scholarly journals Flexural Strengthening of RC Slabs Using a Hybrid FRP-UHPC System Including Shear Connector

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jiho Moon ◽  
Mahmoud M. Reda Taha ◽  
Jung J. Kim
Keyword(s):  
Flexural Strength ◽  
Hybrid System ◽  
Shear Failure ◽  
Full Scale ◽  
Shear Connector ◽  
Flexural Strengthening ◽  
Shear Connectors ◽  
Rc Slab ◽  
Rc Slabs ◽  
Ultimate Load Carrying Capacity

A polymeric hybrid composite system made of UHPC and CFRP was proposed as a retrofit system to enhance flexural strength and ductility of RC slabs. While the effectiveness of the proposed system was confirmed previously through testing three full-scale one-way slabs having two continuous spans, the slabs retrofitted with the hybrid system failed in shear. This sudden shear failure would stem from the excessive enhancement of the flexural strength over the shear strength. In this study, shear connectors were installed between the hybrid system and a RC slab. Using simple beam, only positive moment section was examined. Two full-scale RC slabs were cast and tested to failure: the first as a control and the second using this new strengthening technique. The proposed strengthening system increased the ultimate load carrying capacity of the slab by 70%, the stiffness by 60%, and toughness by 128%. The efficiency of shear connectors on ductile behavior of the retrofitted slab was also confirmed. After the UHPC top is separated from the slab, the shear connector transfer shear load and the slab system were in force equilibrium by compression in UHPC and tension in CFRP.

scholarly journals Strengthening of Concrete Element with Precast Textile Reinforced Concrete Panel and Grouting Material

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3856
Author(s):  
Young-Jun You ◽  
Hyeong-Yeol Kim ◽  
Gum-Sung Ryu ◽  
Kyung-Taek Koh ◽  
Gi-Hong Ahn ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Bending Test ◽  
Strengthening Effect ◽  
Textile Reinforced Concrete ◽  
Concrete Element ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Grouting Material ◽  
Rc Slab ◽  
Rc Slabs

Textile reinforced concrete (TRC) has widely been used for strengthening work for deteriorated reinforced concrete (RC) structures. The structural strengthening often requires accelerated construction with the aid of precast or prefabricated elements. This study presents an innovative method to strengthen an RC slab-type element in flexure using a precast panel made of carbon TRC. A total of five RC slabs were fabricated to examine the flexural strengthening effect. Two of them were strengthened with the precast panel and grouting material and another set of two slabs was additionally strengthened by tensile steel reinforcement. The full-scale slab specimens were tested by a three-point bending test and the test results were compared with the theoretical solutions. The results revealed that the ultimate load of the specimens strengthened with the TRC panel increased by at least 1.5 times compared to that of the unstrengthened specimen. The application of the precast TRC panel and grouting material for the strengthening of a prototype RC structure verified its outstanding constructability.

Mechanical Properties Research of Steel-Concrete Composite Structure's Connector

2013 ◽  
Vol 738 ◽  
pp. 128-132
Author(s):  
Xiu Yong Si ◽  
Jian Bo Zhao ◽  
Xiang Zhong Bai
Keyword(s):  
Bearing Capacity ◽  
Shear Failure ◽  
Rapid Development ◽  
Influence Factors ◽  
Shear Stiffness ◽  
Transmission Mechanism ◽  
Shear Connector ◽  
Force Transmission ◽  
Shear Connectors ◽  
New Type

A new type of PBL shear connector gets more attention with the rapid development of steel-concrete composite structure. The PBL shear connector's static behavior and influence factors thereof are analysed through experiments. The PBL shear connector's force-transmission mechanism is discussed. The conclusions show that the thickness of perforate plate has significant impact of PBL shear connectors design bearing capacity, shear stiffness and ultimate bearing capacity. According to the thickness of perforate plate, the failure mode of PBL shear connector may appear to flexural and shear failure of perforate rebar, shear failure of perforate rebar or shear failure of perforate plate.

Retrofitting and Strengthening Interventions of RC Members Using Ultra High Performance Concrete (UHPC)

2018 ◽  
Author(s):  
Wee Teo ◽  
Kazutaka Shirai ◽  
Yin Hor
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Shear Cracks ◽  
Ultra High Performance Concrete ◽  
Flexural Failure ◽  
Load Carrying ◽  
Rc Slab ◽  
Shear Cracking ◽  
Rc Slabs ◽  
Ultimate Load Carrying Capacity

<p>Two test series with various UHPC strengthening interventions were conducted in this study to investigate the behaviour of composite reinforced concrete (RC) slabs strengthened with UHPC. The first, RE series is a retrofit interventions, tested UHPC as patch material for repairing deteriorated concrete structures. As for the second, OV series is a UHPC overlay interventions, was used to strengthen soffit of RC slab members. The results showed that, in RE series, UHPC safeguard against diagonal cracking compare to conventional RC slab. The UHPC exhibited excellent energy absorption with extensive deflection hardening and ductility during the post cracking range. In OV series, all slabs showed formation of diagonal shear cracks and sign of debonding modes. The UHPC overlay delayed the development of shear cracking. The ultimate load carrying capacity and tendency of flexural failure increase with the overlay thickness.</p>

scholarly journals Experimental Investigation of an RC Slab Culvert Rehabilitated with Grouted CSPs

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Bai-Jian Li ◽  
Wen-Qiang Fu ◽  
Yu-Ting He ◽  
Xin-Sha Fu
Keyword(s):  
Shear Failure ◽  
Estimation Method ◽  
Steel Plates ◽  
Loading Capacity ◽  
Flexural Failure ◽  
Arch Effect ◽  
Load Carrying ◽  
Rc Slab ◽  
Rc Slabs ◽  
Test Loading

The rehabilitation of an existing culvert with corrugated steel plates (CSPs) has been an emerging technology in recent years, but engineers and researchers are not particularly clear about the working principle of the rehabilitated structure. To investigate the mechanical properties of reinforced concrete (RC) slabs rehabilitated with CSPs, laboratory tests were carried out to explore the calculation method and influencing factors of load-carrying capacity of RC slab culverts rehabilitated with grouted CSPs. The results revealed the following: the flexural failure of the prerehabilitated RC slab has little influence on the test-loading capacity of the rehabilitated system; shear failure will occur in the RC slab and grout, and an arch effect will be formed in the CSP and grout after rehabilitation; the higher the shear strength of the concrete of the RC slab and grout, the greater the test-loading capacity of the rehabilitated system: the RC slab and grout greatly contribute to the test-loading capacity of the rehabilitated system; CSP changes the ductility of the rehabilitated system at the failure stage. It was found that the estimation method for the test-loading capacity of the rehabilitated system based on the shear capacities of the RC slab and grout and the flexural capacity of the CSP is reasonable; the maximum difference between the theoretical and experimental results was less than 30%, and the minimum difference between them was 0%.

scholarly journals Experimental Investigation on Composite Deck Slab Made of Cold-Formed Profiled Steel Sheeting

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 229
Author(s):  
Siva Avudaiappan ◽  
Erick I. Saavedra Flores ◽  
Gerardo Araya-Letelier ◽  
Walter Jonathan Thomas ◽  
Sudharshan N. Raman ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Test Results ◽  
Shear Connectors ◽  
Modes Of Failure ◽  
Deck Slabs ◽  
Load Carrying ◽  
Composite Slabs ◽  
Ultimate Load Carrying Capacity ◽  
Ductility Ratio ◽  
Deck Slab

An experimental investigation is performed on various cold-formed profiled sheets to study the connection behavior of composite deck slab actions using bolted shear connectors. Various profiles like dovetailed (or) re-entrant profiles, rectangular profiles and trapezoidal profiles are used in the present investigation. This experimental investigation deals with the evaluation of various parameters such as the ultimate load carrying capacity versus deflection, load versus slip, ductility ratio, strain energy and modes of failure in composite slab specimens with varying profiles. From the test results the performance of dovetailed profiled composite slabs’ resistance is significantly higher than the other two profiled composite deck slabs.

Flexural strengthening of pre-cracked RC slabs with prestressed NSM CFRP laminates and evaluation of strain loss

2021 ◽  
pp. 136943322110105
Author(s):  
M.R. Mostakhdemin Hosseini ◽  
Salvador J.E. Dias ◽  
Joaquim A.O. Barros
Keyword(s):  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Transfer Length ◽  
Rc Structures ◽  
Cracked Concrete ◽  
Flexural Strengthening ◽  
Cfrp Laminates ◽  
Load Carrying ◽  
Rc Slabs

The strengthening intervention of RC structures often involves already cracked concrete. To evaluate the effect of the level of damage prior to the strengthening (pre-cracks) on the behavior of the flexurally strengthened RC slabs with prestressed NSM CFRP laminates, an experimental research was carried out. Two pre-cracking levels of damage were analyzed and, for each one, three levels of prestress were tested (0%, 20% and 40%). The obtained results showed that the strengthening of damaged RC slabs with prestressed NSM CFRP laminates results in a significant increase on the load carrying capacity at serviceability limit states. Pre-cracked RC slabs strengthened with prestressed NSM CFRP laminates presented a load carrying capacity almost similar to the corresponding uncracked strengthened slabs. To determine the effective prestress level in CFRP laminates, the variation of strain over the length of the CFRP and over time was experimentally recorded. The prestress transfer length was also evaluated. The experimental results revealed that the transfer length of CFRP laminates was less than 150 mm, and the maximum value of strain loss out of transfer length (around 14%) was measured close to the cracked section of the damaged RC slabs. Significant part of strain loss in CFRP laminates occurred during 24 h after releasing the prestress load.

scholarly journals Investigations on Efficiently Interfaced Steel Concrete Composite Deck Slabs

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
K. N. Lakshmikandhan ◽  
P. Sivakumar ◽  
R. Ravichandran ◽  
S. Arul Jayachandran
Keyword(s):  
Longitudinal Shear ◽  
Advanced Technology ◽  
Shear Connector ◽  
Premature Failure ◽  
Shear Connectors ◽  
Reinforced Concrete Slabs ◽  
Composite Slabs ◽  
Strength And Stiffness ◽  
The Cost ◽  
Deck Slab

The strength of the composite deck slab depends mainly on the longitudinal shear transfer mechanism at the interface between steel and concrete. The bond strength developed by the cement paste is weak and causes premature failure of composite deck slab. This deficiency is effectively overcame by a shear transferring mechanism in the form of mechanical interlock through indentations, embossments, or fastening studs. Development of embossment patterns requires an advanced technology which makes the deck profile expensive. Fastening studs by welding weakens the joint strength and also escalates the cost. The present investigation is attempted to arrive at a better, simple interface mechanism. Three types of mechanical connector schemes are identified and investigated experimentally. All of the three shear connector schemes exhibited full shear interaction with negligible slip. The strength and stiffness of the composite slabs with shear connectors are superior about one and half time compared to these of the conventional reinforced concrete slabs and about twice compared to these of composite slabs without mechanical shear connectors. The scheme2 and scheme3 shear connector mechanisms integrate deck webs and improve strength and stiffness of the deck, which can effectively reduce the cost of formworks and supports efficiently.

scholarly journals A novel one-sided push-out test for shear connectors in composite beams

2018 ◽  
Author(s):  
Mohammed Abdulhussein Al-Shuwaili ◽  
Alessandro Palmeri ◽  
Maria Teresa Lombardo
Keyword(s):  
Shear Resistance ◽  
Composite Beams ◽  
Full Scale ◽  
Bending Tests ◽  
Shear Connectors ◽  
Shear Connections ◽  
European Standards ◽  
Headed Stud ◽  
The Relationship ◽  
Push Out

Push-out tests (POTs) have been widely exploited as an alternative to the more expensive full-scale bending tests to characterize the behaviour of shear connections in steel-concrete composite beams. In these tests, two concrete slabs are typically attached to a steel section with the connectors under investigation, which are then subjected to direct shear. The results allow quantifying the relationship between applied load and displacements at the steel-concrete interface. Since this relationship is highly influenced by the boundary conditions of POT samples, different experimental setups have been used, where the slabs are either restricted or free to slide horizontally, as researchers have tried to reduce any discrepancy between POT and full-scale composite beam testing. Based on a critical review of various POT configurations presented in the dedicated literature, this paper presents an efficient one-sided POT (OSPOT) method. While OSPOT and POT specimens are similar, in the proposed OPSPOT setup only one of the two slabs is directly loaded in each test, and the slab is free to move vertically. Thus, two results can be obtained from one specimen, i.e. one from each slab. A series of POTs and OSPOTs have been conducted to investigate the behaviour and the shear resistance of headed stud connectors through the two methods of testing. The results of this study than were compared with those of different POTs setups conducted by other researchers. The new OSPOT results show in general an excellent agreement with the analytical predictions offered by both British and European standards, as well as the estimated shear resistance proposed other researchers in the literature. These findings suggest that the proposed one-sided setup could be used as an efficient and economical option for conducting the POT, as it has the potential not only to double the number of results, but also to simplify the fabrication of the samples, which is important in any large experimental campaign, and to allow testing with limited capacity of the actuator. 

ESTIMATION OF THE POWDER-ACTUATED SHEAR CONNECTORS TESTS

2021 ◽  
Vol 295 (2) ◽  
pp. 16-26
Author(s):  
D.V. Konin ◽  
Keyword(s):  
Bearing Capacity ◽  
Estimation Methods ◽  
Shear Connector ◽  
Connection Strength ◽  
Test Results ◽  
European Standard ◽  
Design Code ◽  
Shear Connectors ◽  
Shear Connection

The shear connector design should be executed according to the SP 266.1325800.2016. For the different typed of welded connectors are there analytic dependences, which could be used for shear connection strength estimation. The design code also allows to use powder-actuated Z-shape shear connectors. Their bearing capacity should be proved by tests according to the GOST R 58336-2018. Inasmuch the GOST doesn't consist the test estimation approach, the authors offer the method. For the test estimation methods the test results of 15 series specimen had been used. The results were compared with estimation according to the European standard for the verification.

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