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Anchor Bolt Capacity
According to ACI 318M-05
Appendix D
Introduction
• Batasan maximum fc’ yang diatur dalam ACI 318 adalah 70 MPauntuk cast-in anchor dan 55 MPa untuk post-installed anchor
• Load combination menggunakan Ultimate Strength Design
• Strength reduction factor (Ø)
Tension 0.80
Shear 0.75
General Requirement for Strenght of anchor
• Tension
1. Steel Strength of Anchor in Tension
2. Concrete Breakout Strength of Anchor
3. Pullout Strength in Anchor
4. Concrete Side-Face Blow Out
• Shear
1. Steel Strength of Anchor in Shear
2. Concrete Breakout Strength of Anchor
3. Concrete Pryout Strength of Anchor
Steel Strenght of Anchor in Tension
Kapasitas Anchor Bolt dihitung berdasarkan
rumus berikut :
NSA = n.Ase.futa
n : jumlah anchor
Asa : area of anchor bolt
futa : min (1.9fya or 860 MPa)
Concrete Breakout Strength of Anchor in Tension
Rumus kapasitas breakout strength adalah sebagai berikut
Single Anchor :
Group Anchor :
Concrete Breakout Strength of Anchor in Tension
Dimana :
ANC : projected concrete failure area of single anchor group
ANCO : projected concrete failure area of single anchor with an edge distance equal to 1.5hef
Nb : basic concrete breakout strength of single anchor in tension
Ψed,N : modification factor for edge effect
Ψc,N : modification factor for no cracking effect on service load
Ψcp,N : modification factor for post installed anchor. For cast in taken 1.0
Ψec,N : modification factor for anchor group loaded eccentrically in tension
Concrete Breakout Strength of Anchor in Tension
Perhitungan Nb :
Concrete Breakout Strength of Anchor in Tension
Calculate ANCO
Concrete Breakout Strength of Anchor in Tension
Calculate AN
Concrete Breakout Strength of Anchor in Tension
Calculate AN jika jarak ke pinggir anchor bolt kurang dari 1.5hef
Pull out strength of anchor in tension
Nominal Pullout Strength
For concrete indicate no cracking
Concrete Side-Face Blow Out in Tension
Single bolt capacity :
Group bolt capacity :
Steel Strength Anchor in Shear
Capacity of Single Bolt :
Concrete Breakout Strength Anchor in Shear
Capacity of Single Bolt :
Capacity of Group Bolt :
Concrete Breakout Strength of Anchor in Shear
Dimana :
AVC : projected concrete failure area of single anchor group
AVCO : projected concrete failure area of single anchor with an edge distance equal to 1.5hef
Vb : basic concrete breakout strength of single anchor in shear
Ψed,V : modification factor for edge effect
Ψc,V : modification factor for no cracking effect on service load
Ψec,V : modification factor for anchor group loaded eccentrically in tension
Concrete Breakout Strength of Anchor in Shear
Perhitungan Vb :
Concrete Breakout Strength of Anchor in Shear
Calculate AVCO
Concrete Breakout Strength of Anchor in Shear
Calculate AVC
Calculate AVC on edge
Concrete Breakout Strength of Anchor in Shear
Calculate AVC on group of anchor
Concrete Breakout Strength of Anchor in Shear
Calculate AVC if distance bolt to edge is very deep
Concrete Pryout Strength Anchor in Shear
Capacity of Single Bolt :
Capacity of Group Bolt :
Shear and Tension Interaction
Kesimpulan
Selain dengan kedalaman anchor, jarak antar anchor dan jarak anchor ke pinggir beton mempengaruhi kapasitas tension dan shear darianchor.
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