As barragens de enrocamento com face de concreto (BEFC) têm sido construídas com freqüência crescente em todo mundo. Apesar disso, os critérios de. Many translated example sentences containing “barragens de enrocamento” Simpósio Sobre Barragens de Enrocamento com face de Concreto [ ]. 15 out. PERCOLAÇÃO NAS BARRAGENS DE ENROCAMENTO COM FACE DE CONCRETO EM CONSTRUÇÃO – Nelson L. de S. Pinto.
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Barry Cooke is invaluable. For a more favorable behavior in relation to these efforts, the concrete face should be divided into panels that can reduce or eliminate some of the soliciting baragens above mentioned. This would be an acceptable approach for CFRDs have intrinsic stability in function of the following features: Due to the result of the computations, double reinforcement mesh was adopted in large portion of the concrete face, contrary to the usual practice of using a single mesh in the barrzgens of concgeto face.
On the other hand, the tensile joints seals of the slabs on the abutments regions should be capable to absorb the largest displacements resulting from the compression of the joints in the central area. Compressive joints should be used in a way to allow the movement of the central slabs and relieve the compressive stresses among them.
Enter the email address you signed up with and we’ll email you a reset link. Barry Cooke died in Such width reduction would also restrict the area of the slabs where torsional moments may occur. However, the larger compression stresses may not be only “horizontal” along the whole concrete face.
This prediction must take in place the enrocamneto features, the shape and topography of the valley and the properties of available construction materials.
However, an ordered design approach is fundamental to guarantee an adequate performance of future high CFRD dams. Figure 1 shows a map of horizontal compression stresses in the concrete face, considering the face without joints.
II SIMPÓSIO SOBRE BARRAGENS DE ENROCAMENTO
Numerical model analyses were done to predict probable displacements of the concrete face, which were then imposed to the slabs to obtain the respective stresses.
For enrcamento goal, studies should be developed with numerical models conrceto estimate, from the very beginning of the design, the displacements and stresses in the dam.
The results should receive continuous analysis to allow the necessary actions in the design and in the constructive methods. Skip to main dace. In his works, Cooke states that the principle of precedents must be followed, but it cannot be restrictive to the progress, either for the implementation of higher dams or for the adoption of more cost-effective solutions. Cracks may occur in the concrete face; they would be tolerable since the embankment resists to the flow and the cracks can be easily sealed by placing fine material sandy silt.
Thus, progressive modifications were introduced in the CFRD design, among them: Compressive ehrocamento in the concrete face with 4 Joints MPa These results show that compressible joints are effective to avoid the development of high compressive stresses. However, it seems that his confidence in the stability of this type of dam regarding its resistance to normal operation loads and to the action of eventual water seepage led to adoption of some practical design criteria not totally applicable in very high dams fave in narrow valleys, where stress levels extrapolated the already experienced values.
It must be pointed out that this feature is critical on abutments. The success of these dams, with heights of up to m Chicoasen Dam, in Mexicorestarted the construction of concrete face rockfill dams, attractive for their lower cost and shorter time of construction when local rain fall conditions are facf for soil compaction.
Such major infiltrations were associated to excessive displacements of the slabs in relation to the support plinth, whose perimetral joint was not designed to bear such displacement.
Flávio Alberto Crispel
Compressive stresses in the concrete face without joint MPa Figure 2 shows a map of the compressive stresses in the concrete face considering compressible joints in the region of the face A notable reduction in the the compressive stresses could be observed. All failures occurred in the central slabs caused from high compressive stresses, presenting an unknown behavior in such type of dam.
This model must be dynamic, not only to define the zoning of the embankment as well as future adjustments, in function of the monitoring during the construction. Help Center Find new research papers in: Log In Sign Up. This model doesn’t consider the joints between the slabs of the concrete face. It also presents reflections for criteria development for future design of very high CFRDs in order to avoid such failures. In other cases, leakages occurred by the failure of water stops due to excessive deformation.
The rockfill embankment behavior is conditioned by several factors such as embankment zoning see Oliveira — Ref.
The basic principle stated by Cooke – Ref. They presented a quite safety behaviorbut with significant leakages as they height increased up to 90m. The concern then changed from the perimetral joint to the tensile joints seals in abutment slabs. From toafter the good behavior rnrocamento in six enrcoamento rockfill dams belonging to Pacific Gas and Electric Company USAwith heights between 23 and 45 m, higher dams were built, among them are the Salt Springs Dam USA and Paradela Dam Portugalwith heights of and m, comm.
The instrumentation of the embankment and of the concrete face should be intensified to reflect dam performance, mainly of its singularities. Except for the Salvajina dam, the others were built in narrow valleys. His contribution in the development of this type of dam is invaluable, having participated of all Consultants Committees of CFRDs built in Brazil see Table 1 and practically of the construction of the main dams of this type around the world.
At Campos Novos Dam, built in a narrow valley, the displacements of the superficial benchmarks showed an accentuated move towards the center of the valley. It is worth repeating the technical contribution of Mr. These minimizations are so more expressive as smaller are the widths of the slabs. These suggestions should be analyzed for each case.
Click here to sign up. However, some of these dams presented infiltration problems. These modifications were successfully introduced dee dams built in Brazil and in the world; however, all of them with height below m the height of Foz do Areia dam.
These dams, however, presented serious leakage and maintenance problems. This study aims at presenting a discussion on the main factors of development of these stresses.