AAI AAI Load Calculations & Structural Requirements

Question 1

In ACI 318 anchor design, what does the term 'characteristic bond strength' (τk) represent?

Accepted Answer

The 5th percentile bond strength from testing used as the basis for design

Answer

The average bond strength measured across all test samples

Answer

The maximum bond strength recorded in a test series

Answer

The bond strength at 50% probability of failure

Question 2

Which failure mode for adhesive anchors involves pulling out a cone of concrete around the anchor?

Accepted Answer

Concrete cone breakout

Answer

Bond failure at the adhesive-concrete interface

Answer

Steel rod tensile rupture

Answer

Side-face blowout

Question 3

How does increasing the embedment depth of an adhesive anchor affect its tensile bond capacity?

Accepted Answer

It increases capacity because a larger bonded surface area develops greater total bond force

Answer

It decreases capacity because deeper holes are harder to clean

Answer

It has no effect because bond strength is a material constant

Answer

It increases shear capacity but decreases tensile capacity

Question 4

When adhesive anchors are installed in a group, what design reduction factor must be applied?

Accepted Answer

A group effect factor (ψg) that accounts for overlapping stress cones

Answer

A factor of 0.5 applied to all anchors regardless of spacing

Answer

No reduction is needed for groups of more than two anchors

Answer

A reduction only for shear loads, not tension

Question 5

What is the significance of the sustained load reduction factor for adhesive anchors under long-term tension?

Accepted Answer

Bond strength can creep under sustained tension, so a reduction factor lowers allowable sustained loads

Answer

Sustained loads always increase bond strength through consolidation

Answer

The reduction factor only applies to shear-loaded anchors

Answer

Sustained load reduction applies only in seismic zones

Question 6

Which load combination controls the design of adhesive anchors according to ACI 318 for a typical gravity load case?

Accepted Answer

1.2D + 1.6L

Answer

0.9D + 1.0W

Answer

1.0D + 1.0L

Answer

1.4D