Concrete edge failure after fire is investigated in this study with the focus on the effect that preloading in shear may have on residual capacity of anchors. Headed stud anchors with single stud, two- and four anchor groups are exposed to the various duration of fire and loaded in shear perpendicular to the free edge of the concrete member up to failure, in both hot and cold state (after cooling) conditions. The influence of the edge distance, embedment depth, number of studs and duration of fire on the load-bearing behavior of anchors are studied. The standard ISO 834 fire curve with fire durations of 15, 30, 60 and 90 min is employed in the simulations. The results of extensive numerical simulations show that anchor behavior is significantly influenced by the fire exposure. Due to the thermally induced damage of concrete the failure pattern, stiffness and load capacity significantly changes. After only 15 min of fire, the reduction of resistance can be more than 50% of the reference resistance. Moreover, the numerical investigations show that the preloading has a relatively strong influence on the residual shear load-bearing capacity of anchors after fire exposure.

本研究对火灾后的混凝土边缘破坏进行了研究，重点是剪切中的预紧力可能对锚的剩余承载力产生的影响。带单头螺栓，两个和四个锚钉组的带头双头螺栓锚钉承受着不同的燃烧时间，并在热态和冷态（冷却后）条件下均垂直于混凝土构件的自由边缘承受剪切力直至破坏。研究了边距，埋深，螺柱数量和着火持续时间对锚杆承载特性的影响。在模拟中采用了持续时间为15、30、60和90分钟的标准ISO 834燃烧曲线。大量数值模拟的结果表明，锚固行为受火灾的影响很大。由于混凝土的热诱导破坏，破坏模式 刚度和承载能力发生明显变化。仅燃烧15分钟后，电阻的降低可能超过参考电阻的50％。此外，数值研究表明，预应力对火灾后锚杆的残余剪切承载能力有较大的影响。