scholarly journals Testing and Prediction of Shear Performance for Steel Fiber Reinforced Expanded-Shale Lightweight Concrete Beams without Web Reinforcements

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1594 ◽  
Author(s):  
Xiaoke Li ◽  
Changyong Li ◽  
Minglei Zhao ◽  
Hui Yang ◽  
Siyi Zhou
Keyword(s):  
Steel Fiber ◽  
Lightweight Concrete ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Cracking Resistance ◽  
Shear Performance ◽  
Shear Cracking ◽  
Expanded Shale

In this paper, for a wide application of high-performance steel fiber reinforced expanded-shale lightweight concrete (SFRELC) in structures, the shear behavior of reinforced SFRELC beams without web reinforcements was experimentally investigated under a four-point bending test. Twenty-six beams were fabricated considering the influencing parameters of SFRELC strength, shear-span to depth ratio, longitudinal reinforcement ratio and the volume fraction of the steel fiber. The statistical analyses based on the foundational design principles and the experimental results are made based on the shear cracking resistance, the shear crack distribution and width, the mid-span deflection, the patterns of shear failure, and the shear capacity of the specimens. This confirms the effective strengthening of steel fibers on the shear performance of reinforced SFRELC beams without web reinforcements. Based on the modifications to the formulas of reinforced conventional concrete, lightweight-aggregate concrete or steel fiber reinforced concrete (SFRC) beams, and the validation against the experimental findings, formulas are proposed for the prediction of shear cracking resistance and shear capacity of reinforced SFRELC beams without web reinforcements. Finally, formulas are discussed for the reliable design of the shear capacity of reinforced SFRELC beams without web reinforcements.

scholarly journals Effect of Steel Fiber Content on Shear Behavior of Reinforced Expanded-Shale Lightweight Concrete Beams with Stirrups

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1107
Author(s):  
Changyong Li ◽  
Minglei Zhao ◽  
Xiaoyan Zhang ◽  
Jie Li ◽  
Xiaoke Li ◽  
...  
Keyword(s):  
Crack Width ◽  
Failure Modes ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Shear Crack ◽  
Shear Capacity ◽  
Shear Cracks ◽  
Shear Cracking ◽  
Expanded Shale

To determine the validity of steel fiber reinforced expanded-shale lightweight concrete (SFRELC) applied in structures, the shear behavior of SFRELC structural components needs to be understood. In this paper, four-point bending tests were carried out on reinforced SFRELC beams with stirrups and a varying volume fraction of steel fiber from 0.4% to 1.6%. The shear cracking force, shear crack width and distribution pattern, mid-span deflection, and failure modes of test beams were recorded. Results indicate that the shear failure modes of reinforced SFRELC beams with stirrups were modified from brittle to ductile and could be transferred to the flexure mode with the increasing volume fraction of steel fiber. The coupling of steel fibers with stirrups contributed to the shear cracking force and the shear capacity provided by the SFRELC, and it improved the distribution of shear cracks. At the limit loading level of beams in building structures at serviceability, the maximum width of shear cracks could be controlled within 0.3 mm and 0.2 mm with the volume fraction of steel fiber increased from 0.4% to 0.8%. Finally, the formulas are proposed for the prediction of shear-cracking force, shear crack width, and shear capacity of reinforced SFRELC beams with stirrups.

scholarly journals A Novel Feature Selection Approach Based on Tree Models for Evaluating the Punching Shear Capacity of Steel Fiber-Reinforced Concrete Flat Slabs

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3902 ◽  
Author(s):  
Shasha Lu ◽  
Mohammadreza Koopialipoor ◽  
Panagiotis G. Asteris ◽  
Maziyar Bahri ◽  
Danial Jahed Armaghani
Keyword(s):  
Feature Selection ◽  
Reinforced Concrete ◽  
Predictive Models ◽  
Steel Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Punching Shear ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Flat Slabs

When designing flat slabs made of steel fiber-reinforced concrete (SFRC), it is very important to predict their punching shear capacity accurately. The use of machine learning seems to be a great way to improve the accuracy of empirical equations currently used in this field. Accordingly, this study utilized tree predictive models (i.e., random forest (RF), random tree (RT), and classification and regression trees (CART)) as well as a novel feature selection (FS) technique to introduce a new model capable of estimating the punching shear capacity of the SFRC flat slabs. Furthermore, to automatically create the structure of the predictive models, the current study employed a sequential algorithm of the FS model. In order to perform the training stage for the proposed models, a dataset consisting of 140 samples with six influential components (i.e., the depth of the slab, the effective depth of the slab, the length of the column, the compressive strength of the concrete, the reinforcement ratio, and the fiber volume) were collected from the relevant literature. Afterward, the sequential FS models were trained and verified using the above-mentioned database. To evaluate the accuracy of the proposed models for both testing and training datasets, various statistical indices, including the coefficient of determination (R2) and root mean square error (RMSE), were utilized. The results obtained from the experiments indicated that the FS-RT model outperformed FS-RF and FS-CART models in terms of prediction accuracy. The range of R2 and RMSE values were obtained as 0.9476–0.9831 and 14.4965–24.9310, respectively; in this regard, the FS-RT hybrid technique demonstrated the best performance. It was concluded that the three hybrid techniques proposed in this paper, i.e., FS-RT, FS-RF, and FS-CART, could be applied to predicting SFRC flat slabs.

scholarly journals Failure mode in shear of steel fiber reinforced concrete beams

2018 ◽  
Vol 163 ◽  
pp. 02003 ◽  
Author(s):  
Julita Krassowska ◽  
Marta Kosior-Kazberuk
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Fibre Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Steel Fibres

Experimental tests were carried out to assess the failure model of steel fiber reinforced concrete beams. Experimental research was focused on observing changes in the behavior of the tested elements depending on the amount of shear reinforcement and the fiber. Model two-span beams with a cross-section of 80x180 mm and a length of 2000 mm were tested. The beams had varied stirrup spacing. The following amounts of steel fibres in concrete were used: 78.5 kg/m3 (1.0%) i 118 kg/m3 (1.5%). Concrete beams without fibres were examined at the same time. The beams were loaded in a five-point bending test until they were destroyed. Shear or bending capacity of the element was observed. Fibre reinforced concrete beams were not destroyed rapidly, but they kept their shape consistent under load. Larger number of diagonal cracks with a smaller width were observed in fibre reinforced concrete beams. Failure of concrete beams without fibres was rapid, with a characteristic brittle cracking. Steel fibres revealed the ability to transfer significant shear stress after cracking in comparison to plain concrete.

Shear capacity of cast-in headed anchors in steel fiber-reinforced concrete

2018 ◽  
Vol 171 ◽  
pp. 421-432 ◽  
Author(s):  
Jong-Han Lee ◽  
Baiksoon Cho ◽  
Jae-Bong Kim ◽  
Kun-Joon Lee ◽  
Chi-Young Jung
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

scholarly journals TENSILE BEHAVIOUR OF ULTRA-HIGH-PERFORMANCE STEEL FIBER REINFORCED CONCRETE

2020 ◽  
Author(s):  
Yuechen Yang ◽  
Mohammed Ismail ◽  
Stavroula Pantazopoulou ◽  
Dan Palermo
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Tensile Behaviour ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Splitting Test ◽  
High Performance Steel

Recent developments in the area of Ultra-High-Performance Steel Fiber Reinforced Concrete (UHP-SFRC) enables reduction in steel reinforcement, and has led to enhanced ductility and toughness of structural components owing to its resilient tensile behaviour. This paper presents the results of an experimental study conducted to investigate the tensile behaviour of UHP-SFRC. Four commercial mixes and two in-house mixes were evaluated using the procedures prescribed in the 2018 edition of Annex 8.1 of CSA-S6. Tensile strength of UHP-SFRC was quantified and correlated through the direct tension test, splitting test, inverse analysis of four-point bending test using either code expressions or nonlinear finite element analysis, and a calibrated empirical expression that links this property to the cylinder compressive strength. In addition, the effect of important parameters on flexural strength including casting methodology, volumetric ratio of steel fibers, and aspect ratio (shear span to depth ratio) of bending prisms have been assessed.

Experimental Study on Shear Capacity of Prestressed SFRC Beams

2012 ◽  
Vol 256-259 ◽  
pp. 926-929
Author(s):  
Li Bing Jin ◽  
De Cai Chen ◽  
Ji Peng Qi
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Enhancement Effect ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Factors Affecting

In order to study the shear capacity enhancement effect of prestressed technology to steel fiber reinforced concrete, the practical formulas were proposed for evaluating the shear-strength of unbonded prestressed steel-fiber reinforced concrete beams (UPSFRCB) through the test and study of shear capacity of UPSFRCB with simply supported ends. Various factors affecting the shear strength of UPSFRCB, such as steel fiber, prestress and shear-span to depth ratio were analyzed. The result is of importance to the popularization and application of prestressed steel-fiber reinforced concrete.

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