Could you name at least one material that’s considered one of the building blocks of a house, or building? Well, let me give you one item – rebars! A rebar is actually short for reinforced bar, or reinforcement steel bars. It’s made of a steel bar or mesh of steel wires that are used in reinforced to strengthen the structure and hold the concrete in tension. Let’s hear a couple more fun, fab facts about rebars.
The Basic Functions of a Rebar
A rebar has ribs (literally) which bind it mechanically to the concrete for better binding, and holding of the structure. A common rebar is composed of unfinished tempered steel, which makes it susceptible to rusting.
In a highly-corrosive environment (such as those that are located near the seashore), fiber-reinforced polymer rebars are used. A rebar is usually combined with other steel products, which are melted down and reformed to gain extra strength.
A rebar literally absorbs the shock of an earthquake (for a certain time), before the building or house collapses. This gives the people inside it a “sway warning”, which helps them evacuate the area quickly.
Rebars are also quenched with water at a high pressure, so that the outside surface is hardened and the inner core remains soft, giving the material the amazing ability to sway during an earthquake.
In coastal regions where the salt-infested winds can easily corrode metal, galvanized rebars are utilized to prolong its lifespan. And, when combined with concrete, these become one of the strongest and most resilient objects ever.
Other Fun, Common Facts About the Rebar
A rebar is one of the most commonly-used materials in the construction industry, next to cement, wood, sand, gravel and others. It is used to construct roads, bridges, buildings, irrigation canals, ports, railways, stadiums, high-rise towers and more.
These, and other, structures need to be strong and sturdy, and need to withstand earthquakes, hurricanes and other destructive natural occurrences. When rebars are inserted inside the concrete, these act as tension devices which allow the concrete to withstand high pressure.
Without rebars, the structure will become more fragile, and cannot hold together long enough when an earthquake, or some other calamity, strikes. Hence, a rebar helps enhance the strength and durability of a structure by holding it together.
Rebars are also needed for the construction of building footings, walls and columns, as well as roads and bridges and more. However, it’s not actually necessary in all concrete work, like in the construction of pathways, driveways or curbs.
Rebars are also made of steel, which is melted down to form into liquid. This process requires a lot of heat, since iron has a very high melting point. When steel is melted, it goes into small round openings, which form the share of the rebar.
Some manufacturers even used unfinished steel, which is actually a much cheaper option. However, this rusts easier, and rust can create a lot of internal pressure, which eventually breaks the concrete. However, stainless steel provides a stronger, reliable (yet more expensive) option for a reliable and longer-lasting rebar.
The History of Rebars
Reinforced bars have been used in masonry and construction since the 15th century. In the 18th century, it was used to form the Leaning Tower of Nevyansk in Russia, which was constructed on the orders of wealthy industrialist Akinfiy Demidov. High-quality cast iron was used for this project, and there is little or no evidence of corrosion on the bars up to this day.
However, it was not until the 19th century that rebars displayed their greatest strength, with the eventual embedding of steel bars into concrete, and thus producing modern reinforced concrete.
A guy named Joseph-Louis Lambot of France was known to have built reinforced concrete boats in Paris, while Thaddeus Hyatt of the United States also tested and manufactured reinforced concrete beams.
However, a Frenchman named Joseph Monier is hailed as one of the most notable figures for inventing and popularizing reinforced concrete. As a gardener, Monier patented the manufacture and use of reinforced concrete flower pots in 1867, before he continued towards building reinforced concrete water tanks and bridges.
An English engineer named Ernest L. Ransome, who was working in the US also made a significant contribution to the development of the rebar. Mr. Ransome invented the twisted iron rebar, which was initially ridiculed because the critics though that the twisting would eventually weaken the iron.
But, in 1889 Mr. Ransome worked in the West Coast designing bridges. He helped construct the Alvord Lake Bridge in San Francisco’s Golden Gate Park, which has hailed as the first reinforced concrete bridge ever built in the US. He utilized twisted rebars in this structure. At the same time, a guy named C.A.P. Turner also designed the “mushroom system” of reinforced concrete floor slabs with smooth round rods.
The requirements for deformations on steel bar reinforcement were not standardized in the US until 1950. To be exact, the modern-day requirements for deformations were established in “Tentative Specifications for the Deformations for Deformed Steel Bars for Concrete Reinforcement”, ASTM A305-47T.
One good thing about rebars is that they can actually be recycled as scrap. This means that the rebar is usually combined with other sleep products, melted down and re-formed. And, in many countries across the planet, after the demolition of a concrete structure is finished, the workers are often called in to remove the rebars.
The workers then scour the demolition site, extract the metal using bolt cutters, welding equipment, sledgehammers and other tools. And, once the rebars are collected, they are then sold as scrap.
So, who says that reinforced bars are bad for the environment? Yes, rebars make it possible to reuse scraps from old, junk items and re-form them back into various recycled materials, which helps to save the environment and make houses, buildings and other structure become strong, steady and still!