Device Design and Test of Fatigue Behaviour of Expansion Anchor Subjected to Tensile Loads

China Academy of Building Research, Beijing, China

^* Corresponding author: zhangjinfeng@emails.bjut.edu.cn

Abstract

In order to study on the fatigue behaviour of expansion anchor (M16, grade 8.8) for overhead contact system in electrification railways, a set of safe, practical loading device is designed and a fatigue test campaign was carried out at structural laboratory of China Academy of Building Research on expansion anchor embedded in concrete block. The mobile frame of the loading device was designed well by finite-element simulation. According to some fatigue performance test of expansion anchor with different size and form, the device have been assessed experimentally its dependability. The results were found that no fatigue damage phenomenon occurred in all specimens after 2×10⁶ cycles tensile fatigue test in this specific series. It shows that in the condition of medium level or slightly lower maximum stress limit and nominal stress range, expansion bolt has good fatigue resistance. The biggest relative displacement and the residual relative displacement after test (Δδ = δ₂-δ₁) was also strongly lower than the symbol of the fatigue test failure index of this specific series (0.5mm) in the high cycle fatigue regime. The ultimate tension failures mode after fatigue tests in all tested samples take place in the concrete anchorage zone. The reduction range of the ultimate tensile strength properties of the anchorage system was not obvious, and the concrete was seen to be the weakest link of the system.