Why can't the expansion anchor be used in the seismic fortification zone?


The expansion anchor refers to an anchor bolt that uses […]

The expansion anchor refers to an anchor bolt that uses an expansion member to press the anchor hole wall to form an anchoring action. The expansion type anchor bolts are divided into a torque control type and a displacement control type according to the different control methods of the expansion force during installation. The former is controlled by torque and the latter by displacement.
Due to the relatively short and short-shaped anchor bolts, the buried depth is generally shallow. The stress is mainly caused by the tensile failure of the concrete substrate, which is brittle failure.
The earthquake action is a cyclical load. From the perspective of hysteresis performance and energy consumption, the anchorage joint failure should be controlled to damage the anchor steel and avoid damage to the concrete substrate. However, under the action of seismic reciprocating load, the expansion anchor bolt is prone to a significant drop in bearing capacity, and even pull-out damage occurs, which is easy to form engineering hazards.

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