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.

Application of Chrome steel

Austenitic unblemished steels have wonderful corrosion resistance, additionally, even thick, hot-rolled primary solid solution chrome steel plates afford wonderful toughness and weldability. As a result of these characteristics, they’re widely used as steel materials for welded structures, in the main in industrial machines and plants. within the design and engineering fields too, there’s little question that SUS304—the commonest primary solid solution unsullied steel—will still be the foremost probably candidate for the applying of unsullied steels, visible of the very fact that SUS304 contains a smart balance of properties, available in varied forms, and has already found several applications. Once properly used, it is free from conspicuous erosion for an extended time and displays better performance as a steel material. In distinction, since SUS304 contains a substantial proportion of nickel (a rare metal), it’s rather more costly than general structural steels and structural steels that are subjected to corrosion-protective treatment (e.g., plated steels). Moreover, the worth of SUS304 is at risk of fluctuations within the prices of raw materials. even if increasing importance is hooked up to LCC, the higher than value structure for SUS304 is associate degree impediment to increasing its application below gift domestic conditions that square measure loath to any increase in initial work price. In distinction, ferritic chrome steel sheet (cold-rolled sheet), that doesn’t contain nickel, has seen its applications in vehicles and residential appliances, etc., speedily dilated. Formerly, hot-rolled ferritic chrome steel detailing course in kochi was thought-about unsuitable as a steel material as a result of its inferior toughness and weldability. The technological progress has helped in reducing impurities, etc., in steel producing and application/forming technology, like fastening, hot-rolled ferritic chrome steel containing less than regarding 11 November metal currently has enough properties needed of structural steels, and thence will be utilized in several applications. The characteristics and future prospects of a hot-rolled ferritic chrome steel developed for discipline structure—are as follows. Carbon and element impurities square measure reduced and also the microstructures of the merchandise and heat-affected zones square measure rendered finer. The deformation characteristic is analogous thereto of general structural steels, because the fixed strength utilized in structural style, identical worth as that of SS400 steel for structural use will be adopted. The matter of inferior toughness of welded joints and inferior fastening workability has been eliminated that has been a drawback of ferritic chrome steel. Since the steel contains a relatively tiny proportion of metal, it’s subject to erosion corrosion in outside environments containing fine particles of ocean salt. However, in standard outside environments, the speed of corrosion growth is very low and thence enough structural sturdiness will be secured for prolongedstruction. This steel has been approved by the minister as fixed below Article thirty seven of the Building Law, in order that it will be utilized in general buildings. Additionally, the steel could be a high-durability steel that meets the best level of sophistication three (durability: regarding a hundred years) within the classification of measures against deterioration as outlined within the Housing Quality Promotion Act. The steel is predicted to search out applications within the design and engineering fields, not solely as a fabric for the body of long-lived housing, however conjointly as a replacement sort of structural chrome steel that helps scale back the load of corrosion-protective treatment applied throughout work or maintenance.

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

Developments in the Steel Market

Developments in the Steel Market

Steel is usually used by the industrial sector and the demand for steel often leads the cycle in industrial production. The demand for steel grew only during the year of 2016, In the initial 10 months of 2016, the monthly consumption indicator for the major steel-consuming economies increased by approximately 1.9% There is an improvement in the market and demand for steel is expected to increase this year and possibly in the coming few years, according to the market analysts. This shows expectations of expansion of fiscal policy by the new US Administration, including corporate and personal tax cuts and actions to raise steel-intensive infrastructure investment. Major energy project are also being expedited, and the recent revival of two major oil pipeline projects would add demand for steel tubular goods. Canada’s recent approval of energy pipeline projects will also support demand and production of the country’s steel sector going forward.

In India steel demand has increased in a favorable manner being nearly double over the past decade or so. Steel demand has increased nearly 5% per annum in the last few years, supported by the infrastructure and a series of consumption and investment-boosting reforms, including the “Make in India” initiative which has led to increased FDI. In the recent months the demand for steel may have been effected due to the cash shortage associated with the move to demonetize certain currency notes, but strong GDP growth in the fourth quarter of 2016 suggests that the effects may have been more muted than expected. Over the longer term, steel usage will continue to grow to be a favorable one in India, with per capita consumption converging towards higher world average levels . Within Asia, demand growth has been fastest in economies located in Southeast Asia. A report that was released by the South East Asian Iron and Steel detailing Institutes in March 2017, shows that ASEAN steel demand expanded by almost 13% in 2016, rising to a level of 78 million tonnes. Most economies in the region have posted a double-digit steel demand growth, but Vietnam had the highest growth at 20%. That country’s steel association expects significant growth in steel production over the long term, as local producers try to meet steel demand for infrastructure and to support economic development more broadly. Indeed, the country has one of the fastest growth rates in Asia (capacity has nearly doubled in the last four years).

The steel demand developments have been affected in Japan, that reflects a sluggish investment in industrial, electrical and other machinery. Following a decline of 8% in 2015, apparent steel demand has remained stable in 2016, with steel orders up in the construction sectors (particularly civil engineering) and industrial machinery and equipment’s. The output from the industries has also started to recovering in early 2017, and steel demand is expected to recover in line with improved economic prospects. In Ukraine, the mining and steel industry has undergone considerable disruptions as a result of the conflict. The economy of different country having started to recover from the deep recession, and production from industries having shown signs of recovery in late 2016 and early 2017, steel market conditions should improve somewhat going forward.

Concrete

Concrete

Concrete does not burn – it cannot be ‘set on fire’ unlike most other materials in a building and it does not emit any toxic fumes when affected by fire. It will also not produce smoke or drip molten particles, unlike many plastics and metals. Designing with a non-combustible material results in a structure needing simpler fire detailing and therefore having quicker construction programmers. The outcome of inadequate fire details, poor workmanship and modifications during occupation causing a fire risk are reduced when homes have a non-combustible structure.

Much of design for fire safety is concerned with ensuring that people can escape from the building or structure, fire fighters are protected and the fire cannot spread to other properties or areas. Current building regulations for England and Wales are written with these three aims and there is no requirement for protection of property or to minimize damage beyond this. Clients and project teams may choose to go beyond minimum requirements and choose to provide a higher level of protection against the hazards of fire either to further reduce the risks addressed by the building regulations or to protect property.

In the majority of applications, concrete can be described as virtually ‘fireproof’. The materials when chemically combined within concrete, form a material that is important for fire safety design, and has relatively low thermal conductivity. This low conductivity means that the effect of fire is limited to the surface zones of the concrete with the middle of the element often unaffected. This also gives concrete excellent fire separation performance.

According to Government statistics [2] 60% of total household growth in England up to 2033 will come from households of age 65 or over. Designing beyond regulation, to protect an ageing population including vulnerable occupants, as well as occupants who are very young or with mobility limiting conditions, and therefore may need more time to escape a fire, are more reasons to choose a non-combustible material for structures. The materials used in the buildings can be classified according to the reaction to fire and resistance to fire This will determine whether a material can be used and when additional fire protection needs to be applied to it. EN 13501-1 classifies materials into seven grades (A1, A2, B, C, D, E and F).

The highest possible designation is A1 (non-combustible materials). The UK also has a National classification system, which has ‘non-combustible’, ‘limited combustibility’, Class 0, 1, 2, 3 and 4 (with the lower number indicating lower combustibility, smoke emission or flame droplets).Modern concrete and masonry are classed as A1 in the European system and ‘non-combustible’ in the National system, and do not need any further testing nor additional fire treatments. Designers have a responsibility to consider fire as a real possibility that can affect people’s lives and livelihoods. Choosing non-combustible materials, such as concrete and masonry, for the main structure designing course in kerala of a building, provides an excellent starting point for achieving a safer built environment for us all.

A new method called Hybrid construction integrates all concrete to make best advantage of their different inherent qualities. The accuracy, speed and high-quality finish of precast components can be combined with the economy and flexibility of cast in-situ concrete.

Hybrid concrete construction produces simple, buildable and competitive structures. The contractor is benefited from increased component manufacture, safe and faster construction and consistent performance.

Progressive collapse of structures

Progressive collapse of structures means disproportion in size. Though the disproportion between cause and effect is a common feature, there are various differing mechanisms that produce such an outcome. The readiness to the theoretical treatment, approaches for quantifying indices, and possible or preferable alternate measures can vary accordingly. It is better to distinguish and describe the different types of progressive collapse. The term propagating action refers to the action that results from the failure of one element and leads to the failure of further similar elements.

A progressive collapse can be triggered by accident actions, including fire hazard, gas explosion, terrorist attack, vehicle collision, design and construction errors, and environmental corrosion. Due to industrialization, the buildings with multi-function and high complication become more common of which the safety and stability are far more concerned. Thus during the long-term use, the structure may suffer unexpected accidental actions, causing local damage or failure.

The progressive collapse of building structures is a complicated mechanical behaviour of the entire structural systems under large deformation. Problems such as large displacement, large rotation, contact and collision between specimens are inevitable during progressive collapse. Therefore, it is important to select the appropriate model for analysis to consider these features. Targeting at different objects, various progressive collapse models have been developed. The most representative models are the finite element model and the discrete element model. Before the failure of the entire structure the accurate mechanical behaviour can be calculated, but the following condition such as moving and collision between rigid bodies is hardly represented.

The progressive collapse of building structures can be analyzed using three finite models, they are the fine model, simplified model and multi-scale model. According to the mechanical behaviour of structural members the fine model can be established. This method is widely used for specimen because of its large calculations and large modelling process. Since the fine model is more time consuming and laborious simplified model is more preferred in the investigations on the progressive collapse. The ultimate mechanical behaviour of structures can be known by the simplified finite model. The finite element model can calculate the mechanical behaviour before the failure of the entire structure but the collision between the rigid bodies is not represented. The discrete element method brings out the mechanical behaviour of the structure. The dynamic effect can be known by comparing the internal forces and deformations in the dynamic and static analysis. The dynamic equation for structural progressive collapse is very complex hence is very difficult to obtain the simple mathematical expression of the dynamic effect. The structural ability to withstand the local damage due to accident is known as the robustness of the structure design courses in kerala. There are two classifications of the design methods for progressive collapse of building structures (1) the incident-dependent progressive collapse design; (2) incident-independent progressive collapse design. The first one is more accurate and mostly used with buildings with high safety requirement. The second method is all the more simpler.To put an end to the huge damage caused due to the progressive collapse several international designs and codes have been brought into effect.

Design of steel structures

The steel structure course in kerala should have adequate strength, stiffness and toughness for proper functioning.

Design Process

  1. Preliminary member sizing of beams
  2. Structural analysis – modeling, analysis
  3. Design review – member modifications
  4. Cost of estimation
  5. Preparation of structural drawings and specifications
  6. Loads for structural analysis and design
    1. Dead load
    2. Live load
    3. Mean return period OR
    4. Recurrence interval OR
    5. Live loads for various occupencies
    6. Reduction in basic design live load
    7. Impact Load
    8. Wind load

1. Adaptations to site:

If it is a building, the design must be such that there are suitable arrangements for rooms, corridors, stairways, windows, elevators, emergency exits etc and all this plan should be adapted to site so that it is acceptable and at a reasonable cost. This is called functional planning.

2. Structural scheme:

structural scheme is dependent on functional planning. Structural scheme includes the location of columns in the buildings, it is to be carried out with the functional plan and sufficient space must be calculated between finished ceiling and finished floor for location of columns.

3. Structural analysis:

Once the design is laid out, structural analysis must be performed to determine internal forces that will be produced in the framework. Proper calculations must be made and it should be ensured that structure in reality also behaves as it is supposed to be

5. Factor of safety:

The following factors must be considered while developing of design to provide suitable values of the margin of safety and reliability.

  1. Variability of the material with respect to strength and other physical properties
  2. Uncertainty in the expected loads
  3. Precision with which internal forces are calculated
  4. Possibility of corrosion
  5. Extent of damage, loss of life
  6. Operational importance
  7. Quality of workmanship

The design safety of structures may be evaluated in either of the two ways:

  1. Allowable Stress Design
  2. Load and resistance factor design

A. Allowable stress design:

  • Based on the elastic behaviour of the material.
  • The stress is in allowable limits.
  • The full strength of the material is not utilized but we use less value as the limited stress value.
  • It is based on the elastic behaviour of the material
  • The stress on structural members is kept within the allowable limits
  • Full strength of the material is not utilized and a lesser value of the limited stress value is used.
  • The compressive stress is divided by a factor of safety to obtain an allowable or working stress.

Disadvantages of Allowable stress design

  1. In ASD the internal stress is zero before any loads are applied .
  2. ASD does not give reasonable measure of strength. As strength is more fundamental measure of resistance than allowable stress. Safety is applied only to stress. Loads are considered to be uniform. To overcome the above limitations and drawbacks LRFD was evolved.
  3. During manufacturing of steel when it is cooled, the rate of cooling at the top is different than at the bottom or middle and so it causes differential cooling, thus, introducing induced stress internally.
  4. It does not give reasonable measure of strength. .
  5. Safety is applied only to stress level. Loads are considered to be uniform. If not, only option is the factor of safety.

B.Load and Resistance Factor Design(LRFD)

This is based on the principle that strength of various materials and the applied loads depend on certain factors, and thus the structural elements are designed using reduced strength and increased loads.The strength is reduced on the basis of the strength of the material. The load factor is more for the materials that cannot be easily predicted.

Structural behaviour of Steel

Steel structures comprise a large portion of the existing infrastructure worldwide. A number of factors can potentially cause major problems in steel structures in general and steel bridges in particular. These include corrosion, fatigue, design errors, sub-standard materials, vehicle-caused accidental damage, and lack of proper maintenance. In other cases, steel bridges may not be deteriorated or damaged but are rather in need of upgrading to carry larger loads and increasing traffic volumes. In most cases, the cost of adding a component is far less than the cost of replacement and it takes less construction time and therefore reduces service interruption time.

Conventional repair methods of steel structures courses in kerala generally involve bolting or welding Also, adding heavy steel plates increases the dead load of the structure, which limits the target increase of live load carrying capacity. The continuous process of corrosion and the reduced fatigue life associated with the welded steel plates may reduce the durability, and limit the effectiveness, of conventional repair methods Despite the higher cost of FRP materials, compared to steel, the material cost alone generally comprises a very small portion of the overall project cost.. They also have a minimum visual impact on aesthetic appearance and almost no effect on clearances underneath the retrofitted girders.

Retrofit of existing structures is typically needed when live loads increase beyond those the structures were originally designed for. It may also be required because of an inadequate design, damage, fatigue cracking, or deterioration such as corrosion. The following steps are recommended for upgrading steel bridges 1. Welding cover plates to the critical flange areas of the bridge floor beams. 2. When flange material is added, the existing bolting system may become insufficient. This should be corrected by adding more bolts or substituting larger bolts. 3. Bearing stiffeners may be reinforced by bolting or welding angles or by welding plates. 4. Intermediate stiffeners may also be added by bolting or welding plates. 5. If the web was not originally spliced to resist moment, it may be spliced by adding side plates. 6. Tension truss members can be reinforced by the addition of adjustable bars or cover plates. Cover plates must, however, be welded to the gusset plates. 7. Compression truss members can also be strengthened by adding cover plates, either to convert un-symmetric cross sections to a symmetric geometry, or to reduce the width-to-thickness ratio of the plates that comprise the cross section, in order to avoid local bucking and fully utilize their yield strength.

The inherent high strength and stiffness of steel makes it a more challenging material to strengthen, compared to other materials such as concrete and wood. If steel is retrofitted using a material with a lower Young’s modulus, load transfer and hence load sharing of the strengthening material will only be significant after the steel yields .Carbon fibers have outstanding mechanical properties that could be superior to those of steel. It can be concluded for these studies that the use of CFRP materials with elastic modulus equivalent to that of steel and a reasonably high tensile strength would be most suitable for increasing flexural strength of steel beams. On the other hand, CFRP with even higher modulus or larger cross sectional area would be required to increase stiffness of steel beams.

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.

Fabrication of Steel

The fast growing technology has brought about a big change in the steel Fabrication .Now people prefer readily available fabricated components that can be easily assembled at the site. This ensures a better quality and the work is also completed much faster. At present the fabrication work that is followed in India is based on the old techniques as a result it is inefficient. Thus it is not able to support the growth of steel construction in India. So the structural designers must be aware of the latest methods to be used to bring about a change in the fabrication practices. There are several authorised steel structuring institutes that are authorised to provide coaching regarding the latest steel structuring methods.

The fabrication of steel work for a small project is of assured quality but the same in a large project is poor in quality. The fabrication work at the large construction sites must be equipped with the latest methods and it should not harm the environment. The traditional drilling machines are now being replaced with machine operated tools that are effective in drilling materials that are very thick. Before the components are assembled they are fitted temporarily to check if there are any defects. The reason being when we join manually they may not be aligned properly. Any changes in the alignment can be corrected by heating. When a small area is heated the other areas surrounding the material prevents expansion. Hence, after detecting the minute changes the components are assembled and the alignment is properly taken care of. Proper fastening methods must be used so as to maintain the quality. Designing a structural is costly but it can be effective if it is used in a proper manner.

Steel is a very good material but it is useful only if it is handled by an experienced person who understands the value of it. Fabrication helps in transforming the steel into a product that can be used in large scale construction. Without the proper fabrication steel cannot be used for high pressure applications in big buildings. Welding is the most common method used for fabrication because it is simple to fabricate and it reduces the size of the joint. A welded joint is made by fusing the steel plates along the line of the joint. There are different welding processes used. Metal coating is done to protect the steel from corrosion. The commonly used methods are hot dip galvanising, metal spraying and electroplating. Galvanising is the most common method used for applying metal coating to structural steel designing course in kerala. In this method steel is dipped in molten zinc. Galvanised steel does not require painting. Alternative method of applying metallic coating is metal spraying. The metal in powder form is fed through a special spray gun containing a heat source. Painting is also used to prevent corrosion.

Because of the latest techniques the architectural designs have become more complex and stylish.This is because the quality of the steel used in the designs is good in quality. The use of the latest technology has helped in the formation of three dimensional structures .Fabricated structures can be easily used in any kind of a project but fabrication is a difficult task and has to be done by a professional.