][ STEEL STRUCTURES ][

			Design of a bolted Framed Beam Connection
					P&A 354

Typical bolted framing connections P&A 355
Bolted connections for special situations 357

Framed Beam Connections:
====================
1. Type of Fastening
		bolt type
		angle welded to beam

2. Number of Fasteners
		web bolts in double shear
		column bolts in single shear
		number used on beam web

3. Size of Angles
		depends on
			size of fasteners
			magnitude of load
			size of the supports

4. Length of Angles
		function of size of fasteners
		1.25" edge distance typical
		3" pitch typical, refer to table 11.2
		angle length min. 1/2 beam depth

Problem:
A beam consists of a W27x84 of A36 steel
with Fu = 58 ksi, 
that is needed to develop an end reaction
of 80 kips.
Design a standard framed beam connection
with A 325 F bolts
and angles of A36 steel

	1. bolted connection
	2. standard framed connection
	3. 80 kips end reaction
	4. A 36 steel angle
	5. A 325 F bolts
			A 325 = high-strength bolt
			F = denotes bolt for which
				the limiting resistance is
				that of friction
				P&A 342 = definition
				P&A 344 = Capacity

B. Asked:
	1. Number of Bolts
	2. Bolt Diameter
	3. Angle Thickness
	4. Angle Length

Shear Capacity of Bolts 80 kips min.
n = 5 min. number of bolts
n = 7 max. number of bolts

n = 6, 3/4" bolts, angle 1/4", load 92.8 kips
n = 5, 7/8" bolts, angle 5/16", load 105 kips

No other criterion given we select 7/8" bolts.


2. Bearing on the beam web
Table 4.1 P&A 170 

W27

W27 = web t = 0.460 inch
Total bearing capacity of 5 bolts
bolt diameter = 7/8" = 0.875"
Fu given = 58 ksi
V = n x (bolt diameter) x (web t) x 1.5 Fu
V = 5 x         0.875       x 0.460   x 1.5 x 58
V = 175.1 kips
175.1 > 80 kips
the total bearing capacity of the bolts is larger
than the required load of 80 kips.

3. Shear stress in the net section of the web:
Figure 11.11 b or d P&A 355

w = beam depth - ( n x bolt diameter)
Beam Depth from Table 4.1 P&A 170
= 26.92"

w = beam depth - ( n x bolt diameter)
	bolt diameter = 7/8" + 1/16" = 0.875 + 0.0625
					= 0.9 375
w = 26.92"- (5 x0.9375")
w = 22.23 in

Stress due to the load:
fv = Load / net depth x web thickness
fv = 80 / 22.23 x 0.460
fv = 7.82 ksi

Allowable shear:
Table 8.1 P&A 266

Shear at reduced section = 0.40 Fy 
			   = 0.40 x 36
			   = 14.4 ksi
			7.82 ksi < 14.4 ksi
The actual shear 7.82 ksi is less than the allowable 14.4 ksi                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
4. Block Shear = Tearing of the web end
Combination of tear stress and tension stress
Table 8.1 P&A 266

allowable = 0.30 Fu for shear
allowable = 0.50 Fu for tension

For tension resistance:
w = net cross section
w = edge distance - 1/2 diameter
w = 2.25" - 0.9375/2
w = 1.78"

For shear resistance:
w = edge distance - diameters of bolts
w = 14" - 4.5 x 0.9375
w = 9.78"

For the total resisting force:
V = [(tension w x tw) x (0.50 Fu)] +
	 [(shear w x tw) x (0.30 Fu)]
V = (1.78 x 0.46 x 29) + (9.78 x 0.46 x 17.4)
   = 23.7 + 78.3
   = 102 kips

E. ANSWER 
Because this potential total resistance exceeds the load required, the tearing is not critical.














IRONWORKERS:
=============
Members of a Raising Gang:
====================
1. Pusher - Foreman
2. Connector
3. Tag-Line Man
4. Down-Man
5. Engineer
6. Hocker-on
7. Bolt-Stick Man




	

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College of Architecture

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©Dr. Gruenwald 1996,1997