The detail drawing shows a post-installed mechanical expansion anchor. Which dimension correctly identifies the 'effective embedment depth' (h_ef) used for calculating concrete breakout strength in tension?

• The depth from the concrete surface to the deepest point of load transfer (the expansion mechanism)
• The thickness of the base plate plus the washer and nut
• The total overall length of the steel anchor bolt
• The distance from the concrete surface to the bottom of the drilled hole