scholarly journals A review of literature and code requirements for the crack width limitations for design of concrete structures in serviceability limit states

2019 ◽  
Vol 20 (2) ◽  
pp. 678-688 ◽  
Author(s):  
Mikael Basteskår ◽  
Morten Engen ◽  
Terje Kanstad ◽  
Kjell T. Fosså
Keyword(s):  
Crack Width ◽  
Concrete Structures ◽  
Review Of Literature ◽  
Limit States

Anchorages of stirrups under transverse tension in concrete - development of a design model

2019 ◽  
Author(s):  
Mirhat Medziti ◽  
Daia Zwicky
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Tensile Force ◽  
Concrete Structures ◽  
Experimental Tests ◽  
Reinforced Concrete Beams ◽  
Design Model ◽  
Hook Effect ◽  
Internal Forces ◽  
Negative Bending

<p>According to Swiss code SIA 262 "Concrete structures", stirrups of reinforced concrete beams must "surround the tensile longitudinal reinforcement" and must "be anchored to mobilize the static height of internal forces". For existing concrete structures, Swiss code SIA 269/2 provides stirrup detailing requirements while limiting these directives for stirrup anchorage to the compression zone. In zones of negative bending, these requirements are often not satisfied for execution reasons. This question is addressed in a largely experimental Ra&amp;D project. Anchorage tests were performed and analyzed, with a total of 144 tests on 9 concrete beams. These underwent a longitudinal tensile force up to 1’000 kN to simulate transverse cracking at stirrup anchorages in negative flexure zones. The study parameters are crack width (0, 0.4 and 0.9 mm), stirrup diameter (10 and 14 mm), bar ribbing (smooth and ribbed) and hook angle (90°, 135°, 180° and straight bars). A design model based on the "tension chord model" (TCM) developed at ETH Zurich is proposed. This simple and practical design model has proved ist effectiveness to consider bond effects. Reduction factors for bar diameter (k<sub>Ø</sub>), relative bar ribbing (k<sub>fR</sub>), hook effect (k<sub>θ</sub>) and crack width (k<sub>w</sub>) were taken into account for calibration. Results of analytical calculations are coherent with experimental tests.</p>

Crack width calculation methods for large-scale concrete structures for the Ferry-Free E39

2018 ◽  
Author(s):  
Reignard Tan ◽  
Terje Kanstad ◽  
Mette R. Geiker ◽  
Max A. N. Hendriks
Keyword(s):  
Cross Sections ◽  
Calculation Method ◽  
Crack Width ◽  
Large Scale ◽  
Concrete Structures ◽  
Calculation Methods ◽  
Empirical Formulas ◽  
Eurocode 2 ◽  
Semi Empirical

<p>Motivated by the establishment of a Ferry-Free E39 coastal highway route, crack width calculation methods for design of large-scale concrete structures are discussed. It is argued that the current semi-empirical formulas recommended by Eurocode 2 is inconsistent and overly conservative for cross sections with large bar diameters and covers. A suggestion to formulating a more consistent crack width calculation method is given.</p>

scholarly journals Experimental study of the influence of crack width due to corrosion behaviour using different measurement methods and different exposures

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Corrosion Behaviour ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Surface Corrosion ◽  
Potential Mapping

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.

Service Life of Concrete Structures

2020 ◽  
Vol 309 ◽  
pp. 267-271
Author(s):  
Milan Holicky ◽  
Jiří Kolísko
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Limit State ◽  
Concrete Structures ◽  
Technical Specification ◽  
Working Life ◽  
Degradation Process ◽  
International Standards ◽  
Limit States ◽  
Existing Structures

The concept of service life of structures is included in international standards ISO (under the term Design Working Life), in the European document EN 1990 (Design Service Life) and in the upcoming document CEN for assessment of existing structures - Technical Specification TS (Remaining Working Life). The mentioned documents contain mainly material-independent provisions for the design and assessment of all types of structures and for any category of actions. The submitted paper includes the definition of service life (performance time) tser, which is extended for any concrete structure, considering the resistance of a structure R(t) and the effect of action S(t). Both the aggregate variables R(t) and S(t) are usually random variables significantly dependent on time t. Due to the random variability of the variables R(t) and S(t), the service life tser, needs to be related to the probability that the performance of the structure is weakened or completely eliminated. Basically, serviceability limit states (SLS) and ultimate limit states (ULS) should be considered. In the case of concrete structures another limit state corresponding to the beginning of a specific degradation process (corrosion of reinforcement), denoted tinit, may be important. In specific cases of buildings and bridges a functional (moral) service life may be taken into account. The paper includes also a practical example of assessing the remaining working life of a concrete structure.

Chloride Ion Penetrability of HPFRCC after Loading

2014 ◽  
Vol 507 ◽  
pp. 242-244
Author(s):  
Kyung Joon Shin
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
High Performance Fiber ◽  
Inherent Problem ◽  
Durability Performance

Cracking is one of the most important factors in the serviceability as well as durability performance of concrete structures. Recently, it was recognized that a high performance fiber-reinforced cementitious composite (HPFRCC) provides a possible solution to this inherent problem of cracking by smearing one or several dominant cracks into many distributed microcracks. The purpose of the present study is to explore the ductility characteristics of HPFRCC. The permeability of HPFRCC after subjected to different load levels were measured to identify the effect of reduced cracking among the mixtures. It was confined that the permeability of proposed mixtures was lower than that without microfibers. This means that the proposed materials can reduce the crack width greatly at the same applied loads

Crack width monitoring of concrete structures based on smart film

2014 ◽  
Vol 23 (4) ◽  
pp. 045031 ◽  
Author(s):  
Benniu Zhang ◽  
Shuliang Wang ◽  
Xingxing Li ◽  
Xu Zhang ◽  
Guang Yang ◽  
...  
Keyword(s):  
Crack Width ◽  
Concrete Structures
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