Steel

• Welded connections


  The method of joining two or more pieces of metal together by using heat and/or pressure to melt the parts at the joint, with or without the addition of a filler material
• Welded connections


  • Permanent joints - unlike bolted or riveted connections, welded connections are typically permanent and cannot be easily disassembled
  • Load transfer - welds provide a continuous load path, which can enhance the structural integrity of the assembly
  • Material fusion - the process involves the fusion of the base materials, often with a filler metal that has a compatible composition
  • Versatility - can be used in a wide range of applications, from small-scale manufacturing to large structural assemblies
• Types of Welds


  • Fillet Welds
  • Groove Welds
• Types of welding


  • Shielded Metal Arc Welding (SMAW)
  • Gas Metal Arc Welding (GMAW)
  • Flux-Cored Arc Welding (FCAW)
  • Submerged Arc Welding (SAW)
• Shielded Metal Arc Welding (SMAW)


  Also known as stick welding, this process uses a consumable electrode coated with flux to lay the weld
• Shielded Metal Arc Welding (SMAW)

  • Applications - construction, repair, and maintenance work
  • Advantages - versatile, inexpensive, and portable
  • Disadvantages - slower than other methods, more cleanup required
• Gas Metal Arc Welding (GMAW)


  Also known as MIG (Metal Inert Gas) welding, this process uses a continuous solid wire electrode fed through a welding gun and shielded by a gas
• Gas Metal Arc Welding (GMAW)

  • Applications - automotive, manufacturing, and fabrication
  • Advantages - high welding speed, cleaner welds, easy to learn
  • Disadvantages - equipment can be costly, sensitive to wind (outdoor use)
• Flux-Cored Arc Welding (FCAW)


  Similar to MIG welding, but uses a tubular wire filled with flux. Can be used with or without shielding gas
• Flux-Cored Arc Welding (FCAW)


  • Applications - heavy equipment repair, construction, shipbuilding
  • Advantages - high deposition rates, effective for thick materials, works well outdoors
  • Disadvantages - more complex equipment, higher cost of consumables
• Submerged Arc Welding (SAW)

  This process uses a continuously fed consumable electrode and a blanket of granular fusible flux
• Submerged Arc Welding (SAW)

  • Applications - large structural welds, shipbuilding, pressure vessels
  • Advantages - deep weld penetration, high productivity, minimal smoke and fumes
  • Disadvantages - limited to horizontal and flat positions, not portable
• Welding electrodes


  Materials that conduct electricity and are used to create an electric arc between the electrode and the base metal, which melts and fuses the materials together
• Purlins


  Horizontal structural members in a roof that provide support for the roof covering and transfer loads to the primary structure of the building
• Purlins


  • They typically run parallel to the ridge or slope of the roof and are placed perpendicular to the roof rafters or trusses
  • They help to distribute the weight of the roof evenly
  • They can also serve as a base for attaching roofing materials such as metal sheets or tiles
  • They come in various materials such as wood, steel, or concrete, depending on the design requirements and the structural needs of the building
• Sag rods


  Structural elements used to provide additional support and stability to roof trusses or other roof structures
• Sag rods


  • They are typically installed diagonally between the top chords of the trusses, helping to prevent excessive deflection or sagging of the roof under load
• Tie rods


  Structural elements that can sometimes be used in conjunction with purlins to provide additional stability and support
• Tie rods with purlins

  • The purpose could be to resist lateral forces, prevent buckling or deformation of the purlins, or to enhance the overall rigidity of the roof or building structure
• Steps in Design/analysis of roof purlin

  1. Check for compactness

  2. Compute for the deadload and liveload

  3. Compute for the tangential component and normal component

  4. Compute for the moment due to loading x and y

  5. Compute for Lb,Lp,Lr

  6. Solve for moment capacity of the beam

  7. Check for adequacy of the beam
• Fillet Welds


  used to join two surfaces at approximately right angles to each other in a lap, T, or corner joint
• Groove Welds


  used to join two edges or surfaces that are in the same plane
• Base Plate


  • Crucial structural element used in construction, particularly in steel structures, to transfer the load from a column to the foundation or other supporting structure
  • Ensures stability and effective load distribution, preventing excessive stress concentrations that could compromise the integrity of the structure
• Steps in Design of Base Plate

  1. Solve for Factored Loads

  2. Compute for Required Bearing Area

  3. Determine Dimensions

  4. Resolve for PN, Pu and Pa

  5. Solve for Thickness
• Pu


  Factored Load
• φ


  Resistance Factor
• P


  Service Load
• n


  Load Factor
• Pn


  Nominal Bearing Resistance
• A1


  Area of Base Plate
• A2


  Area of Pedestal
• B


  Width of Base Plate
• C


  Length of Base Plate
• t


  Thickness of Base Plate
• Pa


  Allowable Load
• A W10x49 section is used as a column and is supported by a concrete pedestal
• The column will support a service dead load of 450 kn and a service live load of 650KN
• The concrete strength is class A concrete and the pedestal is 450x450
• Bf


  Flange Width
• A


  Cross-Sectional Area