# Structural Analysis : Classification of Structures Unit 1 Part 1

Que1.1. Define the term’ Structure’. Also  bandy the structural   rudiments.  Answer  Structure  1. A structure is a system of connected  corridor used to support a  cargo.  exemplifications of structures in civil engineering are  structures, islands and   halls.  2. While designing a structure the  mastermind must  regard for its safety,  aesthetic and  utility also taking into consideration  profitable  and environmental constraints.  Structural Elements The common structural  rudiments are as  follows  1. Tie rods 2. shafts 3. Columns  1. Tie Rods( or Bracing Struts) Tie rods or bracing struts are the  structural members  subordinated to tensile force. Tie rods are slender and  are  frequently chosen from rods, bars, angles or channels.  Rod Bar  Angle Channel  Typicalcross-sections  Tie rodFig.1.1.1. Tie rods.  2. shafts  shafts are  generally straight vertical members used primarily to carry   perpendicular loads.  ii. When the  sampling varies, the ray is appertained to as phased or   hunkered . shafts are primarily designed to  repel bending moment.  Bracket of Structures 1 – 4 C( CE- Sem- 5)  Simply supported ray  Cantilevered ray  Fixed- supported ray  nonstop ray 1.1.2. shafts.  3. Columns Columns are  generally  perpendicular and  repel axial compressive  loads. occasionally columns are  subordinated to both an axial  cargo and a  bending moment,  also these columns are known as ray columns.  Que1.2. Explain the bracket of structures in detail.  AKTU 2012- 13, Marks 05  Answer  Bracket of Structures These can be classified as follows  1. On the Base of Structural Forms and Shapes  Linear forms( Cadaverous structures).  ii. Curvilinear forms( face structures).  Linear Forms  They’re articulated structures assembled with  corridor  conforming of  direct  rudiments,  similar as bars and  shafts, the connection between  them being bolted or  concentrated or welded.  Linear forms are preferred for domestic,  sanctioned, and educational  purposes. The direct form is called cadaverous structures.  a) Frame( b) Artificial chalet( c) Plate  exemplifications Frame, high rise structure, stilt, artificial chalet, ground   sundeck, plate,etc.  ii. Curvilinear Forms  Curvilinear forms as single  realities  substantially  enthrall  a space.  b. These structures are idealized as  nonstop system for structural  analysis purpose.  They’re 3- D structures and they’re also  nominated as  face  structures.  exemplifications Dome, shells,  bends,  lines, spherical members,etc.  a) Dome( b) Arch( c) Spherical member  w kN/ m   2. On the Base of Dominant Stress Conditions  Livery stress forms. ii. Varying stress forms.  Livery Stress Forms When the stress across a section is  invariant  over the depth of a member or over the consistence of a panel, such a form  is called livery stress form.  Example Cables,  bends, band member, shellsetc.  ii. Varying Stress Forms When the stress varies over the depth or  consistence, from a maximum compressive stress on one  face to a  maximum tensile stress on the other, such a form is called varying  stress form.  Example shafts, rigid frames, crossbeams, platesetc.  3. On the Base of the Complexity of their Force Analysis  shafts and trusses. ii. lines and  bends.  iii. Frames. iv. face structures.  shafts and Trusses  shafts and trusses are a form of structures.  b. A simply supported ray, supported on a leg at one end and a comber  at the other end is  relatively stable and statically determinate, and  transmits the external loads to the supports  substantially through shear  and moment.  c. Some  generally complex types of  shafts are fixed end  shafts and   nonstop  shafts. These  shafts are statically indeterminate and  can not be answered using equations of static equilibrium alone.  a) Simple ray( b) Fixed end ray  c) nonstop ray  Compression  Tension  d) Stilt  ii. lines and bends  a. These two form of structures are used for long span.  lines are  generally flexible and carry their loads in pressure.  c. The external loads aren’t applied along the axis of the  string and  accordingly  string takes a form of defined  slack.  lines are generally used to support islands and  erecting roofs.  bends are characterized by high axial thrust and  fairly low  bending moment which affect from its distinguished shape as well  as the vertical  responses that developed at the support points.  bends achieve their strength in  contraction. bends must be rigid  in order to maintain its shape.  bends are used in ground structures,  pate roofsetc.  a) Arch( b) Cable structure  iii. Frames  Frames are composed of  shafts and columns that are either leg or  fixed connected.  Frames are characterized by moment  defying members at some  or at all the joints. , this structure is generally  If it has rigid  commonconnections.indeterminate. Frames can be two or three dimensional.  a) Artificial frame() Multi storey   structure frame  iv. face Structure  a. A  face structure is made of a material having  veritably small consistence  compared to its other  confines.  face structures may also be made of rigid material  similar as   corroborated concrete.  c. They may be shaped as folded plates, cylinders or hyperbolic  paraboloids and are appertained to as thin plates or shells.  d. These structures act like  lines or  bends since they support loads  primarily in pressure or  contraction, with  veritably little bending.  a) Spherical shell( b) Hyperbolic paraboloids   Que1.3. Define the term  frame and explain what are the  framed structure system and  nonstop structure system?  Answer  1. Framework A  frame is the  shell of the complete structure  and it supports all intended loads safely and economically.  2. Framed Structure System Assemblage of members forming a frame  to support the forces acting on it, is called the framed structure system.  As frame, high- rise structure, stiltetc.  3. nonstop Structure System Assemblage of  nonstop member  like shells,  pollsetc., are called  nonstop structure system. As  spherical members, space crafts, aircraftsetc.   Que1.4. What do you understand by the term structural  cargo?  Explain different types of loads.  Answer  Structural cargo Structural  cargo is consists of following loads  1. Dead Loads  Dead loads are fixed to the structure and is  substantially  steady with time.  Example Self weight of the structure,  cabinetwork,etc.  ii. Dead loads  live permanently in the structure and are the  introductory  parameter for design in all structural systems.  2. Live Loads Live loads are the loads which are variable in nature, both in  the time and magnitude. These loads are applied over and above the dead or  fixed loads. They’re generally known as assessed loads.  3. Environmental Loads  i. These loads are due to wind, earthquake,  cataracts, landslidesetc., and  caused by natural  miracle.  ii. These loads are  substantially non deterministic because of  misgivings  associated with their  circumstance, time and magnitude and terrestrial  conditions.  4. Man- made Loads Man- made loads are caused by  mortal conditioning. These  loads are  suchlike impact loads, blast loads, dynamic loadsetc.  Types of Loads  1. Bracket of Loads on the Base of Direction in which Loads  are Acting  graveness Loads graveness loads are the dead loads, live loads, snow and  ice loads because they always act vertically  down.  ii. Side Loads The loads which act horizontally as wind loads,  earthquake loads and soil and hydrostatic pressures are known as  side loads.  iii. Directionless loads Thermal loads, loads due to misfit and blasting  loads are known as directionless loads.  2. Bracket of Loads on the Base of Their Variation with  Time  stationary or Monotonic Loads Loads that don’t vary with time and always  act in the same sense are known as monotonic or  stationary  cargo. illustration dead  loads, construction loads, snow loads and earth pressureetc.  ii. Cyclic or Dynamic Loads  Loads that vary with time and change their sense are known as cyclic  or dynamic loads.  Example earthquake loads, impact loads, blast loads and machine   convinced loads. Dynamic  cargo sets the structure to  joggle.  Fatigue  cargo is a special case of dynamic or cyclic  cargo which is applied   constantly on the structure for a long duration. illustration business and   surge  convinced loads.  Que1.6. What do you mean by degree of freedom? Also explain  the kinematic indeterminacy. AKTU 2012- 13, Marks 05  OR  What do you understand by kinematic indeterminacy of  structures? Explain in sufficient detail.  AKTU 2013- 14, Marks 05  Answer  Degree of Freedom  1. When a structure composed of several members which are  subordinated to  loads, the joints  suffer  deportations in the form of gyration and   restatement.  2. The number of independent  common  relegation is called the degree of  kinematic indeterminacy or the number of degree of freedom.  Kinematic Indeterminacy  1. Degree of kinematic indeterminacy or number of degree of freedom is  the sum of degree of freedom in gyration and  restatement.  2. A joint in space can have six possible movements( 3 direct  deportations,  one along each reference axis and 3  reels, one about each reference  axis) hence it has six degree of freedom.  3. In case of a two dimensional system, a free joint has three degree of  freedom( Two  restatement and one gyration) hence in case of two  dimensional system any joint may have  outside of 3 degree of kinematic  indeterminacy.  4. The total kinematic indeterminacy of a structure represents the sum of  all the possible  relegation that  colorful joints of the structure can   suffer.