Anchorage reinforcement

Anchorage type Anchorage reinforcement is similar to the shear type just described, but now the soil acts on both sides of the geotextile because a tensile force tends to pull the geotextile out of the soil. 

A series of prismatic reinforced RubCon samples were produced. The reinforcement material was ribbed steel bar 0 8 mm. The height of samples or depth of a reinforcement anchorage was equaled from 35 up to 120 mm, that is, (4.3 15)0 the thickness of the protection layer was 8, 16, and 24 mm (1, 2, and 3) 0. Displacements of a reinforcing bar relatively the end face of the RubCon prism and load were measured during the tests. Results of these tests are shown in Figure 2.14 and Figure 2.15. 

Destruction of samples with depth of anchorage of 35 and 40 mm (Figure 2.15) occurred as a result of shear of the reinforcement bar and the subsequent splitting of the RubCon prisms. At a depth of anchorage of 45 and 50 mm, destruction occurred due to rupture of the reinforcement. The initial displacements of a nonloaded end of the reinforcement bars were marked at stresses up to 50 MPa in all tested samples. Destruction of samples with a depth of anchorage of 60,80, and 120 mm (Figure 2.14) occurred as a result of the rupture of the reinforcement bar. The initial displacements of a nonloaded end of the reinforcement bars were marked at stresses of 50-200 MPa. As this takes place, the final displacements of the bars did not depend on the thickness of the protection layer. 

Dependence of average bond stress xh on the anchorage depth of the reinforcement bar lr is shown in Figure 2.16. 

FIGURE 2.16 Dependence of average bond stress ib on anchorage depth of reinforcement bar lr. (Reprinted from Yu. Potapov, O. Figovsky, Yu. Borisov, S. Pinaev, and D. Beilin, Joint Work of Reinforcement and Polymer Concrete Matrix, J. Scientific Israel Technological Advantages 4, nos. 3-4 (2002) 14-19. With permission.)... 

Because the development of cracks can not be avoided in the rough environments of the typical applications of refractories, the probability must be reduced that such cracks result in failure. This is possible by reinforcement with fibers. Some materials that have been added to accomplish this are stiff, needle-like chopped wire or slit sheet fibers which are sometimes even supplied with, for example, hooks on their ends to increase anchorage. As schematically shown in Fig. 5.18 steel fibers in the refractory structure arrest the cracks and prohibit their propagation. Newer reinforcement... 

Reinforcing bars must fulfil several requirements regarding strength, ductility, bond to concrete, weldability, etc. To achieve suitable anchorage when embedded in concrete, ribbed bars are normally used. Mechanical properties that are relevant for reinforcing bars are elastic modulus, strength and ductility. For instance, European standards that deal with reinforcement for concrete structures generally pre-... 

In the present discussion, reinforced concrete and prestressed concrete corrosion control methods are combined. Although prestressed concrete bridges have special concerns such as anchorage in both posttensioned and pretensioned structures and ducts for post-tensioned structures, the general corrosion control methods are applicable to both prestressed and conventional reinforced bridges. 

Internal reinforcement Odagiri et al. (1997) investigated relaxation characteristics of 6 and 7.4 mm (0.24 and 0.29 in) diameter AFRP tendons with anchorages. Overall, the relaxation rates for AFRP rods were found to be approximately 11% at 1000 hours, and 15% at 17,700 hours (two years). Creep rupture, the tensile rupture of a material subjected to sustained high stress levels over a period of time, is another important concern for FRP reinforcing bars. 

The end anchorage debonding failure mode is expected for short beams, if the cracks are near to the supports and if the end of the strip is not near to the support. Furthermore, if only a small internal steel reinforcement cross-section exists, the strip must carry a larger portion of the tensile force, which also increases the danger of end anchorage failure. 

British Standards Institution. 1989. British standard code of practice for ground anchorages, BS 8081 1989. Bruce, D.A. Nicholson, P.J. 1988. Minipiles mature in America, Civil Engineering,/15 CE. 58(12) 57-59. Bruce, D.A. 1989. American development in the use of small diameter inserts as piles and in situ reinforcement. Proceedings of International Conference on Piling and Foundation. 1 11-22. 

The reinforcement ratio of the ring beam showed an obvious influence on the load carrying capacity of the joints, and the ductility at the maximum load was improved with the improvement of the inner tube. Meanwhile, the anchorage length 4 and cross-section ratio... 

Paterson, W.S. and Ravenhill, K. Reinforcement connector and anchorage methods, CIRIA Report 92, CIRIA, London, 1981. 

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