scholarly journals Temperature Stress Analysis of Super-Long Frame Structures Accounting for Differences in the Linear Expansion Coefficients of Steel and Concrete

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1519
Author(s):  
Yigang Jia ◽  
Liangjian Lu ◽  
Guangyu Wu ◽  
Bo Zhang ◽  
Huibin Wang
Keyword(s):  
Reinforced Concrete ◽  
Stress Analysis ◽  
Temperature Stress ◽  
Linear Expansion ◽  
Frame Structures ◽  
Reinforced Concrete Structure ◽  
Rc Structures ◽  
Design Elements ◽  
Expansion Coefficients ◽  
The Difference

Temperature stress analysis is of prime importance to ensure the adequate servicing of super-long frame structures during their service life. The existing design codes and recommendations for reinforced concrete (RC) structures provide methodologies for the reinforcement of design elements that neglect differences in the linear expansion coefficients of steel and concrete. In this paper, we present a numerical method based on a degenerated three-dimensional solid virtual laminated element for simulating and analyzing the temperature stress of a two-layer super-long frame reinforced concrete structure subjected to allover cooling action, whereby the difference in the linear expansion coefficients of steel and concrete are taken into consideration. The results show that the difference in the linear expansion coefficients of steel and concrete, with different constraints, affects the temperature stress experienced by each material in the structure, and this difference adversely affects attempts to avoid structure cracking.

scholarly journals Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Alireza Panjsetooni ◽  
Norazura Muhamad Bunnori ◽  
Amir Hossein Vakili
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Nondestructive Evaluation ◽  
Analysis Method ◽  
Reinforced Concrete Structure ◽  
Acoustic Emission Technique ◽  
Rc Structures ◽  
Rc Frames ◽  
Damage Monitoring ◽  
Investigation Process

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures.

scholarly journals Early Crack Detection of Reinforced Concrete Structure Using Embedded Sensors

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3879 ◽  
Author(s):  
Joyraj Chakraborty ◽  
Andrzej Katunin ◽  
Piotr Klikowicz ◽  
Marek Salamak
Keyword(s):  
Reinforced Concrete ◽  
Crack Detection ◽  
Structural Condition ◽  
Probability Of Detection ◽  
Embedded Sensors ◽  
Bending Test ◽  
Reinforced Concrete Structure ◽  
Destructive Testing ◽  
Rc Structures ◽  
Ultrasonic Signals

The damage in reinforced concrete (RC) structures can be induced either by the dynamic or static load. The inspection technologies available today have difficulty in detecting slowly progressive, locally limited damage, especially in hard-to-reach areas in the superstructure. The four-point bending test on the benchmark RC structure was used as a test of the quality and sensitivity of the embedded sensors. It allowed assessment of whether any cracking and propagation that occurs with the embedded sensors can be detected. Various methods are used for the analysis of the ultrasonic signals. By determining the feature from the ultrasonic signals, the changes in the whole structure are evaluated. The structural degradation of the RC benchmark structure was tested using various non-destructive testing methods to obtain a comprehensive decision about structural condition. It is shown that the ultrasonic sensors can detect a crack with a probability of detection of 100%, also before it is visible by the naked eye and other techniques, even if the damage is not in the direct path of the ultrasonic wave. The obtained results confirmed that early crack detection is possible using the developed methodology based on embedded and external sensors and advanced signal processing.

scholarly journals Forensic to the Reinforced Concrete (RC) Structures at Library

2020 ◽  
Vol 19 (1) ◽  
pp. 6-14
Author(s):  
Tang Hing Kwong ◽  
Rudy Tawie ◽  
Siti Rozana Romali
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Strength ◽  
Reinforced Concrete Beam ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structure ◽  
Rebound Hammer ◽  
Rc Structures ◽  
Three Samples ◽  
Eurocode 2

This Forensic project has been proposed to investigate the reinforced concrete structure defect at library. There were found 65 points cracks and 20 points spalling in library such as only at reinforced concrete beam and slab part in first floor. The total of cracks which crack width less than 0.25 mm is 63 points and the crack width between 0.25 mm to 5.00 mm is 2 points only. These cracks had categorized as fine cracks because the crack width not more than 5 mm. There was 21 samples Rebound Hammer test was random measured the existing concrete compressive strength of critical structures which six samples at beams, six samples at slabs, six samples at columns and three samples at staircase in library. The Rebound Hammer test shown that average mid-point strength at beam is 33 N/mm2, slab is 25 N/mm², column is 38 N/mm2 and staircase is 37 N/mm2 . Based on the Eurocode 2, the minimum grade concrete required is 25N/mm2 to do the design for reinforced concrete structures, which all the existing concrete strength were achieved the minimum concrete strength. Finally, the Orion software are used to analysis and determine the size of steel reinforcement, the design found the required bar size of steel reinforcement at the middle span or continuous support is 2T16 & 2T25 or 2T20 & 2T25 but the existing steel reinforcement is 2T12 and 2T20 which the existing steel reinforcement could not be sustained the big loading that applied on the library.

Analytical Study on Dynamic Response of Reinforced Concrete Structure With Internal Equipment Subjected to Projectile Impact

2020 ◽  
Author(s):  
Yukihiko Okuda ◽  
Zuoyi Kang ◽  
Akemi Nishida ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Stress Waves ◽  
Dynamic Responses ◽  
Stress Wave Propagation ◽  
Reinforced Concrete Structure ◽  
Energy Agency ◽  
Rc Structures ◽  
Projectile Impact ◽  
Reactor Building

Abstract In case of a projectile impact on a reactor building of a nuclear power plant, stress waves propagate from the impacted wall to the structure’s interior. It is important to assess the effect of dynamic responses generated by the projectile’s impact on internal equipment, because stress waves are likely to excite high-frequency vibrations of internal equipment. The OECD (Organization for Economic Co-operation and Development) / NEA (Nuclear Energy Agency) launched the IRIS (Improving Robustness Assessment Methodologies for Structures Impacted by Projectiles) benchmark project in order to assess the dynamic response of a nuclear facility to projectile impact, and the third phase of IRIS (IRIS 3) [1] contributes to the investigation of the dynamic responses of reinforced concrete (RC) structures that house internal equipment. We have participated in IRIS 3 and have performed calibration analyses of projectile impact tests on a structure that models a reactor building that houses internal equipment. Specifically, we have developed and validated a numerical approach to investigation of impact responses of an RC structure that houses internal equipment through calibration correction. This paper presents partial simulation results of the dynamic responses of this structure and discusses the effects of support conditions of the internal equipment and stress wave propagation.

Random Analysis of RC Structures during Construction

2011 ◽  
Vol 105-107 ◽  
pp. 981-985
Author(s):  
Jun Zhao ◽  
Wei Wei Jia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Structure ◽  
Stochastic Finite Element Method ◽  
Reinforced Concrete Structure ◽  
Stochastic Finite Element ◽  
Rc Structures ◽  
Stability Of Structures ◽  
Element Method

Since accidents of reinforced concrete structure occur frequently, it is a key issue to ensure the safety and stability of structures during construction. In this paper, each construction cycle was divided into four stages using discrete time method of freezing to establish the computational model. According to random theory, with the characteristics of reinforced concrete structures during construction, a series of recurrence equation is built by stochastic finite element method during construction. Based on a random analysis of practical engineering, the random response time-varying rule of reinforced concrete structure is obtained during construction. The results show that the construction process of reinforced concrete structure could be simulated well based on perturbation stochastic finite element method .Both the mean and standard deviation of deflection of mid-span could be obtained precisely.

scholarly journals Numerical Analysis of Reinforced Concrete Frame Structures Under Various Fire Scenarios

2020 ◽  
Vol 20 (2) ◽  
pp. 189-195
Author(s):  
Ju-young Hwang ◽  
Hyo-Gyoung Kwak ◽  
Yonghoon Lee
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Fire Resistance ◽  
Structural Damage ◽  
Mechanical Strain ◽  
Frame Structure ◽  
Frame Structures ◽  
Rc Structures ◽  
Fire Scenarios ◽  
Fire Conditions

Since structural damage by fire in modern Reinforced Concrete (RC) structures causes significant loss of human life and property, it is important to evaluate the residual capacity of fire-damaged RC structures exposed to high temperatures. In this study, the behavior of fire-damaged RC frame structures (single-bay & three-bay frame), considering non-mechanical strain, was investigated by applying numerical analysis. The behavior mechanism was analyzed by numerical results of the single-bay frame and similar behavior was observed in each member of the three-bay frame. Principally, regarding the three-bay frame structure, the time of fire-resistance was evaluated under various fire scenarios, which included symmetrical and asymmetrical fires within the structure. The results of numerical analysis showed that, as the story load action on the structure increases, the fire-resistance time decreases. Finally, asymmetric fires should be considered for safety assessment against fire because the fire-resistance time under asymmetric fire conditions is shorter than that under symmetric fire conditions for all load conditions.

Condition assessment of reinforced concrete systems with fusion-bonded epoxy-coated rebars

CORROSION ◽  
10.5006/3786 ◽  
2021 ◽  
Author(s):  
Deepak Kamde ◽  
Sylvia Kessler ◽  
Radhakrishna Pillai
Keyword(s):  
Reinforced Concrete ◽  
Electrochemical Impedance ◽  
Field Investigation ◽  
Test Methods ◽  
Coated Steel ◽  
Cell Potential ◽  
Rc Structures ◽  
Eis Technique ◽  
The Difference ◽  
Steel Rebars

Corrosion assessment of reinforced concrete (RC) structures with fusion-bonded-epoxy (FBE) coated steel rebars is a challenge because the common inspection methods and data cannot be applied or interpreted in the same way as that for the systems with uncoated rebars. If corrosion detection tools based on techniques such as half-cell potential (HCP), linear polarization resistance (LPR), or electrochemical impedance spectroscopy (EIS) are used for the assessment of systems with FBE coated steel rebars without considering the difference in the electrochemical conditions between coated and uncoated systems, then, the interpretation can result in the inability to detect ongoing corrosion. Therefore, the objective of this paper is to examine the suitability of these inspection methods and data to be applied to the RC systems with FBE coated steel rebars. For this, the suitability of test methods on HCP, LPR, and EIS for assessing corrosion conditions of RC structures was assessed using laboratory specimens and field structures. Field investigation using HCP shows that the HCP could not detect corrosion of FBE rebars unless the coating was severely disbonded due to corrosion of steel rebars. Also, the suitability of test methods based on HCP, LPR, and EIS was assessed by additional laboratory specimens. Although complex, only the EIS technique could reliably detect the corrosion conditions of the FBE coated steel rebars embedded in concrete. Therefore, a way forward to assess RC structures using EIS technique is proposed.

Numerical investigation on damage performance of a reinforced concrete structure subjected to machine loads

2020 ◽  
Vol 6 (3) ◽  
pp. 132
Author(s):  
Memduh Karalar ◽  
Murat Çavuşli
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Structural Engineering ◽  
3D Model ◽  
Three Dimensional ◽  
Reinforced Concrete Structure ◽  
Rc Structures ◽  
Machine Element ◽  
Rc Structure ◽  
Capacity Performance

Investigation of carrying capacity performance of reinforced concrete (RC) structures is very important for structural engineering. In this study, it is aimed to examine the nonlinear carrying capacity performance of an RC laboratory structure by using three dimensional (3D) modelling approach. For this purpose, Zonguldak Bulent Ecevit University Laboratory Structure is selected and it is modeled as three dimensional by utilizing IDECAD static software. After modelling all beams, columns and floors according to 2018 Turkish earthquake code, concrete classes are determined for all bearing elements and specified concrete classes are defined for all elements of 3D model. Then, structure is analyzed for empty situation (Case 1) and structural performance of building is analyzed to this situation. In the past, a flat of this RC structure has been exposed to strong machine loads. For this reason, a machine which is fixed on the floor is placed in the 3D model and RC structure is analyzed considering nonstructural machine element loads (Case 2). According to analysis results, Case 1 is compared with Case 2 and it is clearly seen that nonstructural machine loads effect nonlinear carrying capacity performance of RC buildings.

New Scheme to Resist Seismic Collapse of RC Frame

2013 ◽  
Vol 753-755 ◽  
pp. 690-693
Author(s):  
Zhi Ping Li ◽  
Jin Xin Hao
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Plastic Hinge ◽  
Reinforced Concrete Structure ◽  
Load Path ◽  
Reinforced Concrete Frame ◽  
Rc Structures ◽  
Seismic Performance Evaluation ◽  
Concrete Frame ◽  
Displacement Based

Earthquake would cause unacceptable damage in reinforced concrete structures. In this paper, two retrofitting methods based on alternative load path are proposed for the reinforced concrete structure. One method is to add steel braces to the structure, and another one is to add tension cables to the structure. Pushover analyses for all frames are carried out using SAP2000. From the analysis results, steel braces or tension cables delay the formation of the first plastic hinge and failure of columns, and can better improve the seismic performance of reinforced concrete frame. The research results can be utilized for displacement-based seismic design and seismic performance evaluation of RC structures.

scholarly journals Trends in the development of composite reinforced concrete structures of pedestrian aboveground overpasses

2021 ◽  
Vol 274 ◽  
pp. 02006
Author(s):  
Valery Eremeev ◽  
Gennady Shmelev ◽  
Pavel Eremeev ◽  
Daniil Eremeev
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Road Construction ◽  
Concrete Bridges ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Structure ◽  
Dynamic Component ◽  
The Road ◽  
Pedestrian Bridges ◽  
The Difference

Pedestrian bridges are an important part of the urban infrastructure that ensures the safety and comfort of pedestrians. They have a number of distinctive features compared to road bridges. Also, the pedestrian load itself has a significant dynamic component, which can lead to the occurrence of resonant phenomena. Composite reinforced concrete bridges are widely used among the road bridges. This is due to the possibility of including the roadway structure in the act, which increases the load-bearing capacity and reliability of the structure. The same advantages are typical for pedestrian aboveground overpasses. However, pedestrian bridges have a number of features that affect the operation of the composite reinforced concrete structure. It is well-known that the difference between bending structures in civil construction and bending structures in bridge and road construction is the ratio of the rigidness of the concrete and steel parts. The load on pedestrian aboveground overpasses is similar to the temporary load in civil buildings, adjusted for a large dynamic component. But at the same time, the spans of pedestrian aboveground overpasses are similar to the spans of road bridges. In this article, the prospects for the development of composite reinforced concrete structures of pedestrian overpasses are reviewed.

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