TMT Steel Bar
Characteristics of Panchakanya TMT Steel Bar
The development of the patented Thermex cooling technology has been a great boon to the construction industry. Panchakanya Steels now manufactures this globally preferred steel for the first time in Nepal. It offers the following characteristics.
High Yield Tensile Strength
Panchakanaya Thermex TMT Bars have better yield and tensile strength to the conventional CTD bars and due to this fact reduction in consumption of steel results in reduction in cost.
High ductility/ Elongation
The unique method of manufacturing process gives combination of strength and ductility that is far better to the limits specified in the standards IS 1786, the value of ductility as measured by elongation is 16% to 25% minimum as against the standard value 14.5% in Grade Fe 415. Thus these superior value of strength and ductility provide designers with greater safety margins.
Better Bondability
TMT bars posseses 40% better bonding strength to the CTD bars, and has 100% better bonding strength when seen in comparison with ordinary mild steel plain round bar. The ribbed pattern of TMT bars have been specially designed to ensure that excellent bond strength exists between the bar and the surrounding concrete.
Better Fatigue Strength:
Studies were conducted on the concrete beam column joint reinforced with Thermex TMT bars to evaluate its performance under repeated reversed loading with inelastic strains as would be encountered during earthquake. The energy dissipation was found to be almost same for each cycle indicating uniformly maintained ductility till failure. This reveals the superior seismic resistant properties for Thermex TMT Bars.
Dimension and Weight Accuracy
Since the diametrical measurement value is very consistent, hence the weight per meter length is accurate.
Choice of Structural materials and system for earthquake resistance
Choice of materials is an important factor in the determination of the structural system capable of undertaking induced loads. Although such a choice may be limited, and dictated by availability. Cost and technology, or other local considerations, it has been well recognized that the best materials in terms of earthquake resistance shall possess high ductility, high strength, weight ratio, homogeneity, orthography and simplicity in making full strength connections. In developing countries it is the mostly chosen material, in order of stability, for high and medium rise of buildings. Steel, pre-cast concrete, masonry and wood are the other materials, which are used for the purpose.
A structural system, with the chosen material, adopted for the earthquake resistance, shall have, in general, adequate strength, stiffness and stability to withstand seismic tremor, which normally is more, complicated than simple dynamic load. Another important factor of structural system is mode of its failure. A substantial deformation before failure is preferred to a sudden failure.
Achievement of these basic requirements depends upon the choice of the structural system, method of design and detailing technique. A movement-resisting frame has been recognized as the most efficient structural system for a building with all joints capable of undertaking movements, thus reducing substantial amount of overturning moment at the base of the building. It has been accepted that the design of a structure to resist forces generated by earthquake within the elastic range is neither economical nor practical. Moreover, it is advantageous when designing for an earthquake to place reliance upon the ability of the structure to dissipate energy with as little a loss of strength as possible during several excursions into the inelastic range of response. As a result, ductile behavior becomes essential for earthquake resistant structures. Appropriate detailing of reinforcements especially at the connections of the members provides substantial improvement in the ductility of the structure.
Importance of such detailing is substantiated by publication of a separate code for detailing for earthquake resistance, like I. S. 13920-1993(1993).
