blog 14 Steel connection system

 Hi there,

STEEL CONNECTION SYSTEM

CONNECTIONS IN STEEL STRUCTURES

-     Connections are structural elements used for joining different members of a structural steel frame work.

-          Steel Structure is an assemblage of different member such as “BEAMS,COLUMNS” which are connected to one other, usually at member ends fast ,so that it shows a single composite unit.

COMPONENTS OF CONNECTION

                                - Bolts

                                - Weld

                                - Connecting Plates

                                - Connecting Angles

CLASSIFICATIONS OF CONNECTION

                                - On the Basis of Connecting Medium.

                                - According to the type of internal forces.

                                - According to the type of structural Elements

                                - According to the type of members joining

ON THE BASIS OF CONNECTING MEDIUM

                                - Riveted Connections

                                - Bolted Connections

                                - Welded Connections

                                - Bolted-Welded Connections







RIVETED CONNECTIONS

                - Used for very long time.

                - Made up of:

                                Round Ductile steel bar called shank. A head at one end

          The length of the rivet should sufficient to form the second head.

                - Design, very similar to bearing type of bolted connection.

BOLTED CONNECTIONS

                - Fastened Together primarily by Bolts.

                - Bolts may be loaded in: Tension Shear Both Tension & Shear

                - Threads of bolts under shear force:

                                Excluded - Increased strength

                                Included - Decreased strength.

                - Types of bolt

                                Bearing type bolts ,High strength friction grip bolts.

ADVANTAGES

                1. The bolting operation is very silent

                 2. Bolting is a cold process hence there is no risk of fire

                3. Bolting operation is more quicker than riveting

.               4. Less man power is required in making the connections.

 DISADVANTAGES

                1. If subjected to vibratory loads, results in reduction in strength get loosened.

                2. Unfinished bolts have lesser strength because of non uniform diameter

WELDED CONNECTIONS

                - whose components are joined together primarily by welds

                - Types of weld

                                Groove ( More reliable than others)

                                Fillet (Mostly used, Weaker than groove and others)                 

                                Plug (expensive – poor transmission of tensile forces)                   

                                Slot (expensive - poor transmission of tensile forces) 

                                Plug and Slot welds – stitch different parts of members together.

POSITION OF WELD

                                Horizontal, Vertical, Overhead, Flat



TYPES OF STRUCTURAL ELEMENT

                                - Single plate angle Connections

                                - Double web angle connections

                                - Top and seated angle connections

                                - Seated beam connections

SINGLE PLATE ANGLE CONNECTIONS

                - Two Step Process

                - A plate is welded to secondary section (beam)

                - An Angle is welded to Primary Section (column or Beam)

                - single shear plate welded to secondary beam and bolted to Primary beam or column.

DOUBLE WEB ANGLE CONNECTIONS

                                     - Two angles welded or shop bolted to the web of a secondary beam.                                      - After erection the angles are bolted or site welded to the primary                                          member (beam or column).

TOP AND SEATED ANGLE CONNECTIONS

                                      - Generally used in case of moment connections.

                                      - Two angles are provided at top and bottom of the beam to resist                                               moment.

                                      - Generally used for lesser moments where heavy loads are not acting

SEATED BEAM CONNECTIONS

                                 - Generally used in case of shear connections.

                                - A seating angle - at bottom of secondary

                                  Beam - shop welded to the primary member.

                                - Seating angle resists vertical shear coming from the beam.

TYPES OF MEMBER JOINTS

                                - Beam to beam connections

                                - Column to column connections (column splices)

                                - Beam to Column Connections

                                - Column Base Plate Connections

With Regards

B.Deepak srinivasan.

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