EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE EFFECT OF SIZE IN POST-TENSIONED CONCRETE DECK SLABS

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Sana Amir ◽  
Cor van der Veen ◽  
Ane de Boer
Keyword(s):  
Size Effect ◽  
Precast Concrete ◽  
Experimental Studies ◽  
Punching Shear ◽  
Small Scale ◽  
Size Factor ◽  
Scaled Model ◽  
Nominal Strength ◽  
Deck Slabs ◽  
Post Tensioned

It is widely known that as the structure of the size increases, its nominal strength decreases. In this paper, the effect of size on punching shear has been quantified for transversely post-tensioned deck slabs cast between flanges of precast concrete girders. A 1:2 scaled model of the bridge was constructed in the laboratory, and experimental and numerical analyses were carried out. However, in order to apply these results on a real bridge, simply using the geometrical scale factors is not sufficient and a structural size effect has to be taken into account. Since a full-scale experimental study was not possible due to the costs involved, a numerical approach using finite element analysis software package TNO DIANA was used to model both the prototype and the real bridge, and a comparison was made to estimate the effect of size on the bearing capacity. It was found that increasing the transverse prestressing level had a positive effect on the punching shear strength of the deck slab. Furthermore, a lower size effect was observed with higher transverse prestressing levels. It is concluded that if a suitable size factor is used, either numerical or small-scale experimental studies can be reasonably used to investigate existing structures.

Residual Strength Prediction Based on Size Effect of Cracked Concrete Members

2021 ◽  
pp. 1-24
Author(s):  
Ragip Ince ◽  
Cenk Fenerli
Keyword(s):  
Fracture Mechanics ◽  
Size Effect ◽  
Residual Strength ◽  
Experimental Studies ◽  
Test Results ◽  
Structural Members ◽  
Cracked Concrete ◽  
Concrete Members ◽  
Peak Loads ◽  
Nominal Strength

In engineering materials, defects, such as cracks, may occur during production and/or due to various reasons. One of the aims of fracture mechanics is to determine the fracture toughness-based residual strength of structural members with cracks. A quasi-brittle material, such as concrete or rock, may include certain defects, such as voids and cracks, even before being exposed to loads. Experimental analyses on concrete members indicated that specimens’ nominal strength values were decreased as their sizes increased while specimen geometry is the same. In fracture mechanics, this condition was defined as the “size effect” in both concrete and reinforced concrete units. In the literature, numerous theoretical and experimental studies were conducted on beams while compact split-tension specimens, particularly notched ones are limited. In this study, six series of notched beams with three different sizes and notched square prismatic specimens with four different sizes were tested. According to the test results, the peak loads were analyzed by using the fundamental theorem of the modified size effect law. In conclusion, two formulae were proposed to predict the flexural strength and the splitting strength of quasi-brittle bodies with cracks.

scholarly journals NUMERICAL INVESTIGATION OF THE BEARING CAPACITY OF TRANSVERSELY PRESTRESSED CONCRETE DECK SLABS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sana Amir ◽  
Cor van der Veen ◽  
Joost Walraven ◽  
Ane de Boer ◽  
Joost C. Walraven
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Numerical Models ◽  
Experimental Studies ◽  
Shear Capacity ◽  
Punching Shear ◽  
Scale Model ◽  
Fe Model ◽  
Deck Slabs ◽  
Concrete Deck

The paper investigates the effect of various geometrical and material parameters on the bearing (punching shear) capacity of transversely prestressed concrete deck slabs by numerical methods. Experiments on a 1:2 scale model of such a bridge were carried out in the laboratory and a 3D nonlinear finite element (FE) model was developed in the finite element analysis software package TNO DIANA (2012) to study the structural behavior in punching shear. A comparison of the experimental and numerical ultimate loads show that the non-linear FE models can predict the load carrying capacity quite accurately with a standard deviation of 0.1 and the coefficient of variation of only 10%. The effect of varying the transverse prestressing level, the presence and size of the ducts, size of the loading plate and the concrete class is also described as part of the parametric study. It was observed that sufficient saving in cost could be made if calibrated numerical models are employed to investigate existing structures rather than doing expensive experimental studies.

Experimental studies and theoretical analysis of the residual properties of three-span small-scale continuous concrete slabs after a fire

2021 ◽  
pp. 103481
Author(s):  
Yong Wang ◽  
Gongchen Wang ◽  
Zhaohui Huang ◽  
Yuner Huang ◽  
Benmiao Wang ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Small Scale ◽  
Concrete Slabs ◽  
Residual Properties

Further analysis of the size effect in indentation hardness tests of some metals

1995 ◽  
Vol 10 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
M. Atkinson
Keyword(s):  
Size Effect ◽  
Strain Hardening ◽  
Indentation Size Effect ◽  
Plastic Hinge ◽  
Small Scale ◽  
Indentation Hardness ◽  
Vickers Indentation ◽  
Indentation Size ◽  
Hardness Tests ◽  
Indentation Tests

The variation of apparent hardness observed in previously reported Vickers indentation tests of metals is reexamined. Common deseriptions of the effect are shown to be inaccurate: the variation of apparent hardness is monotonic but not simple. The effect is consistent with varying size of a previously postulated “plastic hinge” at the perimeter of the indent. This complexity confers uncertainty on the estimation of characteristic macrohardness from small scale tests. Association of the indentation size effect with friction and with strain hardening is confirmed.

scholarly journals Size-effect, asymmetry, and small-scale spatial variation in otolith shape of juvenile sole in the Southern North Sea

Hydrobiologia ◽  
2018 ◽  
Vol 845 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Sophie Delerue-Ricard ◽  
Hanna Stynen ◽  
Léo Barbut ◽  
Fabien Morat ◽  
Kelig Mahé ◽  
...  
Keyword(s):  
Size Effect ◽  
Spatial Variation ◽  
North Sea ◽  
Small Scale ◽  
Otolith Shape ◽  
Southern North Sea

scholarly journals Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Srinivasan Karunanithi
Keyword(s):  
Energy Absorption ◽  
Steel Fibre ◽  
Impact Load ◽  
Impact Resistance ◽  
Experimental Studies ◽  
Absorption Capacity ◽  
Punching Shear ◽  
Geopolymer Concrete ◽  
Energy Absorption Capacity ◽  
Ultimate Failure

The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness.

scholarly journals Theoretical and experimental studies of a gas stamping device with a piston pressure multiplier

2019 ◽  
Vol 18 (1) ◽  
pp. 163-173
Author(s):  
A. Yu. Botashev ◽  
R. A. Bayramukov
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Fuel Mixture ◽  
Small Scale ◽  
Scale Production ◽  
Pressure Treatment ◽  
Energy Of Combustion ◽  
Stamping Process ◽  
Pressure Multiplier ◽  
The Matrix

In many industries, the share of small-scale production plants is significant. In these conditions, compared with traditional methods of pressure treatment, pulse pressure treatment methods, one of the varieties of which is gas stamping, are more efficient. However, the known devices of gas stamping provide mainly stamping of thin-walled parts. To expand the technological capabilities of gas stamping, the authors developed a gas stamping device with a piston pressure multiplier, in which heating and deformation of the stamping workpiece is carried out using the energy of combustion of fuel mixtures in the combustion chamber, in the working cylinder and in the cavity of the matrix. This article is devoted to the study of the workflow of this device. Theoretical analysis of the workflow was carried out, and, as a result, a pattern was determined for the variation of the pressure that performs the stamping process in the working cylinder. In particular, it was found that at the final stage of the stamping process, due to the energy of combustion of the fuel mixture, the pressure in the working cylinder increases 1.5...2 times, which allows a significant increase in the thickness of the parts to be stamped. An experimental gas stamping device with a piston pressure multiplier was developed, and experimental studies were carried out. The studies confirmed the main results of the theoretical analysis: the discrepancy between the theoretical and experimental values of the degree of pressure multiplication in the working cylinder does not exceed 11%.

scholarly journals Size Effect in Fracture of Sandwich Structure Components: Foam and Laminate

2001 ◽  
Author(s):  
Zdeněk P. Bažant ◽  
Yong Zhou ◽  
Drahomír Novák ◽  
Isaac M. Daniel
Keyword(s):  
Size Effect ◽  
Size Effects ◽  
Sandwich Structure ◽  
Maximum Load ◽  
Material Strength ◽  
Large Structures ◽  
Nominal Strength ◽  
Sandwich Plates And Shells ◽  
Extensive Test ◽  
Plates And Shells

Abstract In the design of sandwich plates and shells for very large structures, such as ships in the range of 100 m length, it is very important to take the size effect on the nominal strength into account, and do so in a realistic, physically justified, manner. Before the size effect is addressed for a sandwich structure, it must be understood for its components — the foam core and the laminate skins. In the current practice, the size effects are automatically attributed to the randomness of material strength, as described by the Weibull theory. The purpose of this paper is to show that in both the foam and the laminate there are deterministic size effects, which are generally more pronounced. They are caused by stress redistribution and energy release due to the growth of large fractures or large cracking zones prior to attaining the maximum load. This deterministic size effect is verified and calibrated by new tests of notched specimens of rigid close-cell vinyl foam. A combined deterministic-probabilistic theory of size effect of the laminates is proposed and verified by extensive test data.

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