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%.

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>

Load-Carrying Capacities of Fully Clamped RC Slab Accompanying Compressive-Tensile Membrane Actions: A Theoretical Approach

2020 ◽  
Vol 20 (08) ◽  
pp. 2050094
Author(s):  
Wanxiang Chen ◽  
Lisheng Luo ◽  
Zhikun Guo ◽  
Yingjie Wang
Keyword(s):  
Bearing Capacity ◽  
Carrying Capacity ◽  
Flexural Rigidity ◽  
Load Carrying Capacity ◽  
Membrane Action ◽  
Yield Line ◽  
Load Carrying ◽  
Membrane Effects ◽  
Rc Slab ◽  
Rc Slabs

Fully clamped reinforced concrete (RC) slab is a common structural component possessing better load-carrying capacity over simply supported slab. Currently, typical yield line theory is a popular approach to estimate the bearing capacity of fully clamped RC slab, although it would greatly underestimate the actual ultimate resistance. This paper is devoted to enriching the knowledge of membrane action and its contribution to the load-carrying capacity of the clamped slab. The resistance trajectory of fully clamped RC slab from loading to failure undergoes three phases: the ascending branch raised by outward movement prevention, the descending branch due to crushed concrete and the re-ascending branch caused by reinforcement strain. Applied load–deflection curves of RC slab accompanying compressive-membrane actions are achieved according to the bending theory of normal cross-section. The reserve capacities accompanying tensile-membrane actions in the condition of large deformations are further derived. The whole load–deflection curves that considered compressive-tensile membrane effects are finally presented, where the mid-span displacements are revised by the deflection equations and the softening coefficient of flexural rigidity. It is indicated that the load–deflection relationships of fully clamped RC slabs can be reasonably depicted by taking compressive-tensile membrane effects into account, which are fairly different from yield line approaches. Comparative analysis shows that analytical results are in good agreement with experimental data reported by Park et al. and illustrates that the proposed model is capable of predicting the bearing capacity of fully clamped RC slab with very good accuracy.

Influence of Corrosion Distribution on Estimation of Flexural Loading Capacity of Corroded RC Beams

2017 ◽  
Vol 12 (3) ◽  
pp. 478-486
Author(s):  
Takashi Yamamoto ◽  
◽  
Satoshi Takaya ◽  
Toyo Miyagawa ◽  
Keyword(s):  
Estimation Method ◽  
Rc Beam ◽  
Loading Capacity ◽  
Kriging Method ◽  
Flexural Capacity ◽  
Cross Sectional ◽  
Flexural Loading ◽  
Load Carrying ◽  
Steel Bars ◽  
Inspection Data

A load carrying capacity of the reinforced concrete (RC) member is degraded by the corrosion of reinforcing steel bars due to chloride ion ingress. A lot of researches on the effect of corrosion in the longitudinal tensile reinforcing steel bars on the load carrying behavior have been available up to now. Accurate and quantitative estimation of capacity, however, is often difficult, because of the non-uniformity of corrosion in the member. Thus, a relationship between the spatial distribution of corrosion in the reinforcement including its scatter and the flexural loading capacity of RC member with such distribution of corrosion should be clarified so that the flexural capacity of corroded RC member can be estimated accurately. On the other hand, in case of the practical RC member under the corrosive environment, it should be considered that the flexural capacity often have to be derived from not a large number of inspection data on cross sectional areas of corroded reinforcements. So, in this study, a flexural loading test was performed by using RC beam specimens with the corroded tensile reinforcements provided the distribution of sectional areas. An estimation method of the flexural capacity of corroded RC beam was also shown, considering the distribution and its scatter in sectional areas of corroded reinforcements under the limited inspection data. Furthermore, the estimation of the longitudinal distribution of the cross sectional area of corroded reinforcement was performed by the spatial interpolation using Kriging method. Test results showed the yield and maximum load capacity in the corroded RC beam decreased as the corrosion rate increased. The failure mode of rupture in the reinforcement was shown in the large corrosion. The proposed estimation method was able to lead the safe evaluation of those experimental flexural capacities, determining the appropriate longitudinal characteristic value of the cross sectional area of corroded reinforcement. The flexural capacity can be also safely calculated using the characteristic value of diameters estimated by the corrosion crack width on the surface of the concrete, while the ratio of the experimental flexural capacity to the estimated one decreased as the corrosion loss increased. The distribution of bar diameters in the corroded reinforcement was able to be roughly estimated by using Kriging method. However, it was suggested that the measurement points close to the minimum bar diameter should be included to estimate the flexural capacity on the safe side.

scholarly journals Damage mechanism of existing RC slabs with reinforcing steel plate

2019 ◽  
Vol 258 ◽  
pp. 05011
Author(s):  
Kenta Namba ◽  
Chikako Fujiyama ◽  
Tsutomu Niina
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Simulation Models ◽  
Damage Mechanism ◽  
Steel Plates ◽  
Reinforcing Steel ◽  
Wheel Load ◽  
Element Analysis ◽  
Rc Slab ◽  
Rc Slabs

The purpose of this study was to clarify the damage mechanisms of existing reinforced concrete (RC) slabs with reinforcing steel plates through the use of a three-dimensional nonlinear finite element analysis. An actual wheel load running test was simulated. Two panels of RC slab were cut from existing bridges and were used as the test specimens. Simulation models were built for each specimen with different modeling concepts for the rebar; RC elements, and solid elements. After the wheel load running simulations, the strains were examined through use of the strain contours at various cross sections. In the model using solid element for the rebars, the mechanisms for the generation and development of the horizontal cracks were analyzed in detail. Furthermore, the strain components of the referential elements were carefully analyzed for different loading cycles and positions. Although the decisive cause of the horizontal crack has not been clarified yet, the crack development processes were mostly demonstrated through this study.

scholarly journals Reinforced Concrete Slabs Strengthened with Lap-Spliced Carbon TRC System

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3340
Author(s):  
Hyeong-Yeol Kim ◽  
Young-Jun You ◽  
Gum-Sung Ryu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Textile Reinforced Concrete ◽  
Lap Splice ◽  
Flexural Failure ◽  
Reinforced Concrete Slabs ◽  
Tensile Performance ◽  
Matrix Properties ◽  
Rc Slab ◽  
Rc Slabs

Construction with precast or prefabricated elements requires the connecting of structural joints. This study presents an accelerated construction method to strengthen reinforced concrete (RC) slab-type elements in flexure using precast lap-spliced textile-reinforced concrete (TRC) panels. The objectives of this study are to identify the tensile behavior of a TRC system with lap-spliced textile, and to experimentally validate the performance of the proposed connecting method by flexural failure test for the concrete slabs strengthened by TRC panels with lap-spliced textile. Twenty-one coupon specimens were tested in tension with two different matrix systems and three different lap splice lengths. The influence of the lap splice length and matrix properties on the tensile performance of the TRC system was significant. Five full-scale RC slabs were strengthened by the precast TRC panels with and without the lap splice, and was tested in flexure. The results of the failure test for the strengthened specimens showed that the ultimate load of the strengthened specimen with the TRC panel increased by a maximum of 24%, compared to that of the unstrengthened specimen. Moreover, the failure-tested specimens were re-strengthened by a new TRC panel system and tested again in flexure. The objective of the re-strengthening of the damaged RC slabs by the TRC panel is to investigate whether the yielded steel reinforcement can be replaced by the TRC panel. The initial cracking load and the stiffness of the re-strengthened specimens were significantly increased by re-strengthening.

Three-Stage Approach for Unrestrained Simply Supported RC Slabs under Uniformly Distributed Load

2012 ◽  
Vol 166-169 ◽  
pp. 845-848
Author(s):  
Jun Xian Liu ◽  
Kang Hai Tan
Keyword(s):  
Test Results ◽  
Membrane Action ◽  
Simply Supported ◽  
Load Carrying ◽  
Intrinsic Complexity ◽  
Rc Slab ◽  
History Of ◽  
Three Stages ◽  
Rc Slabs ◽  
Good Agreement

It is known from previous experiments that the load-carrying capacity for RC slabs at large deflection is governed and enhanced by the tensile membrane action. However, due to the intrinsic complexity of concrete properties, it is hard to capture the history of the load-deflection relationship for RC slabs. After reviewing several analytical reinforced concrete models, the author develops a simplified load-displacement semi-analytical model for laterally unrestrained simply supported RC slabs. Three stages have been identified for this model, which are elastic stage, transition stage and pure tensile membrane action stage. Compared with the existing RC slab tests, the author's model shows good agreement with the previous test results.

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 RCC Beams in Shear by Using SBR Polymer-Modified Ferrocement Jacketing Technique

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Rajinder Ghai ◽  
Prem Pal Bansal ◽  
Maneek Kumar
Keyword(s):  
Carrying Capacity ◽  
Shear Failure ◽  
Ultimate Load ◽  
Load Test ◽  
Wire Mesh ◽  
Styrene Butadiene Rubber ◽  
Shear Load ◽  
Butadiene Rubber ◽  
Load Carrying Capacity ◽  
Load Carrying

There is a common phenomenon of shear failure in RCC beams, especially in old buildings and bridges. Any possible strengthening of such beams is needed to be explored that could strengthen and make them fit for serviceable conditions. The present research has been made to determine the performance of predamaged beams strengthened with three-layered wire mesh polymer-modified ferrocement (PMF) with 15% styrene-butadiene-rubber latex (SBR) polymer. Forty-eight shear-designed and shear-deficient real-size beams were used in this experimental work. Ultimate shear load-carrying capacity of control beams was found at two different shear-span (a/d) ratios 1 and 3. The sets of remaining beams were loaded with different predetermined damage levels of 45%, 75%, and 95% of the ultimate load values and then strengthened with 20 mm thick PMF. The strengthened beams were then again tested for ultimate load-carrying capacity by conducting the shear load test at a/d = 1 and 3. As a result, the PMF-strengthened beams showed restoration and enhancement of ultimate shear load-carrying capacity by 5.90% to 12.03%. The ductility of strengthened beams was improved, and hence, the corresponding deflections were prolonged. On the other hand, the cracking pattern of PMF-strengthened beams was also improved remarkably.

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.

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