Modeling Adhesive Anchors in a Discrete Element Framework

Abstract

In recent years, post-installed anchors are widely used to connect structural members and to fix appliances to load-bearing elements. A bonded anchor typically denotes a threaded bar placed into a borehole filled with adhesive mortar. The high complexity of the problem, owing to the multiple materials and failure mechanisms involved, requires a numerical support for the experimental investigation. A reliable model able to reproduce a system’s short-term behavior is needed before the development of a more complex framework for the subsequent investigation of the lifetime of fasteners subjected to various deterioration processes can commence. The focus of this contribution is the development and validation of such a model for bonded anchors under pure tension load. Compression, modulus, fracture and splitting tests are performed on standard concrete specimens. These serve for the calibration and validation of the concrete constitutive model. The behavior of the adhesive mortar layer is modeled with a stress-slip law, calibrated on a set of confined pull-out tests. The model validation is performed on tests with different configurations comparing load-displacement curves, crack patterns and concrete cone shapes. A model sensitivity analysis and the evaluation of the bond stress and slippage along the anchor complete the study.

Discrete element framework for modeling tertiary creep of concrete in tension and compression

“…In this work, a discrete concrete model, the Lattice Discrete Particle Model (LDPM), is used. The LDPM has been widely used in studies of mechanical properties of concrete, [32], as well as in structural applications [33]. The model simulates the macroscopic response of concrete based on the mechanical properties at the mesoscale level accounting for the combined response of the cement paste and aggregates.…”

Flexibility and Load-Bearing Capacity of Roof Bolting as Functions of Mounting Depth and Hole Diameter

“…Under laboratory conditions, the roof bolting is installed to the drill core [7,8], or the rock mass is simulated using a concrete mix glued to the steel cylinders [9,10]. Marcon et al [11] divided the failure mechanisms of the glue-in roof bolting under tensile loading into four mechanisms: concrete cone failure, combined failure, splitting failure; and steel failure. Kilic et al [12] examined the influence of the binding agent on the load-bearing capacity of glue-in ribbed bolts along the whole length in a basalt block.…”

Design for lifecycle robustness of fastening systems

“…This way safe locations without cracks or limited crack width for the placement of anchors can be verified. Recent work on modelling adhesive anchors in a discrete element framework includes [8], the effect of aggregates on the concrete cone capacity is detailed in [9] and the sensitivity to casting orientation is described in [10].…”

“…This way safe locations without cracks or limited crack width for the placement of anchors can be verified. Recent work on modelling adhesive anchors in a discrete element framework includes [8], the effect of aggregates on the concrete cone capacity is detailed in [9] and the sensitivity to casting orientation is described in [10].The future requirements on faster and automated construction, improved life-cycle performance and sustainability of infrastructure in general increasingly promote the use of fastening technology. This paper addresses the concept of lifecycle robustness by introducing an ensemble of technical and management measures, covering the entire life span from design, construction, operation and decommissioning.…”