Written a book on Earthquake Resistant Design of Structures published by Prentice-Hall of India, New Delhi, 2006. Fifteen reprints till September 2016 and approximately 1,00,000 copies already sold. It is referred as text book in Govt. and Pvt. engineering colleges in India including IITs & NITs.
Developed a new integrated large scale Pseudo-Dynamic/Cyclic Test Facility with total overlay of Rs 21.00 Crore. The facility is very useful for the calibrations/ verification and updating the numerical modeling of new/innovative concepts. It consists of (a) Servo-Hydraulic System (Actuators (1± 1000kN/250mm @ 3 @ ± 500kN/250mm 2 @ ± 250kN/250mm, Hydraulic Power Unit (400 l/min at 210 bar), Digital Compact Eight Channel Controller, Digital Image Correlation system, Software with other related items) (b) Strong Floor (12 m x 10m), Reaction Wall (2 Nos of 9m x 9m) and Reaction Frame (6m x 9m with 100 tonne capacity under any combination of loads i.e. axial, flexure shear and torsion (iii) with the 25 tonne overhead crane facility. In addition, a new uni-axial shake table of size 5m x 8m to test the specimen upto 1000 kN under dynamic condition is under process. Shortly, it will integrated with the existing servo-hydraulic system of the facility.
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"Earthquake Resistant Construction of Low & High Rise Building by Using Interlinked Block Masonry with Visco-elastic Link Elements" An alternative technique to construct earthquake resistant housing construction (Low & High Rise) based on the concept of energy dissipation/ damping How is it different? The conventional earthquake resistant measures are based on ductility (capability to undergo large deformations without collapsing) while in the present technology, an effective use of damping (capability to energy dissipation) is explored through friction between the blocks and yielding of visco-elastic link elements. Here, an audio-video film (File name: Interlinked Block Masonry.mp4) of six minutes duration shows design and development along-with experimental tests on shake table and shock table conducted on full scale models on the proposed technology. The interlinked block masonry system with visco-elastic link element is very well tested and directly implemented in the construction of load bearing type of structure (low rise upto 4 storey: directly on block). The same concept is applied on the in-filled RC multi-storied building frame construction and the entire energy has dissipated by the infill panel as can be demonstrated by conducting a test on full scale one storey reinforced concrete frame with visco-elastic energy dissipating infill panel (File name: Frame with flexible infill.mp4). The patent filed: "Earthquake Resistant Visco-Elastic Energy Dissipator Link Elements - Full disclosure CINIITR0000100024 (CRN 024) is under consideration. Publication: Amit Goyal, Pankaj Agarwal (2017) " Earthquake-Resistant Interlinked Block Masonry System with Energy Dissipator Viscoelastic Links" Practice Periodical on Structural Design and Construction (ASCE), Vol. 22, Issue 03, pages 04017001. |
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A rebar coupler sleeve is developed for the seismic retrofitting of severely damaged reinforced concrete columns with buckled reinforcement. The proposed sleeve conforms with the standard requirements of class H coupler, as per Indian Standard IS: 16172: 2014, where it passes all the tests such as static tensile, slip, cyclic tensile, low cycle fatigue along with high cycle fatigue of 2-million cycles. The suggested sleeves of a structural member are interlinked both in lateral and diagonal directions using flat steel bars to form the box-shaped confinement assembly that effectively resists the lateral shearing force at the potential plastic hinge region. Patent Filed: “A System and Method for Seismic Retrofitting of Severely Damaged Reinforced Concrete Frame Buildings using Coupler-Box Section” with an application number 202011007735 dated 24th of February, 2020. Publication: Kothapalli, N.K., Chidambaram, R.S. and Agarwal, P., 2022. Cyclic evaluation of severely damaged RC frames repaired and strengthened through FRP-wrapped coupler-box confinement. Journal of Composites for Construction ASCE, 26(3), p.04022016 |
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To enhance the energy dissipating capacity of the seismic deficient building, a new type of discrete damper is designed. The proposed damper resists applied lateral force through deformable yield link units, which are inserted in the slots of square grid framework, and are made to yield in double-curvature at their respective mid-section. The gravity load transfer of the structure is accomplished by the slide-rubber bearings fabricated using strengthened rubber, stainless steel and Teflon sheets. The adaptive lateral link units are isolated from vertical loads and deform exclusively under applied lateral drifts. The gravity load transfer through the slide-rubber bearings remains persistent under enforced lateral loads. Thus the damper remains intact for gravity load transfer even after its nullified lateral strength. Patent Filed “A Discrete Energy Dissipating Damper Device with Adaptive Yield Link Elements” with an application number 202111027203 dated 17th of June, 2021. |
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A novel energy dissipating hysteretic infill system is conceptualized with the help of slotted concrete blocks interlinked with energy dissipating visco-elastic link elements made-up of styrene-butadiene rubber. This infill system utilizes two sources of energy dissipation mechanisms namely: (i) friction arising between the rigid surfaces of the blocks and (ii) elastomeric damping arising from the straining of visco-elastic energy dissipating link elements that also restrict the translational and rotational movement of each block. The lateral strength and deformation capacity of the energy dissipating hysteretic infill wall under in-plane and out-of-plane direction is significantly higher than the conventional brick infill wall. Publications Pachappoyil, N. S., and Agarwal, P., 2022. Cyclic evaluation of energy dissipating hysteretic infilled reinforced concrete frame: A novel approach as low-cost passive energy-dissipating device, Earthquake Spectra 38(1), 677-701. https://doi.org/10.1177/87552930211031578 Pachappoyil, N. S., and Agarwal, P., 2021. Performance evaluation of the energy dissipating hysteretic infill wall frame considering opening under in-plane and out-of-plane loading, Engineering Structures 249, 113329. https://doi.org/10.1016/j.engstruct.2021.113329 Pachappoyil, N. S., and Agarwal, P., 2021. Performance-based evaluation of energy dissipating hysteretic infilled reinforced concrete frame based on cyclic tests, Journal of Earthquake Engineering, 1-21. https://doi.org/10.1080/13632469.2021.2003271
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