Numerical model for predicting the structural response of composite UHPC–concrete members considering the bond strength at the interface

2019 ◽  
Vol 215 ◽  
pp. 185-197 ◽  
Author(s):  
Hor Yin ◽  
Kazutaka Shirai ◽  
Wee Teo
Keyword(s):  
Numerical Model ◽  
Bond Strength ◽  
Structural Response ◽  
Concrete Members

scholarly journals A numerical approach for evaluating residual capacity of fire damaged concrete members

2020 ◽  
Vol 10 (2) ◽  
pp. 230-242
Author(s):  
Venkatesh Kodur ◽  
Ankit Agarawal
Keyword(s):  
Numerical Model ◽  
Mechanical Response ◽  
Structural Response ◽  
Numerical Approach ◽  
Fire Exposure ◽  
Ambient Conditions ◽  
Concrete Members ◽  
Fire Scenarios ◽  
Residual Capacity ◽  
Residual Response

This paper presents an approach to evaluate residual capacity of fire-damaged concrete structures. The approach involves capturing response in three stages; namely, structural response at ambient conditions (prior to fire exposure), thermo-mechanical response during fire exposure, and post-fire residual response after cooling down of the structural member. The proposed approach is implemented in a comprehensive numerical model developed in the finite element computer program ABAQUS for specifically evaluating residual capacity of an RC beam after exposure to different fire scenarios. Predictions from the numerical model are utilized to highlight importance of each stage of analysis in evaluating realistic residual capacity of fire damaged concrete members.

scholarly journals Fish Cells, a new zero Poisson’s ratio metamaterial—Part I: Design and experiment

2020 ◽  
Vol 31 (13) ◽  
pp. 1617-1637
Author(s):  
Mohammad Naghavi Zadeh ◽  
Iman Dayyani ◽  
Mehdi Yasaee
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Poisson’S Ratio ◽  
Structural Integrity ◽  
Structural Response ◽  
Poisson's Ratio ◽  
Experimental Investigations ◽  
Fish Cells ◽  
Force Displacement ◽  
Model Approach

A novel cellular mechanical metamaterial called Fish Cells that exhibits zero Poisson’s ratio in both orthogonal in-plane directions is proposed. Homogenization study on the Fish Cells tessellation is conducted and substantially zero Poisson’s ratio behavior in a homogenized tessellation is shown by numerical analysis. Experimental investigations are performed to validate the zero Poisson’s ratio feature of the metamaterial and obtain force–displacement response of the metamaterial in elastic and plastic zone. A detailed discussion about the effect of the numerical model approach and joints on the structural response of the metamaterial is presented. Morphing skin is a potential application for Fish Cells metamaterial because of the integration benefits of zero Poisson’s ratio design. The structural integrity of the Fish Cells is investigated by studying the stiffness augmentation under tension and in presence of constraints on transverse edges. Finally, geometrical enhancements for improved integrity of the Fish Cells are presented that result in substantially zero stiffness augmentation required for morphing skins.

scholarly journals The role of cover and rebar characteristics on load-slip behavior of reinforced concrete members in compression

2018 ◽  
Vol 162 ◽  
pp. 04017
Author(s):  
Tareq al-Attar ◽  
Qais Hassan ◽  
Sura Mejbel ◽  
Hussein Dawood
Keyword(s):  
Bond Strength ◽  
Research Work ◽  
Compressive Load ◽  
Concrete Block ◽  
Concrete Cover ◽  
Cross Sectional ◽  
Testing Procedures ◽  
Concrete Members ◽  
Significant Difference ◽  
Set Up

This paper describes a part of an extensive research work devoted to evaluate the bond strength between rebars and concrete through different testing procedures. Main parameters in this part are the concrete cover and rebar diameter. The tested specimen consisted of a single bar embedded in a concrete block with square cross-sectional area and is being tested under compressive load. Three concrete block sizes were cast to offer three different cover for the embedded rebars. The dimensions of these blocks were; 150×150×135, 100×100×135 and 200×200×185 mm. Three bar diameters, 12, 16 and 20 mm, were investigated. The specimens were water-cured and tested at the ages of 7 and 28 days. A new proposed test set-up was used to monitor the load-slip behavior of the specimens. The test results showed that there is no significant difference in bond energy between the two curing ages, 7 and 28 days. The concrete cover has a significant effect on the bond strength between rebar and concrete. By increasing the cover, the confinement offered by concrete increases, bond strength increases, and slip increases. Based on the present results, a concept of effective cover was developed. This concept showed a high correlation with the mode of failure for the tested specimens.

Numerical Analysis of Fire Performance of a Spacial Pre-Stressed Steel Structure in Fire

2013 ◽  
Vol 790 ◽  
pp. 189-192
Author(s):  
Tian Hong Wang ◽  
Jin Can Xu ◽  
Hai Lun Tong ◽  
Xin Tang Wang
Keyword(s):  
Thermal Expansion ◽  
Numerical Analysis ◽  
Numerical Model ◽  
Stress Relaxation ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Fire Performance ◽  
Maximum Value ◽  
In Fire

The numerical model of analysis of fire performance of a spatial pre-stressed steel structure with large span was established based on the software Marc. The thermal response and structural response of the pre-stressed steel structure was computed for some nodes of the structure in fire. The different fire scenes were considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed steel structure.It is concluded that the temperature rise of the nodes of the structure is far behind that of air near the nodes, however they are quite close as the fire lasted for 3600s and almost the same after 7200s.The results show that the displacement of the node right above the inner cable is the maximum and the node above the outer cable has the smallest value of displacement and the maximum value is about two and half times as large as the minimum.The results show that the reason why the cables are out of work is that the equilibrium between the cables and the rods of the structure is lost, but not that the stress relaxation caused by thermal expansion make the cables out of work.

A Numerical Model for Submarine Pipelines With Concrete Coating

2017 ◽  
Author(s):  
Ngoc Nguyen ◽  
Olav Fyrileiv ◽  
Chor Yew Chia
Keyword(s):  
Numerical Model ◽  
Rational Design ◽  
Design Method ◽  
Hot Spot ◽  
Phase 1 ◽  
Structural Response ◽  
Rational Approach ◽  
Operation Conditions ◽  
Applicable Range ◽  
Concrete Coating

This paper presents a numerical model that is used to estimate the structural response of a submarine pipeline with concrete weight coating subjected to loadings commonly encountered in pipeline installation and operation phases. Findings from parametric studies performed with the numerical model are used to widen the applicable range of the simplified concrete crushing criterion in DNV-OS-F101 (2013) and formulate a rational approach for the design of pipeline concrete weight coating under typical installation and operation conditions. The rational design approach will allow for potential selection from a wider range of installation vessels and relaxation of the installation weather window criterion. The design method also provides insights into the strain concentration in the field joint at different strain levels, which is used to assess the field joint welding integrity for pipeline in free spans and in high strain conditions. The numerical model considers nonlinearities in steel and concrete material stress and strain, as well as complex adhesive behaviour of the anti-corrosion coating. Good agreement is obtained between the numerical results and existing experimental data for all the sections along the pipeline model where comparisons are made on moment–strain global behaviour, sliding from the concrete coating, hot spot strain near the field joint and concrete strain. The numerical program is performed within the scope of Phase 1 of the joint industry project called “Design of concrete coating for submarine pipelines”. Laboratory tests to check and improve the numerical model are planned for Phase 2.

Simulating Post Punching Behaviour of RC Slab-Column Connections Using a Micro Model

2016 ◽  
Vol 846 ◽  
pp. 231-236
Author(s):  
Hui Zhong Xue ◽  
Hong Guan ◽  
Xin Zheng Lu ◽  
Yi Li
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Progressive Collapse ◽  
Structural Response ◽  
Calibration Method ◽  
Failure Criteria ◽  
Micro Model ◽  
Structural Behaviour ◽  
Flat Plates ◽  
Rc Slab

Punching shear is a common failure mode occurring at the slab-column connection region of a reinforced concrete (RC) flat plate. Progressive collapse of RC flat plates poses a significant scientific question on the post punching behaviour of such a structural system. The challenge lies in the complex interactions amongst various internal actions including large unbalanced moments and shear forces. Existing numerical models are unable to differentiate the influence of each individual action within the connection region after punching occurs. Therefore, a new numerical model is required to model these actions individually as well as to evaluate their interrelationships. This paper thus aims to propose a numerical method to investigate the structural response of RC slab-column connections by using a micro model, based on a representative post punching failure experiment. In the micro model, concrete is simulated using solid elements whilst the reinforcement is modelled with truss elements. In this micro model, the constitutive laws and failure criteria of materials play a crucial role in describing the model’s structural behaviour. A typical structural response is discussed and a calibration method is established. Ultimately this study is expected to facilitate the development of an effective, yet simplified numerical model for future progressive collapse simulation of slab-column connections.

scholarly journals Finite Element Analysis of the Effect of Currents on the Dynamics of a Moored Flexible Cylindrical Net Cage

2021 ◽  
Vol 9 (2) ◽  
pp. 159
Author(s):  
Zhongchi Liu ◽  
Sarat Chandra Mohapatra ◽  
C. Guedes Soares
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Model ◽  
Analytical Model ◽  
Structural Response ◽  
Wave Theory ◽  
Design Parameters ◽  
Element Analysis ◽  
Net Cage ◽  
Comparison Of The Results

A numerical model associated with wave–current interactions with a moored flexible cylindrical cage was developed based on the finite element method. An analytical model was formulated under the linearised wave theory and small structural response, and a semi-analytical solution was obtained using the Fourier Bessel series solution and least squares approximation method, along with a matching technique. The numerical results from the finite element analysis of the horizontal displacements for different design parameters under a uniform current were compared with the analytical model solutions. It was seen that they had a good level of agreement with their results. The effects of different current speeds and time on the cage shapes were analysed from the finite element results. Further, the mooring forces on the flexible cage for different values of the cage height and cage radius were also presented. The comparison of the results indicated that the numerical model results could be used with confidence in the design of a flexible cylindrical net cage for applications to offshore aquacultures.

scholarly journals FLEXURAL CAPACITY OF CORRODED POST-TENSIONED CONCRETE BEAMS: LARGE SCALE TESTS AND NUMERICAL SIMULATION

2020 ◽  
Author(s):  
Antonino Recupero ◽  
Nino Spinella ◽  
Antonio Marì ◽  
Jesús Miguel Bairan
Keyword(s):  
Numerical Model ◽  
Bearing Capacity ◽  
Large Scale ◽  
Concrete Beams ◽  
Structural Response ◽  
Experimental Results ◽  
Analysis Model ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Post Tensioned

An experimental campaign on corroded post-tensioned concrete beams is being carried out at the University of Messina (Italy). The main goal of the research project is to study the influence of the tendon corrosion on the response behaviour of post-tensioned concrete beams subjected to a transversal load. In 2006, six beams were cast with a tendon placed at the centroid of the cross-section. Corrosion of the tendons was artificially induced in each specimen by injecting a chemical solution or an acid in some parts of the duct. The experimental results have showed how external causes, reproduced by artificial defects, can induce several critical issues, and undermine both the durability and the load bearing capacity of the beams. The load bearing capacity of the beam with defects was reduced until half of the one recorded for the specimen with not corroded tendon. In addition, a non-linear and time dependent analysis model, developed at UPC in Barcelona, was used to simulate the response of the tested beams, with the purpose of experimentally verifying the capacity of the model to capture the effects of corrosion along the time. A parametric study was performed with the numerical model to capture the influence of the degree of corrosion, (defined as the % loss of steel mass) on the serviceability response and on the ultimate capacity. By comparing the theoretical and the experimental results, the degree of corrosion was estimated and compared with that observed subsequently on the tested beams. Good correlation was obtained, thus allowing the numerical model to be used as a “virtual lab” to study the influence of several parameters on the structural response of corroded post-tensioned beams.

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