Anchorage to concrete structures

Background

Over the course of time, various anchorage systems have been developed for fastening both non-structural and structural components to concrete structures. In a sustainable society, buildings and civil structures need to be adjusted to new demands from time to time. This often requires fastening of new or updated applications to parts of the structure using fastening systems of various kinds. In addition, the demand for more flexibility in the design of new structures as well as for strengthening of existing concrete structures has led to an increased use of various metallic anchors.

Many fasteners are installed in structures that are reinforced; however current design models are based on tests of anchors in non-reinforced concrete members. A particular question that has been raised recently is what are the effects of orthogonal surface reinforcement in concrete and variation in concrete strength and geometry on the tensile capacity of fasteners.

The objective of this project is to provide a deeper understanding of several influencing factors that may affect the anchorage capacity and performance. These factors include the global bending stiffness of concrete members (i.e., member thickness, the amount of concrete reinforcing bars and concrete strength) as well as the local stresses in the vicinity of fasteners (i.e. anchor depth and anchor head size).

As the physical experiments are generally expensive, we plan to carry out FE numerical analyses within the framework of fracture mechanics to explain more realistically the influence of the aforementioned parameters. This will help to augment the research for a broad range of concrete geometries and anchor sizes. The numerical evaluations are however validated and verified against available experimental results from the literature as well as an ongoing experimental study.

Expected outcomes of this research are:

• Better understanding of the anchorage failure mechanisms
• Explaining the possible impacts of the variation in the concrete strength and geometry as well as the amount of reinforcing bars
• More refined and realistic models for designing fastening systems