scholarly journals Long-term study of the impact of temperature changes, material aging and service load on the strains of a reinforced concrete structure

2018 ◽  
Vol 66 ◽  
pp. 02006
Author(s):  
Adam Kanciruk
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Temperature Changes ◽  
Long Term Study ◽  
Monitoring Process ◽  
Service Load ◽  
The Impact

The article discusses five year long measurements of strains of a concrete floor of a hangar. That hangar, originally meant for servicing light military aircraft, was rebuilt with a view to making it fit for servicing larger and heavier passenger planes. As part of that redevelopment, a new floor - reinforced concrete slab, capable of withstanding the weight of the planes - was constructed. In the areas of the floor where the greatest loads occur, ie. in the areas of the concrete slab on which the wheels of the three undercarriage legs rest, three strain rosettes were installed so that the slab strains could be measured. The rosettes were connected to two meters - dataloggers. The latter were programmed in such a way as to register the measured strains and additionally temperatures many times during every 24 hours. The monitoring process, conducted in such an automatic way, demonstrated the occurrence of strains resulting from service load, aging of the reinforced concrete, as well as changes in its temperature.

An Assessment of the Long-Term Durability of Concrete in Radioactive Waste Repositories

1985 ◽  
Vol 50 ◽  
Author(s):  
A. Atkinson ◽  
D. J. Goult ◽  
J. A. Hearne
Keyword(s):  
Reinforced Concrete ◽  
Radioactive Waste ◽  
Concrete Slab ◽  
Laboratory Studies ◽  
Preliminary Assessment ◽  
Reinforced Concrete Slab ◽  
Radioactive Waste Repositories ◽  
Waste Repositories ◽  
Durability Of Concrete

AbstractA preliminary assessment of the long-term durability of concrete in a repository sited in clay is presented. The assessment is based on recorded experience of concrete structures and both field and laboratory studies. It is also supported by results of the examination of a concrete sample which had been buried in clay for 43 years.The enoineering lifetime of a 1 m thick reinforced concrete slab, with one face in contact with clay, and the way in which pH in the repository as a whole is likely to vary with time have both been estimated from available data. The estimates indicate that engineering lifetimes of about 103 years are expected (providing that sulphate resisting cement is used) and that pH is likely to remain above 10.5 for about 106 years.

The Curing of Concrete Samples with Water - Experimental Verification of the Concrete Properties

2020 ◽  
Vol 868 ◽  
pp. 65-69
Author(s):  
Marek Ďubek ◽  
Marián Bederka ◽  
Peter Makýš
Keyword(s):  
Reinforced Concrete ◽  
Necessary Conditions ◽  
Concrete Slab ◽  
Strength Properties ◽  
Climatic Conditions ◽  
Reinforced Concrete Slab ◽  
Common Procedure ◽  
Concrete Properties ◽  
Concrete Ceiling

The process of producing a monolithic concrete structure on site is constructed out under different climatic conditions, which can often be unsuitable for setting and hardening of concrete. The necessary conditions for setting and hardening of concrete are ensured by various ways of its curing. In practice, concrete curing is carried out in most cases by water spraying. It is used mostly in reinforced concrete ceiling slabs, which are further discussed in the work. A common procedure is to cure the upper surface of reinforced concrete ceiling slabs. This work therefore deals with the effect of curing of a reinforced concrete slab, on its strength properties. Long-term curing would yield higher values of compressive strength, but it is also necessary to consider how effective it is. As a pilot research in this work is investigating the properties of concrete cubes in various curing. It further develops theoretical possibilities for continuing research.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

Coupled Discrete Element/Finite Element Method for the Analysis of Large Reinforced Concrete Structures Submitted to an Impact

2011 ◽  
Vol 82 ◽  
pp. 284-289
Author(s):  
Laurent Daudeville ◽  
Jessica Haelewyn ◽  
Philippe Marin ◽  
Serguei Potapov
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Heterogeneous Media ◽  
Concrete Slab ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Elements ◽  
Reinforced Concrete Slab ◽  
The Impact ◽  
Element Method

The efficiency of the discrete element method for studying the fracture of heterogeneous media has been demonstrated, but it is limited by the size of the computational model. A coupling between the discrete elements (DEM) and the finite elements (FEM) methods is proposed to handle the simulation of impacts on large structures. The structure is split into two subdomains in each of which the method is adapted to the behavior of the structure under impact. The DEM takes naturally into account the discontinuities and is used to model the media in the impact zone. The remaining structure is modeled by the FEM. We propose an adaptation of the coupling procedure to connect Discrete Element model to shell-type Finite Elements. Finally, the efficiency of this approach is shown on the simulation of a reinforced concrete slab impacted by a tubular impactor.

Investigating the Impact of Temperature Changes, Material Aging, and Service Load on the Strain of a Reinforced Concrete Construction

2014 ◽  
Vol 59 (4) ◽  
pp. 913-924
Author(s):  
Adam Kanciruk
Keyword(s):  
Reinforced Concrete ◽  
Public Transport ◽  
Coal Basin ◽  
Wheel Load ◽  
Temperature Changes ◽  
Coal Beds ◽  
Intensive Exploitation ◽  
Service Load ◽  
Passenger Aircraft ◽  
The Impact

Abstract Intensive exploitation of coal beds in the Upper Silesia Coal Basin led to the degradation of the Katowice-Muchowiec civilian/military airport. As a result, it became necessary to adapt the Pyrzowice military airport for use as a public transport facility. This involved reconstruction of a hangar located at the airport. As part of this process, a new hangar slab was constructed, designed in such a way as to bear the load of passenger aircraft. In the area of the greatest wheel load to the slab, three strain rosettes were installed for the purpose of monitoring the slab strain. The mointoring process - which has been automatically conducted for almost three years now - revealed deformations resulting from service load, the aging of reinforced concrete, and changes of its temperature.

Steel-Reinforced Concrete Floors With The Use Of Bent Steel Profiles

2020 ◽  
pp. 10-14
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Theoretical Research ◽  
Steel Beams ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Steel Reinforced Concrete ◽  
Advantages And Disadvantages ◽  
Concrete Strengthening

The issues of designing a steel-reinforced concrete floor using bent steel profiles are considered. The steel-reinforced concrete flooring consists of a monolithic reinforced concrete slab arranged on a removable formwork, and steel bent profiles. The removable formwork during the concreting process rests on steel beams without additional mounting posts in the floor span. Steel beams accept the weight of the formwork and concrete during the pouring, working on bending. After concrete strengthening, they mainly work on stretching as part of composite steel-reinforced concrete structure. The article has identified the advantages and disadvantages of steel-reinforced concrete flooring with the use of light steel thin-walled bent profiles. Checking the strength of the beam at the concreting stage and evaluating the load-bearing capacity of the floor after the concrete strength is set confirm the performance of this structure. Using the regulatory methodology for SP 266.1325800.2016, the area of implementation of steel and concrete flooring with CFS beams and the nomenclature of applied steel beams have been established. For practical application of the presented design, it is recommended to conduct experimental and theoretical research and develop engineering methods.

Bending Effect On The Mechanism Of Punching The Support Zone Of The Reinforced Concrete Slab

2019 ◽  
pp. 20-28
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Strain State ◽  
Concrete Slab ◽  
Experimental Studies ◽  
Reinforced Concrete Structure ◽  
Stress Strain ◽  
Reinforced Concrete Slab ◽  
Stress Strain State ◽  
Reinforced Concrete Slabs

The analysis of various regulatory methods for calculating reinforced concrete slabs for punching and comparing with experiment results is made. The tested sample, measuring equipment and test bench are described. Dimensions and materials for the production of the prototype were chosen on the basis of experience in the construction of girderless and capless regular monolithic reinforced concrete frames. The results of experimental studies of a fragment of a slab reinforced concrete structure in order to study the stress-strain state, when implementing the mechanism of punching, are presented. The results of observations obtained during the tests are presented. A comparison of the nature of operation of the tested fragment of the slab with the nature of operation of the full-fledged construction is given. A comparative analysis of the stress-strain state of the tested sample and the results of the calculation of the bearing capacity for punching according to various normative methods is performed. According to the results of the experiment, the main criteria determining the implementation of the punching mechanism are established, and a new method for calculating girderless floors is proposed on the basis of a fundamentally different approach in determining the bearing capacity.

scholarly journals Finite Element Analysis of the Stability of a Sinusoidal Web in Steel and Composite Steel-Concrete Girders

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1041 ◽  
Author(s):  
Krzysztof Śledziewski ◽  
Marcin Górecki
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Initial Stresses ◽  
Shear Stresses ◽  
Reinforced Concrete Slab ◽  
The Stability ◽  
The Impact ◽  
The Web ◽  
Composite Steel

This paper presents the results of numerical investigations into the behavior of a sinusoidal web loaded in shear due to buckling in the period from the onset of buckling until failure, as well as the impact of a reinforced concrete slab on the stability of the web. The analysis concerned steel girders and composite girders with the top flange bonded to a reinforced concrete slab. Nonlinear analyses were performed using the finite element method. The results of the investigations support the conclusion that the appearance and propagation of shear stresses in the sinusoidal web of the composite steel–concrete beam are the same as those in an identical non-composite steel beam, but the bracing of the top flanges improves the shear strength and, at the same time, affects the location of initial stresses. In addition, it was found that, despite the three types of buckling, the predominant failure of the sinusoidal webs, regardless of the presence of the concrete slab, is global buckling. It occurs diagonally through several folds at the same time, including deformation of the web over its entire height.

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