Luigi Santarella: Reinforced concrete design culture through the technical literature

To study the brittle/ductile behavior of concrete beams reinforced with low amounts of rebar and fibers, a new multi-scale model is presented. It is used to predict the flexural response of an ideal Hybrid Reinforced Concrete (HRC) beam in bending, and it is validated with the results of a specific experimental campaign, and some tests available in the technical literature. Both the numerical and the experimental measurements define a linear relationship between the amount of reinforcement and the Ductility Index (DI). The latter is a non-dimensional function depending on the difference between the ultimate load and the effective cracking load of a concrete beam. As a result, a new design-by-testing procedure can be established to determine the minimum reinforcement of HRC elements. It corresponds to DI = 0, and can be considered as a linear combination of the minimum area of rebar (of the same reinforced concrete beam) and the minimum fiber volume fraction (of the same fiber-reinforced concrete beam), respectively.

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Study on size effect of fibre reinforced polymer retrofitted reinforced concrete beam–column connections under cyclic loading

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2012-0041 ◽

2013 ◽

Vol 40 (4) ◽

pp. 353-360 ◽

Cited By ~ 6

Author(s):

A.M. Choudhury ◽

S.K. Deb ◽

A. Dutta

Keyword(s):

Reinforced Concrete ◽

Cyclic Loading ◽

Size Effect ◽

Concrete Beam ◽

Reinforced Concrete Beam ◽

Technical Literature ◽

Reinforced Polymer ◽

Reliable Assessment ◽

Fibre Reinforced Polymer ◽

Ultimate Load Carrying Capacity

Studies related to size effect are crucial for reliable assessment of behaviour of structural components subjected to dynamic loadings. The available theories of material behaviour that predict size effects are receiving increasing attention in the technical literature nowadays. This paper presents a study on size effect of fibre reinforced polymer retrofitted reinforced concrete beam–column connections based on experimental investigation under displacement controlled cyclic loading. Three different sizes of geometrically similar specimens have been considered to explore the possible existence of size effect. It was observed that the experimental results corroborate closely the size effect law proposed by Bazănt in all the cases studied. A parameter, energy dissipation of specimens per unit volume was introduced and its correlations with different drift angles for different sizes of the specimen exhibit the existence of size effect. Comparisons were also made among the tests results of control and retrofitted specimens in terms of gain in ultimate load carrying capacity and existence of size effect was distinctly observed.

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Foreign and domestic expertise in strengthening concrete structures with carbon fiber

E3S Web of Conferences ◽

10.1051/e3sconf/202016414014 ◽

2020 ◽

Vol 164 ◽

pp. 14014

Author(s):

Dmitriy Topchiy ◽

Egor Safenkov

Keyword(s):

Reinforced Concrete ◽

Concrete Structures ◽

Protective Layer ◽

Reinforced Concrete Structures ◽

Building Structures ◽

Technical Literature ◽

Protective Properties ◽

Manufacturing Defects ◽

Accelerated Degradation ◽

Number Of Publications

Over the last 10-15 years, Russia has faced a significant increase in the scope of reconstruction work (including restoration and overhaul) for buildings of various purposes aiming to extend the life cycle of existing facilities and to bring buildings in line with requirements of modern regulatory documents in terms of strength and increase in their energy efficiency. Strengthening the building structures with composite materials is by far the most ‘gentle’ method of restoring building structures and improving their operational performance. At the same time, there is only a small number of publications generalizing this type of strenghtening in the domestic scientific and technical literature. During the operation of buildings and structures (especially industrial ones) numerous factors cause accelerated degradation in building structures. This phenomenon is particulary strong in reinforced concrete structures due to their composite base. Practice shows that corrosive damage is one of the main factors of intensive constuction degradation of reinforced concrete structures. Therefore, these damages are caused by manufacturing defects (reduction of concrete protective layer), loss of concrete-against-reinforcement protective properties due to carbonization or damage. Corrosive damage greatly reduces the life capability and durability of reinforced concrete structures, which in turn leads to a decrease in the safety of construction site operations.

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Predicting the Shear Strength of Reinforced Concrete Beams Using Support Vector Machine

Jurnal Teknik Sipil ◽

10.28932/jts.v2i2.1257 ◽

2019 ◽

Vol 2 (2) ◽

pp. 74-95

Author(s):

Cindrawaty Lesmana

Keyword(s):

Support Vector Machine ◽

Shear Strength ◽

Reinforced Concrete ◽

Reinforced Concrete Beams ◽

Machine Learning Techniques ◽

Support Vector ◽

Technical Literature ◽

Depth Ratio ◽

Svm Model ◽

Wide Range

A wide range of machine learning techniques have been successfully applied to model different civilengineering systems. The application of support vector machine (SVM) to predict the ultimate shearstrengths of reinforced concrete (RC) beams with transverse reinforcements is investigated in thispaper. An SVM model is built trained and tested using the available test data of 175 RC beamscollected from the technical literature. The data used in the SVM model are arranged in a format ofnine input parameters that cover the cylinder concrete compressive strength, yield strength of thelongitudinal and transverse reinforcing bars, the shear-span-to-effective-depth ratio, the span-toeffective-depth ratio, beam’s cross-sectional dimensions, and the longitudinal and transversereinforcement ratios. The relative performance of the SVMs shear strength predicted results were alsocompared to ACI building code and artificial neural network (ANNs) on the same data sets.Furthermore, the SVM shows good performance and it is proved to be competitive with ANN modeland empirical solution from ACI-05.

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EXPERIMENTAL STUDY OF PLATES FOR PUNCHING UNDER DYNAMIC LOADING

Construction Materials and Products ◽

10.34031/2618-7183-2021-4-4-41-48 ◽

2021 ◽

Vol 4 (4) ◽

pp. 41-48

Author(s):

N. Trekin ◽

D. Sarkisov ◽

V. Krylov ◽

E. Evstaf'eva ◽

K. Andryan

Keyword(s):

Experimental Data ◽

Reinforced Concrete ◽

Dynamic Loading ◽

Static Load ◽

Dynamic Testing ◽

Experimental Studies ◽

Breaking Load ◽

Technical Literature ◽

Failure Patterns ◽

Static And Dynamic Loading

the issues of strength and deformability of reinforced concrete floors during punching remain insufficiently studied at present, despite the available publications in the technical literature. This article presents the results of experimental studies on punching of fragments of conjugation of flat reinforced concrete monolithic slabs with a column under dynamic loading. The purpose of these studies was to obtain experimental data on the stress-strain state of a fragment of a monolithic floor during dynamic punching with varying thickness and class of concrete, to reveal the failure patterns of experimental samples, and to obtain new experimental data. A setup for dynamic testing is described. Comparison of breaking load for specimens tested under dynamic loading with breaking load for specimens tested for static load is presented. The angles of inclination of the punching shear pyramid under static and dynamic loading are indicated.

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Evolutionary Modeling to Evaluate the Shear Behavior of Circular Reinforced Concrete Columns

Advances in Civil Engineering ◽

10.1155/2014/684256 ◽

2014 ◽

Vol 2014 ◽

pp. 1-14 ◽

Cited By ~ 2

Author(s):

Alessandra Fiore ◽

Giuseppe Carlo Marano ◽

Daniele Laucelli ◽

Pietro Monaco

Keyword(s):

Experimental Data ◽

Shear Strength ◽

Reinforced Concrete ◽

Concrete Columns ◽

Shear Behavior ◽

Evolutionary Modeling ◽

Technical Literature ◽

Strength Models ◽

Structured Representation ◽

Conversion Rules

Despite their frequent occurrence in practice, only limited studies on the shear behavior of reinforced concrete (RC) circular members are available in the literature. Such studies are based on poor assumptions about the physical model, often resulting in being too conservative, as well as technical codes that essentially propose empirical conversion rules. On this topic in this paper, an evolutionary approach named EPR is used to create a structured polynomial model for predicting the shear strength of circular sections. The adopted technique is an evolutionary data mining methodology that generates a transparent and structured representation of the behavior of a system directly from experimental data. In this study experimental data of 61 RC circular columns, as reported in the technical literature, are used to develop the EPR models. As final result, physically consistent shear strength models for circular columns are obtained, to be used in different design situations. The proposed formulations are compared with models available from building codes and literature expressions, showing that EPR technique is capable of capturing and predicting the shear behavior of RC circular elements with very high accuracy. A parametric study is also carried out to evaluate the physical consistency of the proposed models.

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Experimental and theoretical study of the strength of plates for pressure

Vestnik MGSU ◽

10.22227/1997-0935.2021.8.1006-1014 ◽

2021 ◽

pp. 1006-1014

Author(s):

Nikolai N. Trekin ◽

Dmitry Yu. Sarkisov ◽

Sergey V. Trofimov ◽

Vladimir V. Krylov ◽

Elizaveta B. Evstafeva

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Shear Strength ◽

Reinforced Concrete ◽

Experimental Studies ◽

Experimental Models ◽

The Finite Element Method ◽

Technical Literature ◽

Numerical Studies ◽

Element Method

Introduction. The issues of strength and deformability of reinforced concrete floors during punching remain insufficiently studied at present, despite the numerous publications in the technical literature. This article presents the results of experimental studies of the punching shear strength of fragments of conjugation of flat reinforced concrete monolithic slabs with a column under static loading. The purpose of these studies was to obtain experimental data on the stress-strain state of a fragment of a monolithic floor during static punching and to develop a spatial model based on the finite element method with subsequent numerical studies. Materials and methods. Experimental studies were carried out on a test bench. The characteristics of prototypes are given: dimensions, reinforcement, class of concrete and reinforcement. A test setup is described. For the numerical simulation of the slab-column interface, the ATENA software package was used, which allows for physically and geometrically nonlinear calculations of reinforced concrete structures, taking into account the real work of the materials used to create experimental models. Results. Comparison of the results for the breaking load, obtained during the experiment, with the results of numerical modeling by the finite element method and with the results of calculations using the methods of SP 63.13330.2018 and Eurocode 2. The diagrams of the distribution of deformations in reinforcement and concrete, breaking loads and patterns of distribution of cracks in the samples are obtained. Conclusions. The analysis of experimental and numerical studies made it possible to formulate the conditions for the punching shear strength of flat slabs with longitudinal reinforcement and to give recommendations on the strength calculation under central loading.

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Computational algorithm for the verification of reinforced concrete sections in fire situation

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952019000400012 ◽

2019 ◽

Vol 12 (4) ◽

pp. 932-955

Author(s):

E. P. G. PADRE ◽

J. C. L. RIBEIRO ◽

R. C. S. S. ALVARENGA ◽

R. C. SILVA

Keyword(s):

Reinforced Concrete ◽

Structural Design ◽

Room Temperature ◽

Computational Algorithm ◽

Technical Standards ◽

Technical Literature ◽

Element Mesh ◽

Integration Algorithm ◽

Stress Integration ◽

In Fire

Abstract Reinforced concrete structures may have reduced strength due to the degradation of their mechanical properties by temperature. This can increase the risk of structural collapses. Thus, the structural design should consider its behavior at room temperature and in fire situation (ABNT NBR 14432:2001). This study presents the development of an algorithm to verify the strength of any reinforced concrete sections subjected to unsymmetrical bending at room temperature and in fire situation. For this purpose, a stress integration algorithm was implemented from the strain profile of the section according to ABNT NBR 15200:2012, linked to a finite element mesh generator and a thermal analysis algorithm. For validation of the developed program, called Pisafo, the results obtained were compared with those in the technical literature: obtained in experiments (with differences of up to 28.5%) and with recognized software solutions (with differences of up to -14.8%). The largest variations in relation to the experiments can be attributed to the differences between the thermal properties of the concrete in the experiments with those prescribed in the technical standards used by the program and the non-consideration of spalling in the computational analysis.

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Prospects of application of cement concrete coating on transport buildings

Dorogi i mosti ◽

10.36100/dorogimosti2021.23.178 ◽

2021 ◽

Vol 2021 (23) ◽

pp. 178-196

Author(s):

Artur Onyshchenko ◽

◽

Mykola Garkusha ◽

Oleg Fedorenko ◽

Oleksandr Davydenko ◽

...

Keyword(s):

Reinforced Concrete ◽

Crack Resistance ◽

Crack Formation ◽

Concrete Slab ◽

Concrete Pavement ◽

Cement Concrete ◽

Reinforced Concrete Slab ◽

Technical Literature ◽

Cement Concrete Pavement ◽

Prospects Of Application

Introduction. Road bridges are an integral part of the road network of transport infrastructure of Ukraine. The technical condition of the vast majority of road bridges does not meet modern requirements for road safety and structural reliability of structural elements.Problems. There are no recommendations for the design and installation of cement-concrete pavement on the reinforced concrete slab of the carriageway of road bridges, as well as an album of standard solutions of such structures.Goal. Analysis of the causes and types of cracking on cement concrete pavement, technical literature and current regulations on the calculation of crack resistance and durability of cement concrete pavement on the reinforced concrete slab of the carriageway of road bridges.Results. The analysis of application of a cement concrete covering on transport constructions is carried out. The causes and types of crack formation on cement-concrete pavement are established. The analysis of technical literature and current normative documentation on calculation of crack resistance and durability of cement concrete pavement on the reinforced concrete slab of road bridges is carried out.Conclusions. The analysis of prospects of application of a cement concrete covering on transport constructions is carried out in work.Keywords: road bridge, durability, reinforced concrete slab, crack formation, carriageway, crack resistance, cement concrete pavement

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Axial Compressive Strength Models of Eccentrically-Loaded Rectangular Reinforced Concrete Columns Confined with FRP

Materials ◽

10.3390/ma14133498 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3498

Author(s):

Haytham F. Isleem ◽

Muhammad Abid ◽

Wesam Salah Alaloul ◽

Muhammad Kamal Shah ◽

Shayan Zeb ◽

...

Keyword(s):

Reinforced Concrete ◽

Large Scale ◽

Concrete Strength ◽

Concrete Columns ◽

Confined Concrete ◽

Practice Research ◽

Small Scale ◽

Technical Literature ◽

Rc Columns ◽

Strength Models

The majority of experimental and analytical studies on fiber-reinforced polymer (FRP) confined concrete has largely concentrated on plain (unreinforced) small-scale concrete columns, on which the efficiency of strengthening is much higher compared with large-scale columns. Although reinforced concrete (RC) columns subjected to combined axial compression and flexural loads (i.e., eccentric compression) are the most common structural elements used in practice, research on eccentrically-loaded FRP-confined rectangular RC columns has been much more limited. More specifically, the limited research has generally been concerned with small-scale RC columns, and hence, the proposed eccentric-loading stress-strain models were mainly based on the existing concentric-loading models of FRP-confined concrete columns of small scale. In the light of such demand to date, this paper is aimed at developing a mathematical model to better predict the strength of FRP-confined rectangular RC columns. The strain distribution of FRP around the circumference of the rectangular sections was investigated to propose equations for the actual rupture strain of FRP wrapped in the horizontal and vertical directions. The model was accomplished using 230 results of 155 tested specimens compiled from 19 studies available in the technical literature. The test database covers an unconfined concrete strength ranging between 9.9 and 73.1 MPa, and section’s dimension ranging from 100–300 mm and 125–435 mm for the short and long sides, respectively. Other test parameters, such as aspect ratio, corner radius, internal hoop steel reinforcement, FRP wrapping layout, and number of FRP wraps were all considered in the model. The performance of the model shows a very good correlation with the test results.

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