STD

• may be defined as a mixture of art and science, combining the engineer's judgment.

  Structural Design
• is the process of determining the "response" of a structure due to external "actions"

  STRUCTURAL ANALYSIS
• includes changes in the geometry (displacements or deformations) and/or changes in the state of stress of the structure

  RESPONSE
• are the anticipated forces or loads during the lifetime of the structure

  ACTIONS
• are established to evaluate whether an optimum has been achieved

  DESIGN CRITERIA
• ensures that intended results are achieved

  FUNCTIONAL DESIGN
• the selection of the arrangement and sizes of structural elements so that the service loads may be safely carried, and displacements are within acceptable limits.

  STRUCTURAL FRAMEWORK DESIGN
• establish functions of the structure and set criteria for arriving at an optimum design

  PLANNING
• arrangement of the elements to serve the function in planning

  PRELIMINARY STRUCTURAL CONFIGURATION
• select member sizes to satisfy an objective criterion, such as least weight or cost


  PRELIM INARY MEMBER SELECTION
• structural analysis involving modeling the loads and structural framework to obtain internal forces and any desired deflection.

  ANALYSIS
• structural member sizes are determined to satisfy the requirements of the structural analysis

  DESIGN
• are all strength and serviceability requirements satisfied and is the result optimum? Compare with predetermined criteria

  EVALUATION
• repitition of any part of 1 through 7 found necessary or desirable after the evaluation. Usually, only steps 3 through 7 will be subject to iteration

  REDESIGN
• the determination of whether or not an optimum design has been achieved

  FINAL DESIGN
• are static forces that are relatively constant for an extended time

  DEAD LOAD
• the dead weight of a structure includes its full weight

  SELF-WEIGHT
• permanent appliances and any fixed decoration

  SUPERIMPOSED DEAD LOADS
• are usually variable or moving loads and are usually refered to occupational forces from occupancy and intended use

  LIVE LOAD
• it is a condition of a structure at which it ceases to fulfill intended function

  LIMIT STATE
• maximum ductile strength, buckling, fatigue, fracture, overturning, sliding

  STRENGTH LIMIT STATE
• deflection, vibration, permanent deformation, cracking

  SERVICEABILITY LIMIT STATE
• refers to a number of steels that, because of their economy and desirable mechanical properties, are suitable for load-carrying members in structures

  STRUCTURAL STEEL
• the customary way to specify a structural steel is to use an

  ASTM AMERICAN SOCIETY FOR TESTING AND MATERIALS
• an increase in carbon content raises the yield stress but reduces ductility, making welding more difficult

  CARBON STEELS
• uses carbon as chief strengthening element with minimum yield stresses ranging from 220 MPa to 290 MPa


  CARBON STEELS
• have yield stresses from 480 MPa to 840 MPa

  HIGH-STRENGTH LOW-ALLOY STEELS
• in addition to carbon and manganese, these steels contain one or more alloying elements such as columbium, vanadium, chromium, silicon, copper, and nickel

  HIGH STRENGTH LOW-ALLOY STEELS
• have yield stresses of 480 MPa too 690 MPa


  QUENCHED AND TREMPERED ALLOY STEELS
• these steels of higher strength are obtained by heat-treating low-alloy steels


  QUENCHED AND TEMPERED ALLOY STEELS
• quenching 


  RAPID COOLING
• tempering


  REHEATING
• is that unit tensile stress at which the stress-strain curve exhibits a well-defined increase in deformation without an increase in stress

  YIELS STRESS, Fy
• is the largest unit stress that the material achieves in a tension test

  TENSILE STRESS, Fu
• is the slope of the initial straight-line portion of the stress-strain diagram and is usually taken as 200,000 MPa for design calculation for all structural steel

  MODULUS OF ELASTICITY, E
• is the ability of material to undergo large inelastic deformation without fracture


  DUCTILITY
• is the ability of material to absorb energy and is characterized by the area under a stress-strain curve

  TOUGHNESS
• is the ability of steel to be welded without changing its basic mechanical properties

  WELDABILITY
• is the ration of the transverse strain to the longitudinal strain, is essentially the same for all structural steels, and has a value of 0 in the elastic range

  POISSON'S RATIO
• is the ration of the shearing stress to shearing strain during the initial elastic behavior

  SHEAR MODULUS