scholarly journals Pullout performance of steel bars partially bonded in concrete with epoxy resin

2018 ◽  
Vol 11 (3) ◽  
pp. 598-619
Author(s):  
R. H. SOUZA ◽  
M. E. TAVARES ◽  
D. V. FERNANDES
Keyword(s):  
Epoxy Resin ◽  
Cast Steel ◽  
Steel Reinforcement ◽  
Reinforcing Bars ◽  
Structural Bonding ◽  
Test Parameters ◽  
Steel Bars ◽  
Existing Structure ◽  
Bar Diameter ◽  
Sizeable Reduction

Abstract The installation of new reinforcing bars onto an existing structure is a common practice in civil construction both for old and new structures. The use of anchors has been extensively studied and normalized. The placement of steel reinforcement bars in holes filled with epoxy resin, despite their wide use, still lacks a satisfactory methodology for the design of such systems. In this context, the aim of this paper is to present the results of an experimental programme for confined pullout tests, comparing the performance of cast steel reinforcement bars to that of bars bonded to concrete with epoxy resin. The investigated test parameters included the bar diameter, the embedment length and the resin thickness. Tests results showed a significant efficiency of epoxy resin as structural bonding agent and allowed the verification of sizeable reduction in the anchorage lengths for bonded bars.

scholarly journals Experimental Study on Bond Behavior between Plain Reinforcing Bars and Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guohua Xing ◽  
Cheng Zhou ◽  
Tao Wu ◽  
Boquan Liu
Keyword(s):  
Aluminium Alloy ◽  
Structural Characteristics ◽  
Bond Stress ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Bond Behavior ◽  
Reinforcing Bar ◽  
Test Parameters ◽  
Steel Bars ◽  
Plain Bars

To evaluate the bond behavior between the reinforcing bar and surrounding concrete, a total of six-group pullout specimens with plain steel bars and two-group specimens with deformed steel bars, serving as a reference, are experimentally investigated and presented in this study. The main test parameters of this investigation include embedment length, surface type of reinforcing bars, and bar diameter. In particular, the bond mechanism of plain steel reinforcing bars against the surrounding concrete was analyzed by comparing with six-group pullout specimens with aluminium alloy bars. The results indicated that the bond stress experienced by plain bars is quite lower than that of the deformed bars given equal structural characteristics and details. Averagely, plain bars appeared to develop only 18.3% of the bond stress of deformed bars. Differing from the bond strength of plain steel bars, which is based primarily on chemical adhesion and friction force, the bond stress of aluminium alloy bars is mainly experienced by chemical adhesion and about 0.21~0.56 MPa, which is just one-tenth of that of plain steel bars. Based on the test results, a bond-slip model at the interface between concrete and plain bars is put forward.

Repair of historic stone pagoda: Flexural behavior of granite reinforced with stainless steel bars

2020 ◽  
Vol 23 (11) ◽  
pp. 2431-2441
Author(s):  
Woo-Young Lim
Keyword(s):  
Stainless Steel ◽  
Epoxy Resin ◽  
Flexural Behavior ◽  
Test Results ◽  
Reinforcing Bars ◽  
Architectural Heritage ◽  
Steel Bars ◽  
Load Displacement ◽  
Relationship Of ◽  
Stone Pagoda

In the stone-made architectural heritage, one of the most widely used stones is granite. Given its superior material properties and abundant reserves, most Korean stone pagodas were built using granite. For the repair and restoration of the ancient stone pagoda made of granite, understanding of the structural behavior of reinforced granite is crucial. In this study, flexure tests for seven simply supported full-scale granite reinforced with stainless steel bars were conducted to investigate the failure mode and load–displacement relationship. Through the experiments, the feasibility of the suggested method for reinforcement of the damaged granite was also explored. Test specimens were manufactured after injecting epoxy resin by inserting stainless steel bars into the drilled holes, and then each granite substrate was bonded with adhesive epoxy resin. The test results showed that the load–displacement relationship of reinforced granite was highly dependent on the presence of the reinforcement, positioning of the reinforcing bars, and bond capacity of the reinforcing bars. Also, reinforcing bars significantly affected the deformation of the reinforced granite. Based on the test results, four distinct flexural responses of reinforced granite are presented.

Dynamic Behaviour of Reinforcing Steel Bars in Tension

2011 ◽  
Vol 82 ◽  
pp. 86-91 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Nicoletta Tesio
Keyword(s):  
Testing Machine ◽  
Maximum Load ◽  
Gauge Length ◽  
Strain Rates ◽  
Reinforcing Bars ◽  
Static Tests ◽  
Split Hopkinson Tensile Bar ◽  
Steel Bars ◽  
Split Hopkinson ◽  
Reinforced Steel

In this paper the preliminary results of the tensile behavior of reinforced steel in a large range of strain rates are presented. Tensile testing at several strain rates, using different experimental set-ups, was carried out. For the quasi-static tests a universal electromechanical testing machine with the maximum load-bearing capacity of 50 kN was used, while for the intermediate and high-strain rate regimes a hydro-pneumatic apparatus and a JRC-Split Hopkinson Tensile Bar respectively were used. The target strain rates were set at the following five levels: 10-3, 30, 250, 500, and 1000 1/s. The specimens used in this research were round samples having 3mm in diameter and 5mm of gauge length obtained from reinforcing bars. Finally, the material parameters for Cowper-Symonds and Johnson-Cook models were determined.

Study on Evaluation Method of Corroded Reinforcing Steel

2010 ◽  
Vol 26-28 ◽  
pp. 1184-1189 ◽  
Author(s):  
Ying Zi Zhang ◽  
Ying Fang Fan ◽  
Hong Nan Li ◽  
Xue Nan Wu
Keyword(s):  
Weight Loss ◽  
Energy Loss ◽  
Cross Section ◽  
Strain Energy ◽  
Evaluation Method ◽  
Reinforcing Bars ◽  
Reinforcing Bar ◽  
Important Index ◽  
Steel Bars ◽  
Strain Energy Loss

Corrosion ratio is an important index to study the mechanical deteriorates of the steel bars, which has a significant effect to evaluate the residual bearing capacity of reinforced concrete structures. To investigate the mechanical properties of the corroded steel bars, Strain energy loss as corrosion ratio is firstly proposed. Tensile test are conducted on ribbed and plain steels, which are corroded by acceleration corrosion method. Comparing with the weight loss and cross-section loss to describe the effect of corrosion of reinforcing bar, the strain energy loss of reinforcing bars is calculated by Simpson quadrature. Results from this paper and other researchers’ test suggest that the strain energy loss may be a better parameter than weight loss or section loss which to assess the corroded steel bars.

Experimental investigation of the role of reinforcement in the strength of concrete deck slabs

2000 ◽  
Vol 27 (3) ◽  
pp. 475-480 ◽  
Author(s):  
O Shervan Khanna ◽  
Aftab A Mufti ◽  
Baidar Bakht
Keyword(s):  
Steel Reinforcement ◽  
Scale Model ◽  
Transverse Reinforcement ◽  
Deck Slabs ◽  
Steel Bars ◽  
Failure Loads ◽  
Transverse Steel ◽  
Concrete Deck ◽  
Deck Slab

To study systematically the role of each layer of steel reinforcement in conventionally reinforced deck slabs of girder bridges, a full-scale model was built of a 175 mm thick concrete deck slab on two steel girders with a center-to-center spacing of 2.0 m. The 12 m long deck slab was conceptually divided into four 3 m long segments, identified as segments A, B, C, and D. Segment A contained isotropic steel reinforcement in two layers, conforming to the requirements of the Ontario Highway Bridge Design Code (OHBDC). Segment B contained only the bottom layer of steel reinforcement. Segment C contained only the bottom transverse steel bars. Segment D contained only bottom transverse glass fibre reinforced polymer (GFRP) bars having the same axial stiffness, but 8.6 times the axial tensile strength, as those of the steel bars in segment C. Each segment of the deck slab was tested to failure under a central concentrated load, simulating the dual tire footprint of 250 × 500 mm dimension of a typical commercial vehicle. All segments failed in the punching shear mode. The failure loads for the four segments were found to be 808, 792, 882, and 756 kN, respectively; these failure loads are similar in magnitude to that of a 175 mm thick steel-free deck slab with steel straps having nearly the same cross-sectional area per metre length of the slab as those of the bottom transverse steel bars in the first three segments. The tests on the four segments of the full-scale model have confirmed that (i) only the bottom transverse reinforcement influences the load carrying capacity of a reinforced concrete deck slab and (ii) the stiffness of the bottom transverse reinforcement, rather than its strength, is of paramount importance.Key words: arching, deck slab, FRP, shake down, slab-on-girder bridge.

Determination of Some Mechanical Properties of Welded Reinforcing Steel with Self-Shielded Wires by Vibration Tests

2014 ◽  
Vol 1029 ◽  
pp. 206-211 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Burcă ◽  
Raul Moisa ◽  
Dorin Simoiu ◽  
Gheorghe Drăgănescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welding Process ◽  
Steel Reinforcement ◽  
Reinforcing Steel ◽  
Coated Electrode ◽  
Major Disadvantage ◽  
Steel Bars ◽  
Vibration Tests ◽  
The Cost

Reinforced concrete is a material formed by pouring concrete over reinforcement steel bars and wires and sometimes by a polymer that turns by drying in a hard and rigid composite. Welding of steel reinforcement concrete is a relatively difficult operation and with a large amount of work, given by the large number of welds that are needed and when this work is make in site conditions. The most common method of steel reinforcement welding is manual welding with coated electrode. The major disadvantage of this process is low productivity in welding effects on execution time, and the cost of welding. An alternative to manual welding with coated electrode for steel reinforcement welding on site is the welding process with self-shielded tubular wires.The aim of this paper is to determine the mechanical properties of welded reinforcing steel PC 52 with self-shielded wires, using a vibroacustic technique. To validate this method, the results obtained by vibroacoustic signal processing are compared with those determined by the tensile stresses of the same samples.

Development of Splice Connections for Precast Concrete Structures

2014 ◽  
Vol 980 ◽  
pp. 132-136 ◽  
Author(s):  
Ahmad Baharuddin Abd Rahman ◽  
Jen Hua Ling ◽  
Zuhairi Abd Hamid ◽  
Mohd Hanim Osman ◽  
Shahrin Mohammad ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Failure Modes ◽  
Ultimate Load ◽  
Precast Concrete ◽  
Tensile Load ◽  
Test Results ◽  
Steel Bars ◽  
Embedment Length ◽  
Bar Diameter

This paper presents the test results of proposed grouted sleeve connections under increasing tensile load. The objective of this research was to investigate splice connections that could provide tensile strength similar to the full tensile strength of the connected rebars. The parameters varied were splice types, splice length and rebar embedment length. The performance of the splice connection was evaluated based on the load-displacement, ultimate load, displacements and failure modes. The results show that the strength of splice connection depends on the bond strength between sleeve-to-grout and grout-to-rebar; the tensile strength of spliced steel bars and also the tensile strength of sleeve. It is observed that when the grout compressive strength is more than 60N/mm2and bar embedded length is at least 10 bar diameter, the splice connection in BS series is able to provide full tensile strength of the connected rebars.

Effects of strain-ageing on New Zealand reinforcing steel bars

2009 ◽  
Vol 42 (3) ◽  
pp. 179-186 ◽  
Author(s):  
A. Momtahan ◽  
R.P. Dhakal ◽  
A. Rieder
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Yield Strength ◽  
Seismic Design ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Capacity Design ◽  
Plastic Hinges ◽  
Strain Ageing ◽  
Steel Bars

Modern seismic design codes, which are based on capacity design concepts, allow formation of plastic hinges in specified locations of a structure. This requires reliable estimation of strength of different components so that the desired hierarchy of strength of the structural components can be ensured to guarantee the formation of plastic hinges in the ductile elements. As strength of longitudinal reinforcing bars governs the strength of reinforced concrete members, strain-ageing, which has significant effect on the strength of reinforcing bars, should be given due consideration in capacity design. Strain-ageing can increase the yield strength of reinforcing steel bars and hence the strength of previously formed plastic hinges, thereby likely to force an unfavourable mechanism (such as strong beam-weak column leading to column hinging) to take place in subsequent earthquakes. In this paper, the strain-ageing effect of commonly used New Zealand reinforcing steel bars is experimentally investigated. Common New Zealand steel reinforcing bars are tested for different levels of pre-strain and different time intervals up to 50 days, and the results are discussed focussing on the extent of strain-ageing and its possible implications on seismic design provisions. The results indicate that designers need to use a higher flexural strength (in addition to overstrength) for the weaker member in checking the strength hierarchy in capacity design of reinforced concrete frames. Similarly, in designing retrofit measures to restore a damaged reinforced concrete member engineers need to take into account an increase of yield strength of the reinforcing steel bars employed in the member due to the strain-ageing phenomenon and the extent of increase in the yield strength depends on the level of damage.

NUMERICAL ANALYSIS OF CONCRETE BEAM REINFORCED WITH GLASS FIBER REINFORCED POLYMER BARS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Osama A. Mohamed ◽  
Rania Khattab
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Reinforcing Bars ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Frp Bars

The use of fiber reinforced polymer (FRP) bars to reinforce concrete beams has received significant attention in the past decade due to their corrosion resistance, high tensile strength, and excellent non-magnetic properties. Glass FRP (GFRP) reinforcing bars have gained popularity due to the relatively lower cost compared to carbon FRP (CFRP) bars. In this study, sixteen concrete beam finite element models were created using the finite element computer program ANSYS to perform linear and non-linear analyses. Twelve beams were longitudinally reinforced with GFRP bars, while the remaining four beams were reinforced with conventional steel bars as control specimens. In terms of mechanical properties, FRP reinforcing bars have lower modulus of elasticity compared to conventional reinforcing steel and remain linear elastic up to failure. This leads to lack of plasticity and a brittle failure of beams reinforced with FRP bars. The objective of this study is to investigate flexural behavior of concrete beams reinforced with GFRP reinforcing bars. Some of the parameters incorporated in the numerical analysis include longitudinal reinforcement ratio and compressive strength of concrete, both of which affect the flexural capacity of beams. It is shown in this study that replacement of traditional reinforcing steel reinforced bars by GFRP bars significantly decreases mid-span deflection and increases ultimate load. The strain distribution along GFRP longitudinal reinforcing bars is totally different from that of traditional steel bars.

Bond of GFRP Reinforcement with Concrete

2016 ◽  
Vol 691 ◽  
pp. 356-365 ◽  
Author(s):  
Ivan Hollý ◽  
Juraj Bilčík ◽  
Ondrej Keseli ◽  
Natalia Gažovičová
Keyword(s):  
Steel Reinforcement ◽  
Reinforcing Bars ◽  
Tunnel Boring Machines ◽  
Rc Structures ◽  
Factors Affecting ◽  
Glass Fiber Reinforcement ◽  
Boring Machines ◽  
Electromagnetic Transparency ◽  
Corrosion Of Steel ◽  
Gfrp Reinforcement

Corrosion of steel reinforcement is the major cause of deterioration of existing RC structures. Combined effects of moisture, temperature, and chlorides reduce the alkalinity of concrete and exacerbate the corrosion of steel reinforcement, especially for concrete structures subjected to aggressive environments, such as marine structures and bridges and parking garages exposed to de-icing salts. Glass fiber reinforcement polymer (GFRP) bars are suitable alternatives to steel bars in reinforced concrete applications if durability, electromagnetic transparency, or ease of demolition in temporary constructions is sought, that have to be demolished partially by tunnel boring machines (TBMs). The bond of GFRP reinforcement is different from steel reinforcing bars. This paper presents factors affecting the bond strength between GFRP reinforcement and concrete.

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