1. STRUCTURAL MECHANICS

2. MECHANICS  Mechanics is the branch of science concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment.  The scientific discipline has its origins in Ancient Greece with the writings of Aristotle and Archimedes.  During the early modern period, scientists such as Galileo, Kepler, and especially Newton, laid the foundation for what is now known as classical mechanics.  It is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light.  It can also be defined as a branch of science which deals with the motion of and forces on objects.

3. Mechanics - Scientists  Galilei,  Kepler,  Leonardo da Vinci,  Varignon,  d'Alembert,  Stevinus,  Newton,  Lagrange

4.  All motions you see follow the rules of mechanics.  It is the basis of all engineering sciences. Mechanics - Importance

5. Mechanics Non-rigid bodies Rigid bodies StaticsDynamics Strength Mechanics - Branches

6.  Statics is the branch of mechanics that is concerned with the analysis of loads (force and torque, or "moment") on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity. When in static equilibrium, the system is either at rest, or its center of mass moves at constant velocity  Dynamics deals with motion of rigid bodies and equilibrium in dynamic state. In physics, a rigid body is an idealization of a solid body in which deformation is neglected. In other words, the distance between any two given points of a rigid body remains constant in time regardless of external forces exerted on it.

7. Mechanics  Except those:  Fluid Mechanics  Soil Mechanics  Structural Mechnanics  Structural mechanics or Mechanics of structures is the computation of deformations, deflections, and internal forces or stresses (stress equivalents) within structures, either for design or for performance evaluation of existing structures.

8. Structural Mechanics  Structural mechanics analysis needs input data such as:  structural loads,  the structure's geometric representation and support conditions,  the materials' properties.  Output quantities may include:  support reactions,  stresses and displacements.  Mechanics of structures is a field of study within applied mechanics that investigates the behavior of structures under mechanical loads, such as:  bending of a beam,  buckling of a column,  torsion of a shaft,  deflection of a thin shell,  vibration of a bridge.

9. EQUILIBRIUM

10. Free Body Diagram(FBD)

11. Rigid Body  A rigid body is an idealization of a solid body in which deformation is neglected.  In real world, all materials deform.  However, if the deformation is too small, we assume the body is rigid.  The main principle of statics is equilibrium of rigid body.

12. Supports (Mesnet) If one of the two connected bodies is fixed, the place where the other connects to it is called a SUPPORT.

13. Supports  Roller Support

14. Roller Support(Bridge)

15. Supports  Pinned Support

16. Pinned Support (Bridge)

17. Supports  Fixed Support

18. Supports (Steel Structures)

19. STRENGTH  The basic concepts such as equilibrium conditions, support forces used in rigid body mechanics is also used in mechanics of deformable bodies.  Either static or dynamic, in rigid body mechanics, the strength of material under external forces is out of concern. However, in the mechanics of deformable bodies, only the strength of the materials is studied.

20. The main goal of strength is to calculate under applied loads. Stress Strain Displacement

21. Example:

23. Strength  Can the bar resist the applied loads?  Force  Cross sectional area  Material properties

24. Stress  Force per unit area or  Frequency of loads distributed over an area  Normal Stress  Shear Stress

25. Normal stress Axial Force Force applied along the axis of the element. Can be either Compression or Tension. The corresponding stress is called the Normal Stress.

26. Axial Load Axial load Normal stress

27. Axial Load Tension Compression

28. Shear Force The force acting parallel to the surface.

29. Shear Stress Shear Force Shear Stress

30. Strain Strain:  Unit deformation.  Dimensionless (has no units)

31.  -  Graph

32. Normal stress : Hook’s Law: Deformation: Behavior under axial load:

33. Strength: Resistance to stress without failure. Tension Failure Compression

34. Axial loading test

35. Torsion: (Burulma)

37. Beams (Kirişler)  Beams are the structural elements that carry the loads on the floors to the columns. They are regarded as rods.  In reinforced concrete structures, the floor loads are first transferred to the beams and the beams carry these shear and moment loads to the columns.  The length of the beams between the columns is called beam span.  If beam span increases, the sectional height of the beam should also increase.  The vertical deformation of the beam should be under control.

38. Steel Beams:

39. Concrete Beams:

40. Stresses in Beams:

41. Shear and Moment diagrams Loading Reaction Shear Moment

42. Columns (Kolonlar)  Column; is the vertical structural element. The loads on a structure is transferred to the foundation and the soil by the columns.  The dimensions of the columns should not be less than the ones specified in the codes.  Columns have been used since the beginning of the construction history. At the beginning, natural materials such as Stone or wood were used while making the columns, but with the development of technology, concrete and steel, or only steel columns are used.  Columns generally transfer the loads coming from the beams to the soil beneath. Any damage in the columns may result in the failure of the structure.

43. Columns (Kolonlar)

44. Materials  Elastic Material  Plastic Material  Elastoplastic Material (a) Before loading (b) Under loading (c) After the load is removed Elastic Plastic

45. Types of loads Axial load (Tension/compression) Shear Bending Torsion

46. Truss (Kafes Kiriş)

50. Truss Beam Compression (C) Tension (T)

51. Loads:  Dead Loads  Live Loads Dead Load: The loads resulting from the own weight of structure. Live Loads: Human, goods etc. (changeable)

52. Loads:

53.  Dynamic Loads:  Traffic load  Sudden loads  Wind loads  Vibrating machine loads  Earthquake load

54. Earthquake Loads

55. Wind Loads

56. Types of Loading 1. Distributed Load 2. Uniformly Distributed Load 3. Single Load

57. Water Loads

58. Soil Loads

60. Distribution of Load on Bridges

61. Distribution of Load on Arches ARCH

62. Structural System IDEALIZED REAL

63. Structural System IDEALIZED REAL

64. Bridges  A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle.  Intended use of bridges:  Railways  Highways  Pedestrian  Pipe lines  Shipment (Cargo)  Aqueducts

65. Bridges

67. Bridges for pipelines

68. Bridges for shipment Aqueduct

69. According to their structural systems  Arc bridges  Truss bridges  Cantilevers  Suspension bridges  Cable bridges

70. Arc bridges  Most basic and simple bridge  Only need is the arch form  All bridge elements are under compression

71. Arc bridges  All bridge is under compression.  This compression is transferred to the supports and to the soil accordingly.

72. Types of Arc Bridges Non-hinged Double hinged Triple hingedRestrained

73. Arc bridges

74. Truss arc bridge First metal arc bridge

75. Arc bridges

77. Truss bridges  Composed of one or more truss system.  A lot more internal forces developed compared to the arc bridges as the beams work for bending.  Compression occurs at the upper parts and the tension occurs at the lower parts of the beam.

79. Cantilever bridges  In arc and truss bridges, supports take place at both ends. In cantilever bridges, support is at one point.  There are two types of cantilevers. Single Double

80. Cantilever bridges

81. Suspension Bridges  A thinner structural system (cable) compared to truss bridges  We need a flat deck for traffic. Elements of suspension bridges

82. Suspension Bridges  Towers may be steel or reinforced concrete. (were made of stone in the past)  Because the cable or chain in the main structural system will always be under tension loads and never twist, its rigidity is not important. The main issue is that it should have a cross sectional area that can carry the tension loads.  The towers will always be under compression. So their design is easier.  Large spans may be crossed with such bridges.  The rigidity of the suspension bridges are generally not very suitable for railways.  The effect of wind forces should be investigated in detail.  During construction, cables and tower will be effected from the wind.

85. Cable stayed bridge (Kablo gergili köprü)  Cable-stayed bridges, like suspension bridges, are held up by cables. However, in a cable-stayed bridge, less cable is required and the towers holding the cables are proportionately higher.  The first known cable-stayed bridge was designed in 1784 by C. T. (or C. J.) Löscher.  The longest cable-stayed bridge since 2012 is the Russky Bridge over in Russia.  The towers are mainly reinforced concrete but may also be steel.

86. Cable stayed bridge Harp designed Fan designed

87. Harp designed cable stayed bridge