scholarly journals Flexural Behavior of Continuous Beams Made of Self-Compacting Concrete (SCC)—Experimental and Numerical Analysis

2020 ◽  
Vol 10 (23) ◽  
pp. 8654
Author(s):  
Žarko Petrović ◽  
Bojan Milošević ◽  
Andrija Zorić ◽  
Slobodan Ranković ◽  
Biljana Mladenović ◽  
...  
Keyword(s):  
Flexural Behavior ◽  
Engineering Practice ◽  
Structural Elements ◽  
Self Compacting Concrete ◽  
Short Term ◽  
Element Analysis ◽  
Flexural Performance ◽  
Continuous Beams ◽  
Standard Software ◽  
Nonlinear Numerical Model

Self-compacting concrete (SCC) is a type of concrete that is placed in the formwork under its own weight. Although there are many studies showing the behavior of SCC beams, most relate to the behavior of simple supported beams. Unlike those, this is a study of continuous beams made of SCC aimed to analyze their flexural performance as well as to confirm the possibility of using nonlinear finite element analysis (FEA) in the design of such structural elements. An experimental study of three two-span continuous beams of a total length of 3400 mm, with the span between supports of 1600 mm, with 150/200 mm cross section made of SCC exposed to short-term loading, was carried out. The parameter that varied is the percentage of tensile reinforcement, with values of 0.65, 0.86 and 0.94 being selected. As all analyzed beams have shown a satisfactory load-bearing capacity and stiffness, the research confirmed the possibility of using SCC in continuous beams in civil engineering practice. Using Abaqus/Standard software, a nonlinear numerical model is proposed, which is validated and verified against experimental research, as there is only a 5% difference in the numerically calculated ultimate load compared to the experimentally measured values.

scholarly journals Experimental Analysis of Continuous Beams Made of Self-Compacting Concrete (Scc) Strengthened with Fiber Reinforced Polymer (Frp) Materials

2021 ◽  
Vol 11 (9) ◽  
pp. 4032
Author(s):  
Žarko Petrović ◽  
Bojan Milošević ◽  
Slobodan Ranković ◽  
Biljana Mladenović ◽  
Dragan Zlatkov ◽  
...  
Keyword(s):  
Experimental Analysis ◽  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Flexural Behavior ◽  
Engineering Practice ◽  
Fiber Reinforced ◽  
Self Compacting Concrete ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Continuous Beams

Strengthening of concrete structures is applied as a solution for various deterioration problems in civil engineering practice. This also refers to the structures made of self-compacting concrete (SCC), which is increasingly in use, but there is a lack of research in this field. This paper presents an experimental analysis of flexural behavior of reinforced concrete (RC) continuous beams made of SCC, strengthened with fiber reinforced polymer (FRP) materials (glass (GFRP) and carbon (CFRP) bars, CFRP laminates), by the use of near surface mounted (NSM) and externally bonded (EB) methods. Six two-span continuous beams of a total length of 3200 mm, with the span between supports of 1500 mm and 120/200 mm cross section, were subjected to short-term load and tested. The displacements of beams and the strains in concrete, steel reinforcement, FRP bars and tapes were recorded until failure under a monotonically increasing load. The ultimate load capacities of the strengthened beams were enhanced by 22% to 82% compared to the unstrengthened control beam. The ductility of beams strengthened with GFRP bars was satisfactory, while the ductility of beams strengthened with CFRP bars and tapes was very small, so the failure modes of these beams were brittle.

scholarly journals Study on flexural performance of prestressed glulam continuous beams under control influence

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Lidan Mei ◽  
Nan Guo ◽  
Ling Li ◽  
Hongliang Zuo ◽  
Yan Zhao
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Steel Wire ◽  
Material Strength ◽  
Element Analysis ◽  
Control Range ◽  
Flexural Performance ◽  
Continuous Beams

AbstractTraditional glulam beam connection mode has a weak ability to transfer bending moment, leading to insufficient joint stiffness and mostly in the form of simply supported beams. To make full use of material strength, a novel prestressed glulam continuous beam was proposed. On this basis, this paper put forward a new method to further improve the mechanical performance of the beams by controlling prestress. According to the estimated ultimate loads of the beams, six different control range values were formulated, and 12 continuous beams were tested for flexural performance. The effects of prestressing control on the failure modes, ultimate load capacity, and load versus deformation relationships of the glulam continuous beams were analyzed. The test results indicated that the flexural performance of the beams with prestressed control was significantly improved compared to the uncontrolled beams, the ultimate load was enhanced by 13.60%–45.11%, and the average steel wire stress at failure was increased from 70% of the designed tensile strength to 94%. Combined with the finite element analysis (FEA), the reasonable control range of the prestressed control continuous beams was18%–30% of the estimated ultimate load. The research in this paper can provide references for the theoretical analysis and engineering application of similar structures.

scholarly journals Flexural Behavior of Reinforced Concrete Beams Retrofitted with Modularized Steel Plates

2021 ◽  
Vol 11 (5) ◽  
pp. 2348
Author(s):  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Maximum Load ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Flexural Behavior ◽  
Element Analysis ◽  
Flexural Performance ◽  
Structural Capacity

Many structural retrofitting methods tend to only focus on how to improve the strength and ductility of structural members. It is necessary for developing retrofitting strategy to consider not only upgrading the capacity but also achieving rapid and economical construction. In this paper, a new retrofitting details and technique is proposed to improve structural capacity and constructability for retrofitting reinforced concrete beams. The components of retrofitting are prefabricated, and the components are quickly assembled using bolts and chemical anchors on site. The details of modularized steel plates for retrofitting have been chosen based on the finite element analysis. To evaluate the structural performance of concrete beams retrofitted with the proposed details, five concrete beams with and without retrofitting were tested. The proposed retrofitting method significantly increased both the maximum load capacity and ductility of reinforced concrete beams. The test results showed that the flexural performance of the existing reinforced concrete beams increased by 3 times, the ductility by 2.5 times, and the energy dissipation capacity by 7 times.

scholarly journals Flexural Performance of Self Consolidating, Self Cured Concrete Beams -Incorporating Sap

2019 ◽  
Vol 8 (12) ◽  
pp. 1812-1816
Keyword(s):  
Internal Curing ◽  
Flexural Behavior ◽  
Crushed Rock ◽  
Fine Aggregate ◽  
Flow Properties ◽  
Self Compacting Concrete ◽  
Conventional Concrete ◽  
Ambient Temperatures ◽  
Flexural Performance ◽  
Passing Ability

Self- Compacting Concrete (SCC) is a sort of Concrete that possesses high flowing, passing ability, which can be placed and compacted due to its own weight without any peripheral compaction effort, at the same time it is cohesive enough to be handled without any segregation or bleeding distinctiveness. This Research Study presents an experimental exploration Flexural behavior of Internal cured Self Compacting Concrete (ICSCC) with fine aggregate substitution by Crushed Rock Fines (CRF) at 0%& 30%, with silica fume as supplementary for cementitious material. Mix Proportions for ICSCC, controlled specimens SCC and Normal Conventional Concrete (NCC) M40 grade is arrived. For each concrete mixes 150mm X 150mm x150mm cubes and 100 X230 X 1500mm beams were casted and exposed to internal curing at ambient temperatures for 7 and 28 days. The results arrived for ICSCC mixes were paralleled with controlled specimens of SCC and NCC. Appropriate materials were selected to have a better performance to ensure efficient internal curing in the concrete mass. The Flow Properties of SCC, ICSCC mixes have been performed as per EFNARC Stds and results of flow properties were within limits. Analysis made from the experimental exploration is accomplished that the Flexural characteristics for ICSCC mixes curried at ambient temperature found acceptable

scholarly journals Study on Flexural Performance of Concrete Beams Reinforced by Steel Fiber and Nano–SiO2 Materials

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 927
Author(s):  
Ke Shi ◽  
Mengyue Zhang ◽  
Tao Zhang ◽  
Ru Xue ◽  
Pengfei Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Flexural Behavior ◽  
Engineering Practice ◽  
Nano Sio2 ◽  
Flexural Performance ◽  
Practical Engineering ◽  
Novel Material

Steel fiber and Nano–SiO2 reinforced concrete is a novel material of concrete which has great potential to be used in practical engineering. However, there is relatively little literature available on the flexural behavior of steel fiber and Nano–SiO2 materials reinforced concrete (SFNMRC) beams. Hence, the main objective of this paper is to investigate the flexural performance of SFNMRC beams through combined experimental and theoretical studies. A total of 10 specimens were tested to investigate the flexural behavior and the effect of some key parameters, including concrete strength, the volume fraction of steel fiber, and the amount of Nano–SiO2. The load vs. deflection curves of SFNMRC beams during the whole loading process were analyzed in detail. The failure mode was discussed in detail, and the specimens all behaved in a very ductile manner. Furthermore, the test results indicated that bending cracks and concrete crushing were formed in the compression zone of all specimens. With the increase in concrete strength and the volume fraction of steel fiber, both the cracking load and ultimate load of beams increased. The amount of Nano–SiO2 had a limited effect on the flexure performance. Finally, the calculation formula for predicting the flexural bearing capacity of SFNMRC beams was derived with consideration of the effect of steel fiber on the cracked sections after beam cracking. The predicted results show satisfactory agreement with both experimental results. The studies may provide a considerable reference for designing this type of structure in engineering practice.

Flexural Behavior of Steel Fiber Reinforced Self-Stressing Concrete in Continuous Systems

2011 ◽  
Vol 675-677 ◽  
pp. 705-708
Author(s):  
Bo Xin Wang ◽  
Huan An He
Keyword(s):  
Steel Fiber ◽  
Flexural Behavior ◽  
Relative Deformation ◽  
Fiber Reinforced ◽  
Conventional Concrete ◽  
Model Experiments ◽  
Flexural Performance ◽  
Continuous Beams ◽  
Steel Bars ◽  
Joint Material

Steel Fiber Reinforced Self-stressing Concrete (SFRSSC for short) is a new type of high performance cementitious composite with self-expansive performance and high tensile resistance. It can be used as a joint material in the new bridge construction or the old bridge rehabilitation. Because when SFRSSC is restrained by steel bars and other terminal conditions, it can create chemical pre-stressing force to enhance the cracking moments of the continuous beams. For purpose of utilizing the properties of SFRSSC, the primary goal of this research is to apply SFRSSC as a joint material to build continuous bridges. Firstly, the model experiments of 8 continuous Tbeams with SFRSSC layers are carried out. Secondly, based on the model experiments, flexural performance of the beams reinforced by SFRSSC layers is investigated. Owing to enhancement of steel fibers and self-stress induced by steel bars, the layers greatly improve the first-crack strength and stiffness of the continuous T-beams. The test results obviously indicate that the composite SFRSSC-RC continuous T-beams enhance the crack moment 51.4%～121% more than conventional concrete continuous beams. Furthermore, SFRSSC can help cancel out the relative deformation and stress due to new concrete shrinkage between new and existing concrete during the process transforming simply supported beams into continuous beams. It is concluded that flexural performance of continuous T-beams strengthened by SFRSSC is more greatly improved than that strengthened by conventional concrete.

scholarly journals Subway Gearbox Fault Diagnosis Algorithm Based on Adaptive Spline Impact Suppression

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 660
Author(s):  
Zhongshuo Hu ◽  
Jianwei Yang ◽  
Dechen Yao ◽  
Jinhai Wang ◽  
Yongliang Bai
Keyword(s):  
Fault Diagnosis ◽  
Spline Interpolation ◽  
Reference Value ◽  
High Amplitude ◽  
Engineering Practice ◽  
Negative Effects ◽  
Short Term ◽  
Time Domain Signal ◽  
Gearbox Vibration ◽  
Long Time

In the signal processing of real subway vehicles, impacts between wheelsets and rail joint gaps have significant negative effects on the spectrum. This introduces great difficulties for the fault diagnosis of gearboxes. To solve this problem, this paper proposes an adaptive time-domain signal segmentation method that envelopes the original signal using a cubic spline interpolation. The peak values of the rail joint gap impacts are extracted to realize the adaptive segmentation of gearbox fault signals when the vehicle was moving at a uniform speed. A long-time and unsteady signal affected by wheel–rail impacts is segmented into multiple short-term, steady-state signals, which can suppress the high amplitude of the shock response signal. Finally, on this basis, multiple short-term sample signals are analyzed by time- and frequency-domain analyses and compared with the nonfaulty results. The results showed that the method can efficiently suppress the high-amplitude components of subway gearbox vibration signals and effectively extract the characteristics of weak faults due to uniform wear of the gearbox in the time and frequency domains. This provides reference value for the gearbox fault diagnosis in engineering practice.

Vibration-Based Crack Detection in L-Frames

2014 ◽  
Vol 658 ◽  
pp. 261-268
Author(s):  
Jean Louis Ntakpe ◽  
Gilbert Rainer Gillich ◽  
Florian Muntean ◽  
Zeno Iosif Praisach ◽  
Peter Lorenz
Keyword(s):  
Strain Energy ◽  
Crack Detection ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Structural Elements ◽  
Element Analysis ◽  
Accurate Localization ◽  
Mathematical Expressions ◽  
Measurement Results ◽  
Non Destructive

This paper presents a novel non-destructive method to locate and size damages in frame structures, performed by examining and interpreting changes in measured vibration response. The method bases on a relation, prior contrived by the authors, between the strain energy distribution in the structure for the transversal vibration modes and the modal changes (in terms of natural frequencies) due to damage. Using this relation a damage location indicator DLI was derived, which permits to locate cracks in spatial structures. In this paper an L-frame is considered for proving the applicability of this method. First the mathematical expressions for the modes shapes and their derivatives were determined and simulation result compared with that obtained by finite element analysis. Afterwards patterns characterizing damage locations were derived and compared with measurement results on the real structure; the DLI permitted accurate localization of any crack placed in the two structural elements.

Study on Influences of Thickness of Flange of U Rib on Mechanical Behaviors of Orthotropic Monolithic Steel Bridge Deck System

2010 ◽  
Vol 163-167 ◽  
pp. 122-126 ◽  
Author(s):  
Ru Deng Luo ◽  
Mei Xin Ye ◽  
Ye Zhi Zhang
Keyword(s):  
Finite Element Analysis ◽  
Yangtze River ◽  
High Speed ◽  
Bridge Deck ◽  
Steel Bridges ◽  
Engineering Practice ◽  
Steel Bridge ◽  
Mechanical Behaviors ◽  
Element Analysis ◽  
High Speed Railway

Orthotropic monolithic steel bridge deck system stiffened by U rib is very fit for high-speed railway steel bridges because of its excellent mechanical behaviors. Thickness of flange is a very important parameter of U rib and has influence on mechanical behaviors of orthotropic monolithic steel bridge deck system. Based on the engineering practice of Anqing Yangtze River Railway Grand Bridge, the kind and the extents of influences of thickness of flange of U rib on mechanical behaviors of orthotropic monolithic steel bridge deck system are studied with finite element analysis. The results show that thickness of flange of U rib has relative large positive influences on rigidity, strength and stability of orthotropic monolithic steel bridge deck system. 14~18mm is the appropriate range of thickness of flange of U rib for high-speed railway steel bridges.

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