1. CONNECTIONS IN STEEL STRUCTURES
2.  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 fastners,so that it shows a single composite unit.
3.  Bolts  Weld
4.  Connecting Plates  Connecting Angles
5.  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
6.  Riveted Connections  Bolted Connections
7.  Welded Connections  Bolted-Welded Connections
8.  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.
9.  Heating of the rivet  Inserting it to an oversize hole pressure to the head.  Squeezing the plain End by Pneumatic driver Round head.  On Cooling Reduces in Length–Clamping Force
10.  The introduction of high strength structural bolts.  The labour costs associated with large riveting crews  The cost involved in careful inspection and removal of poorly installed rivets.  The high level of noise associated with driving rivets.
11.  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 stregth.
12.  Bearing type bolts  High strength friction grip bolts (HSFG)
13.  The most common type is bearing bolts in clearance holes, often referred to as 1. Black Bolts  Ordinary, unfinished, rough, or common bolts.  Least Expensive  Primarily - Light structures under static load such as small trusses, purlins etc
14. 2. Turned Bolts  Similar to unfinished bolts.  Shanks - Hexagonal Rods  Primarily - Light structures under static load such as small trusses, purlins etc  Expensive – Limited use – Structures with no Slippage Connections
15. 3. Ribbed Bolts • Round head similar to Rivets. • Raised ribs parallel to the shank. • Actual Diameter - slightly Larger than the hole • Tightly fit into the hole. • Popular - Economical in Material & Installation
16.  Uses when bearing type bolts slips under shear  High strength bolts (8G or 10K grade) Pre-tensioned against the plates to be bolted together so that contact pressure developed between the plates being joined  Prevents relative slip when extra shear is applied  Higher Shear Resistance.
17. 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
18.  whose components are joined together primarily by welds. Welding Notations were developed by American Welding Society (AWS).
19. • 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.
20.  Horizontal  Vertical  Overhead  Flat
21.  Economical – Cost of materials and labors.  Efficiency is 100% as compared to rivets (75- 90%)  Fabrication of Complex Structures – Easy – like Circular Steel pipes.  Provides Rigid Joints – Modern Practice is of Rigid Joints.
22.  No provision for expansion or contraction therefore greater chances of cracking.  Uneven heating and cooling - member may distort - may result in additional stresses.  Inspection is difficult and more costlier than rivets
23.  Most connections are Shop Welded and Field Bolted types.  More Cost Effective  Better Strength & Ductility characteristics –Fully welded.
24.  Shear (semi rigid, simple) connections  Moment (rigid) connections
25.  Allows the beam end to rotate without a significant restraint.  Transfers shear out of beam  Most Common Types: Double clip Shear End Plate Fin Plate

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