Influence of the load-bearing behavior of anchorages on the structure-component-interactions during earthquake loading

Fastenings with post-installed anchors have proven suitability as flexible fastening method in structural engineering for the last decades. Post-installed anchors were also used in nuclear power plants to connect non-structural components such as piping systems with reinforced concrete structures. Because nuclear components have a high safety relevance regarding integrity and functionality, high requirements are imposed on the component fastenings as well. This is especially the case for accidental actions such as earthquakes. Due to seismic excitation of the reactor building and the attached non-structural components, the fastening is subjected to dynamic loads. If concrete cracking occurs in the anchorage zone due to high seismic actions, a significant amount of crack cycles can influence the load-displacement behavior of the anchors. The detailed investigation of the load-bearing behavior of fastenings was part of several research projects in the last years after incorrectly installed anchors were found in German nuclear power plants which led to safety concerns regarding the impact on component integrity. The investigations in this thesis shall contribute to the numerical investigation of the whole system building-fastening-piping in case of an earthquake. The general aim of this thesis is to investigate the influence of the local load-bearing behavior of fastenings on the dynamic behavior of the whole system building-fastening-piping in case of seismic actions. After outlining the problem (chapter 1), methodology and general aim (chapter 2), relevant subjects of this thesis are described (chapter 3). In order to develop a numerical model for the load-bearing behavior of a fastening simplified models and model concepts are illustrated which are available in the literature (chapter 4). Based on these analytical models a first estimation of expected anchor displacements in case of seismic actions is carried out. After that, seismic analysis for a reactor building and piping component are carried out separately according to current German nuclear design guidelines (chapter 5). In order to allow a seismic analysis of the whole system building-fastening-piping a numerical model for a fastening with post-installed anchors is developed based on the previously described simplified models (chapter 6). Beyond that, allowable model simplifications are made to facilitate modelling and simulation effort. This numerical model for the fastening is then used for the seismic analysis of the whole system building-fastening-piping (chapter 7). Finally, the results are discussed (chapter 8), concluded (chapter 9) and future research topics relating to this thesis are outlined (chapter 10).