AAR 553 STRUCTURAL THEORIES AND APPLICATIONS STEEL (MATERIAL) BY : NAME STUDENT ID1. INTAN INDAHATI BINTI RAHMAN 20105980372. MAISARA BINTI MOHD RAZALI 20101668873. NUR AQILAH BINTI MASKURI 20103722094. NURUL NAJMI BINTI SALLEH 20107627155. WATI ANAK NYAGON 2010167993 LECTURER : MR. SOHAIMI BIN MAN
CONTENTNo Topic Page .1. Introduction 32. Brief History 43. Steel 54. Steel Durability 75. Elasticity 86. Basic Grades 107. Steel Sections 118. Fire Protection 139. Form of Steel Structures 1510. Conclusion 1711. References 18
INTRODUCTION1. Steel is an alloy made by combining iron and other elements ; carbon, manganese, chromium, vanadium and tungsten.2. They act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another.3. Varying the amount of alloying elements and the form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting steel.4. Steel with increased carbon content can be made harder and stronger than iron, but such steel is also less ductile than iron.
BRIEF HISTORY• Though steel had been produced by various inefficient methods long before the Renaissance, its use became more common after more efficient production methods were devised in the 17th century.• With the invention of the Bessemer process in the mid-19th century, steel became an inexpensive mass-produced material.• Further refinements in the process, such as basic oxygen steelmaking (BOS), lowered the cost of production while increasing the quality of the metal.• Today, steel is one of the most common materials in the world, with more than 1.3 billion tons produced annually.• It is a major component in buildings, infrastructure, tools, ships, automobiles, machines, appli ances, and weapons.• Modern steel is generally identified by various grades defined by assorted standards organizations.
Produced from iron ore by removing the ore’s naturally occurringdensity ρ = 7.7 ÷ 8.1 [kg/dm3] impurities elastic modulus E=190÷210 [GPa]Poisson’s ratio ν = 0.27 ÷ 0.30 High strength inThermal conductivity κ = 11.2 tension and ÷ 48.3 [W/mK] compressionThermal expansion α = 9 ÷27 [10-6 / K] STEEL Physical properties of Able to undergo large steel are related to deformation without the physics of the fracture material Ductile material
• The alloys and the heat treatment used in THE MECHANICAL PROPERTIES OF the production of steel result in different property values and strengthsSTEEL CAN BE CONTROL THROUGH : • Testing must be performed to : determine the final properties of steel ensure adherence to the respective Selection of an standards. appropriate chemical composition MEASUREMENT SYSTEMS USED TO DEFINE THE PROPERTIES OF GIVEN STEEL. Processing and heat treatment Yield Toughness is strength, ductilit measured by y and stiffness Final impact Hardness is are determined microstructure testing determined by using tensile measuring testing. resistance to the penetration of the surface by a hard object.
STEEL DURABILITY• Steel structures should be designed to be long lasting and require little maintenance.• The durability of steel is influenced by exposure conditions, steel quality and fire protection. Steel elements can be exposed to a wide range of conditions • the atmosphere, soil, seawater, or stored chemicals. Rusting and surface degradation • caused by atmospheric conditions should be prevented by anti-corrosion treatment, such as surface preparation or painting. Metal coating (galvanizing or zinc spraying) • provide very good protection giving a rust and surface degradation-free life about 20 years
ELASTICITY A typical curve for steel in tensionThe modulus of elasticity for most structural steel tends to be a constant value of approximately 205kN / mm and E=210,000N / mm
BASIC GRADESThe four basic grades of steel are : 1. S450 2. S355 3. S275 4. S235 The numbers represent the minimum tensile strength of each grade in N/mm. Grade S275 is the most commonly used in steel structures at the start of the twenty-first century.
• The rate of loss of strength is very high at temperatures more than 300 degree Celsius.• Commonly used : Concrete Brick work Light encasement
FORM OF STEEL STRUCTURE• Can be constructed or fabricated out of hot rolled structural steel shapes or cold formed steel sections.• It provides adaptability, speed, lower monitoring/ or control; costs and lower preliminaries.• The effects of environmental and other conditions on the final shape of a steel building should be discussed by the design or construction team in the initial stages of planning the layout and preparing the construction plan.
• The architect should consider aspect such as : 1. The integration of facilities 2. Environmental aspects 3. Internal non-commercial values and spaces 4. Creation of a building that would add some excitement, colour, light and size to provide the visual interest 5. Provision for the easy expansion of the area of the building.• All steel buildings must comply with the current building regulations.• These are statutory instruments approved by parliament covering all aspects of building construction.
CONCLUSIONADVANTAGES• Does not deteriorate with age like timber and concrete• Steel is very strong and flexible.• Steel framed houses are ideal in cyclone/hurricane prone regions.• The best material for bridges and skyscrapers• Can be recycled.• Many section types are made (square, tube, H-section, etc).• Steel is such a versatile material which allows radical architecture.• Steel has a high expansion rate in changing temperatures, and this must be allowed for in the engineering.DISADVANTAGES• Heavy• Maintains its strength indefinitely• Expensive to transport.• Susceptible to corrosion which steel bridges must be painted continuously, particularly in a salty environment.• In conditions of repeated stress and changing temperatures, steel can suffer fatigue and cracks, and more corrosion and energy intensive needed to produce steel.
REFERENCES• Al-Nageim, H., Durka, F., Morgan, W., and Williams D., Structural Mechanics: Loads, Analysis, Materials and Design of Structural Elements, Great Britain, 2010• Key To Metals, http://www.keytometals.com/page.aspx? ID=SteelProperties&LN=EN• Parker, B., Prefabricated House, http://www.localhistory.scit.wlv.ac.uk/arti cles/DarlastonHouses/Prefabs.htm