Grouted anchorages for aramid fibre reinforced plastic prestressing tendons

1993 ◽  
Vol 20 (6) ◽  
pp. 1065-1069 ◽  
Author(s):  
K. S. McKay ◽  
M. A. Erki
Keyword(s):  
Prestressed Concrete ◽  
Steel Tube ◽  
High Ratio ◽  
Aramid Fibre ◽  
Test Results ◽  
Structural Deterioration ◽  
Reinforced Composite ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Lateral Strength

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.

Flexural behaviour of concrete beams pretensioned with aramid fibre reinforced plastic tendons

1993 ◽  
Vol 20 (4) ◽  
pp. 688-695 ◽  
Author(s):  
K. S. McKay ◽  
M. A. Erki
Keyword(s):  
Cyclic Loading ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
Aramid Fibre ◽  
Advanced Composite ◽  
Advanced Composite Materials ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Static And Cyclic Loading ◽  
Corrosive Environments

The durability of reinforced concrete structures has become an increasing concern as our infrastructure ages. In particular is the deterioration of steel reinforcements when used in concrete structures exposed to severe corrosive environments. This paper investigates the feasibility of using noncorroding aramid fibre reinforced plastic (AFRP) tendons as a substitute for steel strand in pretensioned concrete applications. Three AFRP pretensioned beams, 150 × 300 × 2100 mm, were tested under static and cyclic loading. These results indicate that load capacities of the beams were not affected by the cyclic loading. Ultimate strengths were generally greater than predicted, primarily as a result of the ability of the AFRP rods to develop greater tensile stresses than expected. Key words: prestressed concrete, nonmetallic tendons, aramid fibres, advanced composite materials.

Effects of resin pre-coating on interfacial bond strength and toughness of laminar CFRP with and without short aramid fibre toughening

2020 ◽  
Vol 54 (25) ◽  
pp. 3883-3893
Author(s):  
Binhua Wang ◽  
Guangzhi Ding ◽  
Gang Wang ◽  
Sisi Kang
Keyword(s):  
Carbon Fiber ◽  
Adhesive Layer ◽  
Aramid Fibre ◽  
Mode I ◽  
Test Results ◽  
Interfacial Bond Strength ◽  
Treatment Technology ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Aramid Fibres

The brittle adhesive layer in carbon fiber-reinforced polymer (CFRP) laminates was strengthened by using short aramid fibers in this study. To ensure the feasibility and effectiveness of short aramid fiber interfacial toughening at the interface between the carbon-fiber face sheets, the self-prepared short aramid fibre tissue and the wettability treatment technology with resin pre-coating were applied to enable short aramid fibres to be well embedded in the uneven regions in the CFRP fabrics with fibres oriented at 0° and 90° to form a strong pulling resistance. The ultimate load and the mode I interlaminar fracture toughness have been improved by 75% and 103.9% from the double cantilever beam mode I crack propagation tests, respectively. The reinforcing mechanisms within the “composite adhesive layer” as a result of short aramid fibres are discussed together with detailed scanning electron microscopy observations and comparison test results.

Comprehensive investigation of cutting mechanisms and hole quality in dry drilling woven aramid fibre–reinforced plastic with typical tools

2019 ◽  
Vol 233 (14) ◽  
pp. 2471-2491 ◽  
Author(s):  
Sinan Liu ◽  
Tao Yang ◽  
Chang Liu ◽  
Yu Du
Keyword(s):  
Radial Component ◽  
Aramid Fibre ◽  
Twist Drill ◽  
Hole Quality ◽  
Specific Strength ◽  
Reinforced Plastics ◽  
Dry Drilling ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Cutting Mechanisms

Due to high specific strength and strong toughness, aramid fibre–reinforced plastics have been widely used in the aircraft, military, and automobile industries. However, in the hole-making process, these excellent properties make aramid fibre–reinforced plastics difficult to machine and prone to severe entrance and exit damages. In this article, the cutting mechanisms of three typical tools (twist drill, burr tool, and brad drill) are thoroughly investigated during dry drilling of aramid fibre–reinforced plastic. On this basis, systematic experiments are conducted to evaluate the cutting performance and hole quality. At the hole entrance, the cutting edges of the twist drill peel and tear the uncut material, which results in severe fuzzing damage. Due to the radial rake angles of the burr tool and brad drill, the radial component of the cutting force can pre-tension aramid fibres prior to being cut, which effectively reduces the fuzzing defect. At the hole exit, the extrusion action of the chisel edge and the severe chip adherence are the main causes of exit damage for the twist drill and burr tool, respectively. Due to the decrease in the thrust force and improvement in the shearing action, the best hole quality is achieved by the brad drill. To further improve the hole quality, an auxiliary approach using collars is introduced to effectively restrain the damage by enhancing interfacial bonding strength. This article provides comprehensive and available information on tool performance for drilling aramid fibre–reinforced plastics, which can help guide process optimizations to achieve the desired hole quality.

scholarly journals Numerical-Experimental Investigation into the Tensile Behavior of a Hybrid Metallic–CFRP Stiffened Aeronautical Panel

2020 ◽  
Vol 10 (5) ◽  
pp. 1880 ◽  
Author(s):  
Andrea Sellitto ◽  
Salvatore Saputo ◽  
Angela Russo ◽  
Vincenzo Innaro ◽  
Aniello Riccio ◽  
...  
Keyword(s):  
Damage Evolution ◽  
Composite Fiber ◽  
Hybrid Structure ◽  
Tensile Behavior ◽  
Stiffened Panel ◽  
Test Results ◽  
Fiber Reinforced Plastic ◽  
Reinforced Composite ◽  
Reinforced Plastic ◽  
Composite Stiffened Panel

In this work, the tensile behavior of a hybrid metallic–composite stiffened panel is investigated. The analyzed structure consists of an omega-reinforced composite fiber-reinforced plastic (CFRP) panel joined with a Z-reinforced aluminum plate by fasteners. The introduced numerical model, able to simulate geometrical and material non-linearities, has been preliminary validated by means of comparisons with experimental test results, in terms of strain distributions in both composite and metallic sub-components. Subsequently, the inter-laminar damage behavior of the investigated hybrid structure has been studied numerically by assessing the influence of key structural subcomponents on the damage evolution of an artificial initial debonding between the composite skin and stringers.

Study on shear performance of the connection with external stiffening ring between square steel tubular column and unequal-depth steel beams

2020 ◽  
pp. 136943322098166
Author(s):  
Shuhao Yin ◽  
Bin Rong ◽  
Lei Wang ◽  
Yiliang Sun ◽  
Wuchen Zhang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Plastic Hinge ◽  
Steel Tube ◽  
Nonlinear Finite Element ◽  
Steel Beams ◽  
Finite Element Models ◽  
Test Results ◽  
Panel Zone ◽  
Load Paths ◽  
Shear Performance

This paper studies the shear performance of the connection with the external stiffening ring between the square steel tubular column and unequal-depth steel beams. Two specimens of interior column connections were tested under low cyclic loading. The deformation characteristics and failure modes exhibited by the test phenomena can be summarized as: (1) two specimens all exhibited shear deformation in steel tube web of the panel zone and (2) weld fracture in the panel zone and plastic hinge failure at beam end were observed. Besides, load-displacement behaviors and strain distributions have been also discussed. The nonlinear finite element models were developed to verify the test results. Comparative analyses of the bearing capacity, failure mode, and load-paths between the equal-depth and unequal-depth beam models have been carried out.

Cracking behaviour of concrete beams reinforced with fiber reinforced plastic rebars

1996 ◽  
Vol 23 (6) ◽  
pp. 1172-1179 ◽  
Author(s):  
R. Masmoudi ◽  
B. Benmokrane ◽  
O. Chaallal
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Test Results ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Concrete Members ◽  
Reinforced Plastic ◽  
Cracking Pattern

This paper presents the results of an experimental investigation on the cracking behaviour of concrete beams reinforced with fiber reinforced plastic rebars. The effects of reinforcement ratio on the cracking pattern, crack spacing, cracking moment, and crack width are investigated. The test results indicate that the reinforcement ratio has no meaningful effect on the cracking moment, which can be calculated as recommended by the ACI code. Also, the use of the equations adopted by ACI and the European codes for the prediction of crack width of conventionally reinforced concrete members is investigated and due modifications are made. Both relationships show good correlation with the test results; and the prediction of crack width of concrete beams reinforced with these two types of fiber reinforced plastic rebars is now possible. Key words: beam, cracking behaviour, cracking moment, crack width, fiber reinforced plastic, flexure, rebars, reinforced concrete, reinforcement ratio.

Effect of Concrete Release Strength on the Development Length and Flexural Capacity of Members Made With Different Prestressing Wires Commonly Used in Pretensioned Concrete Railroad Ties

2015 ◽  
Author(s):  
Amir Farid Momeni ◽  
Robert J. Peterman ◽  
B. Terry Beck ◽  
Chih-Hang John Wu ◽  
Naga Narendra B. Bodapati
Keyword(s):  
Compressive Strength ◽  
Prestressed Concrete ◽  
Loading Rate ◽  
Test Results ◽  
Development Length ◽  
Concrete Compressive Strength ◽  
Flexural Capacity ◽  
Pretensioned Concrete ◽  
Embedment Length ◽  
Bond Characteristics

A study was conducted to determine the effect of concrete release strength on the development length and flexural capacity of members utilizing five different 5.32-mm-diameter prestressing wires that are commonly used in the manufacture of prestressed concrete railroad ties worldwide. These included two chevron-indented wires with different indent depths, one spiral-indented wire, one dot-indented wire, and one smooth wire (with no surface indentation). A consistent concrete mixture was used for the manufacture of all test specimens, and the different release strengths were obtained by allowing the specimens to cure for different amounts of time prior to de-tensioning. Each prismatic specimen (prism) had a 3.5″ (88.9 mm) × 3.5″ (88.9 mm) square cross section with four wires arranged symmetrically. The prisms were identical except for the wire type and the compressive strength at the time of de-tensioning. All four wires were each initially tensioned to 7000 pounds (31.14 KN) and then de-tensioned gradually when the concrete compressive strength reached 3500 (24.13 MPa), 4500 (31.03 MPa) and 6000 (41.37 MPa) psi. Precise de-tensioning strengths were ensured by testing 4-in.-diameter (101.6 mm) × 8-in.-long (203.2 mm) compression strength cylinders that were temperature match-cured. The prisms were loaded in 3-point-bending to determine the ultimate bond characteristics of each reinforcement type for the different concrete release strengths. A loading rate of 300 lb/min (1334 N/min) was applied at mid-span and the maximum sustained moment was calculated for each test. Two 69-in.-long (175.26 cm) prisms, each having different concrete release strength, were tested with each of the 5 wire types. These prisms were tested at both ends, with a different embedment length assessed at each end. Thus, for each wire type and concrete release strength evaluated, a total of 4 tests were conducted for a total of 60 tests (5 wire types × 3 release strengths × 4 tested embedment lengths). Test results indicate that the concrete compressive strength at de-tensioning can have a direct impact on the ultimate flexural capacity of the members, and this has significant design implications for pretensioned concrete railroad ties. Results are discussed and recommendations made.

scholarly journals Fiber Reinforced Composite Based Functionally Gradient Materials

1998 ◽  
Vol 7 (4) ◽  
pp. 096369359800700 ◽  
Author(s):  
VK Ganesh ◽  
S Ramakrishna ◽  
HJ Leck
Keyword(s):  
Mechanical Properties ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Gradient Material ◽  
Material System ◽  
Test Results ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Functionally Gradient

A method of fabricating fiber-reinforced composite based functionally gradient material is described in this paper. The material has continuously varying mechanical properties along the length. The continuous variation of the mechanical properties is achieved by continuously varying the fiber orientation using the braiding process. The test results indicate an elastic modulus increase by about 42% from the largest braid angle to the smallest braid angle for the material system and the orientation angle considered in the present study.

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