Stability of concrete macro-roughness linings for overflow protection of earth embankment dams

2002 ◽  
Vol 29 (5) ◽  
pp. 762-776 ◽  
Author(s):  
Pedro de Almeida Manso ◽  
Anton J Schleiss
Keyword(s):  
Precast Concrete ◽  
Flow Characteristics ◽  
Concrete Element ◽  
Unit Discharge ◽  
Embankment Dams ◽  
Earth Embankment ◽  
Failure Conditions ◽  
The Stability ◽  
Concrete Elements ◽  
Stability Concept

A macro-roughness lining system for the protection of earth embankment dams during overflow is presented. It consists of precast concrete elements placed on a drainage-separation layer. The main difference between this system and other existing concrete element systems is the stability concept, based on the self-weight of the blocks. Several types of elements were developed and tested in a physical model for a typical dam slope of 1V:3H. Failure conditions were identified after submitting the elements to increasing flow discharges. Furthermore, different foundation drainage and shear conditions between the elements and their foundation and different joint alignments were studied. Flow characteristics were observed and measured for quasi-uniform flow conditions. Based on the experimental results, a stability model was developed to compute the design safety factor. The model is based on the governing overturning equation (predominant failure mechanism) and on assumptions concerning the acting hydrodynamic forces, the hydrostatic uplift, and the concentration of air in the flow. Synoptic design charts were derived for 1V:3H dam slopes, allowing the rapid estimate of the lining characteristics as dimensions and weight for a certain withstood design unit discharge, for various margins of safety. The developed macro-roughness lining system is envisaged for the spillway rehabilitation of existing dams, but also for the design and construction of spillways of low dams (up to 30 m in height) and for the protection of overflow cofferdams.Key words: overflow dams, erosion protection, linings, macro-roughness, stability, drainage and spillways.

Effect of Very Early Prestressing on Ultimate Geometry of Precast Concrete Element

2016 ◽  
Vol 677 ◽  
pp. 49-52
Author(s):  
Lukáš Černosta ◽  
Petr Štemberk
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Precast Concrete ◽  
Small Scale ◽  
Early Age ◽  
Concrete Element ◽  
Load Bearing Capacity ◽  
Shrinkage And Creep ◽  
T Beam ◽  
Concrete Elements

This paper describes an experimental investigation of the effect of early age prestressing on the ultimate geometry and the load bearing capacity of precast concrete elements. The experimental is performed with a small-scale T-beam which are prestress at three different ages. The experimental results obtained after seven days after prestressing are compared with calculated estimations on the shrinkage and creep according to B3 model.

Chromate and amine contact allergies in workers manufacturing precast concrete elements

2016 ◽  
Vol 75 (6) ◽  
pp. 363-369 ◽  
Author(s):  
Martin Mowitz ◽  
Erik Zimerson ◽  
Inese Hauksson ◽  
Ann Pontén
Keyword(s):  
Precast Concrete ◽  
Concrete Elements

scholarly journals Modified mortar pad behavior in the transfer of compressive stresses

2016 ◽  
Vol 9 (3) ◽  
pp. 414-434
Author(s):  
J. D. Ditz ◽  
M. K. EL Debs ◽  
G. H. Siqueira
Keyword(s):  
Precast Concrete ◽  
Concrete Strength ◽  
Compressive Load ◽  
Stress Transfer ◽  
Compressive Stresses ◽  
Bonded Phase ◽  
Concrete Blocks ◽  
Load Tests ◽  
Styrene Butadiene ◽  
Concrete Elements

ABSTRACT This research aims to analyze the compressive stress transfer between precast concrete elements using cement mortar pads modified with polypropylene fibers, styrene-butadiene latex and heat-expanded vermiculite. The stress transfer analyses are performed interleaving a cementbearing pad between two concrete blocks, subjecting the entire specimen to different compressive load tests. The parameters analyzed in the tests are: surface roughness (using bosses on the bonded phase of different thicknesses), compressive strength with monotonic and cyclic loadings. The main results obtained in this study are: a) the presence of pad increased the strength in 24% for thicknesses of imperfections of 0.5 mm and approximately 12% for smooth faces blocks; b) gain of effectiveness of the bearing pad when the concrete strength was reduced; c) for cyclic loading, the bearing pad increased in 48% the connections strength.

scholarly journals Strength criterion for a plane stress reinforced concrete element under a special action

Vestnik MGSU ◽  
2020 ◽  
pp. 1513-1522
Author(s):  
Natalia V. Fedorova ◽  
Vu Ngoc Tuyen ◽  
Igor A. Yakovenko
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Limit State ◽  
Strength Criterion ◽  
Structural Systems ◽  
Variable Loading ◽  
Concrete Element ◽  
Theory Of Plasticity ◽  
Concrete Elements

Introduction. Problem solving focused on the protection of buildings and structures from progressive collapse and minimization of resources, needed for this purpose, is becoming increasingly important. In many countries, including Russia, this type of protection is incorporated into national regulatory documents, and, therefore, any research, aimed at developing effective ways to protect structural systems from progressive collapse under special actions, is particularly relevant. In this regard, the present article aims to formulate effective strength criteria for such anisotropic materials as reinforced concrete to analyze plane stressed reinforced concrete structures exposed to sudden structural transformations caused by the removal of one of bearing elements. Materials and methods. To solve this problem, a variant of the generalized theory of plasticity of concrete and reinforced concrete, developed by G.A. Geniev, is proposed for application to the case of variable loading of a plane stressed reinforced concrete element. The acceptability of generalization of the strength criterion, pursuant to the theory of plasticity of concrete and reinforced concrete under static loading, and the applicability of this criterion to variable static-dynamic loading of reinforced concrete are used as the main hypothesis. An algorithm of an approximate method is presented as a solution to this problem; it allows to analyze the considered stress-strain state of plane stressed reinforced concrete elements. Results. The numerical analysis of the obtained solution, compared with the results of the experimental studies, was used to evaluate the designed strength criterion for reinforced concrete elements located in the area where the column is connected to the girder of a monolithic reinforced concrete frame in case of a sudden restructuring of a structural system. It is found out that the qualitative nature of the destruction pattern of the area under research, obtained in experiments, corresponds to the destruction pattern, identified by virtue of the analysis performed using the proposed criterion. Conclusions. The variant of the reinforced concrete strength criterion designated for the variable loading of a plane stressed reinforced concrete element and an algorithm for its implementation, based on the theory of plasticity of concrete and reinforced concrete developed by G.A. Geniev, is applicable to the analysis of a special limit state of reinforced concrete elements of structural systems of frames of buildings and structures.

A heuristic method with a novel stability concept to perform parallel assembly sequence planning by subassembly detection

2020 ◽  
Vol 40 (5) ◽  
pp. 779-787
Author(s):  
Anil Kumar Gulivindala ◽  
M.V.A. Raju Bahubalendruni ◽  
S.S. Vara Prasad Varupala ◽  
Sankaranarayanasamy K.
Keyword(s):  
Dominant Role ◽  
Heuristic Method ◽  
Development Stage ◽  
Assembly Sequence Planning ◽  
Assembly Sequence ◽  
Content Type ◽  
Sequence Planning ◽  
The Stability ◽  
Parallel Assembly ◽  
Stability Concept

Purpose Parallel assembly sequence planning (PASP) reduces the overall assembly effort and time at the product development stage. Methodological difficulties at framework development and computational issues at their implementation made the PASP complex to achieve. This paper aims to propose a novel stability concept for subassembly detection to minimize the complexities in PASP. Design/methodology/approach In this research, a heuristic method is developed to identify, represent and implement the stability predicate to perform subassembly detection and assembly sequence planning (ASP) at the further stages. Stability is organized into static, dynamic, enriched and no stability between the mating assembly parts. The combination of parts that possesses higher fitness is promoted to formulate the final solution about PASP. Findings The results obtained by applying the proposed concept on complex configurations revealed that stability predicate plays a dominant role in valid subassembly detection and final sequence generation further. Originality/value The value of the presented study lies in the three types of stability conditions and effective integration to existed ASP method. Unlike the existed heuristics in subassembly detection, the proposed concept identifies the parallel subassemblies during ASP.

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