Category Archives: Tekla

What is the influence of manganese in Steel?

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

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.

Steel construction

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.

Factors affecting the Performance of Steel Construction

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.

Corrosion of Steel

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

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 Industry

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.

Residual stresses in Steel sections

Residual stresses in Steel sections

The stresses remaining in unloaded steel sections are of importance in column style as they lead to reduction of flexural stiffness of the columns and consequently during a lower buckling strength .Although residual stresses area unit self-equilibrating, the effective moment of inertia of the cross section are going to be modified once elements of the section, that have residual compressive stresses, area unit yielded. It is noticed that the magnitude of most residual stresses in hot-rolled sections of a moderate steel strength is about up to 30 % of the yield strength and area unit uniformly distributed across the thickness of the plate. A longitudinal residual stress gradients will if truth be told be found in cold-formed HSS tubes. One gradient is thought because the perimeter (membrane) residual stress and is developed parallel to the tube wall. The opposite gradient is thought because a thorough thickness residual stress is developed across the tube wall face and on the cross sectional perimeter. The most dominant parameter that affects the tangent modulus and supreme strength of HSS column is the residual stress gradient. The magnitude of this kind of residual stresses varies from twenty five to 70 % of the fabric yield strength.

Retrofit of existing structures is usually required once live masses increase on the far side of those structures that were originally designed. it may also be needed due to the associate degree of inadequate style, damage, fatigue cracking, or deterioration like corrosion. The subsequent steps for upgrading steel bridges are:

1. Fastening cowl plates to the crucial rim areas of the bridge floor beams.

2. Once rim material is supplementary, the present bolting system could become light. This could be corrected by adding additional bolts or subbing larger bolts.

3. Bearing stiffeners is also strengthened by bolting or fastening angles or by fastening plates.

4. Intermediate stiffeners can also be supplementary by bolting or fastening plates.

5. If the net wasn’t originally spliced to resist moment, it’s going to be spliced by adding facet plates.

6. Tension truss members are often strengthened by the addition of adjustable bars or cowl plates. cowl plates should, however, be welded to the gusset plates.

7. Compression truss may be brought into effect by adding cowl plates, either to convert unsymmetrical cross sections or to cut back the width-to-thickness magnitude relation of the plates that comprise the cross section, so as to avoid native bucking and totally utilize their yield strength.

The usually mentioned ways of retrofitting steel bridges (and structures) generally involve bolting or fastening further steel plates to the structure. These ways, however, have variety of constructability and sturdiness drawbacks. In several cases, fastening isn’t a fascinating answer because of fatigue issues related to weld defects. On the opposite hand, mechanical (bolted) connections that have higher fatigue life, area unit time intense and expensive. Drilling holes for fast connections conjointly ends up in a cross sectional loss further because the introduction of stress raisers. In addition, structural steel designing courses in kerala plates need work instrumentality and will add hefty dead masses to the structure that reduces their strengthening effectiveness. The supplementary steel plates also are prone to corrosion that may lead to a rise in future maintenance prices.

There is a requirement for adopting sturdy materials and cost-efficient retrofit techniques to beat a number of the drawbacks of standard techniques explicit earlier. One among the potential solutions is to use high performance non-metallic materials like FRPs. In general, FRP materials give superior strength-to-weight ratios for retrofit of structures. FRP rigid plates and versatile sheets area unit obtainable and may simply be applied to the surface. FRP versatile sheets especially supply a singular advantage of having the ability to adapt to complicated and hook like surfaces.

Prefabrication

Prefabricated construction could be a new technique and is fascinating for big scale housing programmes. The main aim of prefabrication are :

1) To impact economy in value

2) To boost in quality because the elements is factory-made below controlled conditions.

3) To hurry up construction since no hardening is critical.

4) To use domestically on the market materials with needed characteristics.

5) To use the materials that possess their innate characteristics like lightweight weight,easy workability, thermal insulation and combustibility etc.

Need for Pre fabrication

1. Ready-made structures square measure used for sites that aren’t appropriate for traditional

construction technique like cragged region and additionally once traditional construction

materials aren’t simply offered.

2. PFS facilities may be created at close to a site as is finished to form concrete blocks

used in plane of standard knick.

3. Structures used repeatedly might be standardized .

Advantages:

  • Readymade elements are used
  • Shuttering and staging is greatly reduced.
  • Construction time is reduced and buildings ar completed sooner permitting on
  • Earlier come back of the capital invested with.
  • On-site construction and congestion is reduced.
  • Internal control is easier during a plant mechanical system setting than a construction and Site setting.
  • Manufacture is placed wherever expert labour, power materials house and
  • Overheads are lower.
  • Time spent in weather or dangerous environments at the development web site is minimised
  • Materials for staging is keep partially or fully and used
  • Accessibility of precise structure and expect acquisition.
  • The Time Period is reduced.
  • Fewer enlargement joints are needed.
  • Interruptions in connecting is omitted.
  • Work is completed with a higher technology.
  • Less employees are required.

DISADVANTAGES

  • Careful handling of ready-made elements like concrete panels or steel and
  • glass panels is needed.
  • Attention must be paid to the strength and corrosion-resistance of the change of integrity of
  • prefabricated sections to avoid failure of the joint
  • Equally leaks will generate at joints in ready-made elements.
  • Transportation prices could also be higher for voluminous ready-made sections than for
  • the materials of that they’re created which might usually be packed additional with efficiency.
  • Giant ready-made structures need heavy-duty cranes measurement and handling to position in position.
  • Giant teams of buildings from identical style of ready-made components tend to
  • look drab and monotonous.
  • Native Jobs area very less

Prefabricated building parts are utilized for buildings that are factory-made off

site and shipped later to assemble at the ultimate location a number of the unremarkably used

prefabricated building. The materials employed in the ready-made parts area several.

The modern trend is to use concrete steel, treated wood, metal cellular concrete,

light weight concrete, ceramic product etc. whereas selecting the materials for

prefabrication the subsequent special characteristics area unit to be thought-about.

  • light-weight
  • Thermal insulation property
  • simple workability
  • sturdiness altogether climatic conditions
  • Non combustibility
  • Economy in price
  • Sound insulation

In the olden days building a house was by the use the bricks, timber, cement, sand, steel and construction mixture etc and to construct the house on site from these materials. In ready-made construction solely the foundations are created during this method. While sections of walls floors and roof ar ready-made structures with windows and door frame enclosed and transported to the positioning upraised in to position by a crane and stewed along. tekla structural steel designing courses in kochi

Steel Erection

There are four main steps for steel erection

  • Making sure that the foundations are suitable and safe for erection.
  • Cranes are used for lifting and placing components into position.

Alignment of the structure has to be done by checking that column bases are lined and in level.

  • All the connections have to be checked to make sure that the frame is rigid.

Cranes and Mobile Elevating Work Platforms are usually used for the erection of structural steel designing course in kerala work for buildings. Cranes can be of two types mobile and non-mobile. Mobile cranes include truck mounted cranes, crawler cranes and all-terrain cranes whereas non mobile cranes refers to the tower cranes.

MEWPs are used during steel erection which means it is used to bolt-up the pieces being lifted in by the crane. The MEWPs can be used either on the ground or on the partly erected steelwork to erect lighter steel elements directly .Also the steel work must be able to support the weight of the MEWP. Usually truck mounted cranes do not require a back-up crane and require very little set-up time. These two features mean that they are suitable single day commissions. It requires a larger footprint than what is required for an equivalent crawler crane to achieve a high lifting capacity from a light vehicle. The size of the footprint can be increased using outriggers but to provide a solid base and ensure adequate stability, good ground conditions are necessary.

Crawler cranes are stronger than truck mounted cranes therefore Ground conditions are less critical. Crawler cranes can travel with suspended loads on site, because they are stable without the use of outriggers. They do have a high lifting capacity. Since transportation to and from site is expensive, daily hire is not possible. They are more competitive than truck mounted cranes for long periods.

Because of their size, Tower cranes are assembled on site and their operation also requires a second crane. Dismantling, is also very expensive. They are only used when site conditions are in need for an alternative. A tower crane can be possibly affected due to wind loading, which may affect the working of the crane. The advantages of a tower crane is its ability to lift to greater heights and to lift their capacity over a significant proportion of their radius range. A tower crane can be erected within, the building frame. A tower crane can also be tied to the building frame to provide stability as height increases.

The difficulties during steel erection are related to falls from height, either from working positions or while gaining an access to it. Structural instability or any failure during erection handling, transportation and lifting of heavy components could also be a disadvantage. A dedicated department looks after the hazards and risks in steel construction as well as the issues related to works on construction sites

The main objective of the erection process is to handover the frame to following trades in an acceptable condition. The key aspect here is the accurate positioning of the erected frame, and this depends on an understanding of how the erected position of a steel frame is controlled.

A steel structure is an assembly of a large number of relatively slender and flexible components. Overall accuracies of approximately 1 part in 1000 are sought for plumb and line of the completed structure, using components that may individually be manufactured with greater variability. Apart from that deformations of the structure under self-weight of steel may affect its actual position. The concepts involved and the methods used for control of the erected position of a steel frame must be understood clearly.