This article tackles the design consideration of anchoring to concrete under shear loadings. This is the part two of the previous article, Anchoring to Concrete: Tensile Loadings.

As summarized in the previous article, the Strength design of anchors shall be check and satisfy the following criteria:

- Tension Loadings
- Steel strength of anchor in tension
- Concrete breakout strength of anchor in tension
- Pull out strength in tension
- Concrete side face blowout strength of headed anchor in tension
- Bond Strength of adhesive anchor in tension

- Shear Loadings
- Steel strength of anchor in shear
- Concrete breakout strength of anchor in shear
- Concrete pry out strength of anchor in shear

### Design Requirements for Shear Loadings

#### A. Steel strength of anchor in shear (17.5.1)

The nominal strength of anchor in shear as governed by steel shall be evaluated by the calculations and shall not exceed:

- For cast-in headed stud header (17.5.1.2a)

- For cast-in headed bolts or hooked bolts anchors and post-installed anchors ( 17.5.1.2b)

*where:*

is the effective cross-sectional area of an anchor in shear (sq. inch)

smaller of 1.9 or 125000psi

#### B. Concrete breakout strength of anchor in shear (17.5.2)

The nominal concrete breakout strength in shear of a single anchor or group of anchors shall not exceed:

- For shear force perpendicular to the edge on a single anchor (17.5.2.1a)

- For shear force perpendicular to the edge on a group of anchors (17.5.2.1b)

- For shear force parallel to an edge, or shall be permitted to be twice the value of the shear force determined from above two equations, 17.5.2.1a and 17.5.2.1b.
- For anchors located at corners, the concrete breakout strength shall be determined for each edge with the minimum value to use.

Factors of are as follows:

shall be calculated using the smaller value of

are as follows:

**1.4** for anchors located in a region of a concrete member where analysis indicates no cracking at service load

For anchors located in a region of a concrete member where analysis indicates cracking at service load

**1.0** for anchors in cracked concrete with edge reinforcements smaller than no. 4 bar

**1.2** for anchors in cracked concrete with edge reinforcements of a no. 4 bar

**1.4** for anchors in cracked concrete with edge reinforcements of a no. 4 bar or greater between the anchor and the edge

#### C. Concrete pry out strength of anchor in shear (17.5.3)

The nominal pryout strength, for a single or for group of anchors shall not exceed the following:

where:

For and , refer to Concrete breakout strength of anchor in tension (17.4.2) in the previous article Anchoring to Concrete: Tensile Loadings .

Further checks for both tension and shear loadings has to be performed in accordance with the Interaction of Tensile and Shear Forces for combined shear in Vy&Vz direction and the combined ratio of bi-shear that should not be more than 1.2.

### Anchor Reinforcement Details for Tension

The recommended details as an excerpt from the Fig. R17.4.2.9 OF ACI 318M-14 shall be followed as per the figure below.

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