Construction de l'évacuateur de crues Opinaca

1986 ◽  
Vol 13 (5) ◽  
pp. 558-568
Author(s):  
Michel Massiéra

The Opinaca spillway is one of the concrete structures of the EOL (Eastmain – Opinaca – La Grande) project within the "La Grande" hydroelectric complex at James Bay, Quebec. Three rivers were diverted to the La Grande River to increase the hydroelectric potential of the LG 2 power plant. Opinaca spillway is a reinforced concrete structure 28.7 m wide and 46.6 m long with intake and restitution channels excavated in the rock. This paper describes the different construction phases of the spillway with emphasis on rock excavation and support, grouting, concreting, and quality control. Key words: blasting, bolting, concreting, dowel, excavation, grouting, presplitting, rock, shotcrete, spillway.

2008 ◽  
Vol 15 (2) ◽  
pp. 137-146 ◽  
Author(s):  
Greg C. Bessette

A coupled Euler-Lagrange solution approach is used to model the response of a buried reinforced concrete structure subjected to a close-in detonation of a high explosive charge. The coupling algorithm is discussed along with a set of benchmark calculations involving detonations in clay and sand.


1985 ◽  
Vol 12 (4) ◽  
pp. 838-848
Author(s):  
Michel Massiéra ◽  
Claude Pelchat

The OA-10B dam is one of the earth structures of the EOL (Eastmain – Opinaca – La Grande) project within the "La Grande" hydroelectric complex at James Bay, in the northwest of Quebec. Three rivers, the Eastmain, Petit Opinaca, and Opinaca, were diverted to the La Grande River to increase the hydropotential of the LG-2 power plant. Dam OA-10B, 25 m high, has a zoned section with an impervious moraine central core, and rests mainly on overburden foundations consisting of heterogeneous deposits of glacial till. The paper describes the different construction phases of the dam with emphasis on foundation treatments. Key words: construction, core trench, dam, dewatering, excavation, foundation, glacial till, instrumentation, moraine, treatment.


2020 ◽  
Vol 18 (5) ◽  
pp. 1175-1191
Author(s):  
Utino Worabo Woju ◽  
A.S. Balu

Purpose The aim of this paper is mainly to handle the fuzzy uncertainties present in structures appropriately. In general, uncertainties of variables are classified as aleatory and epistemic. The different sources of uncertainties in reinforced concrete structures include the randomness, mathematical models, physical models, environmental factors and gross errors. The effects of imprecise data in reinforced concrete structures are studied here by using fuzzy concepts. The aim of this paper is mainly to handle the uncertainties of variables with unclear boundaries. Design/methodology/approach To achieve the intended objective, the reinforced concrete beam subjected to flexure and shear was designed as per Euro Code (EC2). Then, different design parameters such as corrosion parameters, material properties and empirical expressions of time-dependent material properties were identified through a thorough literature review. Findings The fuzziness of variables was identified, and their membership functions were generated by using the heuristic method and drawn by MATLAB R2018a software. In addition to the identification of fuzziness of variables, the study further extended to design optimization of reinforced concrete structure by using fuzzy relation and fuzzy composition. Originality/value In the design codes of the concrete structure, the concrete grades such as C16/20, C20/25, C25/30, C30/37 and so on are provided and being adopted for design in which the intermediate grades are not considered, but using fuzzy concepts the intermediate grades of concrete can be recognized by their respective degree of membership. In the design of reinforced concrete structure using fuzzy relation and composition methods, the optimum design is considered when the degree of membership tends to unity. In addition to design optimization, the level of structural performance evaluation can also be carried out by using fuzzy concepts.


2011 ◽  
Vol 189-193 ◽  
pp. 847-852 ◽  
Author(s):  
Lei Tan ◽  
Xi Jun Liu ◽  
Ming Qiao Zhu

With wide applications of FRP in civil engineering, it is necessary to study the durability of FRP reinforced concrete structure. Based on the related research both at home and abroad, the factors affecting durability of FRP reinforced concrete structures and the corresponding improvements have been put forward by analyzing the durability of concrete, FRP materials and reinforced structures, respectively.


Author(s):  
Oleg Rubin ◽  
Anton Antonov ◽  
Sergey Lisichkin ◽  
Kirill Frolov ◽  
Andrey Lisichkin

Introduction. Floorings of the turbine hall and installation sites of the HPP (PSS) are one of the most important reinforced concrete structures, as during operation they are subjected to significant process duties, including those not provided for by the project. Thus, during the testing of crane equipment on the floor surface of the installation site of the Alluriquin HPP under construction, the cargo weighing 22 tons fell, under the influence of which the floor slab was punched, which required a comprehensive study of the condition of the reinforced concrete structure of the floor and the surrounding area of the failure of structures, as well as the development of measures to strengthen the damaged structure. Materials and Methods. Visual and instrumental studies of the stress and strain state (SSS) of the reinforced concrete structure of the turbine hall slab and surrounding structures were carried out with the use of optical devices (MPB-3 reading microscope), Schmidt hammer to determine the strength of concrete structures, as well as the “reinforcement load removal” method to determine the actual stresses in the reinforcement of structures. Results. The punching of the reinforced concrete floor of the installation site with vertical displacements of the edges of through cracks up to 12 mm, as well as the system of cracks formed during the fall of cargo was revealed. The actual stresses in the reinforcement are determined by the “reinforcement load removal” method. On the basis of finite element modeling the actual condition of structures during the period of cargo fall and after the removal of the load is obtained. On the basis of the analysis of results of field and design studies the schematic diagram of strengthening of structures by carbon composite materials is developed. Conclusions. The actual SSS of the reinforced concrete floor of the installation site and its support structures during the period of the cargo fall and after the termination of the impulse load is established. The vertical displacement of the edges of the crack of the floor punching was 17.5 mm during the period of the fall of the load and 12 mm after the removal of the impulse load. Crack opening width in reinforced concrete structures in the cargo drop area reached 2 mm. At the moment when the cargo fell on the floor slab, the values of stresses in the reinforcement cage reached 200 MPa; after the impact — 76.2 MPa. With a view of the subsequent safe operation of the reinforced concrete floor and surrounding structures the basic schemes of their strengthening by external reinforcement on the basis of carbon fiber have been developed, which have been proved by calculation.


2019 ◽  
Vol 258 ◽  
pp. 04002 ◽  
Author(s):  
Kristiyanto Hery ◽  
Triwiyono Andreas ◽  
Muslikh ◽  
Saputra Ashar

The use of precast concrete is known to improve productivity, quality control, and cost efficiency in reinforced concrete structure. The Connection is the most important aspect of precast concrete structures. The connection transfers force between the precast components, determine strength, stiffness, and ductility of the whole structure. Providing joint in the beam-column connection region always cause difficulties during the erection stage. Relocation of the connection at a certain distance from the column to the beam span is an alternative solution that creates the beam-to-beam connection. It will be much easier to assemble the connection that consists of some joints. Research and application of the precast concrete beam-to-beam connection details have published since 1975. This paper reviews the state of the art of research and practical application of beam-to-beam connection system related to connection models, joint locations, and details. It concluded from the review that the developing research leads to improve the performance of earthquake resisting structures


2011 ◽  
Vol 228-229 ◽  
pp. 1047-1050 ◽  
Author(s):  
Tian Hua Jiang ◽  
Jing Rong Peng ◽  
Wei Ming Zhang

When a reinforced concrete structure suffers from a big fire, its quality will change and its bearing ability will be reduced. It is necessary to take a comprehensive testing and to formulate corresponding reinforcement to restore the structure. This article mainly talks about a series of detections and their results of a reinforced concrete culvert which suffered from fire, and then selects a better reinforcement program. It can provide reference for the reinforcement of similar concrete structures.


Vestnik MGSU ◽  
2019 ◽  
pp. 1106-1120
Author(s):  
Andrei V. Deineko ◽  
Valentina A. Kurochkina ◽  
Irina Yu. Yakovleva ◽  
Aleksandr N. Starostin

Introduction. When erecting monolithic reinforced concrete floor slabs, a necessity of construction joints arises. The construction joints are the areas of structural weakening. The construction practice shows that the compliance with the correct technology of the construction joint arrangement is not a sufficient condition to ensure the strength balance of reinforced concrete floor slabs. As a result, the stress-deformation state calculated on the assumption of the concrete slab solidity deviates from the actual state. The relevance of the task is determined by the fact that the conformity of design and actual characteristics of the in-situ reinforced concrete structures as a whole depends on the correct calculations of construction joints. Materials and methods. The problem of implementing the construction joints in the monolithic floor slabs was considered by way of example of a residential building under construction. In the course of construction, pre-construction land surveys were carried out at the areas of the construction joint arrangement. Calculations of reinforced concrete structures using finite element method (FEM) were also performed. Results. As a result of the study, the actual deflections of the floor slabs were measured at the areas of the construction joints and FEM calculations were made on the same floor slabs, both those erected at once and those erected in stages subject to the construction joints. The difference between the calculated and actual deflections is conditioned upon the inaccurate conformity between the mathematical model and the real reinforced concrete structure, its erection and maintenance conditions. It should be noted that the deflection of horizontal reinforced concrete structures is only one of the stress-deformation state parameters that can be measured better than the others. It is shown that if the deflection of a real reinforced concrete structure does not correspond with the design estimation, the other stress-deformation state parameters will differ from the design estimation as well. Conclusions. The influence of joints can be taken into account in the scope of FEM computer-aided calculations with the explicit reproduction of the structure erection by pouring concrete, using engineering approach to the consideration of nonlinearity on the basis of the introducing reduction coefficients to the reinforced concrete effective modulus of elasticity. Solid composition modeling of reinforced concrete provides the best possibilities on taking all sorts of nonlinearity manifestations into consideration.


2021 ◽  
Vol 331 ◽  
pp. 05010
Author(s):  
Jati Sunaryati ◽  
Nidiasari Nidiasari ◽  
Rifqi Yuliandri

Under major load earthquakes, reinforced concrete structures designed according to the current codes will experience an inelastic deformation which is difficult to predict and control. Performance-based plastic design (PBPD) methodology is applied forward to design reinforced concrete structures in this study. In this method, as performance criteria, the target drift and yield mechanisms are preselected. Based on the work-energy balance principle, the design base shear is given as earthquake level and calculated as work required to push the structure as monotonically load to the target drift. The load equals the energy needed by an equivalent single degree of freedom in the same state. The plastic design is utilized to design the desired yield mechanism. The method was adopted on a 10-story reinforced concrete structure with an earthquake load in lateral forces based on SNI 1726:2019 and the Performance-Based Plastic Design (PBPD) method. Pushover analysis was carried out where the structure was pushed to obtain lateral load resistance followed by yielding gradually until plastic deformation occurred collapse From the pushover analysis, the ductility value for SNI 1726:2019 is less ductile than analytical using the Performance-Based Plastic Design (PBPD) method


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