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1
Gálvez, Jaime C., Manuel Elices Calafat i Miguel A. Olivares. "Damage Tolerance in Civil Engineering Components: Implementation to an Anchorage". Key Engineering Materials 417-418 (październik 2009): 73–76. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.73.
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The use of the damage tolerance concept is growing in the design of civil engineering structures. The aim of this paper is to provide some guides to help designing anchorages according to the damage tolerance concept. The paper shows the importance of the small defects, idealized like small cracks, in the structural integrity of these elements. The Stress Intensity Factors (SIFs) induced by small cracks in an anchor head of post-tensioned strand anchorage system are calculated. The study includes the evaluation of the influence of the shape of the anchor head on the SIF. The numerical predictions are compared with experimental results of ½ scaled specimens of Poly-methyl-methacrylate (PMMA).
2
Liu, Zihao, Dan Zhou, Zhongyi Zheng, Zhaolin Wu i Longhui Gang. "An Analytic Model for Identifying Real-Time Anchorage Collision Risk Based on AIS Data". Journal of Marine Science and Engineering 11, nr 8 (5.08.2023): 1553. http://dx.doi.org/10.3390/jmse11081553.
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With the increasing volume of ship traffic, maritime traffic safety is facing a great challenge because the traffic in port becomes more and more crowded and complicated, which will make ship collisions more likely to happen. As a special water area of the port, the anchorage is also threatened by collision risk all the time. For accurately assessing the collision risk in anchorage and its adjacent waters in real time, this paper proposed an analytic model based on Automatic Identification System (AIS) data. The proposed anchorage collision risk model was established in microscopic, macroscopic, and complexity aspects, which considered ship relative motion, anchorage characteristics, and ship traffic complexity, respectively. For validation, the AIS data of the anchorages near the Shandong Peninsular were used to carry out a series of experiments. The results show that the proposed model can identify the anchorage collision risk effectively and has an advantage in dealing with complicated scenarios. The proposed anchorage collision risk model can help maritime surveillance better monitor and organize the ship traffic near the port and provide mariners with a reference about the collision risk situation of the anchorage on their route, which are important to improving maritime traffic safety.
3
McKay, K. S., i M. A. Erki. "Grouted anchorages for aramid fibre reinforced plastic prestressing tendons". Canadian Journal of Civil Engineering 20, nr 6 (1.12.1993): 1065–69. http://dx.doi.org/10.1139/l93-137.
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Nonmetallic prestressing tendons, made of fibre-reinforced composite materials, are being proposed as alternatives to steel prestressing tendons for bridges and parking garage structures, where corrosion is the leading cause of structural deterioration. One type of commercially available nonmetallic tendons is made of pultruded aramid fibres. One of the main problems for these tendons, which is common to all nonmetallic tendons, is that the high ratio of the axial to lateral strength of fibre-reinforced materials requires special attention to the type of anchorage used. For the aramid tendon, the simplest grouted anchorage consists of a steel tube filled with nonshrink grout, into which the end of the tendon is embedded. This note presents the test results of a parametric study on grouted anchorages for pultruded aramid tendons. Key words: prestressed concrete, nonmetallic tendons, aramid fibre, grouted anchorage.
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Shen, Junchao. "Experimental Study on Anchorage Performance of Resin Grout with Steel Segment". Advances in Civil Engineering 2021 (25.05.2021): 1–19. http://dx.doi.org/10.1155/2021/5580555.
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With the advantages of large anchoring force and fast anchoring speed, resin cartridge has become the main anchoring means of geotechnical engineering and underground space engineering support. Based on the theoretical analysis, it is clear that adding aggregate can improve the mechanical properties of grout and the bolt-grout interface stress state; the mechanical properties of aggregate are positively correlated with its improvement effect on anchorage performance. By using the numerical simulation method, it is concluded that the addition of steel segments into the resin grout can improve the stiffness of the anchorage system and enhance the energy absorption and antifailure ability of the anchorage system. Relying on the self-developed anchorage mixing device, the effects of steel segment diameter and addition amount on the anchoring force were studied experimentally, and the optimal addition amount of different types of steel segment to improve the maximum anchoring force was determined.
5
Pamuković, Jelena Kilić, Katarina Rogulj i Nikša Jajac. "Towards Sustainable Management of Anchoring on Mediterranean Islands—Concession Support Concept". Journal of Marine Science and Engineering 10, nr 1 (24.12.2021): 15. http://dx.doi.org/10.3390/jmse10010015.
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The focus of this paper is to define anchorage management model for concession planning purposes to provide quality support to experts in spatial planning when developing maritime spatial plans. The research aim is to develop an anchorage management model that includes decision and concession support concept. Decision support concept is defined in order to support the processes of identifying potential anchorage locations, their evaluation and comparison, and finally, the priority ranking and selection of locations for their construction. The final step is modelling the concession support concept that includes financial analysis to concession parameters definition. The problem of decision making and concession of the anchorage location selection is complex and ill-structured because of the unsystematic and ad-hoc decisions by all included stakeholders. Additionally, the involvement of several stakeholders’ groups with different preferences and background knowledge, a large amount of conflicting and seemingly incomparable information and data, and numerous conflicting goals and criteria impact final decisions. The proposed concepts overcome the above obstacles in order to enable the construction of anchorages in a way of optimal use of maritime space. The model is tested on the island of Brač, Croatia. The methods used to solve the task are SWARA (The Stepwise Weight Assessment Ratio Analysis) for defining the criteria weights and ELECTRE (Elimination and Choice Expressing Reality) for ranking anchorage locations.
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Pham, Quang-Quang, Ngoc-Loi Dang i Jeong-Tae Kim. "Smart PZT-Embedded Sensors for Impedance Monitoring in Prestressed Concrete Anchorage". Sensors 21, nr 23 (27.11.2021): 7918. http://dx.doi.org/10.3390/s21237918.
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This study investigates the feasibility evaluation of smart PZT-embedded sensors for impedance-based damage monitoring in prestressed concrete (PSC) anchorages. Firstly, the concept of impedance-based damage monitoring for the concrete anchorage is concisely introduced. Secondly, a prototype design of PZT-embedded rebar and aggregate (so-called smart rebar–aggregate) is chosen to sensitively acquire impedance responses-induced local structural damage in anchorage members. Thirdly, an axially loaded concrete cylinder embedded with the smart rebar–aggregate is numerically and experimentally analyzed to investigate their performances of impedance monitoring. Additionally, empirical equations are formulated to represent the relationships between measured impedance signatures and applied compressive stresses. Lastly, an experimental test on a full-scale concrete anchorage embedded with smart rebar–aggregates at various locations is performed to evaluate the feasibility of the proposed method. For a sequence of loading cases, the variation in impedance responses is quantified to evaluate the accuracy of smart rebar–aggregate sensors. The empirical equations formulated based on the axially loaded concrete cylinder are implemented to predict compressive stresses at sensor locations in the PSC anchorage.
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Tomaszewicz, Dariusz, Agnieszka Jablonska-Krysiewicz i Jerzy K. Szlendak. "The effect of the stress distribution of anchorage and stress in the textured layer on the durability of new anchorages". Open Engineering 10, nr 1 (21.07.2020): 705–11. http://dx.doi.org/10.1515/eng-2020-0079.
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AbstractThe paper estimated the effect of the distribution of edge and shear stresses occurring in the façade texture layer of three-layer walls of large slab panel buildings, as well as the variability of these stresses depending on the anchorage strength of the anchorage. Bonded anchors with seven different diameters M8 ÷ M30, selected based on catalogues, were analysed. The traction stress was determined based on the destructive force, which is determined by the catalogues of manufacturers of bonded anchors. Depending on the choice of the method of repairing the connections between the textured layer and the structural layer, we give the three-layer walls a new character of work. One of the methods of strengthening the textured layer is the popular COPY-ECO system in Poland. It is a system of two anchors (horizontal and diagonal), reflecting the shape of the work of existing hangers. The article also analyses the variants of oblique anchorages for the M12 anchor with inclination angles of 30∘, 45∘ and 60∘. The extent to which the anchorage inclination angle has been assessed influences the higher parameters of the anchor’s bearing capacity due to the shearing of the textured layer.
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Baryłka, A., i D. Tomaszewicz. "Relationship of the interaction load capacity of anchors on their number and anchoring system". Archives of Materials Science and Engineering 112, nr 2 (1.12.2021): 55–62. http://dx.doi.org/10.5604/01.3001.0015.6286.
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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).
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Sayed-Ahmed, Ezzeldin Y., i Nigel G. Shrive. "A new steel anchorage system for post-tensioning applications using carbon fibre reinforced plastic tendons". Canadian Journal of Civil Engineering 25, nr 1 (1.01.1998): 113–27. http://dx.doi.org/10.1139/l97-054.
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During the past half century, the use of prestressing in different structures has increased tremendously. One of the most important techniques of prestressing is post-tensioning. The main problem associated with post-tensioning in different structures is the corrosion of the prestressing steel tendons even with well-protected steel. New materials, fibre reinforced plastics or polymers (FRP), which are more durable than steel, can be used for these tendons/strands and thus overcome the corrosion problem. However, different shortcomings appear when FRP tendons are introduced to post-tensioning prestressing applications. For carbon fibre plastic tendons (CFRP), there is no suitable anchorage system for post-tensioning applications. Some of the anchorages developed by others for use with FRPs are therefore described and assessed. A new anchorage system developed by the authors, which can be used with bonded or unbonded CFRP tendons in post-tensioning applications, is described. The results of direct tension and fatigue tests on CFRPs anchored with the new system are presented.Key words: anchorage system, cyclic loading, fatigue, fibre reinforced plastics, finite element analysis, post-tension, prestressed concrete, prestressed masonry, strands, tendons.
10
Wu, Bowen, Xiangyu Wang, Jianbiao Bai, Shuaigang Liu, Guanghui Wang i Guanjun Li. "A Study of the Anchorage Body Fracture Evolution and the Energy Dissipation Rule: Comparison between Tensioned Rock Bolts and Torqued Rock Bolts". Advances in Civil Engineering 2021 (15.02.2021): 1–14. http://dx.doi.org/10.1155/2021/5542569.
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Rock bolt support is an effective technique for controlling surrounding rock of deep roadway. The stability of the anchorage body composed of rock bolts and surrounding rock mass is the core in keeping the stability of roadways. In this paper, the UDEC Trigon model was used in simulating uniaxial compressive test on the anchorage body under different pretension loads. The energy equilibrium criterion of the anchorage body under the uniaxial compressive state was proposed. Furthermore, the fracture evolution and the energy dissipation during the failure process of the anchorage body were analyzed. Results showed that before the peak strength, the external work was stored in the anchorage body in the form of the elastic strain energy (Ue). After the peak, energy dissipated through three ways, including the fracture developing friction (Wf), plastic deformation (Wp), and acoustic emission (Ur). Based on the simulation results, the high pretensioned rock bolts can eliminate the continuous tensile fractures in the anchorage body, decreasing the damaging extent of the anchorage body and the energy that was consumed by the following two main approaches: fracture developing friction (Wf) and plastic deformation (Wp). Moreover, the surplus of the elastic strain energy (Ue) and the strength of the anchorage body can be improved. The pretension load had a positive relationship with elastic strain energy and a negative relationship with the anchorage body damage degree. Based on the above research, the transport roadway of the working face 6208 in the Wangzhuang Coal Mine selected tensile rock bolts to establish the high-performance anchorage body. The monitoring data showed that this reinforcement method effectively managed the serious deformation issue of the roadway surrounding the rock masses.
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Jo, Byung-Wan, Yunn-Ju Byun i Ghi-Ho Tae. "Structural behavior of cable anchorage zones in prestressed concrete cable-stayed bridge". Canadian Journal of Civil Engineering 29, nr 1 (1.02.2002): 171–80. http://dx.doi.org/10.1139/l01-087.
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Since the cable anchorage zone in a prestressed concrete cable-stayed bridge is subjected to a large amount of concentrated tendon force, it shows very complicated stress distributions which can cause serious local cracks. Accordingly, it is necessary to investigate the parameters affecting the stress distribution, such as the cable inclination, the position of the anchor plate, the modeling method, and three-dimensional effects. The tensile stress distribution in the anchorage zone is compared to the actual design condition by varing the stiffness of spring elements in the local modeling, and an appropriate position for the anchor plate is determined. The results provide elementary data for the stress state in the anchorage zones and encourage more efficient designs.Key words: finite element analysis, bursting stress, spalling stress, cable anchorage zone, cable-stayed bridge.
12
Kim, Min Sook, i Young Hak Lee. "Load Carrying and Hydrostatic Performances of Innovative Encapsulated Anchorage System for Unbonded Single Strand". Advances in Civil Engineering 2019 (25.08.2019): 1–16. http://dx.doi.org/10.1155/2019/7812623.
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A new anchorage system is proposed having a circular bearing plate and curvature between the bearing plate and the anchor head to improve stress concentration. A lid with a screw instead of the grouting method is also proposed to prevent moisture penetration. The details of the anchorage device have been chosen to reduce stress concentration based on the finite element analysis. Static load test, load transfer test, and hydrostatic test of fabricated devices were carried out according to ETAG 013 to evaluate the proposed design. As results, the anchorage slip and stabilization satisfied the recommendations of ETAG 013. The maximum load in the load transfer test was at least 1.1 times the ultimate tendon strength. The results of the hydrostatic test showed that the developed anchorage device is watertight to protect against corrosion. As a result of bursting force test, it was confirmed that the proposed anchorage device has more advantages than the conventional rectangular anchorage devices in terms of stress distribution.
13
Wang, Haitao, Minghua Cui, Kun Ren i Haoyu Sun. "Nonlinear Finite Element Analysis of Bonding Behavior of Corroded Mortar Anchor under Dynamic Load". Electronic Journal of Structural Engineering 22, nr 3 (28.10.2022): 46–55. http://dx.doi.org/10.56748/ejse.223273.
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The connection between reinforcement and mortar was established through the surface-to-surface contact method. The transient dynamic Full method was adopted for dynamic loading solution. The numerical analysis model for the bonding performance of corroded mortar bolts under dynamic load was established. The numerical analysis results were compared with the test results for verification. The bond properties of the anchorage interface under the conditions of different mortar protection thickness, anchorage length and corrosion rate were analyzed. The results show that the numerical simulation results are in good agreement with the test results. The numerical model can analyze the bonding performance of the corroded mortar bolts. Within a certain limit, the bond stress is positively correlated with the thickness of the mortar protective layer.The larger the anchorage length is, the greater the bonding stress at the loading end will be, and the more uneven the distribution of bonding stress in the anchorage segment will be. However, when the anchorage length reaches a certain value, the continuous increase of anchorage length will have no obvious effect on the improvement of its bonding performance, so there is an optimal anchorage length. With the increase of the corrosion ratio, the bonding stress peck decreased gradually.
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Jia, Lijun, Yuchen Yang i Xiao Cong. "Static Experimental Study on New Arc Multi-Tendon CFRP Cable Anchorage System". Buildings 13, nr 3 (2.03.2023): 669. http://dx.doi.org/10.3390/buildings13030669.
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CFRP has the potential to replace steel cables in large-span cable-stayed bridges due to its high strength and lightweight material properties. However, the weak lateral force performance of CFRP material creates the challenge of anchoring. This study introduces a new inner cone + arc + straight cylinder bond-type anchorage system to optimize CFRP tendons’ force state. Experimental and finite element analyses verified the new anchoring system’s performance. In static load tensile tests, six groups of seven CFRP tendon anchorage systems with different sleeve grooves were used to study the failure mode and load–strain variation law. The difference in mechanical properties between the new and traditional anchorage is evaluated in the finite element analysis. The results indicate that the new anchorage system can lower the stress concentration in the anchorage zone and enhance anchorage performance. The groove design of the sleeve can effectively increase the anchoring efficiency, where the groove depth is proportional to the anchoring efficiency and the groove spacing is inversely proportional to the anchoring efficiency. The magnitude of the stress inhomogeneity in the multi-tendon anchoring system during tensioning is proportional to the beginning conditions and the load size. When the inner wall of the sleeve becomes more abrasive, the force heterogeneity of the anchorage system reduces. The tests and finite element analysis show that the new anchoring may improve stress distribution and anchorage efficiency. In engineering practice, it can be utilized as a dependable anchorage system.
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Bai, Xiaoyu, Xueying Liu, Mingyi Zhang, Yonghong Wang, Zheng Kuang i Nan Yan. "Stress Transfer Properties and Displacement Difference of GFRP Antifloating Anchor". Advances in Civil Engineering 2020 (28.07.2020): 1–18. http://dx.doi.org/10.1155/2020/8894720.
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Glass fiber reinforced polymer (GFRP) antifloating anchors are widely used in reinforcing underground structures. Despite the outstanding application advances of GFRP anchors in the antifloating field, research on the mechanical transmission and deformation properties of the anchor rod and anchorage body is still scarce. This paper introduces pull-out experiments of GFRP antifloating anchors based on the FBG sensor strings technology. The experimental data demonstrates that the distribution curve of the axial stress shows a reversed-S shape, and the shear stress distribution presents the law of increasing first and then decreasing from the position of peak shear stress. The rod-anchorage body displacement difference curves of the anchors with an anchorage length that is closer to the critical anchorage length are smoother than those of the anchors with a larger length difference from the critical anchorage length. Finally, a simplified distribution model of the shear stress is applied for predicting the rod-anchorage body displacement difference, and the experimental data of the anchors with a rod slip failure is more applicable for this model than that of the anchors with a rod rupture failure.
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Werdina, Ghassan M., i Omar Q. Aziz. "Interaction between the Local and General Zone for the Post-tensioned Girder Anchorage Zone". Open Civil Engineering Journal 15, nr 1 (16.04.2021): 50–73. http://dx.doi.org/10.2174/1874149502115010050.
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Background: The use of post-tensioning in girders causes high bearing and compressive stresses in the anchorage zone. In this study, the behavior of the anchorage zone and the interaction between the local and general zone are investigated. The variables included different reinforcements for both the local and general zones for a block of two anchorage devices. Methods: Both experimental and numerical methods have been applied to study the behavior of the anchorage zone. The experimental part of the study involved laboratory testing of sixteen specimens, and the numerical study was conducted using ABAQUS non-linear finite element analysis. Results: Tie reinforcement provided additional confinement for the local zone, and this confinement was more for the specimens with originally less confined spiral reinforcement strength. There was a slight or no effect of the local zone reinforcement on the general zone strength and ultimate load of the anchorage zone when the failure was in the general zone. Conclusion: Confinement of the local zone prevented the brittle bearing and compression failure of this zone.
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Alhusain, Mustafa, i Adil Al-Mayah. "Innovative Wedge Anchorage for CFRP Plates: Development and Testing". Journal of Composites Science 8, nr 3 (14.03.2024): 103. http://dx.doi.org/10.3390/jcs8030103.
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Gripping prestressed carbon fiber-reinforced polymers (CFRPs) in structural strengthening applications is challenging due to CFRPs’ susceptibility to lateral loading. This paper presents a reliable and reusable wedge anchorage for gripping CFRP plates that are 50 mm wide and 1.2 mm thick. The cylindrical anchorage, which is 75 mm long and 76.2 mm in diameter, consists of an external steel barrel, two internal steel wedges, and two soft copper sleeves. The barrel-wedge interface is designed using an innovative arc–linear configuration, through which the desired stress distribution is attained, preventing stress concentration and the premature failure of the CFRP plate. The wedge anchorage was experimentally tested by applying a displacement-controlled tensile load of 0.6 mm/min until the complete fracture of the CFRP plate. The anchorage’s performance was examined under distinct installation conditions by applying different presetting levels: high (40–120 kN) and low (hammering) presetting. It was observed that the anchorage successfully prevented CFRP premature failure in all tests by achieving an average tensile loading of 172.3 (±5.7) kN, exceeding its reported tensile strength of 168 kN (2800 MPa). Minor CFRP displacements of 6.26 (±0.75) mm and 3.33 (±0.16) mm were recorded under low and high presetting levels, respectively. Similarly, the CFRP slippage relative to the wedges for the low and high presetting tests was only 1.18 (±0.75) mm and 0.33 (±0.15) mm, respectively. Also, only minor scratches were observed in the wedge–barrel interface, indicating the absence of extensive plastic deformation.
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Gora, Abdurra’uf Mukhtar, Jayaprakash Jaganathan, Mohammed Parvez Anwar i Hau Y. Leung. "Flexural capacity of bi-directional GFRP strengthened RC beams with end anchorages". International Journal of Structural Integrity 10, nr 2 (8.04.2019): 188–207. http://dx.doi.org/10.1108/ijsi-04-2018-0021.
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Purpose The purpose of this paper is to present the results of experimental and theoretical studies on the flexural capacity of reinforced concrete (RC) beams strengthened using externally bonded bi-directional glass fibre reinforced polymer (GFRP) composites and different end anchorage systems. Design/methodology/approach A series of nine RC beams with a length of 1,600 mm and a cross-section of 200 mm depth and 100 mm width were prepared and externally strengthened in flexure with bi-directional GFRP composites. These strengthened beams were anchored with three different end anchorage systems namely closed GFRP wraps, GFRP U-wraps and mechanical anchors. All these beams were tested with four-point bending system up to failure. The experimental results are compared with the theoretical results obtained using the relevant design guidelines. Findings The experimental results demonstrate a significant increase in the flexural performance of the GFRP strengthened beams with regard to the ultimate load carrying capacity and stiffness. The results also show that GFRP strengthened beams without end anchorages experienced intermediate concrete debonding failure at the GFRP plate end, whereas all the GFRP strengthened beams with different end anchorage systems failed in rupture of GFRP with concrete crushing. The theoretical results revealed no significant difference among the relevant design guidelines with regard to the predicted ultimate moment capacities of the bi-directional GFRP strengthened RC beams. However, the results show that ACI Committee 440 Report (2008) design recommendation provides reasonably acceptable predictions for the ultimate moment capacities of the tested beams strengthened externally with bi-directional GFRP reinforcement followed by FIB Bulletin 14 (2001) and eventually by JSCE (1997). Originality/value The research work presented in this manuscript is authentic and could contribute to the understanding of the overall behaviour of RC beams strengthened with FRP and different end anchorage systems under flexural loading.
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Shi, Wenbao, Yan Li, Wanfeng Li i Shihui Li. "Bearing Characteristics of Surrounding Rock of Deep Mining Roadway with Full and End Bolt Anchorages: A Comparative Numerical and Experimental Study". Advances in Civil Engineering 2021 (15.01.2021): 1–10. http://dx.doi.org/10.1155/2021/8829323.
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The support strength of surrounding rock in deep mining roadways can be significantly improved by replacing the end bolt anchorage with a full one. The support effects of both types of anchorage and the axial stress distribution characteristics in anchored bolt bodies were assessed via the indoor pull-out test, simulated via the FLAC3D software, and verified by field measurements. The stability and variation patterns of the axial force, as well as the evolution law of bearing characteristics of surrounding rock, were analyzed. The results indicate that the polymorphic deformations of deep mining roadway surrounding rock and the bolt support body interact synchronously. The axial force evolution trend in bolt bodies with end anchorage revealed by field tests was consistent with the laboratory test results, in contrast to that of full anchorage. Although stress distribution laws in both sides of the mining roadway were the same for both types of anchorage, the vertical stress peak and damage range of full-anchored surrounding rock slightly exceeded those of the end-anchored one. The anchored area bearing a higher load alleviated the stress concentration of the surrounding rock. Since the deformations in fully and end anchored surrounding rocks increased gradually and sharply, respectively, the full anchorage is more conducive to deformation moving control of deep mining roadway surrounding rock. The research results can provide theoretical guidance for the design and construction of deep mining roadway bolt support.
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Eligehausen, Rolf, Werner Fuchs i Thomas M. Sippel. "Anchorage to concrete". Progress in Structural Engineering and Materials 1, nr 4 (lipiec 1998): 392–403. http://dx.doi.org/10.1002/pse.2260010408.
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López, J. Alfredo, Francisco J. Carrión, Juan A. Quintana, Didier Samayoa-Ochoa, María G. Lomelí i Pablo R. Orozco. "Verification of the Ultrasonic Qualification for Structural Integrity of Partially Concrete Embedded Steel Elements". Advanced Materials Research 65 (marzec 2009): 69–78. http://dx.doi.org/10.4028/www.scientific.net/amr.65.69.
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Failure of one upper anchorage element in a cable-stayed bridge and its consequent analysis concluded that the main cause of the failure was a deficient heat treatment that resulted in large micro structural grain size and low fracture toughness, vulnerable to fatigue damage. Previous research studies demonstrated that ultrasonic evaluation could provide some insight of the microstructural integrity by correlating the ultrasonic response to the grain size. Thus, this technique was used to inspect the 112 elements in service in the bridge and 16 were qualified as structurally deficient, without direct verification of the grain size, since these elements were partially embedded in the concrete structure. Late rehabilitation of the bridge considered the replacement of the 16 structural deficient anchorage elements, plus 4 elements qualified in good condition, to complete a reliability analysis for the remaining 92 elements from the statistical mechanical properties of the removed pieces. Rehabilitation made possible the confirmation of the initial diagnosis made by ultrasonic inspection and fatigue cracks were identified in some elements. This study demonstrated that the ultrasonic non destructive evaluation is highly reliable for structural integrity qualification of steel structural elements partially embedded in concrete.
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Meyer, Avery, Nicola M. Pugno i Steven W. Cranford. "Compliant threads maximize spider silk connection strength and toughness". Journal of The Royal Society Interface 11, nr 98 (6.09.2014): 20140561. http://dx.doi.org/10.1098/rsif.2014.0561.
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Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress–strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue—the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system.
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Kabantsev, Oleg, i Mikhail Kovalev. "Failure Mechanisms and Parameters of Elastoplastic Deformations of Anchorage in a Damaged Concrete Base under Seismic Loading". Buildings 12, nr 1 (13.01.2022): 78. http://dx.doi.org/10.3390/buildings12010078.
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The article addresses mechanisms of anchorage failure in a concrete base studied within the framework of physical experiments. The authors investigated the most frequently used types of anchors, such as the cast-in-place and post-installed ones. The anchorages were studied under static and dynamic loading, similar to the seismic type. During the experiments, the post-earthquake condition of a concrete base was simulated. Within the framework of the study, the authors modified the values of such parameters, such as the anchor embedment depth, anchor steel strength, base concrete class, and base crack width. As a result of the experimental studies, the authors identified all possible failure mechanisms for versatile types of anchorages, including steel and concrete cone failures, anchor slippage at the interface with the base concrete (two types of failure mechanisms were identified), as well as the failure involving the slippage of the adhesive composition at the interface with the concrete of the anchor embedment area. The data obtained by the authors encompasses total displacements in the elastic and plastic phases of deformation, values of the bearing capacity for each type of anchorage, values of the bearing capacity reduction, and displacements following multi-cyclic loading compared to static loading. As a result of the research, the authors identified two types of patterns that anchorages follow approaching the limit state: elastic-brittle and elastoplastic mechanisms. The findings of the experimental research allowed the authors to determine the plasticity coefficients for the studied types of anchors and different failure mechanisms. The research findings can be used to justify seismic load reduction factors to be further used in the seismic design of anchorages.
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Pušić, Danijel, i Zvonimir Lušić. "Multi-Criteria Decision Analysis for Nautical Anchorage Selection". Journal of Marine Science and Engineering 11, nr 4 (27.03.2023): 728. http://dx.doi.org/10.3390/jmse11040728.
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Considering that moorings and anchorages for vessels have recently become an important factor in nautical tourism, the selection of their locations is a complex and demanding process. This paper examines numerous criteria from different perspectives to determine the most favourable/optimal locations for nautical anchorages, meeting the conditions and recommendations of professionals from several domains, by applying the methods of multi-criteria analysis. The goal of solving the problem this way is to meet the expectations of future users, spatial planners, possible investors, and concessionaires interested in doing business in these areas, as well as entities that strive to preserve and protect marine and underwater animal life and the environment by preventing their degradation and pollution. However, since there are no precisely defined recommendations for the establishment of nautical anchorages, in the procedures for determining the locations of nautical anchorages, it is possible to use general criteria they must fulfil. The best locations for nautical anchorages may be found, and this research represents a transparent, repeatable, and well-documented approach for methodically solving the problem. This is demonstrated by a comparison of many methods of multi-criteria analysis, utilizing a variety of parameters. On the other side, this calls for proficiency in a wide range of disciplines, including architecture, geodesy, marine safety and transport, architecture, biology, ecology, mathematical programming, operational research, information technology, environmental protection, and others. The best locations for nautical anchorages should be chosen based on the size and number of vessels, available space, depth, distance from the coast, level of protection of the anchorage waters, and many other limiting factors, keeping in mind that the spots which simultaneously satisfy a greater number of significant criteria are preferable. Using multi-criteria analysis methods (AHP (Analytical Hierarchy Process) and TOPSIS (The Technique for Order of Preference by Similarity to Ideal Solution)), evaluating and classifying criteria as well as assigning weight values to selected criteria, this paper investigates the possibility of obtaining the best locations from a group of possible ones. The most important factor when applying multi-criteria analysis methods refer to the following: vessel safety (navigation), hydrometeorological, spatial, economic, and environmental criteria. The main contribution of the paper displays in the proposal to optimize the decision-making process, when determining the optimal locations of nautical anchorages, in accordance with previously defined criteria.
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Yong, Nie, Zhao Yufei i Du Guangjin. "Dynamic response of full-length bonded anchor cable in rock slope". E3S Web of Conferences 233 (2021): 03010. http://dx.doi.org/10.1051/e3sconf/202123303010.
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The research on the anchoring mechanism of slope anchor cable under earthquake action is not in-depth. Therefore, it has become an urgent problem in engineering practice to study the seismic characteristics of slope anchoring system and then realize the optimal design of slope anchoring. In this paper, the dynamic response of a rock slope strengthened with a full-length bonded anchor cable is studied by centrifuge model test. It is found that the internal structure of the rock slope has an important effect on the length of the bonded anchor cable. The structural surface will lead to an increase of the effective anchorage length, and the stress concentration of anchor cable will occur at the structural surface. This provides some references for the optimization of traditional anchorage theory.
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Vavrus, Martin, i Jakub Kralovanec. "Study of Application of Fiber Reinforced Concrete in Anchorage Zone". Buildings 13, nr 2 (14.02.2023): 524. http://dx.doi.org/10.3390/buildings13020524.
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In the case of post-tensioned or geotechnical structures, the anchorage zone is considered a critical part of the design and construction process. Generally, the failure of the anchorage zone is one of the most common problems. High-bearing stresses create significant transverse tension. For these reasons, conventional reinforcement, usually in the form of closed stirrups, must be designed. The presented analysis is focused on the possible increase of load-carrying capacity of the anchorage zone with steel fiber-reinforced concrete. Three types of specimens were analyzed. The first type of specimen represented the anchorage zone made from standard reinforced concrete. The second and third series of specimens were designed from fiber-reinforced concrete with two different volumes of steel fibers added into the anchorage zone. The parameters used in the numerical analysis of the anchorage zone were experimentally determined on a set of beam specimens. In the analysis, the anchorage zone was loaded by a node force applied on a steel load distribution plate placed on the top edge of the bloc. The performed numerical study suggests that the load-bearing capacity can be increased by adding fiber-reinforced concrete with a higher volume of fiber (Dramix 3D 55/30, volume of fiber of 110 kg/m3) into the vicinity of the anchorage plate.
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Lian, Shao, Ou Jinping i Zhou Zhi. "Development of a new anchorage system for carbon fiber–reinforced polymer rods using extrusion process". Advances in Structural Engineering 25, nr 5 (10.01.2022): 1002–14. http://dx.doi.org/10.1177/13694332211057265.
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Carbon fiber–reinforced polymer (CFRP) rods have been considered as a candidate material for prestressed concrete applications because of their superior properties. For current applications, successful use of CFRP rods is linked to an efficient anchorage system design. This paper presents a newly developed anchorage system for CFRP rods and the design concept that the extrusion process is used to generate gripping force. The proposed anchorage system consists of a steel barrel and an aluminum sleeve, and an extrusion region is designed on the outside of barrel to generate a suitable contact pressure distribution on the CFRP rod. A mathematical model was proposed to estimate the contact pressure on the CFRP rod and the capacity of anchorage system. The simulation of extrusion and loading process was conducted with a three-dimensional (3D) finite-element (FE) model. The key design parameters of anchorage system were analyzed to obtain an optimized parameter combination. The experimental validation showed that the new anchorage system is capable of allowing the CFRP rod to attain the ultimate tensile strength.
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Cui, Zhen, Maochu Zhang i Qian Sheng. "Mechanical Behavior of the Rock-Concrete Interface for a Bridge Anchorage Structure Using Discrete Element Method". Journal of Marine Science and Engineering 10, nr 2 (7.02.2022): 221. http://dx.doi.org/10.3390/jmse10020221.
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Traditionally, the numerical simulation work of a bridge gravity anchorage structure is performed with a continuous method, such as the finite element method (FEM). However, since the rock mass and gravity anchorage structure are assumed to be continuous in the FEM, the interaction between the rock mass foundation and the concrete of the anchorage is not frequently considered. This paper aims to investigate the problem of the interaction between the rock mass foundation and the concrete of the anchorage. The discrete element method (DEM), which has been verified to be suitable for the modelling of contact problems of discrete blocks, is introduced in this paper to simulate the mechanical behavior of the rock-concrete system of the gravity anchorage structure and its rock mass foundation. Based on the in-situ scale model test for a bridge, the mechanical behavior of the rock-concrete interface was discussed with the DEM method. With the calibrated DEM model, the displacement of the foundation rock mass, contact stresses, and yield state on the rock-concrete interface were numerically investigated. The anti-sliding effect of the keyway and the step at the bottom of the gravity anchorage structure was analyzed. The results show that the anchorage deformation under the design conditions is basically characterized by the rigid rotation around the keyway of platform #2, and that such rotation subsequently affects the anti-shear capacity of the entire gravity anchorage to a large extent. The anchorage scale model could remain stable under the design lateral load such that the rock-concrete interface would remain intact and sufficient shear resistance could be provided by the keyway and steps.
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Zhang, Tao, Qingzhen Lu, Jun Yan, Shichao Wang, Qianjin Yue, Shanghua Wu, Hailong Lu i Jinlong Chen. "Numerical Study on Flexible Pipe End Fitting Progressive Failure Behavior Based on Cohesive Zone Model". Journal of Marine Science and Engineering 11, nr 1 (5.01.2023): 116. http://dx.doi.org/10.3390/jmse11010116.
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Flexible pipes are extensively used to connect seabed and floating production systems for the development of deep-water oil and gas. In the top connection area, end fitting (EF) is the connector between the flexible pipe and floating platform, as a critical component for structural failure. To address this issue, a combined numerical and experimental prediction method is proposed in this paper to investigate the failure behavior of flexible pipes EF considering tensile armor and epoxy resin debonding. In order to analyze the stress distribution of the tensile armor and the damage state of the bonding interface as the tensile load increases, a finite element model of the EF anchorage system is established based on the cohesive zone model (CZM). Additionally, the effects of the epoxy resin shear strength (ss) and the steel wire yield strength (ys) on the structural load-bearing capacity are discussed in detail. The results indicate that wire strength and interface bonding have a substantial effect on the anchorage system’s failure behavior, and the low-strength wire anchorage system has a three-stage failure behavior with wire yielding as the predominant failure mode, while the high-strength wire anchorage system has a two-stage failure behavior with interface debonding as the predominant failure mode.
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Michels, Julien, Jose Sena-Cruz, Christoph Czaderski i Masoud Motavalli. "Structural Strengthening with Prestressed CFRP Strips with Gradient Anchorage". Journal of Composites for Construction 17, nr 5 (październik 2013): 651–61. http://dx.doi.org/10.1061/(asce)cc.1943-5614.0000372.
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Campbell, T. I., N. G. Shrive, K. A. Soudki, A. Al-Mayah, J. P. Keatley i M. M. Reda. "Design and evaluation of a wedge-type anchor for fibre reinforced polymer tendons". Canadian Journal of Civil Engineering 27, nr 5 (1.10.2000): 985–92. http://dx.doi.org/10.1139/l00-048.
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The development of a wedge-type anchorage system for fibre reinforced polymer (FRP) tendons, as part of an overall corrosion-free post-tensioning system, is outlined in this paper. A stainless steel anchor is described, and results from numerical models and load tests to evaluate its behaviour under loads from anchor set, as well as static and repeated tendon tension, are presented. An alternative wedge-type anchorage system made from ultra-high performance concrete is also described. It is shown that, although significant progress has been made in development of the anchorage, further work is required to make it more robust.Key words: FRP tendons, post-tensioning, anchorage, corrosion-free, mathematical models, load tests, concrete.
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Feng, Bo, Xin Wang i Zhishen Wu. "Evaluation and prediction of carbon fiber–reinforced polymer cable anchorage for large capacity". Advances in Structural Engineering 22, nr 8 (19.02.2019): 1952–64. http://dx.doi.org/10.1177/1369433219829806.
Pełny tekst źródłaStreszczenie:
Aiming to address the problems of stress concentration on conical wedge anchorage, a fiber-reinforced polymer cable anchorage with segmental variable stiffness of the load transfer medium was proposed. The key parameters that affect the anchorage behavior were investigated. The mechanical properties of the carbon fiber–reinforced polymer tendon and load transfer medium were tested. The failure mode, anchoring efficiency, stress, and displacement in the anchor zone were studied. The parameter optimization was performed using an experimentally verified finite element simulation. The parameters of the anchorage system with large capacity were evaluated. The results demonstrate that the compressive strength of the load transfer medium is the designed stress limit for the anchorage system. The cable does not slip or become damaged in the anchor zone, and the anchoring efficiency reaches 91%. The distribution of the shear and radial stress on the cable surface is smooth, and the stress concentration is greatly relieved. The result of the finite element simulation is consistent with the experimental values when the friction coefficient is 0.15, and the material and geometric parameters of the anchorage system with cable forces of 5000, 10,000, 15,000, and 20,000 kN are suggested. The geometric parameters of the anchor system with diverse cable capacity can be preliminarily designed based on the fitting equations.
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Zhang, Burong, i Brahim Benmokrane. "Design and evaluation of a new bond-type anchorage system for fiber reinforced polymer tendons". Canadian Journal of Civil Engineering 31, nr 1 (1.01.2004): 14–26. http://dx.doi.org/10.1139/l03-062.
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Corrosion resistance, high strength, and advantageous strength-to-weight ratio enable fiber reinforced polymers (FRPs) to have substantial potential to replace steel tendons in prestressed applications. One of the main technical obstacles to wide use of FRPs in the construction industry is the methodology to anchor FRP tendons to achieve their full strength. High tensile to compression and shear strength ratios make it necessary to develop a new anchorage design concept for FRP tendons. This paper gives a literature review of bond-type anchorage systems and the mechanics of stress transfer by bond from FRP tendons to grout and reports an experimental study on a newly developed bond-type anchorage system with carbon fiber reinforced polymer (CFRP) Leadline 8-mm-diameter rods. The test program consisted of nine monotonic tensile tests, two pullout tests, and two proving tests on the anchorage system with Leadline single- or 9-rod tendons. The test results showed that the developed anchorage system with 250-mm bond length ensures full development of the tensile strength of Leadline mono-rod tendons. The bond strength of Leadline 9-rod tendons is 14 MPa for a bond length of 95 mm, 62% of that of mono-rod ones with a bond length of 80 mm. The anchorage system with a 400-mm bond length gives at least 90% of the tensile strength of Leadline 9-rod tendons and also demonstrates an acceptable sustained loading behaviour in accordance with existing codes.Key words: anchorage, bond stress, creep, grout, polymers, rod, slip, tendon.
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Wang, Zhongling, Xiaohong Zheng, Qiqi Wang i Qian Wang. "An Experimental Study on the Bond–Slip Relationship between Rebar and Ultra-High-Performance Concrete Grouted in Bellows". Buildings 13, nr 9 (18.09.2023): 2375. http://dx.doi.org/10.3390/buildings13092375.
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Ultra-high-performance concrete (UHPC)-filled duct connection is an innovative solution for joining assembled structures, in which the anchorage performance of the rebar and UHPC filled in bellows plays a critical role in determining the overall connection effectiveness. To establish a reliable anchorage length and a bond–slip relationship between rebar and UHPC within a bellow, a total of 16 specimens were conducted, and pullout tests were carried out. Two parameters were considered, including the diameter ratio (D/d), representing the proportion of the diameter of the bellow D to the diameter of the steel bar d, and anchorage length (L). By analyzing the failure modes, load versus deflection curves, and steel strain data, the influences of the diameter ratio and anchorage length on the anchorage performance were discussed. The test results showed that the failure mode changed from rebar pullout to rebar breakage as the anchorage length increased from 3 d to over 10 d. The reliable anchorage length of the rebar was recommended to be at least 10 d with a diameter ratio (D/d) of 2.4. Moreover, a fitting bond–slip model was proposed based on the experimental bond–slip curves between the rebar and UHPC interface within the bellows with high precision. These findings constitute a crucial basis for the comprehensive stress analysis of assembled structures connected using UHPC grouted in bellows.
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Farbák, Matúš, Jozef Jošt, Richard Hlinka i Miroslav Rosmanit. "Numerical Analysis of the Load-Displacement Behaviour of Cast-in-Place Progressive Anchorage in Reinforced Concrete Members". Applied Sciences 11, nr 5 (6.03.2021): 2343. http://dx.doi.org/10.3390/app11052343.
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Modern construction requirements for building structures are currently focused on reducing the time required for construction, dealing with the lack of qualified human resources and ensuring comprehensive construction work quality. The problems mentioned above of today’s construction industry are significantly reduced by modern prefabrication and the efficient use of the most common building materials—steel and concrete. Critical components of such construction systems are their joints. Currently, there are many different types of joints of precast concrete structural elements. Integral parts of these joints are the various anchorages. For connecting load-bearing components, cast-in-place anchor systems are preferred to post-installed ones. The appropriate design of this small but crucial structural component is a complicated engineering issue in some cases. The finite element method (FEM) represents a practical opportunity to design and analyze anchorage systems in detail. A detailed numerical study based on an experimental program was performed to understand cast-in-place anchors’ real behavior and clarify some of the parameters of their design. This paper explains the creation of a numerical model, compares the FEM model with the performed experiments and presents the interesting results of the performed parametric study.
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Peng, Wen Xiang, Ming Kai Xu, Yi Fan Chen, Zheng Hao Chen i Zhuo Yang. "Field Experiment Research of the Polycystic Aeration Bolt: Model Design and Anchorage Mechanism". Advances in Civil Engineering 2021 (18.01.2021): 1–10. http://dx.doi.org/10.1155/2021/6669368.
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As a new type of bolt, the polycystic aeration bolt has a broad application prospect in soft soil area; however, its design and production are still in the stage of constant exploration and improvement. From the perspective of bolt material and engineering cost, the important components of the polycystic aeration bolt were analyzed by combination with the existing bolt models, and a new structural design scheme of a kind of polycystic aeration bolt which can be used in practical engineering was presented in this paper. Then, the stress and failure mode of this bolt were discussed, and the theoretical equation of the bearing capacity was derived by using the elastic-plastic theory. In addition, the assembly and fabrication technology of this bolt in practical foundation pit engineering was described in detail. Finally, the field pull-out test of the polycystic aeration bolt was carried out, and the test results were compared with those of the conventional grouting bolt, which indicated that this new bolt has a greater advantage in bearing capacity than the conventional grouting bolt, verifying the feasibility of the structural design scheme of the polycystic aeration bolt proposed in this paper.
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Luo, Xinyang, Ping Cao, Taoying Liu, Qingxiong Zhao, Gang Meng, Zhi Fan i Weiping Xie. "Mechanical Behaviour of Anchored Rock Containing Weak Interlayer under Uniaxial Compression: Laboratory Test and Coupled DEM–FEM Simulation". Minerals 12, nr 4 (17.04.2022): 492. http://dx.doi.org/10.3390/min12040492.
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The reason for instability in a rock mass with a weak interlayer is not only the sliding failure of the rock interlayer structural plane but also the tip crack propagation caused by the stress concentration at the tip of the interlayer. In this study, a uniaxial compression test of an anchored rock mass with a weak interlayer was carried out to determine the influence of the anchorage on the failure pattern and the strength of samples with different interlayer dip angles. In addition, the coupled DEM–FEM numerical simulation method was used to study the internal stress evolution of the sample and the stress distribution of the anchor under the anchorage effect. The results showed that the anchorage effect on reinforcement and strength enhancement was greatest for the sample with an interlayer dip angle of 30°. Under the anchorage effect, crack initiation was limited and there was more shear failure in the samples. The reinforcement range of the anchorage effect for anchors with restrained ends was larger than for anchors with free ends. When the rock–anchor interface was unbonded, the effect of the free-ends anchor reflected the residual friction, but the restrained-ends anchor still worked by limiting the lateral expansion of the rocks. The stress values and deformation of the anchors decreased gradually with an increase in dip angle.
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Cui, Nannan, i Shiping Huang. "ON THE OPTIMAL STRUT-AND-TIE MODELS AND DESIGN APPROACH FOR THE CABLE-PYLON ANCHORAGE ZONE". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 25, nr 6 (25.06.2019): 576–86. http://dx.doi.org/10.3846/jcem.2019.10374.
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The cable-pylon anchorage zone is a typical D-region in a cable-stayed bridge, for which there has been no uniform simplified design method until now. In this paper, based on the extensive statistics of actual projects, topology optimization techniques and principle of minimum strain energy, two precise strut-and-tie models for the cable-pylon anchorage zone are proposed, which can clearly reveal the load-transmitting mechanism of the anchorage zone. Th e explicit geometric parameters of the strut-and-tie models are derived; thus, the designers can directly use these models. A simple design procedure to deploy prestressing tendons in the anchorage zone is also introduced, whose effectiveness and convenience are demonstrated by two design examples. A new design named the “one-way prestressing tendons PC cable-pylon” is also discussed regarding its application scope.
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Soraghi, Ahmad, i Qindan Huang. "Simple rebar anchorage slip macromodel considering corrosion". Engineering Structures 262 (lipiec 2022): 114357. http://dx.doi.org/10.1016/j.engstruct.2022.114357.
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Ye, Hanhui, i Zhijian Chen. "Structural Condition Assessment and Temperature Effect Analysis of Cable–Pylon Anchorage Zone Using Long-Term SHM Data". Advances in Civil Engineering 2023 (8.08.2023): 1–22. http://dx.doi.org/10.1155/2023/7431867.
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To study the temperature effect in the anchorage zone of a long-span cable-stayed bridge, a wavelet multiresolution analysis and layered stripping method were used in this paper. Based on long-term structural health monitoring data, the signals were decomposed and reconstructed at multiple time scales, confirming temperature to be the main factor causing the stress change in the anchorage zone. The results of structural condition during operation showed that the general compressive stress level of the anchorage zone was low. However, the tensile stress level of the sidewall was high, which led to a severe concrete cracking. Excluding the influence of the seasonal temperature, the compressive stress increased slightly, the horizontal tensile stress in the upstream inner pylon wall increased, and the crack width increased gradually. By analysing the daily temperature effect on the upstream and downstream pylon walls, the regression model proposed in this study can be used to predict the daily temperature effect at any time in the diurnal cycle. The accuracy of the model is reliable within 6 days, but for the location of severe cracks, the monitoring data should be updated in real time to ensure the precision.
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Park, Young-Ha, Moon-Young Kim, Jong-Myen Park i Se-Jin Jeon. "An Improved Equation for Predicting Compressive Stress in Posttensioned Anchorage Zone". Advances in Civil Engineering 2020 (28.02.2020): 1–12. http://dx.doi.org/10.1155/2020/5635060.
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Validity of the approximate equation for predicting compressive stress in the posttensioned anchorage zone presented in the AASHTO LRFD Bridge Design Specifications was investigated in this study. Numerical analysis based on the finite element method (FEM) and theoretical analysis showed that the AASHTO formula gives relatively accurate stress values when the effect of duct holes is neglected. However, it was found that the formula can significantly overestimate the stresses in the actual prestressed concrete member with spaces occupied by ducts. Therefore, an improved equation was proposed for the existing AASHTO equation to consider the effect of the duct holes on the stress distribution. This resulted in relatively accurate prediction of the distribution and magnitude of the compressive stresses even with the presence of the duct holes. The proposed equation was also validated by comparing with the stresses measured in the test of a posttensioned full-scale specimen. This study is expected to contribute to the design of the anchorage zone in prestressed concrete structures by suggesting a more reasonable way to assess the appropriateness of anchorage devices.
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Lee, Sang-Moon, i Woo-Young Jung. "Evaluation of anchorage performance of the switchboard cabinet under seismic loading condition". Advances in Mechanical Engineering 12, nr 5 (maj 2020): 168781402092630. http://dx.doi.org/10.1177/1687814020926309.
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In this study, the seismic response of the anchorage used for switchboard cabinets at a power plant was presented based on the results of an experiment and numerical simulations. In the experimental study, shaking table tests were performed to investigate the overall structural behavior of switchboard cabinets. The finite element modeling was conducted using the ABAQUS program, and in order to validate the proposed finite element model, the natural frequency, stress, and displacement were compared with the experimental results. A slight difference was found in the results due to the problem cup-like deformation at the anchorage of the bottom, but it showed reasonable agreement when considering the results for all behaviors. Using the proven model, nonlinear dynamic analysis was performed using three types of a period waves. The maximum stress on the anchorage occurred when a long-period wave was applied, and the horizontal maximum displacement of the cabinet was approximately 10 times greater than when an ultra-short-period wave was applied. It is expected that the flexibility of the cabinet stiffness resulted in more structural weakness, especially under a long-period wave, and that is recommended to focus on displacement rather than stress when establishing seismic design guidelines for switchboard cabinets.
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Kim, Joung Rae, Hyo-Gyoung Kwak, Byung-Suk Kim, Yangsu Kwon i El Mahdi Bouhjiti. "Finite element analyses and design of post-tensioned anchorage zone in ultra-high-performance concrete beams". Advances in Structural Engineering 22, nr 2 (20.07.2018): 323–36. http://dx.doi.org/10.1177/1369433218787727.
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This article presents analyses and the design of a post-tensioned anchorage zone made of ultra-high-performance concretes with three-dimensional finite element analyses. The structural behavior was investigated through the failure modes and cracking patterns to show the anchorage zone resistance enhancement with an increase of the strength in concrete. Since the anchorage failure is usually initiated from the local zone in the case of ultra-high-performance concrete beams that have compressive strength of more than 80 MPa, the placement of reinforcements can effectively be used to enhance the strength and ductility for the local zone. However, ultra-high-performance concrete requires a smaller amount of reinforcement than normal-strength concrete. Parametric analyses are carried out to show the effect of the spiral reinforcement on the strength of the anchorage zone, and comparison with the design guidelines in NCHRP Report 356 is made. Finally, improved guidelines are suggested to cover the design of ultra-high-performance concrete.
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Li, Lifeng, Weili Gong, Huilin Deng, Xiaohu Zhang i Gan Li. "Distribution Pattern of Anchorage Stress and Water Sensitivity Analysis of Red Clay". Shock and Vibration 2020 (19.02.2020): 1–12. http://dx.doi.org/10.1155/2020/6272576.
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Red clay is a special soil layer with complex engineering properties distributed in tropical and subtropical regions. An anchor cable support is a common form of red clay slope support. The effectiveness of the anchor cable support is mainly determined by the anchoring force provided by the red clay stratum. Increase of the water content will lead to the rapid deterioration of the mechanical properties of red clay, which will lead to the reduction of the anchoring force of the slope anchor cable and lead to the failure of the support. Based on the classical Phillips and uniform anchorage shear stress distribution theory, this paper puts forward a uniform-exponential distribution pattern of anchorage shear stress according to the specific characteristics of red clay by using the characteristics of the peak shear strength and residual shear strength of the rock and soil mass. With increasing anchorage force, the dynamic evolution (single exponential distribution ⟶ double single exponential distribution ⟶ uniform index exponential complex distribution ⟶ uniform distribution) of the anchorage shear stress is analysed. Based on the peak and residual test of the cohesive force and internal friction angle, the relationship between the anchoring force and buried depth and water content is established by analysing the factors influencing the anchoring force. It can be found from the field test that, according to the relationship established, the limit anchorage force of the anchor cable in the red clay stratum can be calculated and the water sensitivity of the anchor cable’s limit anchorage force can be quantitatively analysed.
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Iekel, Philip P., Brent Phares i Michael Nop. "Performance Investigation and Design of Pile-to-Pile Cap Connections Subject to Uplift". Transportation Research Record: Journal of the Transportation Research Board 2672, nr 52 (18.09.2018): 278–90. http://dx.doi.org/10.1177/0361198118796733.
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Substructure bridge components are designed to resist gravitational forces such as dead load and vehicular live load, as well as lateral forces including wind, vehicular braking, and centrifugal force effects. Significant lateral forces can create “uplift” conditions on some portions of the foundation. A review of current design techniques regarding uplift in the pile-to-pile cap connection indicates a lack of uniformity in the design process across state agencies stemming from minimal research performed in this area. In addition, approved uplift anchors for use in the field have not been tested. In order to close this gap, twenty-one full-scale steel H-pile specimens were fabricated and tested in Iowa State University’s Structural Engineering Laboratory to test the capacity of the pile-to-pile cap connection under static tensile loading. Specimens were cast both with and without anchorage and with 12” and 24” embedment depths in order to understand the behavior of the connection and to determine a suitable anchorage detail and design approach for uplift cases. Findings revealed that: (i) capacity of bare piles is generally underestimated and could be more frequently considered for uplift design; (ii) concrete cracking leads to a loss of bond in these types of connections; and (iii) positive anchorage or embedment that extends above the lower rebar mat of the footing is necessary to develop a high capacity connection.
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Tanaka, H., R. Park i B. McNamee. "Anchorage of transverse reinforcement in rectangular reinforced concrete columns in seismic design". Bulletin of the New Zealand Society for Earthquake Engineering 18, nr 2 (30.06.1985): 165–90. http://dx.doi.org/10.5459/bnzsee.18.2.165-190.
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Four reinforced concrete columns with 400 mm (15.7 in) square cross sections were tested under axial compressive load and cyclic flexure to simulate severe seismic loading. The longitudinal reinforcement consisted of eight bars. The transverse reinforcement consisted of square perimeter hoops surrounding all longitudinal bars and cross ties between the intermediate longitudinal bars. The major variable of the study was the type of anchorage used for the hoops and cross ties. The anchorage details involved arrangements of perimeter hoops with 135° end hooks, cross ties with 90° and/or 180° end hooks, and cross ties and perimeter hooks with tension splices. Conclusions were reached with regard to the effectiveness of the tested anchorage details in columns designed for earthquake resistance.
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Yao, Guowen, Xuanbo He, Hong Long, Jiangshan Lu i Qianling Wang. "Corrosion Damage Evolution Study of the Offshore Cable-Stayed Bridge Anchorage System Based on Accelerated Corrosion Test". Journal of Marine Science and Engineering 11, nr 5 (22.04.2023): 896. http://dx.doi.org/10.3390/jmse11050896.
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The cable-stayed bridge anchorage system is prone to serious corrosion problems in the offshore environment, threatening its service safety. Based on the copper accelerated salt spray (CASS) test, the anchorage system was subjected to accelerated corrosion and then dissected along the axial direction to study the corrosion damage evolution of the internal structure. This revealed the evolution of corrosion damage in the anchorage system of offshore cable-stayed bridges. The results show that in the offshore environment, a large number of corrosion factors enter the interior of the cable anchorage system through the splicing seam at the junction of the anchor cup and the connecting barrel, and spread to both ends, thus causing corrosion damage to the anchor cup, connecting barrel, filling medium and cable steel wires. Inside the cable of the anchorage system, cross-sections with a higher corrosion level on the outer circle steel wires will also have a higher overall corrosion level. The outer circle steel wires are less able to meet the strength requirements, because they withstand most of the corrosion effects, and the corrosion pits on the surface of the steel wires will render them much weaker than the design tensile strength and fracture. After the CASS test, the ductility of cable steel wires decreases from the inner circle to the outer circle, and the higher the corrosion level of steel wires, the more obvious the brittle indications; the steel wires tend to undergo brittle failure. In the design and manufacture of the cable-stayed bridge anchorage system, special attention should be paid to the corrosion protection of the splicing seam, as well as the corrosion condition and residual strength of steel wires in the outer circle of the cable, to delay the degradation of the mechanical properties and brittle damage of the anchorage system.
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Ding, Wan Tao, Jin Hui Liu i Shu Cai Li. "Discussion on Anchor Structures’ Deterioration Analysis Parameter Caused by Reinforcement Corrosion under Erosion Environment Condition". Applied Mechanics and Materials 268-270 (grudzień 2012): 827–30. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.827.
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Because of long-term chloride erosion and alternate drying-wetting effect, anchorage support structure of underground engineering is liable to reinforced corrosion and its strength is decreased. According to previous research theory and test results, reinforced corrosion to deteriorate load-bearing role of anchorage support structure system is studied by means of numerical analysis FLAC3D and idea of finite element strength reduction. The results are as follows: (1) losses in the anchor structural performance in underground engineering with corroded reinforcements are caused by three factors: losses in the effective cross-sectional area of anchoring body, losses in the mechanical performance of reinforcing bars and losses in the bond performance of anchoring body. (2) Based on reinforcement mechanical model in FLAC3D, deterioration of mechanical performance of anchor structures caused in underground engineering was analyzed due to reinforcement corrosion. And according to idea of finite element strength reduction and results of laboratory test, deterioration analysis parameter caused by corrosion can be reduced accordingly. The research results can provide the theory support to analyze corrosion deterioration of anchor structure in underground engineering using numerical simulation.
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Geng, Tiesuo, Shuanghua Chen, Liuqun Zhao i Zhe Zhang. "Research on Bonding Performance of Anchorage Caisson Foundation with Different Contact Surfaces and Grouting Bed". Buildings 11, nr 8 (19.08.2021): 365. http://dx.doi.org/10.3390/buildings11080365.
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In view of the first domestic offshore suspension bridge with caisson foundation, this paper mainly studies the bonding properties between underwater pre-filled aggregate grouting bed and anchorage caisson foundation. Through the test, the cohesive force of adding ordinary concrete between the anchorage caisson foundation and the grouting bed, the cohesive force of adding paper base asphalt felt between the anchorage caisson foundation and the grouting bed, and the cohesive force of adding geotextile between the anchorage caisson foundation and the grouting bed are measured, respectively. When the contact surface is concrete and geotextile, the fracture form of the specimen was analyzed by numerical simulation, and the AE variation trend of the two specimens have been studied. The results of this article can provide references for other projects.
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Chen, Yun, Nai Long Zhu i Shuai Gao. "An Energy Dissipation Device Based on Shape Memory Alloys for Frame Structures". Applied Mechanics and Materials 580-583 (lipiec 2014): 1591–94. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1591.
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This paper proposes an energy dissipation device based on shape memory alloys (SMA) for frame structures. By setting anchorage device below and near the inflection point of the first storey columns, a set of force cable and energy dissipation cable using SMA are installed symmetrically in the anchorage device and the bottom of them fixed in the ground. Analytical study including the push-over and time-history analysis were investigated by ANSYS finite element program to a new CFST frame and an ordinary CFST frame. Studies have shown that the device can effectively control the structural displacement response and acceleration response, dissipating large amounts of earthquake energy. Therefore, the energy dissipation devices had a better value and prospects in engineering.