India the world’s fifteenth-largest importer of steel. In 2017,we have imported 9 million metric tonnes of steel, a 9.7% decrease at 8 million metric tons in 2016. India’s steel imports showed 6% of all steel globally in 2016. Based on the information the data of India’s 2017 steel imports was almost a quarter of of the world’s largest steel importers, the US..In terms of cost steel 7 % of of the overall production is imported in 2017.India imports steel from almost 80 countries and territories. Five major countries represent the highest import sources for India’s imports of steel, with 250 thousand metric tons which accounts for 80% of India’s steel imports in 2017 .Since 2005 india has alternated between being an internet steel businessperson and an internet steel bourgeois. Imports and exports have displayed a roughly inverse relationship, as imports declined sharply with export growth. Since the most up-to-date low purpose steel , India’s imports have increased to thirty eight %.India announced a steel trade surplus of 181.7 thousand metric tons in 2016. In 2017, however, a jump in exports and a decrease in imports resulted in a very vital increase within the surplus to seve 7.1 million metric tons. India’s crude production has grown to 59.6 p.c between 2009 and 2017. Production in 2016 was up to half dozen to a 101.4 million metric tons from 95.6 million metric tons in 2017. Apparent consumption (of steel demand) has half-tracked comparatively closely with production over the amount however was slightly outpaced by production within the majority of years. In 2017, apparent consumption was a small amount but production. Import penetration shriveled 0.9 proportion points from 10.3 % in 2016 to 9.4 %in 2017 because the decline in apparent consumption was offset by the decrease in imports.Prime Producers Before economic reforms in 1991,production in India was focused among state -owned firms. currently,non-public firms dominate crude production in India . The highest half dozen producers accounted for 55.5 million metric tons, or 56.7 %of total 2017 production.The top five supply countries for India’s steel imports depicted concerning 79 % of the overall steel import volume in 2017 at 7.0 million metric tons (mmt).Asian country accounted for the biggest share of India’s imports by supply country at concerning 30%(2.6 mmt), followed by China at concerning 28 %(2.5 mmt), Japan at concerning 15 %(1.3 mmt), Indonesia at 3.1%(0.3 mmt), and Taiwan at 30 %(0.3 mmt). The U S Stratified twelfth as a supply for India’s steel imports.Indian import concerning a 110.0 thousand metric tons from the u. s.in 2017 —or so associate 8 5 increase from 102.0 thousand metric tons in 2016. Trends in Imports from prime Sources the amount of India’s steel imports shriveled in 5 of India’s major ten steel import sources between 2016 and 2017. India’s imports from Russia showed the best decrease in volume, down 45.1% by volume from 2016, followed by China (down 25.5%),Federal Republic of Germany(down 17.4%),Indonesia (down 16.5%), and Japan (down 8.9%). India’s imports from Vietnam jumped 677.5 percent. India’s imports from Taiwan, Ukraine, France and Asian country showed will increase in volume between 2016 and 2017, up 32.5 percent, 29.1 percent, and 12.7, and 8.4 percent severally.The general price of India’s imports shriveled in four of its prime 10 sources. The decreases in steel price between twenty 16 and 2017 enclosed India’s imports from Russia (down 20.6%),Federal Republic of Germany(down 16.6%), France (5.1%), and China (1.5%). Imports from Vietnam surged 384.1 whereas Ukrayina (68.1%), Taiwan (42.4%), Asian country(32.5%),Indonesia (29.1), and Japan (12.9) all hyperbolic in price in 2017.
The use of multistorey composite structures (steel columns, steel beams, and reinforced concrete slabs) became a necessity. The multi storey composite structures are used for different types of buildings such as office buildings, bank buildings, industrial buildings, public buildings, high-rise parking buildings, etc. These kind of buildings can be seen around the world, in the highly developed countries depicting their financial and technical power. The safety and function expressed through control of the mass, stiffness, strength, and ductility at the structural design of the multi storey composite structures, and mostly of the connections of the elements exposed under cyclic-horizontal loading (such as earthquake, wind loading) in combination with other loading is of highest priority for this kind of structures. The behavior of the beam-column connections in the multi storey frame structures (MSFS) is viewed as a whole and it’s in direct correlation and dependence with the behavior of their main constructive fundamental elements (steel deisgning courses in kerala beams, columns and the elements for their connection) . In other words, the way the beams, the columns and their elements of connection behave, that way the MSFS behaves. The behavior of the beam-column connection in the MSFS again is dependent on the constructive solution. However, dominant in this paper is the research of new or modified constructive solutions of the connections, and all with the purpose of improving their loading capacity in conditions of real external loading. Some constructive solutions can be controlled by the dissipation of energy, meaning,they can be controlled by the stress and deformation distribution in the sections of the elements of the MSFS i.e. the constructive solution of the connection directly influences the appearance of the plastic hinges in some of the sections of the elements, when their loading capacity is exhausted. In the numerical modeling of the beam-column connection the demands of the new codes ,, are incorporated, which is the well-known concept of the seismic resistant structure that proposes development of plastic hinges in the beams, and columns.
Consequently, the size of the static influence that dictates the order of the plastic hinge appearance should be taken under consideration i.e., column bending strength should be larger then beam bending strength. With the alternative of the collapse mechanism (the order of the element’s plastification) and generally the mechanism of energy dissipation, two different approaches exist: The first approach is based on the contribution of the panel–zone in the energy dissipation with the purpose of its reduction and also accepting a part of the plastic deformations, without excluding the contribution of the columns and the beams. The second approach does not include the panel zone in the energy dissipation. As a result, the end parts of the beam must accept the plastic deformations. Thus the beam–column connection can be specified in detail. During design of connections it is important to control the weight, stiffness, strength and the ductility of the material of the elements. This is due the fact that their behavior depends on the mentioned parameters of the elements in the connections . The deformation (rotation) capability is inversely proportional to the capacity of carrying of the beam i.e. the semi rigid connections have bigger plastic deformations and possibility for bigger rotation during the use of their total capacity to carry, but they have smaller capacity to carry comparing to the ones with rigid connection.
In reinforced concrete structure, steel which is equally strong in compression and tension, is used to combine with concrete to improve the resistance of concrete to tensile force!, The steel used to provide reinforcement in concrete structures is termed reinforcing steel. In earthquake resistance reinforced concrete structures, reinforcing steel plays an extremely important role which is significantly more demanding that its basic function. This is due to the philosophy of capacity design of reinforced concrete structures to utilize both strength and energy dissipation characteristics of the system • The energy dissipation characteristics are utilized to absorb and dissipate the dynamic seismic loads to avoid brittle failures. This energy dissipation mechanism relies on the ductility of the structure in the post-elastic range. In the strong column-weak beam design concept, the ductility of the structure is ensured by the development of plastic hinges in beams adjacent to column-beam joints in preference to hinges forming in the columns. The absorption and dissipation of energy by post-elastic deformation in plastic hinges depends almost entirely on the ductility of the reinforcing steel • Steels used for reinforcement in this structure should be capable of accommodating significant amounts of strain without failure. Therefore, the ductility of reinforcing steel becomes an important requirement in the design of earthquake resistant reinforced concrete. The plastic hinge behavior of reinforced concrete members is also very dependent on the stress-strain characteristic of the reinforcing steel • During an earthquake, strains in the steel of plastic hinge regions may increase beyond the Luder strain, consequently strain-hardening occurs. This strain increase may lead to large strength increases, particularly if the strain hardening rate of the steel is high and if the steel has a short Luder strain which results in strain hardening occurring soon after yielding. Ideally, the Luder strain should be as large as possible so that the plastic strain is accommodated with a minimum of strain hardening. As a result of this flexural over strength, during subsequent earthquakes, plastic hinges may be formed in regions which have not been designed as such. Thus, relocation of the plastic hinge within the structure could give rise to an undesirable failure mode. In the design of seismic resisting concrete structures, an over strength factor which is greater than unity is included in the calculation of the steel stress at the beam plastic hinges to take into account the possibly large increase in flexural strength. Strain ageing of reinforcing steel also has a significant effect on the properties of seismic reinforced concrete structures • Strain ageing of the longitudinal reinforcing steel at plastic hinges subsequent to the first formidable seismic loading can increase the flexural strength at the plastic hinges as a result of the increase in yield strength of the steel during the ageing process. The flexural over strength brings the same effect as when strain hardening of steel occurs, i.e. causing the plastic hinges to form at alternative and undesirable regions in the structure during subsequent earthquakes. Cold bent reinforcing bars in the form of standard bends, returns or hooks contained in most regions in reinforced concrete structure will strain age during service at ambient temperature • As a result of strain age embrittlement, these strain aged regions will be susceptible to brittle failure, which may cause catastrophic fracture of the structure. It is therefore, very important to understand the effect of strain ageing on the mechanical properties of reinforcing steel used in earthquake resistant reinforced concrete structures. Unfortunately, information regarding strain hardening and strain ageing of reinforcing steels are not specified in appropriate standards, nor is the data on Luder strain.
Manganese is a major alloying element, has complex interactions with carbon and is used to control inclusions. Manganese is beneficial to surface quality in all carbon ranges with the exception of rimmed steels and is particularly beneficial in high-sulfur steels. Manganese provides lesser strength and hardness in comparison to carbon. The increase depends on the carbon content – higher-carbon steels being affected more by manganese. Higher-manganese steels decrease ductility and weldability (but to a lesser extent than carbon). Manganese also increases the rate of carbon penetration during carburizing.
The effects of manganese can be summarized as.1. Lowers the temperature at which austenite begins to decompose 2. Extends the metastable austenitic region and delays the commencement of all the austenite decomposition reactions 3. Favors the formation of lower bainite and suppresses the upper bainite reaction on isothermal transformation 4. Is the most effective alloying addition for lowering the martensite-start (MS) temperature 5.Favors the formation of e-martensite 6.Has little effect on the strength of martensite and on the volume change from austenite to martensite 7. Has little or no solution-hardening effect in austenite and between 30–40 MN/m2 per wt. % in ferrite (by lowering the stacking-fault energy of austenite, manganese increases the work-hardening rate) 8. By lowering the MS temperature, manganese prevents the deleterious effects of auto tempering 9. Lowers the transformation temperature, causing substantial grain refinement 10. In general, lowers the tough-to-brittle impact transition temperature (due to its grain-refinement action) 11. Increases the propensity for weld cracking due to the effect on hardenability. The severity of its influence depends to a great extent on the type of steel and the welding techniques. 12. Does not increase the susceptibility of the steel to delayed fracture due to hydrogen absorption 13. Improves the fatigue limit 14. Reduces the number of cycles to failure under high strain conditions 15. Forms five carbides (Mn23C5, Mn15C4, Mn3C, Mn5C2 and Mn7C3), the dominant one being Mn3C, which forms a continuous range of solid solutions with Fe3C, thus reducing the solubility of carbon in a-iron 16. Prevents the formation of an embrittling grain-boundary cementite. 17. Suppresses the yield extension in deep-drawing steels by virtue of its grain-refinement effect 18. Suppresses strain aging 19. In combination with nitrogen, has a solid-solution hardening effect and improves high-temperature properties 20. Extends the range of use of low-carbon steels 21. Has a strong influence on the pearlite morphology of high-carbon steels 22. Extends the range of use of high-carbon steels through its grain-refining and pearlite-refining actions 23. Raises strength values in bainitic steels by reducing grain size and increasing dispersion hardening 24. Allows bainitic steels to be produced by air hardening 25. Increases hardenability 26. Slows down the temper reactions in martensite 27. Assists interphase precipitation 28. Improves austemper and martemper properties 29. Increases temper embrittlement unless the carbon content is very low and trace element impurities are minimal 30. In spring steels, promotes ductility and fracture toughness without undue loss in tensile strength 31. Removes the risk of hot shortness and hot cracking when the ratio of manganese to sulfur is greater than 20:1 by forming a higher melting-point eutectic with sulfur than iron sulphide 32. Has a major influence on the anisotropy of toughness in wrought steels due to the ability to deform manganese sulfides during hot working 33. Forms three manganese sulfide morphologies (Type I, II and III) dependent upon the state of oxidation of the steel 34. Enhances free-cutting steels 35. Increases the stability of austenite 36. Has similar atomic size as iron 37. Lowers the stacking-fault energy of austenite (in contrast to alloying element additions such as chromium or nickel) 38. Allows lower solution temperatures for precipitation-hardening treatments in highly alloyed austenite due to increased carbon solubility 39. Forms s intermetallic compounds suitable for precipitation-hardened austenitic steel detailing course in kochi 40. Plays a major role in controlling the precipitation process that occurs during isothermal transformation to austenite 41. Increases the rate of carbon penetration during carburizing 42. Contributes, in combination with nitrogen, to the performance of work hard enable austenitic stainless steels 43. Improves hot corrosion resistance in sulfurous atmospheres 44. Enhances wear-resistance in carbon-containing austenitic steels where the manganese content is between 12-14% 45. Improves response of low-alloy steels to thermomechanical treatments 46. Strengthens certain steels by producing an austenitic structure using manganese-containing compounds 47. Enhances the performance of TRIP steels 48. Promotes Ferro-elastic behavior in appropriate steels 49. Less tendency to segregate within the ingot 50. In general, improves surface quality.
Erection of Steel
Erection of steel structures is that the method by that the fictitious structural members are assembled along to create the structure. The erection is generally distributed by the erection contractor. The erection method needs right smart coming up with in terms of fabric delivery, material handling, member assembly and member affiliation. Correctly coming up with of fabric delivery would minimize storage demand and extra handling from the positioning storage, significantly significant things. Erection of steel work might be created safe and correct if temporary support, false work, staging etc. are erected. Before erection the fictitious materials ought to be verified at web site with relation to mark numbers, key arrange and shipping list. The structural parts received for erection ought to be stacked in such some way that erection sequence isn’t affected because of improper storing. Care conjointly ought to be taken in order that steel structural designing parts shouldn’t are available in contact with earth or accumulated water. Stacking of the structures ought to be exhausted such some way that, erection marks and mark numbers on the parts square measure visible simply and handling don’t become tough. a spread of ways may be utilized for the erection of a structure. Normally, the choice of the strategy is influenced by the sort of the structure, web site conditions, equipment, quality of ball-hawking labour, etc. obtainable to the erector. However, notwithstanding the strategy adopted the most aim throughout erection is that the safety and preservation of the soundness of the structure the least bit times. Most structures that collapse do thus throughout erection and these failures square measure fairly often because of an absence of understanding on someone’s a part of what another has assumed regarding the erection procedure. Before the commencement of the erection, all the erection instrumentality tools, shackles, ropes etc. ought to be tested for his or her load carrying capability. Such tests if required could conjointly be recurrent at intermediate stages also. Throughout the complete erection, the steel work ought to be firmly fast or otherwise mounted and braced to require care of the stresses from erection instrumentality or the hundreds carried throughout erection. additionally to the current, adequate provisions to resist lateral forces and wind masses throughout erection ought to even be created consistent with native conditions. Unremarkable bracing are engineered into every type of structures to grant them a capability to face up to horizontal forces made by wind, temperature and also the movements of crane and different plant in and on the building. Bracing may be permanent or temporary. Temporary bracing needed at some stages of the work should have properly designed connections and will be specifically cited within the erection technique statement. the choice on sequence of erection like that member ought to be erected 1st for providing initial stability to the structure or whether or not temporary bracing ought to be used for this purpose ought to be taken at AN early stage of designing of the erection method. Any miss-alignment at initial stage can impair the performance, of the structure once completed. Early or unauthorized removal of temporary bracing could be a common reason for collapse in an exceedingly part completed frame. once having thought-about the requirement for putting in temporary bracing and also the ought to delays fixing permanent bracing, thought ought to run to the general economy of holding the temporary bracing and maybe deed out the permanent bracing . It is a pricey and doubtless dangerous business to travel into a structure entirely so as to require out temporary members, or to insert parts that had to be unnoticed quickly.
Structural steels are sometimes made by rolling steel solid from the steel making method when reheating it to a temperature higher than 850°C. Rolling consists of passing the steel through a series of rolls that kind the solid steel into the form and thickness needed. A big selection of shapes and sizes are presently rolled or out there. The properties of steel for the most part result from the influence of micro structure and grain size the different factors like non-metallic inclusions are vital. The grain size is powerfully influenced by the cooling rate, to a lesser extent by different aspects of warmth treatment and by the presence of little quantities of components like atomic number 41, metallic element and atomic number 13. Thus, the assembly of steel and steel product involves heat and therefore the effects of heating and cooling throughout. The chemical composition of steel is essentially determined once the steel is liquid except for a given chemical content the structure is essentially determined by the speed at that it’s cooled and should be altered by ulterior reheating and cooling below controlled conditions. Carbon steels are for the most part composed of iron with up to one.7% carbon, however the addition of comparatively little quantities of different components greatly influences its behavior and properties. For structural functions it’s fascinating that steel be ductile and weldable, and consequently most structural carbon steels are low-carbon steel with carbon within the vary zero.15 to 0.29% and should embody little quantities of metal, element and copper. the right production of steel structures may be a complicated method involving creating the steel, process it into helpful product, fabricating these product into helpful assemblies or structures by cutting, drilling and fitting, and erection and grouping these parts, assemblies, and structures into buildings or bridges. it’s vital to investigate processes as a result of they’ll have a significant result on the investigated environmental impact of a steel structure, however they ordinarily don’t specify or would like details of exactly however the steel is made, rolled or fashioned. Presently, attachment is maybe the foremost vital method employed in the fabrication and erection of structural steel designing course in kerala work. it’s used terribly extensively to hitch parts to form up members and to hitch members into assemblies and structures. attachment used and done well helps within the production of terribly safe and economical structures as a result of attachment consists of primarily connection steel element to steel element with steel that’s intimately united to each. Corrosion of steel takes place by a fancy chemical science reaction between the steel and atomic number 8 that’s expedited by the presence of wetness. Structural needs further protection and therefore the usual strategies are paint systems or exciting. steel is an environmentally friendly artefact which means less environmental impacts compared with the opposite trendy structural parts. The usage of steel to implement the property criteria from the extraction and mineral processing of raw materials, through the look and construction of buildings to the tip of life is extremely vital for overall property. Steel and concrete bridge structures have similar impacts on the atmosphere. Steel will totally justify its claims to be the best construction material. It’s ability implies that instead of being destroyed to form means for a replacement building with modified use, a steel-framed building will typically be reconfigured for a replacement use, and given an entire vogue by ever-changing its protection. The long span capabilities of steel construction provides clear areas that may be simply reconfigured, providing the prospect of extending a building’s helpful life. At the tip of a building’s helpful life its steel frame may be simply demolished and components of it either re-used or recycled; de-mountability may be designed into a steel building, permitting house owners to arrange for future use on another web site. Steel employed in construction won’t visit lowland as even scrap steel includes a price and could be a very important part within the method of manufacturing new steel. Steel may be recycled which means subsequent re- cyclings do nothing to cut back its qualities; it’s not simply recycled, however multicycled.
Design is that the start line in any project, the mixing between the look and construction phases can lead to bigger crew productivity as construction concerns are taken under consideration at the design stage. Designers of steel structures ought to remember not solely with style method necessities for the structures however additionally with fabrication and erection strategies to make sure that a steel Structure design course in kerala style will be safely, economically and dependably dead (fabricated, assembled and erected),these could verify whether or not a style is sensible and value economical. There are 2 separate phases of design: • Structural style • style for Erection. Fabrication is that method wont to manufacture steel structures parts which will, once assembled and joined, form a whole frame. The frame usually uses without delay out there normal sections that are purchased from the shaper or steel shareowner, along side such things as protecting coatings and bolts from alternative specialist suppliers. Fabrication involves handling of the stock members, cutting them to size, punching and drilling for connections, and getting ready the connections, in addition as search painting or finishes once needed. The principal activities at the fabrication works: Pre-assembly butt attachment Cutting and identification Drilling and edge preparation Assembly attachment Fitting of stiffeners Shear connectors Trial erection (rarely carried out) Coating application. There are several factors that has to be thought-about throughout the fabrication and have an excellent impact on up the crew productivity for the development of steel structure projects: • Accuracy • Handling and transportation • Shortage materials • broken or defective material • Delivery priority • Schedule time for fabrication. Steel shall be hold on and handled in an exceedingly manner that forestalls injury or distortion. And don’t store materials on the structure in an exceedingly manner which may cause distortion or injury to members of the structure. unreal steel shall be delivered in an exceedingly sequence which will allow economical and economical fabrication and erection and don’t adversely have an effect on productivity, wherever the delivery of materials on dates before beginning the period of erection appropriate time helps to boost the crew productivity wherever they’ll be reviewed and transferred to the erection at the appropriate time, The transfer of materials to the erection website before beginning the method of erection is one among the foremost necessary factors that have an effect on the up crew productivity. In developing the erection methodology totally different aspects of weather will have an effect on productivity, detail coming up with, and therefore the behavior of the structure. And cause hazards for health & safety. The character of the weather at the actual website throughout the amount of the year once erection is to require place must be appreciated, as will its significance for every operation. Safety within the erection steel structure has invariably been a significant issue. Where reliable records are there, steel construction is found to be one among the foremost dangerous on safety and health criteria. Though abundant improvement in steel construction safety has been achieved, the erection steel structure still continues to lag behind most alternative activities with relevance safety. The principal safety objectives once building steelwork are: • Safe access and dealing positions; • Safe lifting and inserting of steel components; • Stability and structural adequacy of the part-erected structure. Quality concerns would like special care. Particularly once the assembly (construction/installation) isn’t in situ, value of remedial works could go extraordinarily high if attention isn’t paid to quality assurance. Within the trendy construction market, quality may be a major performer in construction organization. Created By
Corrosion of Steel
Reinforcing steel corrosion is one of the most serious deterioration mechanisms in reinforced concrete structures and is also an important issue that needs be considered when evaluating and rehabilitating RC structures. Fortunately, there are two self-defense mechanisms that can be employed to protect reinforcing steel against corrosion ,physical protection provided by the dense and relatively impermeable structure of concrete and chemical protection provided by the high alkalinity of the pore solution. The ﬁrst mechanism involves concrete of sufﬁcient depth and good impermeable quality. The second one is a thin oxide covering that forms around reinforcing steel bars due to the high alkalinity of pore solutions, which contain high concentrations of soluble calcium, sodium and potassium oxides, in freshly mixed concrete. However, the random distribution of pore spaces suggests that aggressive substances such as chloride, carbon dioxide, oxygen, moisture, etc. may penetrate through weak points in the concrete cover trigger the corrosion of reinforcing steel bars in concrete and finally induce cracking of the concrete. The aggressiveness of the environment is a very important factor to consider when examining concrete that shows signs of possible distress Generally, corrosion attack is initiated either due to the carbonation of the concrete or due to diffusion of the chloride ions to the reinforcing steel bar surface or both. On account of different aggressive mechanisms, the corrosion due to concrete carbonation is much more uniform than that caused by chloride attack and, hence, it is much less susceptible to local attack .On the other hand, corrosion of reinforcing steel structural course in kerala and the consequent cracking of concrete due to the ingress of chloride ions to the reinforcing steel bar surface is more than that due to carbonation of concrete. Not only will corrosion affect the load-carrying capacity of the reinforcing steel bar, but it may also impair its ductility, which presents a serious problem for the safety of old and monumental constructions in seismically active areas. A lot of research has been done to the corrosion of reinforcement in RC, dealing with various issues related to the conﬁguration of corroded reinforcing steel bars, the load– displacement relationship, residual strength, ductility, etc. The effect of reinforcement corrosion on the residual strength has been of great interest. The ductility of reinforcing steel is normally represented by two parameters, the ratio between the yield and the total strengths and the elongation ratio. The elongation ratio is the average strain of a corroded steel bar in its gauge length. The elongation ratio associated with a shorter gauge length is much greater than that of a greater gauge length and the gauge length was taken as ﬁve times the initial diameter of the steel bar . The elongation ratio decreases with increased corrosion level, although the rates of decrease are different for steel bars corroded in simulated solutions and those corroded in concrete. For the steel bars corroded in simulated solutions the decrease rate is about 0.2, which represents a moderate loss of ductility as corrosion increases; for the steel bars corroded in concrete , the decrease rate is about 0.8, which represents a drastic loss in ductility as corrosion increases. The contribution of the highly localised peak strain does not provide a correspondingly large contribution to overall elongation (Cairns et al., 2005); therefore, the steel bars corroded in concrete present a lower elongation ratio than those corroded in simulated solutions for the same cross-sectional loss. The reinforcing steel bars subjected to local or pitting attack may suffer a signiﬁcant loss of ductility. As far as the fracture pattern is concerned, fracture of the reinforcing steel bar usually occurred at pitted sections and usually happened with a less ductile fracture when the notch was wide and deep.
Steel and Seismic Design
The different aspects of a seismic design has always been a concern when it comes to the designing of steel structure design course in kerala. A number of strategies are important to the design of structures that will behave adequately in strong earthquakes. The major aspects that are considered are continuity, adequate stiffness and strength, regularity, redundancy etc. Continuity. All of the pieces that comprise a structure must be connected to each other with sufficient strength that when the structure responds to shaking, the pieces don’t pull apart and the structure is able to respond as an integral unit. An important aspect of continuity is having a complete seismic load resisting system so that a force that is applied anywhere in the structure has a means of being transmitted through the structure and to the foundation. In addition to vertical frames, a complete seismic load resisting system must also include horizontal diaphragms to transmit inertial forces to the vertical frames. Stiffness and Strength. Structures must have sufficient stiffness so that the lateral deformations experienced during an earthquake do not result in instability and collapse. Structures must have sufficient lateral and vertical strength such that the forces induced by relatively frequent, low intensity earthquakes do not cause damage and such that rare, high-intensity earthquakes do not strain elements so far beyond their yield points that they lose strength. Regularity. A structure is said to be regular if its configuration is such that its pattern of lateral deformation during response to shaking is relatively uniform throughout its height, without bringing a lot of deformation in small areas of the structure. It is important to avoid excessive twisting of structures because it is difficult to predict the behavior of a structure that twists excessively. It also is important to avoid concentrations of deformations in structures because these concentrated deformations can become very large, leading to extreme local damage in the area of the concentration and a loss of vertical load. Redundancy is important because of the basic design strategy embodied in the building codes, which anticipates that some elements important to resisting lateral forces will be loaded beyond their elastic limits and will sustain damage. If a structure has only a few elements available to resist earthquake-induced forces, when these elements become damaged, the structure may lose its ability to resist further shaking. However, if a large number of seismic load resisting elements are present in a structure, and some become damaged, others may still be available to provide stability for the structure. Defined Yield Mechanisms. The most important strategy is to Design a predetermined yield mechanism. In this approach, which is often termed capacity design, the designer must decide which elements of the structure are going to yield under strong earthquake excitation. In order to sustain yielding without undesirable strength loss elements are detailed . At the same time, all of the other elements of the structure, such as gravity load-carrying beams, columns and their connections, are proportioned so that they are strong enough to withstand the maximum forces and deformations that can be delivered to them by an earthquake, once the intended yield mechanism has been engaged. In essence, the members that are designed to yield act as structural “fuses” and protect other elements of the structure from excessive force. This strategy ensures that critical members important to the vertical stability of the structure and its ability to carry gravity loads are not compromised.
Steel is manufactured as a product with no major trade barriers across national boundaries to be seen currently. Steel production in India has increased by a compounded annual growth rate and steel continues to have a stronghold in traditional sectors such as construction, housing and ground transportation. Special steels are increasingly used in engineering industries such as power generation, petrochemicals and fertilizers growth in India is projected to be higher than the world average, as the per capita consumption of steel in India. India occupies a central position on the global steel map. The growth of the steel industry worldwide through mergers and acquisitions has already thrown up several significant concerns. The domestic steel industry has become market oriented and integrated with the global steel industry. The private players could expand their operations and bring in new cost effective technologies to improve competitiveness not only in the domestic but also in the global market. Private sectors contribution to the total output has thus been increasing in India. Development of the private sector has caused a tremendous growth in all aspects of steel industry that is capacity, production, export and imports.
The steel industry is showing promising future growth as major players in the industry have announced their plans for significant investments in expanding their capacities. Rapid development of the steel industry with active participation of private sector and integration of India steel industry with the global steel industry has also induced the government to come up with a National Steel Policy in 2005. The pre-reform steel market in India was controlled in all relevant areas. Competition was restricted in this market that had no real role to play in the growth of the individual companies or their performance and the allocative efficiency of investible resources. The prices fixed by the government were more on political consideration and not strictly on the basis of costs of production or markets demand and supply balance. There are no facts to establish that there is formal or ‘written down’ agreements on prices among the major players. There must be difference between situations such as (i) price rise necessitated by factors external to the industry e.g. increase in capital cost, rise in border steel prices and hence erosion of profitability and (ii) expectation of demand-supply gap providing an opportunity to increase profit Intervention by the government on matters of pricing steel long products also in the recent times has also pointed to the acceptance of the government that the major steel producers have substantial value in the market and act according to the substantial net impact on the market to move the trends in the desired direction. Steel sector was the first to be liberalized and there are enough players; though the industry is concentrated in some segments. However, this in no way suggests that the sector should be subject to regulation, which also includes the government. Regulations must be restricted to market failures like natural monopolies, externalities and asymmetric information between buyers and sellers. The government’s current approach to informally control steel prices is based on the assumption that a few steel detailing course in kochi producers have sufficient command over the market and that they can be discussed to uniformly cut prices to whatever objective to fulfill. Author