Anchorage Depth Research Articles

Anchorage force transfer mechanism and bearing capacity theoretical of pawl bolt anchored in plain concrete

In this paper, the anchorage mechanism and bearing capacity of the special type of pawl bolt anchored in concrete under uplift load were studied. Static tests were carried out on two typical pawl bolts, namely 135° and 180° pawl bolts, and the effects of anchorage depth and pawl type on their failure modes were studied. The experimental results show that the uplift bearing capacity of pawl bolt is improved more effectively than that of smooth bolt. The two typical failure modes of pawl bolts under uplift load are concrete breakout failure and bolt yield failure. The concrete breakout failure exclusively occurs with anchorage depth of 5d, while the failure mode could change from concrete breakout failure to bolt yield failure with the increase of anchorage depth. The finite element model was established to elucidate the failure mechanism of anchorage bolt and concrete. The crack propagation and diffusion angle distribution of anchorage concrete can be directly judged by concrete tensile damage and stress vector in simulation analysis. Additionally, a calculation method to accurately predict the uplift bearing capacity of pawl bolt was proposed, which considered the effect of diffusion angle θi on the uplift bearing capacity and further discusses the change law of cone diffusion angle θi and concrete crack propagation. The calculated results exhibited a concordance with the experimental and numerical results, which shows that the formula presented in this paper can be considered reliable and can guide the practical engineering design.

Anchorage failure mechanism and uplift bearing capacity of L- & J-anchor bolts in plain concrete

This paper studies the anchorage failure mechanism and bearing capacity characteristics of hooked (L- & J-) anchor bolts in plain concrete under uplift load. Static tests on L- & J- anchor bolts were carried out to study the influence of different parameters (such as bolt diameter, anchorage depth, and bolt hook length) on the failure mode of hooked anchor bolts. The test results show that the uplift bearing capacity of L- & J- anchor bolts is greatly improved compared with that of smooth bolts. Two typical failure modes, that is, concrete breakout and bolt failure. In specific, the concrete breakout occurred in the L- & J- anchor bolts with anchorage depth of 5d, and the failure mode changed from concrete breakout to bolt failure as the anchorage depth increased. The finite element model was further established to investigate the stress development of the anchorage bolt and concrete and thus reveal the anchorage failure mechanism. Furthermore, a calculation method was proposed to accurately predict the uplift bearing capacity for the hooked anchor bolts with concrete breakout, where the change rule of the breakout cone diffusion angle θi and concrete crack propagation were mainly discussed. It reveals that the anchorage depth greatly influenced the diffusion angle when the concrete breakout occurs, and the diffusion angle on both sides of L- & J- anchor bolts presented an asymmetric distribution. Compared with the code ACI318, the proposed formula considered the effect of breakout cone diffusion angle on bearing capacity, and the calculation results coincided well with the experimental and numerical results, implying that the proposed formula in this paper can be considered reliable to guide the practical engineering design.

Modified post-installed adhesive anchorage test: Investigation of in-place compressive strength of concrete and influential factors

This paper presents the Modified Post-installed Adhesive Anchorage test (MPAA) as a method for evaluating the in-place compressive strength of concrete. It considers various influential factors, including test surface characteristics, concrete strength, anchorage depth, bolt diameter, and rebar location. Additionally, a formula for calculating concrete compressive strength, applicable to various influencing factors, was suggested. The findings demonstrate the effectiveness of MPAA in assessing in-place compressive strength of concrete with a high degree of precision. Following pull-out test, the prevalent failure modes observed were vertebral failure and vertebral-bond composite failure. Moreover, diverse concrete strengths, anchorage depths, and rebar locations demonstrated differing impacts on failure modes, while test surface characteristics and bolt diameter exerted less noticeable effects. The pull-out force-displacement curve during pull-out displayed three discernible phases: the elastic phase, crack propagation phase, and descent phase. When conducting on-site assessments, it is advisable to situate test points on the side surfaces of the members. Furthermore, factors like cover thickness and rebar location should be thoroughly evaluated when positioning test points. This encompasses the prudent choice of anchorage depth and bolt diameter to improve test precision. The suggested formula for calculating compressive strength exhibited minimal error and is applicable in determining concrete compressive strength for a wide range of practical engineering contexts. This study not only establishes a theoretical underpinning and offers support for standard revisions but also furnishes valuable guidance for conducting on-site testing procedures.

Field test of GFRP bar anti-floating anchor slurry-rock interface bonding performance

Based on fiber Bragg grating (FBG) sensing and monitoring technology, the slurry-rock interface bonding characteristics of glass fiber reinforced polymer (GFRP) anti-floating anchor and steel anti-floating anchor were investigated through the field pull-out destructive test of GFRP bars and steel anti-floating anchor. The differences in slurry-rock interface bonding properties between GFRP anti-floating anchor and steel anti-floating anchor were defined. In addition, the distribution law of shear stress and axial stress at the slurry-rock interface of the GFRP anti-floating anchor was revealed along the anchoring depth. The results showed that the axial stress at the slurry-rock interface of the GFRP anti-floating anchor is maximum at the hole opening and decreases as depth increases. The axial stress reduces to zero at the anchorage depth of about 2.4 m. The shear stress at the slurry-rock interface increases and then decreases. The slurry-rock interface bonding curve of the GFRP anti-floating anchor is approximately a straight line, while the slurry-rock interface bonding curve of the steel anti-floating anchor is a broken line with an obvious inflection point. Comparing different materials and types of anti-floating anchors indicate that the bond performance of steel anti-floating anchors is slightly higher than that of GFRP anti-floating anchors, and the bond strength of anti-floating anchors’ slurry-rock interface improves with the increase of anchor bar diameter. The synergistic effect among anchor bars, grout, and rock mass of the GFRP anti-floating anchor exceeds that of the steel anti-floating anchor. Using the finite element software ABAQUS to GFRP anti-floating anchor rod on rock interface bonding performance simulation, the simulation results was coincident with the test result.

Strengthening shear deficiency in undamaged reinforced concrete beams using innovative 45° mechanical steel stitches

In this study, beams with insufficient shear capacity were reinforced with U-shaped Mechanical Steel Stitches (MSS), which is an innovative approach. MSSs were applied at an angle of 45 degrees along the shear span on both faces of the beam body. A total of eight shear beam specimens, one of which is a reference and the other seven with different MSS spacing, were examined under vertical loads. The diameter, anchorage depth and mechanical properties of the MSSs and the geometry, longitudinal and transverse reinforcements of the reinforced concrete beam were kept constant. By changing the MSS intervals (from d/5 to d), the change was investigated in terms of strength, ductility, stiffness and energy consumption capacities. As a result of the study, 54% increase in shear capacity was observed in the beam with the most tightened MSS spacing (d/5). However, the nominal yield and total energy consumption capacity increased by 144% and 366%, respectively, compared to the reference beam. While splitting damage was most frequently observed in the MSS application with d/5, the damage turned into diagonal tension collapse, which is more abrupt and brittle as the spacing increases to d/2 range. As the MSS interval in beams increased from d/5 to d/2, the nominal yield stiffness of the beams showed a decreasing trend between 2.1% and 21.2% compared to the reference beam. Based on the experimental results, the developed novel strengthening methods can applicable to beams if the interval of MSS spacing is tightened enough.

Bond strength analysis of post-installed rebar with chemical adhesive in concrete mixed with marble powder and glass fiber

This study investigates the impact of marble powder as a part of fine aggregate and the addition of glass fiber on the bond strength of concrete and deformed high-strength post-installed steel rebars using the epoxy chemical as an adhesive. Five marble dust powder (MDP) substitution percentages (i.e. 0%, 10%, 20%, 30%, and 35%) and the addition of glass fiber (i.e. 0.5%, 1%, and 1.5%) were used. The performance of deformed high-strength post-installed rebars in conventional concrete and concrete modified with 35% marble powder and 1% glass fiber was examined here utilizing pull-out tests on a total of 96 specimens. To examine the bond behaviors of deformed high-strength post-installed rebars at the epoxy–conventional concrete interface and epoxy-modified concrete with MDP and glass fiber interface, test criteria included concrete compressive strength, anchorage depth of rebar into concrete, rebar diameter, and concrete cover to rebar diameter ratio. For post-installed high-strength deformed rebar, bond stress–slip relationships were determined, examined, and subsequently compared with prior work and readily available codes. It was found that none of the specimens exhibited pull-out failure and that the majority of them displayed concrete splitting, concrete rapture, or rebar rapture failure. This suggests that epoxy resins are particularly successful as bonding agents to retrofit concrete structures at the steel–concrete contact. A closed-form equation for predicting the bond strength for post-installed high-strength deformed rebar was also created using regression analyses on the experimental data. With a significant coefficient of determination (R2 = 0.85) the observed predicted bond strengths and the test data were quite similar.

Investigation of pull-out characteristics of connections for post-installed rebar utilizing mortar-based binders and chemical adhesives

ABSTRACT In this study, various types of adhesives were tested for their ability to adhere steel reinforcement bars to old concrete during a pull-out test when they were used in connection to a post-installed re-bar. The cylinder samples were 150 mm in diameter and had anchors made of rebar that varied in diameter (8 mm, 10 mm, 12 mm, 16 mm, and 20 mm) and embedded depth (10, 12.5, 15, and 20 times the rebar diameter). In contrast to the control group of (60 Nos.) cast-in-situ rebar concrete specimens, the other samples (240 samples) were post-installed-rebar concrete specimens with various bonding agents, epoxy-based chemical adhesive, vinyl-ester-based chemical adhesive, and cement-based binders (geopolymer mortar, conventional mortar). The results showed that while they all performed better than cement-based mortar-bonded specimens, the use of the epoxy-based chemical adhesive and vinyl-ester-based chemical adhesive pull-out load values were closely related. The anchorage depth and rebar diameter both improve the bond strength which reflects in terms of pull-out load. The anchorage depth and the region of contact with the adhesives or binder determine the failure mechanism of post-installed rebar connections. Due to the higher strength at the interface between the binder and the rebar in comparison to the binder-concrete, larger rebar diameters favour splitting or failure of concrete.

Mechanical criteria and analytical modeling of mixed-state wetting on multiscale surfaces: Of the importance of nanoscale topography for water-repellency

Multiple natural surfaces exhibit excellent water-repellent properties. Such surfaces systematically demonstrate multiscale surface topographies. However, current mechanical criteria for composite-wetting equilibrium can only be applied on model micrometric pillars. This paper suggests a theoretical basis on the foundation of which we introduce multiscale mechanical criteria for mixed-state equilibrium on real surfaces. A method for the analytical modeling of mixed-state wetting on real textured surfaces and the retrieval of critical wetting parameters such as the total solid-liquid contact area and the total triple line perimeter at the effective anchorage depth is introduced. This method is applied to the case of the sacred Lotus leaf on which we predict the effective anchorage depth of the triple lines. Results show that the nanoscale topography of these leaves leads to the minimization of the effective anchorage depth of the droplet on the sides of the micrometric asperities, a determining parameter with regards to its effect on the total solid-liquid contact area and the total triple line perimeter, unveiling a little more the role of nanoscale wax crystals in nature’s strategies for water-repellency.

Study on bonding performance and load transfer model between polyurethane anchor bolts and silty soil

The bonding performance between the anchor anchorage body and soil is an important index to evaluate the anchoring performance of anchor bolts. In this work, the vertical polyurethane grouting anchor bolt is taken as the research object, and the bonding performance between polyurethane anchorage body and silty soil was studied by 13 sets of field pull-out tests, and the distribution law of the axial force and the bonding stress of the polyurethane anchor bolts along the anchoring depth, as well as the influence of the diameter (D = 60 mm, 75 mm, 90 mm, 100 mm, 120 mm), density (ρ = 0.2 g/cm3, 0.3 g/cm3, 0.4 g/cm3, 0.5 g/cm3, 0.6 g/cm3) and length (L = 2.0 m, 2.5 m, 3.0 m, 4.0 m, 5.0 m) of the polyurethane anchorage body on the bonding strength between the polyurethane anchorage body and silty soil were analyzed in detail, and finally the load transfer equation of polyurethane anchorage body under vertical pull-out load was obtained by theoretical derivation. The results show that the error between the calculated results of the load transfer equation and the experimental results is less than 12%, which further indicates that the load transfer equation derived in this paper can reasonably describe the distribution of axial force and bonding stress along the anchorage depth of the polyurethane anchor bolts. The axial force of polyurethane anchor bolt is the largest at the top of the bolt body, and decreases along the anchoring depth, and the axial force at the bottom is far less than that at the top. Polyurethane anchor bolt has significant bonding stress concentration phenomenon, with the increase of load the peak bonding stress and bonding stress distribution area increases, and shifts to the bottom of the anchorage body. The borehole diameter, anchorage body density, and anchorage body length all have important effects on the bonding strength: the bonding strength increases with the increase of anchorage body density, and the increase is more obvious in the case of small density, and the increase of bonding strength becomes smaller after the density exceeds 0.4 g/cm3, the bonding strength decreases with the increase of anchorage body length and borehole diameter.

Numerical Investigation of the Formation of a Failure Cone during the Pullout of an Undercutting Anchor.

Previously published articles on anchors have mainly focused on determining the pullout force of the anchor (depending on the strength parameters of the concrete), the geometric parameters of the anchor head, and the effective anchor depth. The extent (volume) of the so-called failure cone has often addressed as a secondary matter, serving only to approximate the size of the zone of potential failure of the medium in which the anchor is installed. For the authors of these presented research results, from the perspective of evaluating the proposed stripping technology, an important aspect was the determination of the extent and volume of the stripping, as well as the determination of why the defragmentation of the cone of failure favors the removal of the stripping products. Therefore, it is reasonable to conduct research on the proposed topic. Thus far, the authors have shown that the ratio of the radius of the base of the destruction cone to the anchorage depth is significantly larger than in concrete (~1.5) and ranges from 3.9-4.2. The purpose of the presented research was to determine the influence of rock strength parameters on the mechanism of failure cone formation, including, in particular, the potential for defragmentation. The analysis was conducted with the finite element method (FEM) using the ABAQUS program. The scope of the analysis included two categories of rocks, i.e., those with low compressive strength (<100 MPa) and strong rocks (>100 MPa). Due to the limitations of the proposed stripping method, the analysis was conducted for an effective anchoring depth limited to 100 mm. It was shown that for anchorage depths <100 mm, for rocks with high compressive strength (above 100 MPa), there is a tendency to spontaneously generate radial cracks, leading to the fragmentation of the failure zone. The results of the numerical analysis were verified by field tests, yielding convergent results regarding the course of the de-fragmentation mechanism. In conclusion, it was found that in the case of gray sandstones, with strengths of 50-100 MPa, the uniform type of detachment (compact cone of detachment) dominates, but with a much larger radius of the base (a greater extent of detachment on the free surface).

Analysis of Foundation Pit Excavation Deformation and Parameter Influence of Pile-Anchor-Ribbed-Beam Support System

The support system is the most important part of foundation pit engineering, which mainly determines the safety of foundation pit engineering. Based on the characteristics of the foundation pit of Changsha international financial center, the original pile-anchor-beam (PAB) support system is improved into a new form of support system, the pile-anchor-ribbed-beam (PARB) support system. This study establishes a numerical simulation model to calculate the surface settlement and the deformation of the retaining structure caused by the excavation of the foundation pit by using the PAB and PARB support systems, respectively. Finally, this study analyzes the influence of pile anchorage depth, ribbed beam size and waist beam size on the support effect. The field monitoring data are in good agreement with the numerical simulation results, which verifies the validity and accuracy of the numerical calculation model. The support effect of the new PARB support system is 30% higher than that of the original PAB support system. The position of maximum surface settlement is about 0.5 times the excavation depth from the retaining structure, and the position of maximum lateral deformation of the pile is about 0.9 times the excavation depth from the pile top. The increase in pile embedded depth and ribbed beam size can significantly improve the support effect, while the change of waist beam size does not improve the support effect significantly.

Overall pull-out behavior of group anchored steel strands with 90-degree hooked type

The Precast Prestressed Assembled Structural (PPAS) system is a novel prefabricated structure system, which mainly adopts the group anchor technology for 90-degree hooked steel strands in the connection of beam-column members. For this connection, however, the anchorage performance of the group anchored steel strands with 90-degree hooked type has not been fully understood. For this reason, the overall pull-out tests on the 12 test specimens of group anchored 90-degree hooked steel strands were carried out by adopting the overall pull-out test device. The test results indicated that with the increase of the layout quantity of the steel strands in the concrete column from one row of one column (1 steel strand) to three rows of four columns (12 steel strands), the anchorage capacity, anchorage stiffness and energy dissipation capacity of the group anchor specimens were significantly improved, but its anchoring efficiency presents a three-stage change rule of slow attenuation (0.065) - gentle attenuation (0.025) - fast attenuation (0.105). The variation of the anchorage depth of the steel strands in the concrete column has more pronounced effects on the failure mode and pull-out load-overall slip response, indirectly affecting its ultimate anchorage capacity, overall slip, anchorage stiffness, and anchoring efficiency, but hardly affecting its energy dissipation capacity. Additionally, the anchoring efficiency is strongly related to the failure mode of the test specimens. For the failure mode of the steel strand fracture, the anchoring efficiency is always not less than 0.85, which is significantly higher than that of the overall pulling out of the steel strands, always between 0.70 and 0.80. • The overall pull-out tests on the group anchored 90-degree hooked steel strands were successfully carried out. • The multiple 90-degree hooked steel strands with smaller anchorage lengths tended to be overall pulled out. • Increasing the layout quantity of steel strands in the concrete column can effectively improve the anchoring capacity. • Group anchored 90-degree hooked steel strands exhibited higher anchoring efficiency. • The influence of the group anchor effect on its anchorage performance cannot be negligible.

Experiment and design approach of steel-to-laminated bamboo lumber screwed connections under load parallel to grain

As a new type of green building material, laminated bamboo lumber (LBL) has attracted more and more attention in the field of civil engineering. Dowel connections is one of the most significant connection methods for LBL, in which screw has the advantages of low cost and simple installation. This paper experimentally investigates screwed connections with LBL as main members and steel plate as side members, in which the effects of screw diameter, anchorage depth, end distance, center-to-center distance and row distance are studied. 45 single-screwed connection specimens were tested by symmetrically configured lateral resistance tests and 2 failure modes of screw pull-out and screw cut-off were observed, corresponding to 2 yield modes of screws. 18 double-screwed connection specimens were tested to propose design recommendations to avoid brittle failure between screw holes in LBL. Then the test results were compared with the predicted values calculated by NDS-2018, Eurocode 5 and GB/T 50005-2017. Based on the assumption of ideal elastoplastic model, a theoretical formula was derived and verified by test results. Besides, experimental load-slip curves were compared with those of Foschi model, which showed that Foschi model can be used to predict load-slip curves under the appropriate relative stiffness between fasteners and members. This research provides a scientific basis and favorable information for the engineering design and applications of LBL structures with screwed connections.

Mechanical Steel Stitches: An Innovative Approach for Strengthening Shear Deficiency in Undamaged Reinforced Concrete Beams

In this study, reinforced concrete beams with insufficient shear capacity were strengthened on both sides of the beam along the shear openings by a novel approach: Mechanical Steel Stitches (MSS). This innovative method facilitates the application of strengthening the beams with a low-cost solution. In this concept, six specimens were experimentally investigated under vertical load. While one of the specimens was tested as a reference, the others were strengthened with MSS application at different ratios (ρMS), ranging from 0.2% to 1% at both the beams’ shear span. MSS were applied with the angle of 90° considering stirrup logic. The diameter, anchorage depth and mechanical properties of the MSSs were kept constant, and their effects on the strengthening of the beams in terms of ductility, strength, stiffness, and energy dissipation capacities were investigated by changing the spacing of the MSSs. The results revealed that increasing MSS ratio caused a dramatic positive change in the behavior in terms of both strength and energy dissipation capacity. MSSs to be made at appropriate intervals ((%1) MSS ratio or (d/5) MSS spacing) significantly improved the shear capacity. However, a 43% loss in stiffness occurred with the increase in ρMS since the MSSs are applied to the beams by drilling and anchoring from the outside.

An experimental study to determine the optimum depth of steel anchors in RC subjected to shear force

Unlike existing in-plane strengthening RC shear-walls, anchors are used in strengthening of RC buildings to attach out-of-plane RC shear-walls or steel profiles. It is necessary to know the shear capacity as well as the ductile and nonlinear behavior of the anchor bolts as a connector to be used in the transfer of the shear force between the existing and new elements in strengthening. Considering that the existing RC structures in Türkiye are designed, according to the earthquake codes, with C14 concrete compressive strength until 1998, C18-20 until 2007, C20 until 2018 and also C25 after 2018, knowing the optimum anchorage depth depending on the concrete strength is of great importance in the strengthening analyzes of these structures. In this study, it was aimed to determine the shear performance and optimum anchorage embedment depth of steel sleeve expansion anchor bolts in RC. For this purpose, a total of 72 push-shear tests were conducted on M10 bolts for 6 different classes of low and normal strength concrete and 4 different anchorage depths. As a result of the experiment, it was observed that the shearing capacity of the anchor bolts increased with the increase of concrete strength and anchorage depth. However, for an optimum anchorage embedment depth, it has been observed that the anchor shear capacity reaches the maximum and remains constant without being affected from increment of the embedment depth and the change in concrete strength.

Shear Behavior of FRP Connectors in Precast Sandwich Insulation Wall Panels

Glass fiber reinforced polymer (FRP) composite connectors used in precast sandwich insulation wall panels directly affect the safety of the wall. In practical applications, a precast concrete sandwich insulation wall panel is transported to the construction site for hoisting 3–5 days after steam curing, and its concrete strength typically reaches approximately 70% of the design strength (i.e., the concrete strength after natural curing for 14 days). This study investigated the natural curing of concrete for 14 days and analyzed the mechanical properties of FRP connectors with two different sections in terms of their failure mode, failure process, and load–displacement curves. Numerical analysis and finite element parametric analysis of the connectors were conducted based on experimental data. The average ultimate shear capacity of a single rectangular-section connector was 8.37 kN and that of the cross-section connector was 8.37 kN. The connectors exhibited a good shear resistance, and the rectangular-section connectors had better ductility than the cross-section connectors. The wall panel exhibited three types of failure modes: splicing failure of the fiber layer of the connector, fiber fracture in the anchorage of the connector, failure of the concrete of the anchorage, and mainly material damage of the connector itself. The error between the load simulation value and test value of a single connector was less than 10% of the numerical simulation error requirement, and the finite element simulation results were reliable. The results of the parametric simulation of the shear capacity showed that the distance between connectors, anchorage depth, and insulation layer thickness had a significant influence on the shear performance of concrete connectors.

Load Transfer Behavior and Failure Mechanism of Bird’s Nest Anchor Cable Anchoring Structure

To research the internal load transfer behavior and failure mechanism of a bird’s nest anchor cable anchoring structure based on a pull-out test, a bond-slip failure model is established on the basis of statistical damage theory, and the distribution formula of shear stress at anchorage agent–rock interface is deduced. Combined with theoretical analysis, bird’s nest anchor cable pulling out test and particle flow code (PFC) numerical simulation test, as well as axial force distribution of the cable and shear stress distribution of its interface, help reveal its load transfer behavior and failure mechanism. Results show that: (1) The established bond-slip model can reflect the internal load transfer behavior and failure process of bird’s nest anchor cable anchorage structure. (2) The shear stress of the anchorage agent interface increases exponentially to the peak value and then decreases exponentially to the residual strength. The process is repeated at every location of the anchorage agent interface. The curve of the axial force and shear stress of the bird’s nest anchor cable is a negative exponential distribution with anchorage depth, and the maximum value occurs at the load end. (3) The crack of the anchorage agent interface extends from the load end to the other end and finally cuts through the whole interface. Rock mass generates radial cracks by the split effects of the bird’s nest. The failure mode is a combination of the debonding slip of the interface and the shear failure of the rock mass. The shear stress distribution and failure mode of the anchor structure are basically consistent according to laboratory tests and simulation tests, and PFC2D better reflects the internal load transfer behavior, failure mechanism, and failure process of the bird’s nest anchor cable under tensile loads.

Engineering Properties of New Claw Connectors for Alkali-Resistant Glass-Fiber-Reinforced Plastics.

To optimize the engineering properties of connectors, a new claw-shaped alkali-resistant glass-fiber-composite-reinforced connection member was designed in this study. Tensile, shear, and durability tests were conducted on the joint. Moreover, numerical analysis was performed, and the performance of the proposed connector was verified in engineering applications. Hence, the following conclusions hold: (1) At the same shear diameter and anchorage depth, the anchorage performance and shear resistance of claw connectors are better than those of rod connectors. (2) Claw connectors with an anchorage depth of 3.5 cm and a hollow joint with an outer diameter of 14 mm exhibit an excellent overall performance. (3) Alkali-resistant glass-fiber-reinforced plastics exhibit good durability. (4) The ANSYS numerical model can be used to accurately predict the load–displacement variation law of the pull-out and shear of the connectors. (5) Through research, it has been proven that claw-shaped connectors have good pull-out resistance, shear resistance, and durability, and the structure has good stability in engineering applications. Therefore, the structure can provide a significant reference for similar projects.

Cast – in anchor channels used to support curtain wall facades – numerical study of additional anchor reinforcement

As the architectural trend for ever greater spans for glass framing elements keeps its momentum, we are dealing with larger reaction loads onto the elements connecting these to the concrete slab, respectively onto the anchoring system. Therefore, this numerical study has the scope of researching the use of standard cast-in anchor channels, commonly used to support curtain wall façade systems, that are positioned and cast-in relatively close to the edge of the reinforced concrete slab; as well as researching the evolution of the relationship between the concrete strength, slab thickness, anchorage length, the distances between the anchors, the T-bolt positioning, (lever arm of shear force on t-bolt), and the geometry of the “ski plates”. Whilst many studies have been performed regarding the performance of both the concrete and these fastening systems, there is not sufficient information/classification relating to the influence of the welded “skis “, and as to what the optimal sizes and geometries are, when used in a class of concrete where this is critical. The main conclusion desired to be achieved is to find the optimal reinforcement plate (ski) shape and position for the given concrete and anchorage depth, allowing for a more accurate connection design, and to provide options for the instances where clashes occur.

Relationship of the interaction load capacity of anchors on their number and anchoring system

Purpose: The article presents the possibilities of using anchoring systems in the walls of three-layer large slab panel buildings. The use of diagonal anchors allows to increase the effective anchorage depth, which significantly increases the durability of the façade textured layer. Design/methodology/approach: Pilot tests have confirmed the necessity to use an anchor system in various configurations. Findings: The documents used included the conclusions of the pilot tests on the real object and the main experimental tests carried out on concrete samples. Research limitations/implications: The design of new anchorage systems and the proposed theoretical models for estimating their theoretical load capacity are based on the Guidelines contained in the European Technical Approvals. Practical implications: Single bonded anchorages used in engineering practice require evaluation in order to increase the durability of larger areas of the façade textured layer. Originality/value: The possibility of differentiating system anchors makes it possible to use them in very thin structural layers (diagonal anchors).