Earthquakes have been a recurring nightmare for builders and communities in regions prone to seismic waves. The sheer destructive force of these seismic vibrations has the potential to wreak havoc, causing substantial losses in terms of both lives and property. In this, the choice of the right construction material is important for ensuring the safety of construction.
When it comes to construction material for earthquake-prone zones one cannot underestimate the role of steel rebars; in this most builders and engineers often contemplate between TMT bars and TOR Steel. Having a lot of similarities between them makes both a reliable choice, but for the seismic-prone zone which one is better? As a leading TMT bar supplier, we will deep dive into the definitions, the manufacturing process, and features to unbiasedly analyse which is better for earthquake-resistant construction.
TOR is the full form of Toristeg Steel Corporation of Luxembourg, it is a European brand name and is often used for Cold-Twisted Deformed (CTD) steel bars. The TOR Steel is produced from mild steel billets with restricted carbon content, TOR steel possesses more tensile stress than any other steel bars, but not more than TMT bars. One of its properties is a high elasticity value that comes from the surface distortion created by the twisting of the material after the elongation process. Later on, this process builds residual stress making TOR steel corrosion-prone.
TMT stands for Thermo Mechanically Treated. The term is described as a high-reinforcement bar with a strong outer core and soft inner core. The TMT bar supplier comes up with these bars that have proven to be extremely viable for reinforcing concrete structures. In the present era, TMT bars are generally used as tensioning devices for reinforcing concrete and helping to resist condensation forces. TMT bars are known for their ability to show strength, and sturdiness to build a robust appearance and provide superior reinforcement to any concrete structure, these steel bars are a perfect choice for building earthquake-resistant buildings.
TMT bars, owing to their advanced manufacturing process, exhibit superior strength and ductility, making them ideal for earthquake-prone areas. The thermo-mechanical treatment imparts robustness to the outer layer while maintaining a flexible inner core, allowing structures to absorb and dissipate seismic energy effectively.
On the other hand, TOR steel bars, with their twisted and deformed design, have been stalwarts in the construction industry. While offering commendable ductility and bonding with concrete, they face tough competition from TMT bars. In seismic scenarios, TMT bars tend to outshine TOR steel bars due to their higher tensile strength, better corrosion resistance, and enhanced ability to withstand stress.
The bars are quite different from each other, we are at the section where the differentiation of both bars will be properly mentioned in every aspect.
High-strength steel produces our TMT Bars and goes through different manufacturing processes. It involves three essential stages such as hot rolling, quenching and then self-tempering. The primary stage is where the billets are heated to an elevated temperature and then passed quickly via a series of rolling mills that form a thin steel strip, which then cools down rapidly with the help of water jets. This method is called quenching, which hardens the outer surface. The third and final step is finally where the bars are allowed to self-temper by re-heating, which creates a soft inner core while perfectly maintaining a solid external layer.
TOR bars on the other hand go through a slightly different manufacturing process. It involves twisting or cold twisting of steel wire rods. The rods are twisted mechanically to boost their tensile strength. Then the twisted rods are utilized to build TOR bars, which are available from 6mm to 25mm diameters.
TMT bars have higher tensile strengths when we talk about the comparison between TOR and TMT bars. For the loads on structural elements, high-quality steel TMT bars come out with lower steel content, whereas the TOR steel come out with 20% higher steel content. For a project employing TMT bars, the overall consumption amounts to 200 tons, whereas TOR steel usage in the same project totals 240 tons. Thus masking the use of TMT bars will result in a massive saving of 40 tons of steel.
The ductility of a steel bar highlights the ability of the structural component to distort without falling after achieving a failure load. When the comparison between the two bars arises, TMT bars are superior to TOR steel bars. Additionally, TMT bars also possess stunning strength that allows them to help a structure get 2% extra sturdiness. On the contrary, TOR steel bars have lower strength and ductility.
The elongation process points to the ability of a material to stretch before failure. It plays an essential role in the ductility of steel bars. In comparison with TOR steel bars, TMT steel bars have better elongation capability. The hard outer layer and the soft inner core of TMT bars make the building structure flexible and strong and protect the structure against natural calamities like earthquakes.
The bendability of steel bars is also an important property that helps the structure to stand firm. TMT bars have much higher ductility than TOR steel bars. This makes them the most suitable material to work with that can be moulded and bent as per the shape required.
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The leading TMT Bar supplier, SEL Tiger while working with TMT bars identifies that the bars are highly weldable with lower carbon. TMT bars do not need any pre or post-casting treatment like TOR bars which makes them easy to handle during the manufacturing process.
TMT bars have better corrosion resistance than TOR steel bars. TMT bars have a protective oxide film on their surface, which is configured during the quenching process. The film mentioned above serves as a barrier to corrosive components and boosts the longevity of the bars.
The bond between TMT Bar and concrete is perfect but TOR steel bars fall short while bonding with concrete. The ribs of TMT bars provide superior bonding ability that guides to a stringer stricture and increased longevity. When the TMT bar is combined with superior strength the bars become an ideal choice for building structures that can withstand earthquakes.
In the arena of earthquake-resistant construction, both TMT steel and TOR steel have their merits. However, when viewed through the lens of earthquake resistance, it becomes apparent TMT bars emerge as contemporary champions. Their superior strength, ductility and corrosion resistance make them the go-to choice for builders and engineers.
As a leading TMT bar supplier, we invest in modern technology, state-of-the-art manufacturing units for quality testing, and in-house R&D to innovate and ensure the TMT bars manufactured at SEL Tiger qualify and exceed the demand for the construction industry.
TMT bars generally exhibit higher tensile strength and ductility compared to TOR steel bars. This makes TMT bars more resilient to seismic forces and preferable for earthquake-resistant construction.
Fe 415, Fe 500, and Fe 550 D are some of the TMT bar grades which are beneficial for high-rise construction and civil construction.