scholarly journals Assessment of Destructive Impact of Different Factors on Concrete Structures Durability

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 225
Author(s):  
Janusz R. Krentowski
Keyword(s):  
Concrete Structures ◽  
Wood Dust ◽  
Engineering Practice ◽  
Dust Explosion ◽  
Construction Process ◽  
Safety Hazards ◽  
Building Conditions ◽  
Case Methods ◽  
Prestressed Girders ◽  
Temperature Load

The durability of concrete structure members is dependent on several factors that should be analyzed at each stage of the construction process. Omitting any of these factors might lead to the augmentation of harmful interactions and, as an effect, to safety hazards and the degradation of a structure or its parts. The article, based on several years of studies on exploited concrete structures, presents the effects of an incorrect analysis of selected factors resulting in the occurrence of faults significantly influencing the possibility of safe use of the objects. The described cases include, but are not limited to, the consequences of an improper assessment of building conditions after a biogas explosion in a fermentation chamber, the effect of a wood dust explosion, fire temperature and firefighting action on the prestressed girders, the stages of degradation of bearing structures supporting gas tanks exploited in an aggressive environment, and the consequences of omitting the temperature load in relation to the upper surface of a plate covering the fire pond. In each case, methods of restoration of the damaged elements were proposed, and their application to engineering practice was described. The practical aspects of the conducted research and implemented interventions were indicated.

scholarly journals Lumped damage mechanics as a diagnosis tool of reinforced concrete structures in service: case studies of a former bridge arch and a balcony slab

2021 ◽  
Vol 15 (58) ◽  
pp. 21-32
Author(s):  
Rafael Cunha ◽  
Camila Vieira ◽  
David Amorim
Keyword(s):  
Reinforced Concrete ◽  
Case Studies ◽  
Damage Mechanics ◽  
Low Cost ◽  
Concrete Structures ◽  
Structural Condition ◽  
Numerical Analyses ◽  
Engineering Practice ◽  
Reinforced Concrete Structures ◽  
Diagnosis Tool

Reinforced concrete structures may need repair in order to ensure the designed durability. Such necessity vary in cause and effect, but the structural diagnosis serves as the basis for adopting intervention measures. The assessment of the structural condition usually is made in loco, but sometimes numerical analyses are required as a low cost and effective preliminary diagnosis. In general, numerical analyses use hundreds or thousands of finite elements and nonlinear theories that are not often used in engineering practice. As an alternative, lumped damage mechanics (LDM) uses key concepts of classic fracture and damage mechanics in plastic hinges throughout well-known quantities such as ultimate moment and cracking moment. Such theory describes the concrete cracking by a damage variable, which can be used as a diagnosis criterion. Therefore, this paper presents LDM as a diagnosis tool to analyse actual structures. The case studies presented in this paper are a former bridge arch tested in China and a balcony that collapsed in Brazil. The results show that LDM numerical response of those structures are quite close to laboratory observations (former bridge arch) and in loco measurements (balcony).

Research on Measure-Control Technology of Large-Span Suspendome during Construction Period

2011 ◽  
Vol 105-107 ◽  
pp. 2010-2014
Author(s):  
Yong Quan Wang ◽  
Zheng Xing Guo ◽  
Bin Luo
Keyword(s):  
Steel Structure ◽  
Internal Force ◽  
Test Methods ◽  
Engineering Practice ◽  
Control Methods ◽  
Construction Process ◽  
Construction Period ◽  
Large Span ◽  
Axial Forces ◽  
Construction Mechanics

In order to ensure the prestress establishment of large-span suspendome, research on the measure-control methods for large-span suspendome during prestress construction process is performed, by summarizing the existing measure and test methods. According to engineering practice at present, the paper classifies the measure-control content of large-span suspendome during prestress construction period into two parts: internal force of cable-strut and deformation of steel structure. Taking practical project of a gymnasium as an example, the axial forces of hoop cables, radial steel tie rods and struts are measured, and also the verticality of struts. The test results are analyzed, and compared with the calculated value. The results show that, the internal forces of cable-strut and verticality of struts can both meet the design requirement, by mechanical analyzing and precise monitoring of the whole prestress construction process. The conclusion is that, before the prestress construction of large-span suspendome, construction mechanics analysis must be carried out in details to determine the control content and its target value, right measure-control methods are chosen, and then the effective establishment of prestress can be achieved.

scholarly journals Crack detection using modified spectral clustering method assisted with FE analysis for distress anticipation in cement-based composites

2021 ◽  
Author(s):  
Ajitanshu Vedrtnam ◽  
Santosh Kumar ◽  
Gonzalo Barluenga ◽  
Shashikant Chaturvedi
Keyword(s):  
Crack Propagation ◽  
Real Time ◽  
Crack Detection ◽  
Compressive Loading ◽  
Concrete Structures ◽  
Spatial Relationship ◽  
Fracture Pattern ◽  
Wood Dust ◽  
Compression Tests ◽  
Fe Modelling

Abstract The present work aimed to develop an efficient way of capturing real-time crack propagation in concrete structures. The image processing was utilized for crack detection, while finite element modeling (FEM) and scanning electron microscopy (SEM) were used for quantitative and qualitative analysis of crack propagation. A green cement-based composite (CBC) containing saw dust was compared to a reference M20 grade concrete under compressive loading. Crack propagation during compression tests was captured using an 8-megapixel mobile phone camera. The randomly selected images showing crack initiation and propagation in CBCs were used to assess the crack capturing capability of a spectral analysis based algorithm. A measure of oriented energy was provided at crack edges to develop a similarity spatial relationship among the pairwise pixels. FE modelling was used for distress anticipation, by analyzing stresses during the compressive test in constituents of CBCs. SEM analyses were also done to evaluate cracked samples. It was found that FE modeling could predict the crack prone regions that can be used jointly with the image analysis algorithm, providing real-time inputs from the crack-prone areas. Green CBC were compared to reference concrete samples, showing reliable results. The replacement of OPC with wood dust reduced compression strength and produced a different fracture pattern regarding reference concrete. The results of the study can be used for distress anticipation and early crack detection of concrete structures for preventive support and management.

Displacement Back Analysis Based on Differential Evolution Algorithm in Metro Station Engineering

2011 ◽  
Vol 55-57 ◽  
pp. 527-532
Author(s):  
An Nan Jiang ◽  
Jun Xiang Wang
Keyword(s):  
Differential Evolution ◽  
Differential Evolution Algorithm ◽  
Back Analysis ◽  
Engineering Practice ◽  
Construction Process ◽  
Analysis Program ◽  
Global Optimization Algorithm ◽  
Metro Station ◽  
Displacement Back Analysis ◽  
Evolution Algorithm

In this paper differential evolution algorithm (DE) which is a new global optimization algorithm is introduced into the displacement back analysis, and the self-developed back analysis program based on DE is used in metro station engineering. The results show that the superiority of DE and the practicability of intelligent displacement back analysis program, more importantly, it is being applied to engineering practice to provide reference and advanced prediction for the construction process.

scholarly journals Experimental Study on Anchorage Performance of Steel Bars with FRP Confined Rings

2018 ◽  
Vol 175 ◽  
pp. 01037
Author(s):  
Qiao Jin ◽  
Jinglong Li ◽  
Meng Gao ◽  
Xuebin Wen ◽  
Zeming Zhao
Keyword(s):  
Concrete Structures ◽  
Tensile Tests ◽  
Construction Process ◽  
Grouting Material ◽  
Steel Bar ◽  
Steel Bars ◽  
Local Destruction ◽  
Reliable Performance ◽  
Static Tensile ◽  
Restrained Ring

In order to study the performance of reinforcement anchorage connection with FRP restrained ring, static tensile tests were carried out on 66 specimens, The main parameters considered in the test such as the diameter of steel bars, the diameter and thickness of the restraint ring, the strength of concrete and the length of anchorage. The result shows that the anchorage performance of the steel bar can still be guaranteed even if the anchorage length reaches 0.8la, There is no slip and local destruction phenomenon between FRP restraint ring and internal grouting material and peripheral concrete. The study conclusions also indirectly prove that the proposed technique is a reinforcement connection method for fabricated concrete structures with many good performances including the reliable performance, simple construction process and good economic benefit, which is suitable for construction industrialization of prefabricated reinforced concrete structures..

The Research of the Governance of Instability Retaining Wall

2014 ◽  
Vol 1065-1069 ◽  
pp. 85-88
Author(s):  
Gang Qiu ◽  
Xin Sheng Ge
Keyword(s):  
Retaining Wall ◽  
Retaining Walls ◽  
Design Parameters ◽  
Engineering Practice ◽  
Construction Process ◽  
Reinforcement Scheme ◽  
Soil Nail ◽  
Joint Construction ◽  
Jet Grouting ◽  
Pavement Reinforcement

According to retaining walls of joint construction buildings and office building of the mine of three yuan weizi town, outdoor pavement reinforcement of engineering practice, introduced the design parameters and construction process of the high-pressure jet grouting pile, soil nail wall and drilling grouting, the results showed that reinforcement scheme is reasonable and feasible, there is reference to other similar projects.

Kostenstufen der Betonsanierung, oder warum es nicht immer besser ist, sofort zu sanieren / Stages of expenses for restoration of concrete structures, or why it is not always the best solution to restore immediately

1999 ◽  
Vol 5 (4) ◽  
pp. 359-386
Author(s):  
R. Wolfseher
Keyword(s):  
Surface Treatment ◽  
Concrete Structures ◽  
The Other ◽  
Optimal Time ◽  
Actual State ◽  
Construction Process ◽  
Different Types ◽  
The One ◽  
The Right ◽  
Bearing Structure

Abstract Restoration of concrete structures implies repair of damage and a surface treatment which prevents future damage of the load bearing structure in case it is renewed in time. Depending on the performance of the protective surface treatment the substrate has to be prepared more or less carefully. On the one hand it is worth while to apply an inexpensive solution appropriate for a given situation and on the other hand to predict the optimal time for a necessary intervention. Different types of surface treatments can be attributed to discrete stages of expenses. In this contribution it is shown that based on a reliable analysis of the actual state, the cheapest type of restoration can be found in an unambiguous way and executed at the right moment. At the end examples are given. The necessary investment can be optimized. Finally, it will be underlined that money spent for quality control during the construction process can be considered to be an investment yielding 17% interest.

The Characteristics and Construction of CFG Pile Composite Foundation

2015 ◽  
Vol 744-746 ◽  
pp. 656-659
Author(s):  
Su Qing Cao ◽  
Mei Yang ◽  
Xiao Fei Xin
Keyword(s):  
Composite Foundation ◽  
Engineering Practice ◽  
Construction Technology ◽  
Construction Process ◽  
Treatment Scheme ◽  
Engineering Characteristics ◽  
Cfg Pile Composite Foundation ◽  
Cfg Pile

This paper expounded the engineering characteristics and construction technology of CFG pile composite foundation, introduced the construction process of CFG pile and main points for attention, and proved that CFG pile treatment scheme is practical and feasible combined with the engineering practice.

Monitoring carbon steel behavior under biotic and abiotic conditions

2015 ◽  
Vol 1768 ◽  
Author(s):  
E.J. León ◽  
D.A. Koleva ◽  
H.M. Jonkers ◽  
J.M.C. Mol ◽  
H. Terryn ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Steel ◽  
Common Knowledge ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Engineering Practice ◽  
Reinforced Concrete Structures ◽  
Initial Surface ◽  
Abiotic Conditions ◽  
Simulated Environment

ABSTRACTDeterioration of concrete structures, together with corrosion of reinforcing steel due to the action of microorganisms, is known as Microbiologically Induced Corrosion of Concrete (MICC). The activity of microorganisms can initiate and further accelerate both steel corrosion and cement-based matrix degradation in reinforced concrete structures. The mechanism is related to initial surface colonization and further bio-products (and aggressive substance respectively) penetration into the bulk concrete matrix, reaching the reinforcement level. Common knowledge is that bio-deterioration-related infrastructure degradation, maintenance and repair have a significant economic impact worldwide. However, due to the complexity of all related mechanisms, a durable and feasible solution is still to be achieved for the engineering practice. This paper briefly points out main bio-degradation related mechanisms for concrete, steel and reinforced concrete structures and presents results on the electrochemical response of carbon steel in simulated environment under biotic and abiotic conditions.

scholarly journals The Modelling of Digital Twins Technology in the Construction Process of Prefabricated Buildings

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yun Zhou ◽  
Xiao Wei ◽  
Ying Peng
Keyword(s):  
Building Construction ◽  
Construction Process ◽  
Safety Hazards ◽  
Building Information Modelling ◽  
Information Modelling ◽  
Maximum Value ◽  
Digital Twins ◽  
Potential Safety ◽  
Building Information ◽  
Building Components

In the process of building construction, traditional architectural design and construction methods take a long time. The built buildings perform poorly in terms of energy usage and energy conservation. The study expects to explore the potential safety hazards of prefabricated buildings during the construction process. On this basis, a modelling study of the construction process is carried out. The study uses Digital Twins (DTs) technology and prefabricated Building Information Modelling (BIM) to conduct in-depth modelling research on the building construction process. The prefabricated building construction system oriented to DTs technology can well solve the problems of structural damage and deformation in the production, transportation, and assembly process of building components. Especially in prefabricated buildings, it can monitor and accurately predict the damage of building components that may occur in the entire system due to structural problems and material problems in real time. Regarding the building information model, the study uses third-party software to transfer the assembly information to the network cloud to further realize the display of the BIM. The study shows that the maximum value of the effective risk cases selected is 130, and its effective rate is 100%; after processing the data, it is found that the initial value is always stable, and its value is 1; the extracted value is always changing, the maximum value is 0.86, and the minimum is 0.75. By this result, the conclusion is that DTs technology and BIM can effectively monitor the indicators of risk problems during the construction of prefabricated buildings and can further reduce potential safety hazards. Through building information modelling, the development of intelligent industrialization of building construction design and the in-depth study of construction modelling has practical application value.

Sign in / Sign up

Export Citation Format

Share Document