Experimental and Numerical Investigation of Reinforced Concrete Pile Subjected to Near-Field Non-Contact Underwater Explosion

2020 ◽  
Vol 20 (06) ◽  
pp. 2040003
Author(s):  
Qiushi Yan ◽  
Chen Liu ◽  
Jun Wu ◽  
Jun Wu ◽  
Tieshuan Zhuang
Keyword(s):  
Reinforced Concrete ◽  
Numerical Model ◽  
Failure Mode ◽  
Numerical Study ◽  
Lateral Displacement ◽  
Near Field ◽  
Concrete Strength ◽  
Underwater Explosion ◽  
Load Bearing ◽  
Damage Pattern

High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.

SEISMIC PERFORMANCE OF GFRP-RC RECTANGULAR COLUMNS: NUMERICAL STUDY

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ehab El-Salakawy ◽  
Fangxin Ye ◽  
Yasser Mostafa Selmy
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Axial Load ◽  
Numerical Study ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Concrete Columns ◽  
Load Level ◽  
Reinforced Concrete Columns ◽  
Rectangular Columns

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

scholarly journals PREDICTING THE STRUCTURAL PERFORMANCE OF SANDWICH CONCRETE PANELS SUBJECTED TO BLAST LOAD CONSIDERING DYNAMIC INCREASE FACTOR

2019 ◽  
Vol 10 (1) ◽  
pp. 45-58
Author(s):  
Mohammad Hanifehzadeh ◽  
Mir Mohammad Reza Mousavi
Keyword(s):  
Numerical Study ◽  
Near Field ◽  
Concrete Strength ◽  
Plate Thickness ◽  
Superior Performance ◽  
Blast Load ◽  
Structural Performance ◽  
Concrete Core ◽  
Explicit Finite Element ◽  
Maximum Deformation

The safety of the civil structures could be significantly improved against shock waves and blast loads by using steel concrete steel (SCS) protective walls. A numerical study has been performed to simulate the response of SCS wall subjected to a near-field blast load. A conventional SCS panel subjected to near-field blast load and its structural performance is evaluated in terms of maximum damage and deformation. The simulations performed using ABAQUS\EXPLICIT finite element package and built-in concrete damage plasticity concrete constitutive formulation. The maximum deformation, plastic strain, and failure mode under different loading scenarios have been investigated. The aim of this study is predicting the structural response of the SCS panel with different blast charge and identification of optimum configuration in terms of concrete strength and plate thickness. In the second part of the study, two novel sandwich configurations consisting of a corrugated metal sheet and the concrete core are proposed and compared with the conventional protective walls. The optimum parameters for each structural component are identified using an optimization procedure. Based on this study, using the proposed wall configuration will results in superior performance compared to the conventional walls while the extra cost of fabrication is insignificant.

Experimental Study on the Mechanical Properties of Reinforced Concrete Columns after Exposure to Fire

2011 ◽  
Vol 243-249 ◽  
pp. 5122-5127
Author(s):  
Jia Feng Xu ◽  
Ming Zhe Liu ◽  
Yue Feng Tang
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Room Temperature ◽  
Ultimate Load ◽  
Concrete Columns ◽  
Load Bearing Capacity ◽  
Reinforced Concrete Columns ◽  
Load Bearing

This paper provided three test data pertaining to the mechanical properties of reinforced concrete columns after exposure to ISO834 standard fire and three comparative test data pertaining to the mechanical properties of reinforced concrete columns at room temperature, mainly concerning the influence of fire on failure mode, distortion performance and ultimate load bearing capacity of reinforced concrete columns under axial and eccentric compression. Test results show that the failure mode of reinforced concrete columns after exposure to fire is basically same with that at room temperature. With the same concrete strength and heating condition, the bearing capacity of specimens reduces as the eccentricity increases. Strain along the section height of eccentric columns after fire basically agree with the plane section supposition while the flexural rigidity and ultimate load bearing capacity decreases obviously. The residual load bearing capacity of reinforced concrete columns after exposure to fire is only about 25% to 37% of that at room temperature.

scholarly journals Cyclic Responses of Two-Side-Connected Precast-Reinforced Concrete Infill Panels with Different Slit Types

Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Guohua Sun ◽  
Fei Li ◽  
Qiyou Zhou
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Failure Mode ◽  
Damping Ratio ◽  
Concrete Strength ◽  
Plastic Hinge ◽  
Cyclic Behavior ◽  
Lateral Stiffness ◽  
Lateral Strength ◽  
Energy Dissipation Capacity

This study aimed to study the cyclic behavior of two-side-connected precast-reinforced concrete infill panel (RCIP). A total of four RCIP specimens with different slit types and height-to-span ratios modeled at a one-third scale were tested subjected to cyclic lateral loads. The failure mode, hysteretic behavior, lateral strength, stiffness degradation, ductility, and energy dissipation capacity of each RCIP specimen were determined and analyzed. The specimens experienced a similar damage process, which involved concrete cracking, steel rebar yielding, concrete crushing, and plastic hinge formation. All the specimens showed pinched hysteretic curves, resulting in a small energy dissipation capacity and a maximum equivalent viscous damping ratio lower than 0.2. The specimens with penetrated slits experienced ductile failure, in which flexural hinges developed at both slit wall ends. The application of penetrated slits decreased the initial stiffness and lateral load-bearing capacity of the RC panel but increased the deformation capacity, the average ultimate drift ratios ranged from 1.41% to 1.99%, and the lowest average ductility ratio reached 2.48. The specimens with high-strength concrete resulted in a small slip no more than 1 mm between the RC panel and steel beam, and the channel shear connectors ensured that the RC infill panel developed a reliable assembly with the surrounding steel components. However, specimens with concealed vertical slits (CVSs) and concealed hollow slits (CHSs) achieved significantly higher lateral stiffness and lateral strength values. Generally, the specimens exhibited two-stage mechanical features. The concrete in the CVSs and CHSs was crushed, and flexural plastic hinges developed at both ends of the slit walls during the second stage. With increasing concrete strength, the initial lateral stiffness and lateral strength values of the RCIP specimens increased. With an increasing height-to-span ratio, the lateral stiffness and strength of the RC panels with slits decreased, but the failure mode remained unchanged.

Experimental and Numerical Evaluation of UHPFRC Slabs Subjected to Contact and Close-In Explosion

2020 ◽  
Vol 309 ◽  
pp. 180-185
Author(s):  
Ondřej Janota ◽  
Marek Foglar
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
High Performance ◽  
Numerical Evaluation ◽  
Numerical Models ◽  
Blast Resistance ◽  
Near Field ◽  
Fibre Reinforced Concrete ◽  
High Performance Fibre

This paper presents achievements in the field of the numerical simulation of the fibrere reinforced concrete (FRC) and ultra-high performance fibre reinforced concrete (UHPFRC). The numerical simulations were performed to verify results of two experimental programmes focused on the blast resistance of FRC and UHPFRC. The response of the FRC and UHPFRC slabs to the contact and near-field blast was studied in these two experiments. As the detail behaviour of specimens could not be observed because of the blast load, the numerical models were prepared. The accuracy of the numerical models was evaluated based on the comparison of numerical and experimental results. Different approaches for blast simulation were tested and compared. The results indicate that the various phenomena (e.g. overpressure propagation, stress cumulation, crack propagation and damage extend) can be successfully simulated. However, the comparison of the soffit velocity, measured with the PDV unit and numerical model showed shortcomings of the numerical model. These numerical model inaccuracies are discussed and their reasons presented.

scholarly journals DETERMINATION OF THE CRITERIA OF DEFORMATION IN A SPECIAL LIMITING STATE

2021 ◽  
Vol 17 (1) ◽  
pp. 108-116
Author(s):  
Nikolay Trekin ◽  
Emil Kodysh ◽  
Sergey Shmakov ◽  
Tere Terekhov ◽  
Konstantin Kudyakov
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Rational Design ◽  
Progressive Collapse ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Load Bearing Capacity ◽  
Limiting State ◽  
Load Bearing

Constructive measures taken to ensure the integrity of the entire building or its part in emergency situations with design based on the existing criteria of the limiting state method leads to a significantincrease of the construction cost. One of the ways to reduce additional costs of construction while the protection design against progressive collapse is the possible use of additional reserves of deformability of load-bearing elements. It leads to redistribution of loads and the use of non-destroyed structures. It also leads to possible changes of limiting states in non-standard emergency design situations, taking into account the peculiarities of the operation of structures in a special limiting state at a stage close to destruction. In the GOST 27751-2014 «Reliability for constructions and foundations. General principles» calculated states of the firstand second groups of limiting states are given, and for a special limiting state only the area of its permissible application is indicated. The work of reinforced concrete structures at the stage close to the depletion of the load-bearing capacity is little reflectedin the scientificand technical literature; the work of reinforced concrete structures at the unloading stage due to the redistribution of forces is represented in single publications. The article presents theoretical studies based on experimental data on the deformation of bent reinforced concrete beam elements at a stage close to the maximum load-bearing capacity and at the stage of unloading up to the transformation of a structural element into a mechanism. The influenceof the longitudinal reinforcement, the class of reinforcement, prestressing and the concrete strength on the deformation of reinforced concrete bending elements is considered in the article. The research of the behavior of structural elements continuation at this stage is relevant and contributes to the development of economical and rational design solutions for protection against progressive collapse and in the design of earthquake-resistant buildings.

scholarly journals Strength Capacity and Failure Mode of Shear Connectors Suitable for Composite Cold Formed Steel Beams: Numerical Study

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3627
Author(s):  
Sherif A. Elsawaf ◽  
Saleh O. Bamaga
Keyword(s):  
Numerical Model ◽  
Failure Mode ◽  
Numerical Study ◽  
Steel Beams ◽  
Composite Action ◽  
Shear Connectors ◽  
Strength Capacity ◽  
Cold Formed Steel ◽  
Headed Stud ◽  
Channel Beam

In this paper, the findings of numerical modeling of the composite action between normal concrete and Cold-Formed Steel (CFS) beams are presented. To obtain comprehensive structural behavior, the numerical model was designed using 3-D brick components. The simulation results were correlated to the experimental results of eight push tests, using three types of innovative shear connectors in addition to standard headed stud shear connectors, with two different thicknesses of a CFS channel beam. The proposed numerical model was found to be capable of simulating the failure mode of the push test as well as the behavior of shear connectors in order to provide composite action between the cold-formed steel beam and concrete using the concrete damaged plasticity model.

The mathematical modelling of corrosion in hot dip galvanized steel reinforced concrete

2011 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
A. Hegyi ◽  
H. Vermeşan ◽  
V. Rus
Keyword(s):  
Mathematical Model ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
Equation System ◽  
Galvanized Steel ◽  
Steel Reinforced Concrete ◽  
Numeric Model ◽  
Physical And Mathematical Models ◽  
Physical Phenomena ◽  
The Mathematical Model

Abstract In this paper we wish to present the numerical model elaborated in order to simulate some physical phenomena that influence the general deterioration of steel, whether hot dip galvanized or not, in reinforced concrete. We describe the physical and mathematical models, establishing the corresponding equation system, the initial and boundary conditions. We have also presented the numeric model associated to the mathematical model and the numeric methods of discretization and solution of the differential equations system that describes the mathematical model.

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