computations simpson strong-tie® company, inc
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NO. 1 OF 5 SHEETS
PROJECT: CONCRETE SLAB ANCHORAGE NEAR EDGE: 2.75" EDGE, CRACKED
SUBJECT: ANCHORAGE CALCULATIONS FOR WIND DESIGN
COMPUTATIONS
DATE: JUNE 8, 2015
BY: SF CHK:_______
SIMPSON STRONG-TIE® COMPANY, INC.The World’s “No Equal” Structural Connector Company5956 W. Las Positas Blvd. ● Pleasanton, California 94588Telephone: (800) 999-5099 ● Fax: (925) 847-1597
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NO. 2 OF 5 SHEETS
PROJECT: CONCRETE SLAB ANCHORAGE NEAR EDGE: 2.75" EDGE, CRACKED
SUBJECT: ANCHORAGE CALCULATIONS FOR WIND DESIGN
Line ANCHOR RUN: 1 inch Diameter ASTM A36 Anchor Bolt Reference
COMPUTATIONS
DATE: JUNE 8, 2015
BY: SF CHK:_______
SIMPSON STRONG-TIE® COMPANY, INC.The World’s “No Equal” Structural Connector Company5956 W. Las Positas Blvd. ● Pleasanton, California 94588Telephone: (800) 999-5099 ● Fax: (925) 847-1597
45 D.5.2 Concrete Breakout Strength of Anchor Only in Tension
46
47
48
49 Where: = 794 in2
[Eq. D5]
50 where C 1 to C 4 shall not exceed
51 1.5h eff = 14.09 in.
52 A Nc = 567.33 in2
53 ψ ed,N = 1 if C min > 1.5 heff [Eq. D9]
54 [Eq. D10]
55
56 ψc,N = 1.00 ψ c,N = 1.0 for cracked concrete [D.5.2.6]
57 [Eq. D6]
58
59 where, k=24 for castinplace anchors and if [D.5.2.2]
60 11 in. < h eff < 25 in then [Eq. D7]
61
62
63 Nb= 48836 lbs
64 Ncb= 26,481 lbs
65
66 D.5.3 Anchor Pullout Strength (Initial Abrg for plate bearing for pullout)
67 [Eq. D13]
68 Where: ψc,P = 1.0 ψc,P = 1.0 for cracked concrete [D.5.3.6]
69 Np = A brg 8 f' c [Eq. D14]
70 Abrg = [(� x D Abrg 2 / 4)] Area of Rod. D Abrg = min (Fnut+2t), bw
71 Fnut= 1.6250 in For F & G, see:
72 Gnut= 1.875 in ASME D18.2.2
73 bw= 2.7500 in
74 t= 0.625 in
75 Abrg= 5.154 D Abrg = 2.750 in.
76 Np = 206167 lbs
77 Npn = 206,167 lbs Recheck N pn below for 'Block Shear' Limit State
78
79 D.5.4 Concrete SideFace Blowout Strength
80
81
82 Required only if anchor is near an edge where c a1 <0.4h eff
83
84 If anchor is located in a corner where the perpendicular edge (c a2 ) is less than 3c
85 from the edge, the value of N sb shall be multiplied by (1 + C a2 /C a1 ) / 4 where
86 1 < C a2 /C a1 < 3
87
88 Nsb= 70,635 lbs
[D.5.2.3]
N pn = ψc,P N p
[Eq. D16]
[Eq. D3]
A Nc = (C1 + C2) × (C3 + C4)[D.5.2.1]
Increase A nc per
D.5.2.8
ψed,N = 0.759
heff= 9.39 inh eff in Eq D3 to D10 shall be limited to
C max /1.5 when C max < 1.5h eff (for 3 or 4 edges)
bNcNedNco
Nccb N
A
AN ,, ���
cbrgasb fAcN 1160�
29 efNco hA �
5.1' efcb hfkN �
efef
Ned hcifh
c5.1
5.13.07.0 min
min, ����
3/5'16 efcb hfN �
NO. 3 OF 5 SHEETS
PROJECT: CONCRETE SLAB ANCHORAGE NEAR EDGE: 2.75" EDGE, CRACKED
SUBJECT: ANCHORAGE CALCULATIONS FOR WIND DESIGN
Line ANCHOR RUN: 1 inch Diameter ASTM A36 Anchor Bolt Reference
COMPUTATIONS
DATE: JUNE 8, 2015
BY: SF CHK:_______
SIMPSON STRONG-TIE® COMPANY, INC.The World’s “No Equal” Structural Connector Company5956 W. Las Positas Blvd. ● Pleasanton, California 94588Telephone: (800) 999-5099 ● Fax: (925) 847-1597
89 Add Anchor Reinforcement per D.4.1.1 & D.5.2.9
90 Quantify anchor reinforcement by achieving Nsa<Nn
91 Nn = Ncb =Nn rebar , Where N n rebar is the minimum of N n rebar , N pn , N sb
92 A s : f y :
93 Anchor Reinforcement Size. Place @ 45 deg angle 2 psi 0.31 60000
94 Anchor Reinforcement Yield Strength 2
95 d rebar:
96 Nsa = nAsfy 0.625
97 Bars parallel to edge n = 2.67 Minimum number of legs for this design
98 2 n legs actual = 8
99
100 8
101
102 N n rebar = nA s f y x0.707 = 105,202 lbs > 35,133 lbs Ductile
103 Straight Horizontal Leg Development of Anchor Reinforcement: 19 in.
104
105 Determine slab area needed to be influenced by anchor reinforcement
106
107 Testing Indicates that adding anchor reinforcement can still form a breakout past the anchor reinforcement
108 bends similar to App. D concepts for overlapping breakout areas for multiple anchors. At near edge
109 conditions, testing showed that breakout extended a dimension equal to 1.5xhef when parallel to edge,
110 and a dimension equal to hef from anchor reinforcement bends when extending into the slab.
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Max Legs that can be placed for edge
detail, considering 4 parallel to edge:
ACI 31811
12.2.3
NO. 4 OF 5 SHEETS
PROJECT: CONCRETE SLAB ANCHORAGE NEAR EDGE: 2.75" EDGE, CRACKED
SUBJECT: ANCHORAGE CALCULATIONS FOR WIND DESIGN
Line ANCHOR RUN: 1 inch Diameter ASTM A36 Anchor Bolt Reference
COMPUTATIONS
DATE: JUNE 8, 2015
BY: SF CHK:_______
SIMPSON STRONG-TIE® COMPANY, INC.The World’s “No Equal” Structural Connector Company5956 W. Las Positas Blvd. ● Pleasanton, California 94588Telephone: (800) 999-5099 ● Fax: (925) 847-1597
133 Determine slab area needed to be influenced by anchor reinforcement (cont.)
134
135 Reinf Bot Cover:
136 Where, N cb = 1.2N sa 0.75 in
137 hef is measured to bend in anchor reinforcement.
138 Where: anchor reinf h ef = 10.625 in.
139 A nco = 1016 sq in & Anc is measured from anchor reinf. Bends
140 Where,
141
142 ψed,N = 0.76 1
143 ψc,N = 1.00
144
145 Solve for Anc:
146 A nc = (N sa x A nco ) /((ψ ed,N x ψ c,N ) x (k x h ef1.5 x f' c
0.5 ))
147
148 *Min A nc = 801 in2 A nc / A nco = 0.79
149 Actual A nc = 1327 in2 A nc / A nco = 1.31
150
151 New Breakout at Anchor Reinforcement, Check N cb > Nsa
152 N cb for Anchor Reinforcement = 58,215 lbs > 35,133 lbs
153
154 Vertical Block Shear consideration for shallow slabs
158 Testing Indicates that an additional failure mode is possible with a shallow embedment when resisting the
159 breakout area with anchor reinforcement. A vertical 'block shear' can form at the outer edges of the bearing
160 plate. This 'block shear' is separate from Pullout and is dependant on embedment depth, beraring surface
161 area and concrete strength.
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167 Size bearing plate so that 'block shear' is not the design limit state
168
169 Nblock shear > Ncb = 58,215 lbs
170 Minimum Plate Width Reqd., W = �Nblock shear/( f'c x block shear area x block shear coef. )
171 number of plate edge faces considered, n = 3
172 Minimum required W = 2.75 in.
173 Use Plate W = 2.75 in. No Plate Size Increase Required
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182
* A nc min needed to max out
breakout.
k=24 for castin
place anchors
Indicate whether anchor reinf. condition
needs to consider cracked
bNcNedNco
Nccb N
A
AN ,, ���
29 efNco hA �
,,,2.1 bNcNedNco
Ncsa N
A
AN ���
5.1' efcb hfkN �
NO. 5 OF 5 SHEETS
PROJECT: CONCRETE SLAB ANCHORAGE NEAR EDGE: 2.75" EDGE, CRACKED
SUBJECT: ANCHORAGE CALCULATIONS FOR WIND DESIGN
Line ANCHOR RUN: 1 inch Diameter ASTM A36 Anchor Bolt Reference
COMPUTATIONS
DATE: JUNE 8, 2015
BY: SF CHK:_______
SIMPSON STRONG-TIE® COMPANY, INC.The World’s “No Equal” Structural Connector Company5956 W. Las Positas Blvd. ● Pleasanton, California 94588Telephone: (800) 999-5099 ● Fax: (925) 847-1597
183 LRFD Design Design Strength Capcity Summary
184 ø = 0.70 For all concretegoverened limit states
185 ø = 0.75 For anchor steel strength limit state
186 ø = 0.75 For anchor reinf. per ACI 318 [D.5.2.9]
187 SF = 1.00 Seismic Factor, S F = 0.75, (for use w/concrete limit only) [D.3.3.4.4]
188
189 øNsa = 26,350 lbs 1. ACI 318 anchor steel strength in tension
190 øNcbSF = NA 2a. Breakout strength beyond anchor reinf. Seismic [D.3.3.4.5]
191 øNcbSF = 40,751 lbs 2b. Breakout strength beyond anchor reinf. Wind
192 øNn rebar = 78,901 lbs 3. Anchor reinf. Strength [D.3.3.4.5]
193 øNpnSF = 144,317 lbs 4. Pull out strength
194 øNsbSF = 49,444 lbs 5. Sideface blowout strength
195 øNcbSF = 18,537 lbs LRFD Breakout without anchor reinforcement ( 2c )
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199 Allowable Uplift Capacity Summary
200
201 øNn (LRFD) = 40,751 lbs Anchor Reinf. Controls for ASD Conversion
202 = 0.6 ASD conversion factors: 0.7 for seismic,0.6 for wind 2012 IBC,1605
203 × øNn (ASD) = 24,450 lbs 3. Anchor Reinf. Controls at ASD Load Combos
204 Rn = 34,165 lbs For ASD steel limit, consider AISC 36010, J.3
205 Ω= 2 ASD safety factor for wind and seismic
206 Rn/Ω (ASD) = 17,082 lbs 6. Steel Tension per AISC at ASD
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211 Anchor Reinforcement Layout Summary:
212 Anchor Reinf. Bar: #5 Legs Reqd: 2.67
213 Bar Yield, fy = 60000 psi Anchor Reinf.
214 Min Bot Clear Cover: Legs: 8 Legs
215 0.750 in SA18XXKT
216 Anchor Reinforcement Detail: 6/SA1
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LRFD limits 1 5
consider ACI 318
strength level values
Governing LRFD Capacity = 26,350 lbs1. ACI 318 Anchor Steel Tensile
Controls at LRFD
AISC 36010
[J.3]
Governing ASD Capacity = 17,082 lbs6. AISC Bolt Steel Tensile Controls
at ASD
ACI 31811
[D.4.3]
LRFD Limit
Shallow Anchor
Assembly Kit:
ASD Limit
For ASD conversion,
consider only LRFD
limits 2 through 5.
Limit 6 is the AISC
36010 J.3 ASD
Anchor Steel Limit