Search

Fastenings in concrete are widely applicable in construction. A significant benefit of fastening technology lies in the fact that it can adapt to various geometries and construction sequences. As a result, the need to design and realize a fastening in structural elements with unconventional geometric configurations can be encountered. Existing design standards rely on the concrete capacity design (CCD) method for concrete‐related failures, which typically covers detailing situations with rectangular configurations of the fastenings and the concrete members. However, the lack of guidelines for a wider range of applications may lead to over‐conservative dimensioning or design constraints. This study investigates the influence of beveled concrete edges on the load‐bearing behavior of anchors. As part of the research, a series of experiments and numerical simulations were conducted. The results derived from the investigations are used to develop an analytical concept that extends the area of applicability of the CCD method and can be used for reliable dimensioning of fastenings close to non‐rectangular concrete edges and geometrical boundaries. [ABSTRACT FROM AUTHOR]

• A new form of steel beam-concrete wall joints with T-shape connectors is proposed. • Tensile behaviour of the joint is researched by experimental and analytical method. • The embedded depth of the connector significantly influences the joint behaviour. • Breakout failure and web yield failure are two main typical failure modes. • An analytical model for predicting pulling resistant capacity is proposed. Nowadays, reinforced concrete core wall–steel frame hybrid structural systems are widely used in high-rise buildings. In this type of structural system, the steel beam–concrete wall (SBCW) joints bear significant cyclic tensile and compressive loads under earthquake motions. Considering that most of the compressive loads are transferred to the slabs rather than the joint core, the pulling resistant capacity of the joints plays a very important role in the seismic behaviour of the entire structure when neglecting the tensile strength contribution of concrete slabs. In this study, the pullout behaviour of a new form of SBCW pinned joints with T-shaped steel connectors was tested, and the load–displacement curves, failure modes, as well as stress and strain development of the specimens were analyzed. Two failure modes were observed in the experiments: one is the breakout failure mode characterized by the pullout of the concrete pyramid with lower strength and stiffness, and the other is the web yield failure mode characterized by the yielding of the web plate of the T-shaped steel connector with higher strength and stiffness. The failure mode that was experienced mainly depended on the embedded depth of the T-shaped steel connector. Then, an analytical model for predicting the pulling resistant capacity of the joint was proposed. In this model, the calculation method corresponding to the breakout failure mode, which is based on the principle of virtual work, can assess the respective contributions of concrete, shear studs and stirrups to the pulling resistance capacity of the joint, and the calculation method corresponding to the web yield failure mode is simplified by calculating the yield strength of the web plate of the T-shaped steel connector. Finally, the proposed model was verified by experimental results. [ABSTRACT FROM AUTHOR]

Abstract Knowledge of the in situ stress state of rock mass is fundamental for engineering, geological and geophysical applications. In situ stress state determination requires in principle the evaluation of the three principal stresses and the related principal directions, but it is widely recognized in the literature that the maximum horizontal stress is the most difficult component to accurately estimate. In the context of borehole methods, this paper proposes a step-by-step analytical procedure to estimate some bounds to the maximum horizontal stress, starting from a geomechanical description of the rock and relying on information generally available in the engineering practice. The procedure is divided in substeps, each one requiring additional information about the mechanical properties of the rock and on the geometrical properties of the failed portion of rock: more information available implies a lower uncertainty on in situ stress estimate. Furthermore, since the proposed procedure is analytical, it allows a complete and very easy implementation in a spreadsheet. The aim of the work is thus to provide a rigourous but simple analytical tool that can be used in engineering practicte to estimate some bounds to the maximum horizontal in situ stress state. The approach is finally validated by means of both numerical simulations, performed with a sophisticated numerical tool, and experimental field data coming from the literature. Highlights • Determination of in situ stress state is crucial for any underground application in many fields of engineering. • Borehole methods have been accepted to be one of the most reliable method to estimate in situ stress state. • A step-by-step analytical procedure is presented to estimate the in-situ stress state relying on drilled borehole information. • Any step of the procedure reduces of the bounds of the maximum horizontal stress, at the cost of more information required. • The procedure is validated by means of both simulations with advanced numerical methods and in situ literature data. [ABSTRACT FROM AUTHOR]

• The pull-out force capacity of the anchors increased with increasing overburden stress. • No significant influence of the anchoring detail was found on the pull-out force capacity. • Existing formulas did not accurately predict the experimental peak pull-out force values. The seismic response of historical masonry buildings is largely controlled by the effectiveness of wall-to-diaphragm connections, which can be improved using injection anchors. Despite their use, there is a need for a better understanding of the performance of such anchoring system in stone masonry walls. This paper presents quasi-static pull-out tests performed on twelve specimens to investigate the behaviour of injection anchors in rubble stone masonry walls when breakout failure occurs. For each specimen, the experimental results are presented in terms of force–displacement curves, propagation of damage and crack pattern. It is shown that the anchoring details adopted in this study had a negligible influence on the pull-out force capacity of the anchoring system, while an increase in peak pull-out force was observed with increasing overburden stress applied. Because stone masonry specific capacity formulations have not yet been presented in the literature, the capacity is predicted using state-of-the art formulations for the pull-out load capacity of anchors installed in brick masonry. The limits of their applicability are discussed using the obtained experimental results. [ABSTRACT FROM AUTHOR]

The paper presents the results of a numerical analysis (FEM) describing the effect of the undercutting head angle on the formation of the rock mass failure zone during the initial stages of failure propagation. The research was carried out in the context of developing a technology for rock extraction by controlled pull-out of undercut anchors installed in the rock mass. The focus was on the initial stage of crack propagation and its trajectory for anchors embedded at an assumed constant depth and a value of the friction coefficient of the rock against the anchor head. It is shown that smaller angles favor smaller stripping angles and an increased radial impact of the head on the rock material (in the plane perpendicular to the head axis), while the impact of heads with larger angles is found to favor larger fracture penetration angles and faster penetration towards the free rock surface. [ABSTRACT FROM AUTHOR]