Upload
cocococo1
View
221
Download
0
Embed Size (px)
Citation preview
8/13/2019 Jacobs 2010 Nascc
1/59
2010 NASCC / Structures Congress
Orlando, Florida
May 13, 2010
8/13/2019 Jacobs 2010 Nascc
2/59
8/13/2019 Jacobs 2010 Nascc
3/59
Overview of Revisions to Chapter I in the 2010AISC Spec.
Section I6: Load Transfer
Outline
8/13/2019 Jacobs 2010 Nascc
4/59
Minimal Change?
2010 Chapter I
8/13/2019 Jacobs 2010 Nascc
5/59
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
8/13/2019 Jacobs 2010 Nascc
6/59
5 Main Sections
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
8/13/2019 Jacobs 2010 Nascc
7/59
8/13/2019 Jacobs 2010 Nascc
8/59
5 Main Sections
12 Specification Pages
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
9 Main Sections
8/13/2019 Jacobs 2010 Nascc
9/59
5 Main Sections
12 Specification Pages
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
9 Main Sections
27 Specification Pages
8/13/2019 Jacobs 2010 Nascc
10/59
5 Main Sections
12 Specification Pages
22 Commentary Pages
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
9 Main Sections
27 Specification Pages
h
8/13/2019 Jacobs 2010 Nascc
11/59
5 Main Sections
12 Specification Pages
22 Commentary Pages
Minimal Change?
2010 Chapter I
2005 Specification 2010 Specification
9 Main Sections
27 Specification Pages
41 Commentary Pages
2010 Ch I
8/13/2019 Jacobs 2010 Nascc
12/59
Concrete and Steel Reinforcement by Reference to ACI
Local Buckling Provisions for Axial and Flexural Members
Expanded and Clarified Load Transfer Provisions
Consolidated Shear Provisions
Added Diaphragm and Collector Beam Section
Added New Provisions for Shear Stud Strength
Major Revisions and Additions
2010 Chapter I
2010 Ch I
8/13/2019 Jacobs 2010 Nascc
13/59
Concrete and Steel Reinforcement by Reference to ACI
Local Buckling Provisions for Axial and Flexural Members
Expanded and Clarified Load Transfer Provisions
Consolidated Shear Provisions
Added Diaphragm and Collector Beam Section
Added New Provisions for Shear Stud Strength
Major Revisions and Additions
2010 Chapter I
2010 Ch t I
8/13/2019 Jacobs 2010 Nascc
14/59
Concrete and Steel Reinforcement by Reference to ACI
Local Buckling Provisions for Axial and Flexural Members
Expanded and Clarified Load Transfer Provisions
Consolidated Shear Provisions
Added Diaphragm and Collector Beam Section
Added New Provisions for Shear Stud Strength
(Steel Anchors)
Major Revisions and Additions
2010 Chapter I
2010 Ch t I
8/13/2019 Jacobs 2010 Nascc
15/59
Concrete and Steel Reinforcement by Reference to ACI
Local Buckling Provisions for Axial and Flexural Members
Expanded and Clarified Load Transfer Provisions
Consolidated Shear Provisions
Added Diaphragm and Collector Beam Section
Added New Provisions for Shear Stud Strength
(Steel Anchors) Did NOT Revise Standard Composite Beam Design and
Associated Anchor Strengths
Major Revisions and Additions
2010 Chapter I
2010 Ch t I
8/13/2019 Jacobs 2010 Nascc
16/59
I1: General Provisions
I2: Axial Members I3: Flexural Members
I4: Combined Forces
I5: Special Cases
Outlines
2010 Chapter I
2005 Specification 2010 Specification
I1: General Provisions
I2: Axial Force I3: Flexure
I4: Shear
I5: Combined Forces
I6: Load Transfer
I7: Composite Diaphragms
I8: Steel Anchors
I9: Special Cases
8/13/2019 Jacobs 2010 Nascc
17/59
Overview of Revisions to Chapter I in the 2010AISC Spec.
Section I6: Load Transfer
Outline
I6 L d T f
8/13/2019 Jacobs 2010 Nascc
18/59
What Is Load Transfer?
I6: Load Transfer
I6 L d T f
8/13/2019 Jacobs 2010 Nascc
19/59
What Is Load Transfer?
I6: Load Transfer
I6 Load T ansfe
8/13/2019 Jacobs 2010 Nascc
20/59
What Is Load Transfer?
I6: Load Transfer
1. Force Introduction (I6.1)
I6: Load Transfer
8/13/2019 Jacobs 2010 Nascc
21/59
What Is Load Transfer?
I6: Load Transfer
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)
I6: Load Transfer
8/13/2019 Jacobs 2010 Nascc
22/59
What Is Load Transfer?
I6: Load Transfer
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)
3. Force Transfer (I6.3)
I6: Load Transfer
8/13/2019 Jacobs 2010 Nascc
23/59
What Is Load Transfer?
I6: Load Transfer
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)
3. Force Transfer (I6.3)
4. Detailing Provisions (I6.4)
I6 1: Force Introduction
8/13/2019 Jacobs 2010 Nascc
24/59
What Is Load Transfer?
I6.1: Force Introduction
1. Force Introduction (I6.1)
2. Force Allocation
3. Force Transfer
4. Detailing Provisions
I6 1: Force Introduction
8/13/2019 Jacobs 2010 Nascc
25/59
How is External Force Applied?
I6.1: Force Introduction
8/13/2019 Jacobs 2010 Nascc
26/59
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
27/59
Force Allocation
I6.2: Force Allocation
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)
3. Force Transfer (I6.3)
4. Detailing Provisions (I6.4)
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
28/59
Force Allocation Requirement:
I6.2: Force Allocation
The applied external forces shall bedistributed within the composite sectionbased on the same ratio of steel section
strength to reinforced concrete sectionstrength as represented by the plasticcapacity model.
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
29/59
Plastic Model
I6.2: Force Allocation
Encased Composite Columns
Pno = AsFy + AsrFysr+ 0.85Acfc (Eq. I2-4)
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
30/59
Plastic Model
I6.2: Force Allocation
Encased Composite Columns
Pno = AsFy + AsrFysr+ 0.85Acfc (Eq. I2-4)
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
31/59
Plastic Model
I6.2: Force Allocation
Encased Composite Columns
Pno = AsFy + AsrFysr+ 0.85Acfc (Eq. I2-4)
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
32/59
Plastic Model
I6.2: Force Allocation
Encased Composite Columns
Pno = AsFy + AsrFysr+ 0.85Acfc (Eq. I2-4)
Filled Composite Columns
Pno = AsFy + C2fc (Ac+Asr x (Es/Ec))
(Eq. I2-9)
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
33/59
Example
I6.2: Force Allocation
Pno = AsFy + AsrFysr+ 0.85Acfc
Say: AsFy = 67% of Total Pno
8/13/2019 Jacobs 2010 Nascc
34/59
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
35/59
Example
I6.2: Force Allocation
Pno = AsFy + AsrFysr+ 0.85Acfc
Say: AsFy = 67% of Total Pno
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
36/59
Example
I6.2: Force Allocation
Pno = AsFy + AsrFysr+ 0.85Acfc
Say: AsFy = 67% of Total Pno
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
37/59
Example
I6.2: Force Allocation
Pno = AsFy + AsrFysr+ 0.85Acfc
Say: AsFy = 67% of Total Pno
I6 2: Force Allocation
8/13/2019 Jacobs 2010 Nascc
38/59
Example
I6.2: Force Allocation
Pno = AsFy + AsrFysr+ 0.85Acfc
Say: AsFy = 67% of Total Pno
Vr = Pr (1-AsFy/Pno) Eq. I6-1
(For External Force Applied to Steel Only)
Vr = Pr (AsFy/Pno) Eq. I6-2
(For External Force Applied to Concrete Only)
I6 3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
39/59
Force Transfer
I6.3: Force Transfer
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)3. Force Transfer (I6.3)
4. Detailing Provisions
8/13/2019 Jacobs 2010 Nascc
40/59
I6 3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
41/59
Direct Bearing (I6.3a)
Shear Connection (I6.3b) Bond (I6.3c)
Mechanisms for Force Transfer
I6.3: Force Transfer
Filled Sections Encased Sections
Direct Bearing
Shear Connection
Rn Vr (LRFD)
Rn/ Vr (ASD)Rn = Mechanism Strength
Vr = Longitudinal Shear
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
42/59
Direct Bearing (I6.3a)
I6.3: Force Transfer
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
43/59
Direct Bearing (I6.3a)
I6.3: Force Transfer
Rn=1.7fcA1
=0.65 (LRFD) =2.31 (ASD)
8/13/2019 Jacobs 2010 Nascc
44/59
8/13/2019 Jacobs 2010 Nascc
45/59
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
46/59
Shear Connection (I8.3)
I6.3: Force Transfer
Table From Pallares and Hajjar, 2010
8/13/2019 Jacobs 2010 Nascc
47/59
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
48/59
Shear Connection Strength (I8.3)
I6.3: Force Transfer
hef/d > 4.0: 81% of Anchors Failed in Steel
hef/d > 4.5: 85% of Anchors Failed in Steel
hef/d > 5.5: 98% of Anchors Failed in Steel
2010 AISC Specification: Allows StrengthDetermination by Steel Strength Alone If
h/d>5.0
Rn = AscFu Eq. I8-3
8/13/2019 Jacobs 2010 Nascc
49/59
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
50/59
Shear Connection Strength (I8.3)
6 3 o ce a s e
Rn = AscFu Eq. I8-3
=0.65 (LRFD)
=2.31 (ASD)
Nanchors= Vr/ Rn
Nanchors= Vr/(Rn/)From Pallares and Hajjar, 2010
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
51/59
Shear Connection (I8.3)
Steel Steel
Anchor Anchor
Diameter Area LRFD ASD
in (mm) in2 (mm
2) in (mm) in (mm) kips (kN) kips (kN)
3/4 0.44 3 3/4 5 1/4 18.7 12.4
(19) (284) (95) (133) (83) (55)
7/8 0.60 4 3/8 6 1/8 25.4 16.9
(22) (380) (110) (154) (113) (75)
1 0.79 5 7 33.2 22.1
(25) (491) (125) (175) (148) (98)
N1"h" refers to the installed height of the stud from the top of the stud head to the connected base.
N2Standard stock shear connectors as determined from Nelson Stud Welding S3L Type (Nelson, 2010) taking burnoff into account.
N3Available shear strength determined using Equation 2010 AISC I8-3 assuming Fu = 65 ksi (450 MPa).
3/4 x 4 3/16 3/4 x 5 7/8
7/8 x 5 3/16 7/8 x 7 3/16
1 x 6 1/4 N/A
Normal Weight Concrete Lightweight ConcreteAvailable Shear Strength
N3
Minimum Length
"h"N1
Minimum Length
"h"N1
Corresponding
Standard Stock
Shear ConnectorN2
Corresponding
Standard Stock
Shear ConnectorN2
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
52/59
Bond (I6.3c)
Applicable to Filled Columns Only
60 psi Nominal Bond Strength (Fin)
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
53/59
Bond (I6.3c)
Applicable to Filled Columns Only
60 psi Nominal Bond Strength (Fin)
For Rectangular Filled Columns:
Rn = B2CinFin =0.45 (LRFD)
=2.31 (ASD)
B = Width of Section at Loaded Face
Cin = 4 if connection away from ends of member, 2 if atend of member
I6.3: Force Transfer
8/13/2019 Jacobs 2010 Nascc
54/59
Bond (I6.3c)
Applicable to Filled Columns Only
60 psi Nominal Bond Strength (Fin)
For Circular Filled Columns:
Rn = 0.25D2CinFin =0.45 (LRFD)
=2.31 (ASD)
D = Outside Diameter of HSS
Cin = 4 if connection away from ends of member, 2 if atend of member
I6: Load Transfer
8/13/2019 Jacobs 2010 Nascc
55/59
Detailing Provisions
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)3. Force Transfer (I6.3)
4. Detailing Provisions (I6.4)
I6.4: Detailing
8/13/2019 Jacobs 2010 Nascc
56/59
Load Introduction Length
g
I6.4: Detailing
8/13/2019 Jacobs 2010 Nascc
57/59
Load Introduction Length
g
Steel Anchors required forencased columns along fulllength at 24 in. o.c. max
Filled Columns only require stud
anchors in load introductionzone (if used for sheartransfer).
Summary
8/13/2019 Jacobs 2010 Nascc
58/59
Summary
y
1. Force Introduction (I6.1)
2. Force Allocation (I6.2)3. Force Transfer (I6.3)
4. Detailing Provisions (I6.4)
8/13/2019 Jacobs 2010 Nascc
59/59