Variation of Structural Capacity of Reinforced Concrete Slab Due to the Repeated Cyclic Loading Idealized for Thermal Load

2010 ◽  
Vol 452-453 ◽  
pp. 697-700
Author(s):  
Soo Yeon Seo ◽  
Seung Joe Yoon ◽  
Hyun Do Yoon
Keyword(s):  
Cyclic Loading ◽  
Concrete Slab ◽  
Weather Data ◽  
Effect Of Temperature ◽  
Reinforced Concrete Slab ◽  
Structural Capacity ◽  
Long Term Effect ◽  
Test Parameters ◽  
Rc Slabs

A variation of temperature by sunlight acting on a RC roof slab causes a change of stress in concrete since it expands during summer and is compressed during winter. This behavior repeats annually and affects structural capacity of member for both serviceability and ultimate level. In this paper, a variation of cyclic temperature loading is calculated by analyzing the weather data of Korea for 20 years. In addition, an experimental work is planned to find the long term effect of temperature change. Four RC slabs are made with same dimension. Test parameters are loading duration (10, 20, 30 years). Observation of stiffness variations according to cyclic loading duration shows that the serious stiffness drop happens after 10 year's cyclic loading at summer while after 30 year's loading at winter. From the failure test, maximum strength of specimen that experienced repeated preloading was approximately 12% less than standard specimen without any repeated preloading.

scholarly journals Proposition of Thin-Layer Repairing Methods Using Low-Elasticity Polymer Portland Cement Materials and Glue and Study on the Fatigue Resistance of Reinforced Concrete Slab

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Tadashi Abe ◽  
Kiyoshi Ito ◽  
Noriyuki Kozakai ◽  
Takayoshi Kodama
Keyword(s):  
Fatigue Resistance ◽  
Concrete Slab ◽  
Wheel Load ◽  
Reinforced Concrete Slab ◽  
Repair Method ◽  
High Durability ◽  
Rc Slabs ◽  
Reinforcement Measures ◽  
Repair Cycle

In this repair method, two types of adhesives, such as a penetrable adhesive and a high-durability adhesive, were applied to the adhesion interface of the materials to be repaired, and then cast. The repair method was then evaluated for fatigue resistance using wheel load running tests. It was developed to ensure the long-term integrity of the repair material and RC slabs. The results of the experiments confirmed that this repair method provides significantly better fatigue resistance than the conventional construction method. Moreover, this study proposes two wet repair cycles and one dry repair cycle with reinforcement measures to improve the load-bearing performance.

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.

Pre-Test and Analysis of a Reinforced Concrete Slab Subjected to Blast From a Non-Confined Explosive

2018 ◽  
pp. 272-287
Author(s):  
Fausto B. Mendonça ◽  
Girum S. Urgessa
Keyword(s):  
Dynamic Analysis ◽  
Large Scale ◽  
Concrete Slab ◽  
Wave Parameter ◽  
Experimental Program ◽  
Small Scale ◽  
Maximum Displacement ◽  
Reinforced Concrete Slab ◽  
Test Experiment ◽  
Rc Slabs

A large scale experimental program consisting of testing 10 RC slabs with different variations of concrete compressive strength, reinforcement ratio and retrofit was conducted in Brazil. As part of that test program, a small-scale blast pre-test setup and associated dynamic analysis were conducted in order to confirm the proper functioning of the blast test sensors (pressure gages, displacement meter and accelerometers). The results of the pre-test were compared with theoretical blast wave parameter predictions using established equations and maximum displacement predictions using simplified dynamic analysis. The pre-test experiment provided useful insights and was shown to be critical for the success of the subsequent large scale blast tests.

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.

Updating Performance and Reliability of Concrete Structures Using Discrete Empirical Bayes Methods

2002 ◽  
Vol 124 (4) ◽  
pp. 239-244 ◽  
Author(s):  
Marc A. Maes
Keyword(s):  
Empirical Bayes ◽  
Concrete Slab ◽  
Random Variable ◽  
Reinforced Concrete Slab ◽  
Bayes Methods ◽  
Likelihood Functions ◽  
Chloride Corrosion ◽  
Empirical Bayes Methods ◽  
New Framework

When performing a probabilistic assessment of the reliability of deteriorating structures, we often need to integrate the results of different inspections in time, within the models used to analyze the progress of deterioration. A new framework is described in this paper. It rests on a special case of the empirical Bayes method where the non-observable parameter is a discrete random variable with a relatively small number of outcomes. Various likelihood functions are derived. They are based on mixtures of deterioration scenarios. It is shown how the method can be used to calibrate the response of a stochastic deterioration model and to merge with a time-dependent reliability analysis. Examples relating to the long-term chloride corrosion in a reinforced concrete slab are presented in the paper.

scholarly journals Comparison of Predicted and Experimental Behaviour of RC Slabs Subjected to Blast using SDOF Analysis

2018 ◽  
Vol 68 (2) ◽  
pp. 138 ◽  
Author(s):  
F. B. Mendonca ◽  
G. Urgessa ◽  
K. Iha ◽  
R. J. Rocha ◽  
J.A.F.F. Rocco
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Experimental Program ◽  
Reinforced Concrete Slab ◽  
Peak Displacement ◽  
Blast Damage ◽  
Reinforced Concrete Slabs ◽  
Military Facilities ◽  
Rc Slabs ◽  
Sdof Analysis

<p>Explosions emanating from terrorist attacks or military weapons cause damage to civilian and military facilities. Understanding the mechanical behaviour of reinforced concrete structures subjected to blast is of paramount importance for minimizing the possible blast damage. A full-scale experimental program consisting of six reinforced concrete slabs with compressive strengths of 60 MPa, 50 MPa and 40 MPa, measuring 1.0 m × 1.0 m × 0.08 m, and subjected to 2.7 kg of non-confined plastic bonded explosive, was conducted in blast test area of Science and Technology Aerospace Department (Brazilian Air Force). This paper compares experimentally measured peak displacement values with theoretical values. Theoretical analysis was carried out using single degree of freedom (SDOF) models. The comparison showed that SDOF analysis worked very well in predicting the reinforced concrete slab peak displacement against blast effects. Qualitative analysis after the experiments showed that the blast wave shape generated by the cylindrical explosive was not uniformly distributed on the slabs for the standoff distance of 0.927 m∕kg1/3.<br /><br /></p>

scholarly journals Performance of Reinforced Concrete Slab with Opening Strengthened Using CFRP

Fibers ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 25
Author(s):  
Syafiqah Shahrul Aman ◽  
Bashar S. Mohammed ◽  
Mubarak Abdul Wahab ◽  
Abdullah Anwar
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Sufficient Information ◽  
Reinforced Concrete Slab ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Cfrp Sheet ◽  
And Performance ◽  
Rc Slabs

Openings in reinforced concrete (RC) slabs are not commonly prescribed in design codes. Even when they are, they raise concerns regards to the size of the openings and the location of the applied loads. Lack of sufficient information about the load-carrying capacity of the slabs with openings and performance is another concern. Hence, this research addresses the structural behavior of slabs with openings coated with Carbon Fiber Reinforced Polymer (CFRP) sheet. In the experimental part, ten slabs were cast with a dimension of 1000 mm × 530 mm × 25 mm, among which nine slabs had openings and one slab was without opening (control slab). The configuration of the CFRP sheet includes coating in the form of single, double, and triple layers. Experimental results show that the slab with a triple coating of the CFRP layer offers the maximum resistance towards the loading rate. Moreover, with the increase in CFRP layers, the value of deflection is minimized.

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.

The Effect of Temperature Changes on the Thyroid-Pituitary Relationship in Teleosts

1958 ◽  
Vol 35 (4) ◽  
pp. 824-831
Author(s):  
P. Y. FORTUNE
Keyword(s):  
High Temperatures ◽  
Environmental Temperature ◽  
Marked Effect ◽  
Term Effect ◽  
Effect Of Temperature ◽  
Thyroid Activity ◽  
Temperature Changes ◽  
Long Term Effect ◽  
Different Levels

1. It is confirmed that TSH has a more marked effect on the teleost thyroid at high temperatures. 2. The secretion of TSH is increased at high temperatures. 3. The temperature to which the animal is subjected prior to the experiment has no long-term effect on thyroid activity. 4. The thyroid-pituitary relationship is affected by temperature changes, and it is suggested that the TH:TSH ratio may be set at different levels by altering the environmental temperature.

Sign in / Sign up

Export Citation Format

Share Document