick arches from just a few decades earlier.) Steel headers, whether in the form of angles or I-beams, could span across openings with minimal deflection, effectively transferring the weight of the masonry above to the supporting wall sections. This capability opened up new possibilities for builders, enabling the design of larger openings, taller structures, and more complex masonry configurations. The use of steel headers also facilitated the integration of other structural elements, such as reinforced concrete and steel framing systems, into masonry construction. This combination of materials allowed for greater flexibility in design, enabling the construction of buildings that were previously impractical using traditional masonry techniques alone. The mass production of steel also made it an economical choice for construction projects, making it accessible to a wider range of builders and developers. This accessibility, coupled with the material’s strength and durability, contributed to the widespread adoption of steel headers in masonry construction throughout the late 19th and early 20th centuries. (In an alleyway of this type, it’s important for vehicles to be able to enter into this type of facility, but the opening could not be as easily created without a steel support element.) The Imposed Load of Masonry HeadersMasonry headers, such as steel lintels or reinforced concrete beams, play a crucial role in supporting the weight of the masonry above openings in walls. While bricks are capable of withstanding significant compressive forces when stacked vertically, they lack the inherent tensile strength and bonding capacity to remain indefinitely suspended in a horizontal or arched configuration without proper support. Bricks are typically held together by mortar, a cementitious material that acts as a binding agent between the individual units. However, mortar itself possesses relatively low tensile strength compared to its compressive strength. Over time, the mortar can deteriorate due to various factors, such as environmental exposure, moisture intrusion, or thermal cycles, leading to a gradual weakening of the bond between the bricks. Even with a perfect mortar installation, there is an inherent limitation to the adhesive strength and cohesive bonding capacity of the mortar itself. Unlike resilient materials like elastomeric sealants or structural adhesives, mortar lacks the necessary flexibility and tensile strength to reliably hold the bricks together in a suspended or unsupported configuration for an extended period. (The picture above shows a massive vertical portion of a building supported by a single element of steel above this side of the passageway of the opening.) When bricks are stacked vertically, the weight of the masonry above is transferred through compressive forces, which the bricks can effectively withstand. However, in a horizontal configuration above an opening, the weight of the masonry creates tensile forces that pull the bricks apart. Without a supporting structure like an arch or lintel, these tensile forces will eventually overcome the limited bonding strength of the mortar, leading to separation and potential collapse of the masonry above the opening. Brick and mortar assemblies are designed to primarily resist compressive forces, not tensile forces. The inherent properties of these materials make them well-suited for load-bearing walls and structures where the weight is transferred vertically, but they lack the necessary tensile strength and cohesive bonding to remain indefinitely suspended or unsupported in a horizontal configuration. To address this limitation, structural headers like lintels or arches are introduced above openings in masonry walls. These elements are designed to transfer the weight of the masonry above the opening to the adjacent wall sections or support structures, effectively resisting the tensile forces and preventing the bricks from separating and collapsing. Arches accomplish this by distributing the load through compressive forces along their curved shape, while lintels or beams span the opening and resist the tensile forces through their inherent strength and rigidity. By providing this crucial support system, structural headers ensure the long-term stability and integrity of masonry constructions, preventing the potential failure and collapse that could occur if the bricks were left unsupported above an opening. We can HelpWe can help with a variety of historic masonry restoration needs and upkeep, from modest tuckpointing and or repointing to complicated and extensive historic masonry restoration. Infinity Design Solutions is a historic restoration specialist contractor specializing in both historic masonry restoration such as tuck pointing our repointing, and brick repair. If you have questions about the architectural details or facade of your historic building in Washington DC, reach out and say hello and if we can help, we’ll be glad to assist you. You can email us or call us on the telephone at the following link: contact us here. <p>The post Heavy Steel and Iron Girders Carrying Brick Masonry – Part I of II first appeared on Infinity Design Solutions.</p> Via https://www.ids-dmv.com/masonry/heavy-steel-and-iron-girders-carrying-brick-masonry-part-i-of-ii/
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