Strain rate behaviour of adhesive anchors in masonry

• Tested adhesive anchors in concrete block and clay brick masonry under impact load.
• Two different masonry penetration angles: 45° and 90°, were investigated.
• Proposed dynamic increase factors to determine dynamic strength of adhesive anchors.
• DIF of 0.8 is recommended for adhesive anchors embedded in clay brick.
• DIF of 1.0 and 1.21 are recommended for 6.4-mm and 9.5-mm anchors in concrete block.

Global terrorism has led to increasing use of anti-shatter film to upgrade window glass to mitigate the hazard associated with glass breakage. When the anti-shatter film is anchored, blast loading is transferred to the structure of the façade through steel anchors. Adhesive anchor are commonly used to fasten window frames to concrete and masonry elements. However, their behaviour in masonry is not very well researched.This paper presents an experimental program to study the behaviour of steel anchors in masonry substrates under impact loading. The adhesive anchor-substrate systems consisted of steel rods bonded to clay brick or concrete masonry units with an epoxy-based adhesive. Two penetration angles of 45° and 90° and different embedment depths were investigated. The adhesive anchor-substrate systems were tested in a specially designed drop mass test frame.Dynamic increase factors were recommended for design of anchors embedded in masonry under blast loading. The test results show that clay brick substrate is very brittle and leads to a dynamic increase factors of less than 1.0. For steel anchors in concrete masonry substrate, dynamic increase factors of greater than 1.0 are recommended for design of adhesive anchor-substrate systems under high rates of loading such as blast and impact.