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Dr. Akanshu Sharma
Institute of Construction Materials, TU Stuttgart, Pfaffenwaldring 4G, 70569 Stuttgart, Germany

Basic Info


Research Keywords & Expertise

0 Inelastic static and dynamic analysis of reinforced concrete structures
0 Static and dynamic testing of RC structures and sub-assemblages
0 Seismic retrofitting of structures with innovative techniques
0 Seismic behavior of cast-in and post-installed anchors in concrete
0 Seismic performance assessment of RC structures

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Anchorages with supplementary reinforcement
Numerical modeling of structures under seismic loads
Seismic behavior of cast-in and post-installed anchors in concrete
Performance of RC structures subjected to fire loads

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Short Biography

Akanshu Sharma is a Junior Professor at the Institute of Construction Materials, University of Stuttgart, where he received his Doctor of Engineering in 2013. His research interests include inelastic seismic analysis and retrofitting of reinforced concrete structures, the behavior of concrete under high loading rates and fastening in concrete structures.

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Journal article
Published: 28 August 2021 in CivilEng
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Anchorages of non-rectangular configuration, though not covered by current design codes, are often used in practice due to functional or architectural needs. Frequently, such anchor groups are placed close to a concrete edge and are subjected to shear loads. The design of such anchorages requires engineering judgement and no clear rules are given in the codes and standards. In this work, numerical investigations using a nonlinear 3D FE analysis code are carried out on anchor groups with triangular and hexagonal anchor patterns to understand their behavior under shear loads. A microplane model with relaxed kinematic constraint is utilized as the constitutive law for concrete. Two different orientations are considered for both triangular and hexagonal anchor groups while no hole clearance is considered in the analysis. Two loading scenarios are investigated: (i) shear loading applied perpendicular and towards the edge; and (ii) shear loading applied parallel to the edge. The results of the analyses are evaluated in terms of the load-displacement behavior and failure modes. A comparison is made between the results of the numerical simulations and the analytical calculations according to the current approaches. It is found that, similar to the rectangular anchorages, and also for such non-rectangular anchorages without hole clearance, it may be reasonable to calculate the concrete edge breakout capacity by assuming a failure crack from the back anchor row. Furthermore, the failure load of the investigated groups loaded in shear parallel to the edge may be considered as twice the failure load of the corresponding groups loaded in shear perpendicular to the edge.

ACS Style

Boglárka Bokor; Akanshu Sharma. Numerical Investigations on Non-Rectangular Anchor Groups under Shear Loads Applied Perpendicular or Parallel to an Edge. CivilEng 2021, 2, 692 -711.

AMA Style

Boglárka Bokor, Akanshu Sharma. Numerical Investigations on Non-Rectangular Anchor Groups under Shear Loads Applied Perpendicular or Parallel to an Edge. CivilEng. 2021; 2 (3):692-711.

Chicago/Turabian Style

Boglárka Bokor; Akanshu Sharma. 2021. "Numerical Investigations on Non-Rectangular Anchor Groups under Shear Loads Applied Perpendicular or Parallel to an Edge." CivilEng 2, no. 3: 692-711.

Journal article
Published: 30 July 2021 in Engineering Structures
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Due to notch effect of the holes, the anchors installed in concrete are highly likely to be intercepted by cracks that may form due to thermal and/or mechanical loads on the structure. The presence of cracks, alters the behaviour of anchors by reducing their stiffness and load carrying capacity. The behaviour of anchors in steel fiber reinforced concrete (SFRC) is one of the prime focuses in anchor technology today. However, the current research lacks the knowledge on the behaviour of anchors in SFRC intercepted by a crack. This paper investigates the behaviour of single bonded anchors intercepted by a crack (cracked concrete) in SFRC undergoing concrete cone breakout failure. Experimental investigations are carried out on bonded anchors installed in SFRC with different concrete grades and different fiber content. The tests are performed on the anchors in uncracked concrete and corresponding tests in cracked concrete show that the enhancement of performance of the anchors due to SFRC in uncracked concrete and cracked concrete is rather similar and the relative reduction in stiffness and strength of the anchors in cracked compared to uncracked concrete is equivalent in SFRC and in normal concrete. Based on the tests, a new proposal for the concrete cone capacity of anchors in cracked SFRC is proposed.

ACS Style

Norbert Vita; Akanshu Sharma. Behaviour of single bonded anchors in non-cracked and cracked steel fiber reinforced concrete under short-time tensile loading. Engineering Structures 2021, 245, 112900 .

AMA Style

Norbert Vita, Akanshu Sharma. Behaviour of single bonded anchors in non-cracked and cracked steel fiber reinforced concrete under short-time tensile loading. Engineering Structures. 2021; 245 ():112900.

Chicago/Turabian Style

Norbert Vita; Akanshu Sharma. 2021. "Behaviour of single bonded anchors in non-cracked and cracked steel fiber reinforced concrete under short-time tensile loading." Engineering Structures 245, no. : 112900.

Review
Published: 24 May 2021 in CivilEng
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During earthquakes, buildings are subjected to loads well beyond their usual demands, resulting in high stresses in the structural components and additional inertial forces coming from the non-structural elements. When post-installed anchors are used to form the connection between non-structural or structural members and the primary reinforced concrete structure, these anchors are also subjected to high seismic demands. To determine whether a post-installed anchor is suitable for such applications, it is assessed for its performance under seismic demands. In this review paper, the current European approach for testing and qualification of post-installed anchors under seismic actions is reviewed and discussed in the context of structural applications where anchors are used to form the connection between structural members that participate in the load-transfer mechanism against seismic loads. The first part of this paper provides a description of the testing procedures and the criteria against which the anchor performance is assessed. The procedures and assessment criteria are discussed regarding the suitability in the case of the above-described structural applications. In the second part, the qualification of anchors under seismic actions is discussed in the light of an upcoming performance-based design approach for anchors. In such an approach, information on the displacement and hysteretic behavior of an anchor in a broader range of the load–displacement curve is of vital importance. Therefore, additional testing approaches might be required in order to supplement the information on anchor performance provided in the current testing procedures. One such testing approach for pulsating tension load is reported.

ACS Style

Erik Stehle; Akanshu Sharma. Review of Testing and Qualification of Post-Installed Anchors under Seismic Actions for Structural Applications. CivilEng 2021, 2, 406 -420.

AMA Style

Erik Stehle, Akanshu Sharma. Review of Testing and Qualification of Post-Installed Anchors under Seismic Actions for Structural Applications. CivilEng. 2021; 2 (2):406-420.

Chicago/Turabian Style

Erik Stehle; Akanshu Sharma. 2021. "Review of Testing and Qualification of Post-Installed Anchors under Seismic Actions for Structural Applications." CivilEng 2, no. 2: 406-420.

Journal article
Published: 03 May 2021 in CivilEng
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Beam-column-joints (BCJ) in reinforced concrete (RC) frames are known to be critical against seismic actions. Hence, several researchers have conducted related investigations. The loading history used in the experimental investigations must be a sufficiently accurate and conservative representation of seismic loading on the structure and should trigger all possible critical failure mechanisms in the subassembly. Presently, there is significant diversity in the loading histories used for seismic investigation of structural subassemblies. This paper intends to propose an optimum loading history for considering bidirectional (horizontal) seismic action on 3D-RC BCJ subassemblies. To this end, the available loading histories (unidirectional and bidirectional) for simulation of seismic loads on RC joint subassemblies are reviewed in the context of the demands they impose on the joints. Finite element modeling and analyses are used as a tool for investigating the response of 3D-BCJ subassembly under different bidirectional loading states.

ACS Style

Vinay Mahadik; Akanshu Sharma. Bidirectional Loading History for Seismic Testing of 3D Frame Joints. CivilEng 2021, 2, 349 -369.

AMA Style

Vinay Mahadik, Akanshu Sharma. Bidirectional Loading History for Seismic Testing of 3D Frame Joints. CivilEng. 2021; 2 (2):349-369.

Chicago/Turabian Style

Vinay Mahadik; Akanshu Sharma. 2021. "Bidirectional Loading History for Seismic Testing of 3D Frame Joints." CivilEng 2, no. 2: 349-369.

Journal article
Published: 12 April 2021 in Engineering Structures
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In recent years, the use of post-installed anchors to connect the haunch elements with the structural members has been investigated proficiently. It represents a promising alternative for strengthening of joints of existing reinforce concrete (RC) structures (moment resisting frames) with low invasion. The efficacy of the fully-fastened-haunch-retrofit (FFHR) solution has been proven by past works for two-dimensional RC beam-to-column joints, subjected to cyclic loading, without transverse beam and slab. In these cases, the presence of the haunch, providing a suitable design of the anchoring system, modifies the strength hierarchy shifting the mode of failure from joint’s shear breakout to the formation of the plastic hinge in the beam. However, due to the presence of the slab and transverse beam, as the authors discussed elsewhere, an increase both (i) in the joint resistance and (ii) in the beam flexural resistance must be expected, but particular care must be taken to the non-symmetric behavior. In this regard, results obtained for two RC beam-to-column sub-assemblies with transverse beam and slab retrofitted using FFHR are presented. The structural behavior under cyclic load is compared with the as-built identical specimen. The applicability of the FFHR to existing RC structures, is confirmed but, at high level of ductility demand, both anchorage break-down and reduced displacement capacity are observed.

ACS Style

A. Marchisella; G. Muciaccia; A. Sharma; R. Eligehausen. Experimental investigation of 3d RC exterior joint retrofitted with fully-fastened-haunch-retrofit-solution. Engineering Structures 2021, 239, 112206 .

AMA Style

A. Marchisella, G. Muciaccia, A. Sharma, R. Eligehausen. Experimental investigation of 3d RC exterior joint retrofitted with fully-fastened-haunch-retrofit-solution. Engineering Structures. 2021; 239 ():112206.

Chicago/Turabian Style

A. Marchisella; G. Muciaccia; A. Sharma; R. Eligehausen. 2021. "Experimental investigation of 3d RC exterior joint retrofitted with fully-fastened-haunch-retrofit-solution." Engineering Structures 239, no. : 112206.

Journal article
Published: 31 October 2020 in CivilEng
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Anchor channels are cast in concrete and allow the connection of components using channel bolts. In recent years, the design to value resulted in ever thinner concrete elements, which often cannot accommodate the required embedment depth of standard anchor channels. For this reason, channels may be fitted with short anchors. While existing design provisions allow for the calculation of the tension capacity also for shallow embedded anchor channels, tests are required to determine product‑specific parameters for the economic shear loads design. The presented study investigated the performance of shallow embedded anchor channels tested in shear. The detailed evaluation of the test data demonstrates that testing of the minimum embedment is conservative and that the load-displacement behavior of channels with welded I‑sections is comparable to that of channels with forged headed studs. In addition, a new evaluation approach is proposed.

ACS Style

Christoph Mahrenholtz; Akanshu Sharma. Load Capacity of Shallow Embedded Anchor Channels. CivilEng 2020, 1, 243 -252.

AMA Style

Christoph Mahrenholtz, Akanshu Sharma. Load Capacity of Shallow Embedded Anchor Channels. CivilEng. 2020; 1 (3):243-252.

Chicago/Turabian Style

Christoph Mahrenholtz; Akanshu Sharma. 2020. "Load Capacity of Shallow Embedded Anchor Channels." CivilEng 1, no. 3: 243-252.

Journal article
Published: 21 October 2020 in CivilEng
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Fire safety is a critical performance aspect of construction products, and post-installed anchors and rebars are no exemption in that regard. During their service life, anchors and rebars are subjected to different kinds of load actions, so they have to be qualified and designed for critical safety performance. While the qualification guidelines for static and seismic loading have matured to conclusive requirements over the past two decades, the requirements for determining the resistance to fire are just about to consolidate. This contribution strives to provide clarity on the fire rating of post-installed anchors and rebars. For this, the current status of the regulations, as well as the underlying background, is reviewed after a brief introduction. Typical examples of fire ratings in the field of post-installed anchors and rebars are given, and recent research undertaken to close the last regulative gaps is briefly presented.

ACS Style

Philipp Mahrenholtz; Akanshu Sharma. Fire Rating of Post-Installed Anchors and Rebars. CivilEng 2020, 1, 216 -228.

AMA Style

Philipp Mahrenholtz, Akanshu Sharma. Fire Rating of Post-Installed Anchors and Rebars. CivilEng. 2020; 1 (3):216-228.

Chicago/Turabian Style

Philipp Mahrenholtz; Akanshu Sharma. 2020. "Fire Rating of Post-Installed Anchors and Rebars." CivilEng 1, no. 3: 216-228.

Journal article
Published: 17 June 2020 in Fibers
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Use of organic resins such as epoxy and vinyl esters as bonding materials in fibre reinforced polymer (FRP) strengthening of concrete members is widely accepted. However, the performance of organic resins is compromised when exposed to high temperature and extreme weather conditions leading to reduced durability of the strengthened systems. The present study attempts to evaluate the effectiveness of inorganic (cement mortar and geopolymer mortar) bonding materials for shear strengthening of prestressed concrete (PSC) beams using the near-surface mounting (NSM) technique. Different types of bonding materials are used in this study for NSM shear strengthening including: (i) epoxy resin, (ii) high strength cement grout (HSCG) and (iii) geopolymer mortar. Bond tests were first conducted to evaluate the pull-out/bond strength of different bonding materials. Bond tests revealed that epoxy resin had the highest bond strength followed by geopolymer mortar and HSCG. Sixteen full-scale PSC beams were cast with and without stirrups. The beams were strengthened using NSM CFRP laminates oriented at 45-degree configuration and then tested under a three-point bending configuration. Experimental results revealed that the performance of high strength cement grout and geopolymer mortar was similar but with a lesser efficiency compared to the epoxy resin.

ACS Style

Vikas Singh Kuntal; M. Chellapandian; S. Suriya Prakash; Akanshu Sharma. Experimental Study on the Effectiveness of Inorganic Bonding Materials for Near-Surface Mounting Shear Strengthening of Prestressed Concrete Beams. Fibers 2020, 8, 1 .

AMA Style

Vikas Singh Kuntal, M. Chellapandian, S. Suriya Prakash, Akanshu Sharma. Experimental Study on the Effectiveness of Inorganic Bonding Materials for Near-Surface Mounting Shear Strengthening of Prestressed Concrete Beams. Fibers. 2020; 8 (6):1.

Chicago/Turabian Style

Vikas Singh Kuntal; M. Chellapandian; S. Suriya Prakash; Akanshu Sharma. 2020. "Experimental Study on the Effectiveness of Inorganic Bonding Materials for Near-Surface Mounting Shear Strengthening of Prestressed Concrete Beams." Fibers 8, no. 6: 1.

Technical paper
Published: 05 December 2019 in Structural Concrete
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Concrete pryout failure mode of a group of relatively shallow embedded anchors welded to a steel base plate has not been extensively investigated in the past. Therefore, the failure mechanism and resistance of such anchor groups needs to be clarified. In this paper a three‐dimensional (3D) finite element parametric study for quadruple (2 × 2) anchor groups loaded in shear with no influence of edges is carried out. In the study, embedment depth of anchors and anchor spacing in both directions are varied. The results show that the increase of anchor spacing perpendicular to the shear load direction has no major influence on the concrete pryout capacity, whereas the increase in anchor spacing parallel to the loading direction significantly increases the pryout capacity. For anchor spacing greater than a particular threshold value, the pryout resistance of a group of anchors is approximately equal to the resistance of a single anchor multiplied by the number of anchors. Based on the results of the study, a design formula for anchor group failing in pryout is proposed and compared with the current design code recommendations.

ACS Style

Khalil Jebara; Joško Ožbolt; Akanshu Sharma. Pryout capacity of headed stud anchor groups with stiff base plate: 3D finite element analysis. Structural Concrete 2019, 21, 905 -916.

AMA Style

Khalil Jebara, Joško Ožbolt, Akanshu Sharma. Pryout capacity of headed stud anchor groups with stiff base plate: 3D finite element analysis. Structural Concrete. 2019; 21 (3):905-916.

Chicago/Turabian Style

Khalil Jebara; Joško Ožbolt; Akanshu Sharma. 2019. "Pryout capacity of headed stud anchor groups with stiff base plate: 3D finite element analysis." Structural Concrete 21, no. 3: 905-916.

Fachthema
Published: 29 November 2019 in Beton- und Stahlbetonbau
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Hinterschnittdübel werden in kerntechnischen Anlagen zur nachträglichen Befestigung von maschinentechnischen Komponenten an Stahlbetontragwerken eingesetzt. Um die Integrität der Komponenten auch bei außergewöhnlichen Einwirkungen wie Erdbeben zu garantieren, müssen die Dübel eine ausreichende Tragfähigkeit aufweisen. Für die Annahme einer ausreichend starren Befestigung müssen darüber hinaus bleibende Dübelverschiebungen in engen Grenzen gehalten werden, da Dübelverschiebungen unmittelbaren Einfluss auf die Lastverteilung und ‐übertragung der Rohrhalterungen haben. Zum Nachweis von Tragfähigkeit und Verschiebungsverhalten von sicherheitstechnisch wichtigen Dübelbefestigungen werden Zulassungsversuche nach europäischen und deutschen Richtlinien bei unterschiedlichen Belastungen und bei unterschiedlichen Rissbreiten bzw. Risskollektiven durchgeführt. Um die Übertragbarkeit des Verschiebungsverhaltens bei Zulassungsversuchen auf realitätsnahe Belastungsbedingungen zu überprüfen, werden Ergebnisse von Zulassungsversuchen und Ergebnisse von großmaßstäblichen Erdbebenversuchen miteinander verglichen.

ACS Style

Dr.‐Ing. Jan Hofmann; ‐Ing. Fabian Dwenger; Jun.‐Prof. Dr.‐Ing. Akanshu Sharma; ‐Ing. Klaus Kerkhof. Verschiebungsverhalten von Hinterschnittdübeln unter Zuglast bei Rissöffnen und ‐schließen. Beton- und Stahlbetonbau 2019, 115, 54 -61.

AMA Style

Dr.‐Ing. Jan Hofmann, ‐Ing. Fabian Dwenger, Jun.‐Prof. Dr.‐Ing. Akanshu Sharma, ‐Ing. Klaus Kerkhof. Verschiebungsverhalten von Hinterschnittdübeln unter Zuglast bei Rissöffnen und ‐schließen. Beton- und Stahlbetonbau. 2019; 115 (1):54-61.

Chicago/Turabian Style

Dr.‐Ing. Jan Hofmann; ‐Ing. Fabian Dwenger; Jun.‐Prof. Dr.‐Ing. Akanshu Sharma; ‐Ing. Klaus Kerkhof. 2019. "Verschiebungsverhalten von Hinterschnittdübeln unter Zuglast bei Rissöffnen und ‐schließen." Beton- und Stahlbetonbau 115, no. 1: 54-61.

Technical paper
Published: 05 November 2019 in Structural Concrete
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This work experimentally investigates the efficacy of hybrid strengthening technique using a combination of near‐surface mounted (NSM) carbon fiber laminates and externally bonded (EB) carbon fiber‐reinforced polymer (CFRP) wraps for short reinforced concrete (RC) columns under eccentric loads. The performance of the hybrid FRP strengthened column elements was compared with the members strengthened using only NSM CFRP laminates or only EB CFRP wraps. The behavior of columns without and with different types of strengthening under concentric and eccentric compression was also compared. The tests showed that the RC column elements upgraded using hybrid strengthening displayed significant improvement in both the stiffness and strength, especially under eccentric compression. The performance improvement was primarily due to the substantial contribution of NSM laminates to the bending resistance. Existing analytical models were used to validate the observed behavior. The analytical results obtained had a close match when compared to the experimental results.

ACS Style

Maheswaran Chellapandian; Suriya Prakash; Akanshu Sharma. Experimental investigations on hybrid strengthening of short reinforced concrete column elements under eccentric compression. Structural Concrete 2019, 20, 1955 -1973.

AMA Style

Maheswaran Chellapandian, Suriya Prakash, Akanshu Sharma. Experimental investigations on hybrid strengthening of short reinforced concrete column elements under eccentric compression. Structural Concrete. 2019; 20 (6):1955-1973.

Chicago/Turabian Style

Maheswaran Chellapandian; Suriya Prakash; Akanshu Sharma. 2019. "Experimental investigations on hybrid strengthening of short reinforced concrete column elements under eccentric compression." Structural Concrete 20, no. 6: 1955-1973.

Journal article
Published: 14 October 2019 in Fibers
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The effectiveness of hybrid fibre-reinforced polymer (FRP) strengthening is evaluated for rapid repair of the pre-damaged plain concrete (PC) and reinforced concrete (RC) columns. The objective of this study is to understand the efficiency of hybrid technique for completely restoring the initial stiffness, load carrying capacity and ductility of pre-damaged columns under cyclic compression loads. Two series of PC and RC square columns were cast. The columns were pre-damaged by loading up to 80% of peak load capacity for three cycles under pure compression. After cyclic damage, the columns were strengthened with two techniques, namely (a) near-surface mounted (NSM) carbon FRP (CFRP) laminates and (b) hybrid FRP technique, which uses a combination of NSM and externally bonded (EB) CFRP fabric. Analytical modelling was carried out for predicting the behaviour of columns with initial cyclic pre-damage. Additionally, a phased three-dimensional nonlinear finite element (FE) analysis was performed to validate the behaviour of pre-damaged columns with different strengthening techniques. Test results show that cyclic pre-loading and resulting damage causes a reduction in axial stiffness of all damaged specimens. Hybrid strengthening completely restored the stiffness and strength under compression. Prediction of analytical and FE analysis correlated well with the tests.

ACS Style

M. Chellapandian; Saumitra Jain; S. Suriya Prakash; Akanshu Sharma; Jain. Effect of Cyclic Damage on the Performance of RC Square Columns Strengthened Using Hybrid FRP Composites under Axial Compression. Fibers 2019, 7, 90 .

AMA Style

M. Chellapandian, Saumitra Jain, S. Suriya Prakash, Akanshu Sharma, Jain. Effect of Cyclic Damage on the Performance of RC Square Columns Strengthened Using Hybrid FRP Composites under Axial Compression. Fibers. 2019; 7 (10):90.

Chicago/Turabian Style

M. Chellapandian; Saumitra Jain; S. Suriya Prakash; Akanshu Sharma; Jain. 2019. "Effect of Cyclic Damage on the Performance of RC Square Columns Strengthened Using Hybrid FRP Composites under Axial Compression." Fibers 7, no. 10: 90.

Journal article
Published: 21 September 2019 in Construction and Building Materials
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In this work, experimental and numerical studies are performed to investigate the influence of elevated temperature on the residual (post-heating) behavior of masonry. Two different types of solid brick units namely, clay bricks and calcium silicate bricks, were used in the study. The tests were performed on the individual brick units, the mortar as well as the masonry prisms (brickwork bricks and mortar). The specimens were subjected to elevated temperature reached at a relatively low heating rate and the target temperature was retained for a minimum of 2 h to ensure uniform heating of the specimen followed by slow cooling to room temperature. The residual performance of the specimens was tested to verify the influence of temperature on the behavior of masonry. The numerical (3D finite element) modeling of the specimens was performed and temperature dependent microplane model was used as the constitutive law for the brick and mortar. The numerical modeling approach has been validated and shown to be able to realistically simulate the residual behavior of masonry after exposure to elevated temperature. The results of experimental and numerical study show a relatively moderate influence of temperature on the strength but a strong influence on the stiffness of the masonry system.

ACS Style

Josipa Bošnjak; Serena Gambarelli; Akanshu Sharma; Amra Mešković. Experimental and numerical studies on masonry after exposure to elevated temperatures. Construction and Building Materials 2019, 230, 116926 .

AMA Style

Josipa Bošnjak, Serena Gambarelli, Akanshu Sharma, Amra Mešković. Experimental and numerical studies on masonry after exposure to elevated temperatures. Construction and Building Materials. 2019; 230 ():116926.

Chicago/Turabian Style

Josipa Bošnjak; Serena Gambarelli; Akanshu Sharma; Amra Mešković. 2019. "Experimental and numerical studies on masonry after exposure to elevated temperatures." Construction and Building Materials 230, no. : 116926.

Journal article
Published: 01 June 2019 in Journal of Bridge Engineering
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This paper discusses the efficacy of different fiber-reinforced polymer (FRP) techniques on the behavior of RC columns under uniaxial high eccentric compression. Eight RC columns were strengthened using three FRP strengthening schemes: (1) near surface mounting (NSM), (2) external bonding (EB), and (3) hybrid strengthening, which uses a combination of NSM and EB. All the columns were tested under an eccentricity (e) to column depth (h) ratio of 0.63. The results obtained from the experiments were compared with the results of numerical analysis using the finite-element (FE) software developed at the University of Stuttgart. The hybrid FRP-strengthened specimens showed better performance compared with only NSM or EB in enhancing the peak strength and ductility by 51% and 277%, respectively, when compared with the control RC columns. Moreover, the brittle bond failure typically observed in NSM-strengthened columns was effectively prevented through FRP confinement in hybrid strengthening. The FE modeling approach developed in this work effectively captured the overall behavior of RC columns under eccentric compression. An extensive parametric analysis using the validated modeling approach was performed to quantify the effectiveness of the different strengthening techniques for a wider range of design parameters.

ACS Style

Maheswaran Chellapandian; Suriya Prakash; Vinay Mahadik; Akanshu Sharma. Experimental and Numerical Studies on Effectiveness of Hybrid FRP Strengthening on Behavior of RC Columns under High Eccentric Compression. Journal of Bridge Engineering 2019, 24, 04019048 .

AMA Style

Maheswaran Chellapandian, Suriya Prakash, Vinay Mahadik, Akanshu Sharma. Experimental and Numerical Studies on Effectiveness of Hybrid FRP Strengthening on Behavior of RC Columns under High Eccentric Compression. Journal of Bridge Engineering. 2019; 24 (6):04019048.

Chicago/Turabian Style

Maheswaran Chellapandian; Suriya Prakash; Vinay Mahadik; Akanshu Sharma. 2019. "Experimental and Numerical Studies on Effectiveness of Hybrid FRP Strengthening on Behavior of RC Columns under High Eccentric Compression." Journal of Bridge Engineering 24, no. 6: 04019048.

Technical paper
Published: 31 May 2019 in Structural Concrete
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Though anchor channels with channel bolts are used in practice since long time, the codification of their design rules was just recently finalized in Europe with the issuing of the new EN 1992‐4. In the United States, full consolidation of the design rules for anchor channels with channel bolts in ACI 318 is yet to be included. The design requires product‐specific design data that are provided in qualification certificates. Qualification is carried out in Europe and in the United States according to published qualification guidelines. Currently, the qualification guidelines and design rules are not fully harmonized between Europe and the United States, sometimes resulting in significantly different design outcomes. This paper describes the framework of qualification and design, provides a comprehensive compendium of all design rules required for anchor channel‐channel bolt‐systems, and points out the differences between Europe and the United States with regard to qualification and design.

ACS Style

Christoph Mahrenholtz; Akanshu Sharma. Qualification and design of anchor channels with channel bolts according to the new EN 1992‐4 and ACI 318. Structural Concrete 2019, 21, 94 -106.

AMA Style

Christoph Mahrenholtz, Akanshu Sharma. Qualification and design of anchor channels with channel bolts according to the new EN 1992‐4 and ACI 318. Structural Concrete. 2019; 21 (1):94-106.

Chicago/Turabian Style

Christoph Mahrenholtz; Akanshu Sharma. 2019. "Qualification and design of anchor channels with channel bolts according to the new EN 1992‐4 and ACI 318." Structural Concrete 21, no. 1: 94-106.

Journal article
Published: 24 January 2019 in Fibers
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Addition of steel fibres to concrete is known to have a significant positive influence on the mechanical properties of concrete. Micro polypropylene (PP) fibres are added to concrete to improve its performance under thermal loads such as in case of fire by preventing the phenomena of explosive spalling. An optimum mixture of steel and micro PP fibres added to concrete may be utilized to enhance both the mechanical and thermal behaviour of concrete. In this work, systematic investigations were carried out to study the influence of elevated temperature on the mechanical properties and physical properties of high strength concrete without and with fibres. Three different mixtures for high strength concrete were used, namely normal concrete without fibres, Steel fibre reinforced concrete and Hybrid fibre reinforced concrete having a blend of hooked end steel fibres and micro PP fibres. The specimens were tested in ambient conditions as well as after exposure to a pre-defined elevated temperature and cooling down to room temperature. For all investigated concrete mixtures the thermal degradation of following properties were investigated: compressive strength, tensile splitting strength, bending strength, fracture energy and static modulus of elasticity. This paper summarizes the findings of the tests performed.

ACS Style

Josipa Bošnjak; Akanshu Sharma; Kevin Grauf. Mechanical Properties of Concrete with Steel and Polypropylene Fibres at Elevated Temperatures. Fibers 2019, 7, 9 .

AMA Style

Josipa Bošnjak, Akanshu Sharma, Kevin Grauf. Mechanical Properties of Concrete with Steel and Polypropylene Fibres at Elevated Temperatures. Fibers. 2019; 7 (2):9.

Chicago/Turabian Style

Josipa Bošnjak; Akanshu Sharma; Kevin Grauf. 2019. "Mechanical Properties of Concrete with Steel and Polypropylene Fibres at Elevated Temperatures." Fibers 7, no. 2: 9.

Technical paper
Published: 20 December 2018 in Structural Concrete
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Recent developments in the field of adhesives have led to the availability of post‐installed reinforcing bar (rebar) systems with high strength mortar. The bond strength of these mortar‐rebar systems can reach significantly higher values than the bond strength of cast‐in rebar systems in normal strength concrete. However, based on the boundary conditions of concrete cover, concrete strength, transverse reinforcement, etc., the usable bond strength of post‐installed rebar system could be limited by concrete splitting prior to attainment of the bond strength. In order to study the influence of above‐stated boundary conditions on the usable bond strength of post‐installed rebar, a new test specimen is designed on the basis of the beam‐end specimen. The specimen allows for testing of the post‐installed rebar system under realistic boundary conditions and clearly defined bonded zone while measuring unloaded‐end slip and the width of splitting cracks.

ACS Style

Justus Rex; Akanshu Sharma; Jan Hofmann. A new test specimen to investigate the bond behavior of post‐installed reinforcing bars. Structural Concrete 2018, 20, 583 -596.

AMA Style

Justus Rex, Akanshu Sharma, Jan Hofmann. A new test specimen to investigate the bond behavior of post‐installed reinforcing bars. Structural Concrete. 2018; 20 (2):583-596.

Chicago/Turabian Style

Justus Rex; Akanshu Sharma; Jan Hofmann. 2018. "A new test specimen to investigate the bond behavior of post‐installed reinforcing bars." Structural Concrete 20, no. 2: 583-596.

Journal article
Published: 08 December 2018 in Engineering Structures
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A large number of studies confirm the beneficial effects of the steel fiber reinforcement in concrete structures. The addition of steel fibers to the concrete mix leads to better mechanical and physical concrete properties including higher fracture energy, reduced crack widths, higher impact and abrasion resistance, increased durability. Due to the increasing popularity of using anchorages in steel fiber reinforced concrete (SFRC), it is essential to understand the behavior of anchorages in SFRC and to validate the applicability of the current provisions for the design of anchorages for use in structural concrete. However, there is only little research available on the behavior of anchorages in SFRC. This paper presents the results of experimental investigations on tension and shear loaded steel anchors in normal-strength plain concrete (PC) and in SFRC. The comprehensive test program includes 62 pull-out and shear loading tests on single anchors and on anchor groups. The test results are discussed in detail to emphasize the influence of steel fiber reinforcement on the load-displacement behavior of fastening systems. The results indicate that the fiber content has a positive effect on the load-displacement behavior of the anchorages, in general. A better utilization of fastening systems can be attained due to the more ductile behavior and due to the crack bridging mechanism of the SFRC. Furthermore, in certain applications and parameter combinations the ultimate load in case of concrete failure may be higher in SFRC compared to PC.

ACS Style

Máté Tóth; Boglárka Bokor; Akanshu Sharma. Anchorage in steel fiber reinforced concrete – concept, experimental evidence and design recommendations for concrete cone and concrete edge breakout failure modes. Engineering Structures 2018, 181, 60 -75.

AMA Style

Máté Tóth, Boglárka Bokor, Akanshu Sharma. Anchorage in steel fiber reinforced concrete – concept, experimental evidence and design recommendations for concrete cone and concrete edge breakout failure modes. Engineering Structures. 2018; 181 ():60-75.

Chicago/Turabian Style

Máté Tóth; Boglárka Bokor; Akanshu Sharma. 2018. "Anchorage in steel fiber reinforced concrete – concept, experimental evidence and design recommendations for concrete cone and concrete edge breakout failure modes." Engineering Structures 181, no. : 60-75.

Journal article
Published: 06 December 2018 in Fibers
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Increased loading rates on fasteners may be caused by high ground accelerations as a consequence of e.g., nuclear explosions, earthquakes or car collisions. It was concluded by Hoehler et al. (2006) that fasteners under rapid loading rates show an increased ultimate resistance in the concrete dominant failure modes or the ultimate resistance is at least as large as under quasi-static loading. Due to the increased demand on using fasteners in steel fiber reinforced concrete (SFRC), it is intended to show how the ultimate concrete cone capacity of fasteners changes under higher than quasi-static loading rate in normal plain concrete (PC) and in SFRC. This paper presents the results of an extensive experimental program carried out on single fasteners loaded in tension in normal plain concrete and in SFRC. The test series were conducted using a servo-hydraulic loading cylinder. The tests were performed in displacement control with a programmed ramp speed of 1, 100, 1000, and 3500 mm/min. This corresponded to calculated initial loading rates ranging between 0.4 and 1600 kN/s. The results of the tension tests clearly show that the rate-dependent behavior of fasteners in SFRC with 30 and 50 kg/m3 hooked-end-type fibers fits well to the previously reported rate-dependent concrete cone behavior in normal plain concrete. Additionally, a positive influence of the fibers on the concrete cone capacity is clearly visible.

ACS Style

Boglárka Bokor; Máté Tóth; Akanshu Sharma. Fasteners in Steel Fiber Reinforced Concrete Subjected to Increased Loading Rates. Fibers 2018, 6, 93 .

AMA Style

Boglárka Bokor, Máté Tóth, Akanshu Sharma. Fasteners in Steel Fiber Reinforced Concrete Subjected to Increased Loading Rates. Fibers. 2018; 6 (4):93.

Chicago/Turabian Style

Boglárka Bokor; Máté Tóth; Akanshu Sharma. 2018. "Fasteners in Steel Fiber Reinforced Concrete Subjected to Increased Loading Rates." Fibers 6, no. 4: 93.

Journal article
Published: 17 November 2018 in Construction and Building Materials
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This paper investigates the axial compression and bending interaction behavior of reinforced concrete (RC) columns repaired and strengthened with different FRP (Fiber Reinforced Polymer) techniques after severe damage. The columns were initially damaged under different axial compression to bending load ratios. The loads were applied at different eccentricity (e) to depth (h) ratios to have (i) pure compression (e/h = 0), (ii) eccentric compression (e/h = 0.63) and (iii) pure flexure (e/h = ∞). After initial damage, the specimens underwent severe concrete core degradation with the main steel reinforcement reaching its yield strain. Later, the specimens were repaired using high strength cement grout (HSCG) and further strengthened using (i) near surface mounting (NSM) of carbon FRP (CFRP) laminates and (ii) hybrid FRP technique with a combination of NSM laminates and external bonded (EB) fabrics. After that, the columns were loaded again until failure. An axial compression (P) – bending moment (M) interaction diagram was developed experimentally for the severely damaged columns. Also, the interaction curves were developed analytically using strain compatibility procedure with the modified constitutive models. Experimental results reveal that the specimens repaired and strengthened using hybrid FRP technique can effectively restore the original capacity under different eccentric load levels. The analytical predictions showed a close match when compared to the experimental observations.

ACS Style

M. Chellapandian; S. Suriya Prakash; Akanshu Sharma. Axial compression–bending interaction behavior of severely damaged RC columns rapid repaired and strengthened using hybrid FRP composites. Construction and Building Materials 2018, 195, 390 -404.

AMA Style

M. Chellapandian, S. Suriya Prakash, Akanshu Sharma. Axial compression–bending interaction behavior of severely damaged RC columns rapid repaired and strengthened using hybrid FRP composites. Construction and Building Materials. 2018; 195 ():390-404.

Chicago/Turabian Style

M. Chellapandian; S. Suriya Prakash; Akanshu Sharma. 2018. "Axial compression–bending interaction behavior of severely damaged RC columns rapid repaired and strengthened using hybrid FRP composites." Construction and Building Materials 195, no. : 390-404.