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   Bolt  .... Bolt is a metal pin with a head at one end,a shank threaded at the other end to receive a nut.  Types of bolt   1- unfinished bolts or black bolts or C grade bolts.  2- Turned bolts  3- Ribbed bolts  4- High strength bolts  1-Unfinished bolts   Other name of unfinished bolts- ordinary bolt, rough bolt, black bolt  Unfinished bolts generally used for light structures subjected to static loads and for secondary members such as purlins, bracing ,roof trusses etc.  They are not recommended for connections subjected to fatigue, vibration and impact load. These bolts are forged  from low carbon rolled steel circular rods.  2- Turned Bolts   These are similar to unfinished bolts, with the difference that the shanks of these bolts are formed  from a hexagonal rod. The surface of these bolts are prepared and machine carefully to fit in the hole.  3- Ribbed Bolts   These type of bolts have a ro...

   Connections ....   S teel structures are formed by connecting available standard section.Connection form an important part of any structure and are designed more conservatively than the individual members. The connections provided in steel- structures can be classified as follows  (1)- Riveted connection. (2)- Bolted Connection. (3)- Welded Connection. (4)- Pinned Connection. (1)- Riveted connection. R iveted connection is  old and at this time not in use  ,but for rehabilitation of older structure an understanding of its behaviour and design is essential.   A rivet is made up of a round  ductile  steel bar piece called shank with a head one end.  Important points. Shank - A rivet is made up of a round ductile steel bar called shank as shown in fig. Grip - distance between the under sides of the two heads. The grip length should not be more than 4d. Nominal Diameter - The diameter of shank is called the nominal Diameter  Pat...

  Specific Gravity   The  ratio  of the mass of a solid or liquid to the mass of an equal volume of distilled water at 4°C (39°F)  or  of a gas to an equal volume of air or hydrogen under prescribes conditions of temperature and pressure. Determination of specific Gravity  Specific gravity can be determined by the Pycnometer or by 500 ml flask or by  50 ml density bottle  Note   (Important) P ycnometer 900 mL  → if water used in Pycnometer for determination of specific gravity then it is only for coarse grain soil. If we used  Kerosene  oil for determination of specific gravity then Pycnometer can be used for both type of soil i.e fine grained soil and coarse grained soil.  500 mL flask  →Can be used  both type of Soil fine soil and caorse grained soil  ( in water or kerosene oil) 50 ml density bottle  →Can be used  both type of Soil fine soil and caorse grained soil( in water or kerosene oil)...

    Special types of concrete  (1)- High strength concrete (2)- Light weight concrete (3)- Heavy weight concrete (4)- pre- packed concrete  (5)- polymer concrete  (6)- Fibre reinforced concrete  (7)- Ready Mixed concrete (RMC)  (8)- pre -stressed concrete  (1) High strength concrete   High strength concrete (HSC) is considered to be the one having a compressive strength in excess of 40 MPa .To produce concrete above this strength more stringent quality control and more care in selection and proportioning of materials are needed. Most cement used to produce HSC,have fineness in the range of 300-400 m2 /kg with an exception of high early strength cement for which fineness should be at least 450 m2/kg  (2)- Light weight concrete Light weight concrete are lighter in weight (1.6 kN/m3 to 22 kN/m3) as compared to normal concrete (24 kN/m3) . Light weight concrete is obtained by putting in light weight aggregate instead of normal heavy weight a...

  Design of steel structures       methods for designing of steel structures are as follows  . (1)- Working stress method or Elastic method. Note  -  working stress method   is the oldest method for designing of steel structures  (2)- Ultimate load Design or Plastic design method  (ULD) (3)-Limit state methods . It is new design procedure (1)- Working stress method or Elastic method.(WSM) In this method  working stress should be less or equal to permissible stress. i.e   [Working stress ≤ Permissible stress.]  Disadvantages of working stress.(WSM) (1)- It fails to provide a uniform overload capacity of all parts and types of structure. (2)-It does not take into account the non- linear relationship between stress and strain and the ability of structural members to resist loads even after local yielding. (3) It is un economical method (4) It is considered linear elastic behaviour.   (2)- Ultimate load Design or Pla...

  Pitch   It is the distance between the centre of two consecutive rivets measure along a row of rivets i.e measure parallel to the stress in a member .It is denoted by p . Minimum pitch  If    Φ = 20mm then  p min = 2.5x21.5= 54mm  Where    Φ = nominal Diameter of rivet Maximum pitch  Maximum pitch is kept under following standard. (a) pitch maximum when tacking rivets are provided then take lesser value of  32t or 300mm,  where t= thickness of plate of least thickness  (b)- For tension member it should be lesser value of  16t or 200mm. (c) For compression memeber  12t or 200mm  which is less. Gauge(g) -  it is the distance between adjacent rivets lines which is perpendicular to the stress in a member .it is denoted by g  Edge distance    it is distance between centre of rivet and edge of the plate measured perpendicular to the direction of load. End distance  it is distance between...

   Self compacting concerete   Self compacting concrete (SCC) is concerete which is able to flow under its own weight, completely filling formwork & Achieving full compaction, even in the congested places  The scc mixes  have these attributes beacuse of their good deformabilty enabling them to maintain homogeneity at a fresh state. It can be placed and compacted under its self weight with little or no vibration Effort & which is at the same time is cohesive enough to be handled without segregation and bleeding. Viscosity modifiers admixture added to fresh concrete to increase cohesion and segregation resistance. Viscosity modifiers admixture increase the plastic viscosity and improve the stability of the mixture  at a constant fluidity.  Admixture added during the mixing process of concrete in small quantities related to the mass of the cementious binder to modify the properties of fresh  or hardened concrete . Material for SCC  ...

   Steel structures  Definition-  it is combination of members which is designed for specific purpose. Structural steel   Structural steel is a material used for steel construction.Steel is an alloy of iron and carbon.Apart from carbon by adding small percentage of manganese, sulphur, phosphorus,chrome nickel and copper. Note  . Cast iron -  percentage of carbon varies 2%-4%  Wrought iron  -  percentage of carbon 0.15% Steel  -  percentage of carbon  0.15%  Mild steel - percentage of carbon 0.15%-0.30%  Physical properties of structural steel . (1)- Density - 78.5kN/m3 (7.85gm/cc)or (7850 kg/m3). (2) Co-efficient of linear expansion-  12x10^6/°C. (3)-Young's Modulus -2.04x10^5 Mpa or 2x10^5 N/mm2. (4)-Modulus of Rigidity - 0.84x10^5 - 0.98x10^5 N/mm2 Types of steel structure   (1)- Frame building  (2)- Plate girder used for bridges . (3)- Steel arch bridge  . (4)- Industrial building . (5)- Tr...