In the design of anchorage equipment in concrete structures the beneficial effects of reinforcement are, in most cases, not considered. The American ASCI 349-06 code opens up for a more detailed analysis where the beneficial impact of reinforcement on anchor capacity can be taken into account. How this analysis can be done is, however, not explicitly described in the code.
The response of mechanically loaded anchors in reinforced concrete structures can only be understood by a combination of testing and numerical simulations. As concrete is a complex material, interaction between anchors, reinforcement and concrete is consequently also complex. Reported work within this area in the open literature is limited why efforts are needed to fill this gap.
Inspecta Nuclear AB and Scanscot Technology AB have, in a previous work funded by SSM (SSM 2013: 27), studied the possibility to transfer mechanical loads from embedded anchors to the concrete and its reinforcement. The results from that study clearly shown that the reinforcement has a beneficial effect on anchor capacity in both tension and shear.
In the current research project, the response of headed anchors in reinforced and non-reinforced concrete structures is further investigated by means of finite element simulations based on the numerical approach developed in the previous work.
The main objective is to get a better understanding of how different type and amount of reinforcement may increase the capacity of anchor plates for a number of new configurations and loading conditions.
Some of the results are as follows
- surface reinforcement has a negligible influence on the failure load level for anchor plates loaded in tension,
- the location of shear reinforcement links is of importance for the tension capacity of anchor plates in shear reinforced structures,
- surface reinforcement has only a small effect on the pry-out failure load level for anchor plates far from concrete edges and loaded in shear,
- the ratio between the tension load and the shear load is of great importance for anchor plates simultaneously loaded in tension and shear, and
- comparisons between numerical simulations and the European CEN/TS 1992-4-2 code show good agreement for investigated non-reinforced structures. This gives confidence in the numerical approach used in this investigation.
The results can be used in safety assessment of concrete structures, as well as in specifying the requirements applicable to the analysis of concrete structures at the Swedish nuclear facilities.