Ioannis Boumakis

fischer Austria GmbH

This paper investigates the potential influence of different aggregates in the concrete mix design on the concrete cone resistance of different types of anchors as well as the anchor stiffness. In fact, bonded anchors with three different adhesives and mechanical anchors and concrete screws of two types were installed in five different concrete mix...

Cast-in fasteners, like headed-studs, are important elements widely used in safety-critical applications of the building industry. They allow the connection of structural components through transfer of stresses from load-bearing elements to concrete. Their tensile strength in an unconfined configuration with wide supports depends on the concrete’s...

To assure high safety levels and functionality over the lifespan of concrete structures (50–100 years), it is important to understand the material’s behavior. As widely known, concrete changes its performance over time typically leading to enhanced material properties if deterioration mechanisms are neglected (e.g. Alkali-Silica Reaction). This con...

Chemically bonded anchors are connecting elements that allow transfer of stresses by adhesion. Their strength and failure mechanism depend on the concrete's confinement, properties of the bonding agent and the installation method. Several investigations on their sustained load behavior have been performed and current standards have adopted the use...

The mechanical performance of fibre reinforced concrete presents aspects still under investigation, mostly those regarding the long-term behaviour. Even if creep and shrinkage are two well-known phenomena that characterize concrete, in case of FRCs, and in particular of macro-synthetic Fiber reinforced concretes (MSFRCs), there are no reliable mode...

The safe design of fastening systems, especially considering the multi-decade performance, relies on a thorough understanding of mechanisms and processes that lead to excessive deformations or even failure in course of time. According to current design guidelines and standards, adhesive anchor system are designed based on the uniform bond model. Th...

Given the growth in structural applications of fibre reinforced concretes (FRCs), the characterization of their mechanical performance, and the formulation of predictive models are necessary. When dealing with FRCs long-term behaviour, concrete creep deformations can be predicted but the fiber–matrix interaction produces new effects, i.e. non-linea...

Motivated by tunnel accidents in the recent past, several investigations into the sustained load behavior of adhesive anchors have been initiated. Nevertheless, the reliable lifetime prediction of bonded anchor systems based on a relatively short testing period still represents an unsolved challenge due to the complex nonlinear viscoelastic behavio...

Motivated by tunnel accidents in the recent past several investigations into the sustained load behavior of adhesive anchors have been initiated. Nevertheless, the reliable life-time prediction of bonded anchor systems based on a relatively short period of testing still represents an unsolved challenge due to the complex non-liner viscoelastic beha...

This contribution studies a well-known failure criterion and its application to the life-time prediction of adhesive anchor systems under sustained load. The Monkman-Grant relation, which has been previously applied to a wide range of materials, is for the first time applied to adhesive anchors installed in concrete. It postulates a linear relation...

Recently, a large experimental campaign was completed that attempted to establish a link between petrography of the coarse aggregate, the concrete material properties and the system response in terms of concrete cone capacity. The investigation focused on three normal strength concretes having different coarse aggregate types (quartz, limestone, ba...

This contribution studies a well-known failure criterion and its application to the life-time prediction of adhesive anchor systems under sustained load. The Monkman-Grant relation, which has previously been applied to a wide range of materials, is now applied to adhesive anchors installed in concrete. It postulates a linear relationship between th...

Nowadays, fastening systems represent a very important part of the construction industry due to their versatility and use in reconstruction. Therefore, it is essential to study and understand phenomena and effects influencing the lifetime of a fastening system. However, the mechanisms are complex and not yet fully understood. As a result, numerical...

The safe design of fastening systems requires an accurate understanding of all time-dependent phenomena that may lead to damage or even failure during its service life of typically 50 years. Generally, safety and serviceability requirements are ensured through rigorous experimental testing during the approval phase. In the case of time-dependent ph...

In this contribution, a computational framework for the analysis of tertiary concrete creep is presented, combining a discrete element framework with linear visco-elasticity and rate-dependency of damage. The Lattice Discrete Particle Model (LDPM) serves as constitutive model. Aging visco-elasticity is implemented based on the Micro-Prestress-Solid...

In the last decades, fastening systems have become an essential part of the construction industry. Post-installed mechanical anchors are frequently used in concrete members to connect them with other load bearing structural members, or to attach appliances. Their performance is limited by the concrete related failure modes which are highly influenc...

Due to serious accidents caused by anchor failures, it became obvious that a more fundamental insight into the long-term performance of fastening systems under sustained load is needed, even though the failures were ultimately attributed to human error. Current design and approval guidelines for adhesive anchors are based on an incomplete understan...

The safe and accurate prediction of the long-term performance of concrete structures is an important task. As a result, it is fundamental to understand phenomena, which influence the load bearing capacity in course of time. The main source of concrete aging is the ongoing hydration, which is influenced by the concrete mix design as well as the envi...

In the last decade, the construction industry saw a shift towards rehabilitation and modular construction in order to address the growing demand for faster construction on one side, and change in usage and sustainability on the other side. Consequently, post installed fastening systems have become an important part of civil engineering structures a...

Das letzte Jahrzehnt ist durch eine kontinuierliche Verschiebung der Bauindustrie weg von reiner Gewinnmaximierung und Tragfähigkeitsüberlegungen hin zu nachhaltigen und ressourcenschonenden Baukonzepten gekennzeichnet. Nachträglich installierte Befestigungsmittel stellen eine wesentliche Komponente für schnelles, effizientes modulares Bauen aber a...

Concrete structures represent a significant part of our infrastructure. Considering the full lifetime of engineering structures, it is quintessential for a safe and sustainable design to predict, as accurately as possible, the technical lifetime of these structures. As a result it is crucial to have knowledge about the long-term performance of the...

Kurzfassung Um den heutigen Design-und Funktionalitätsstandards gerecht zu werden, finden Verbindungsmittel wie Verbund-und mechanische Anker vielfältige Anwendungsgebiete im Betonbau. Daher ist es von äußerster Wichtigkeit, das Verhalten des Verankerungsgrundes, sowie des Gesamtsystems zu verstehen, um langfristig sichere und nachhaltige Strukture...

For decades, concrete plays an important role worldwide as a structural material. Construction planning and reliability assessment require a thorough insight of the effects that determine concrete lifetime evolution. This study shows the experimental characterization as well as the results of subsequent aging simulations utilizing and coupling a Hy...

The macroscopic continuum creep simulation always neglect internal creep/relaxation at lower scales due to the internal self-equilibrated stresses. So far, a comprehensive model for concrete creep at the meso-scale level has been lacking. In this paper, such a shortcoming is over come by the explicit implementation of the solidification-microprestr...

The efficient and permanently safe design of fastening systems requires a thorough understanding of all involved load carrying mechanisms and their potential change in course of time due to deterioration and material aging. The latter are determined by the involved materials - concrete, steel, and, depending on the system, the mortars. In this cont...