Department of Civil Engineering
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Item Methodology for Predicting the Structural Response of FRP-Concrete Composite Beams Using Abaqus/CAE Software Package(Springer, 2022-07) Singh, Shamsher BahadurA Fiber Reinforced Polymer (FRP)-Concrete composite beam system comprises of several contact interactions, sub-components with varying geometries, and complex material behavior. Evaluating the flexural response of such structures through experimental campaigns is highly expensive and time-consuming as obtaining the desired output variables requires the specimens to be heavily and precisely instrumented. A numerical simulation could provide a much better alternative in this case as it can simulate the complete mechanical response of the physical system with relatively much ease and economy. However, the complexities involved with the problem regarding contact interactions and complex material behavior, make such analysis suffer from several convergence difficulties. The chapter is an attempt to overcome these difficulties by establishing a methodology that can be followed for modeling and analyzing such structures.Item Durability Evaluation of Carbon Fiber –Reinforced Polymer Strengthened Concrete Beams: Experimental Study and Design(ACI, 2005) Singh, Shamsher BahadurThis paper deals with the durability of the reinforced concrete (RC) beams externally strengthened with carbon fiber-reinforced polymer (CFRP) plates and fabrics under adverse environmental conditions such as 100% humidity, saltwater, alkali solution, freeze-thaw, thermal expansion, dry-heat, and repeated load cycles. The deflections, strains, failure loads, and failure modes of strengthened beams exposed to different independent environmental conditions and repeated load cycles are presented. To determine the design strength of CFRP-strengthened beams exposed to long-term environmental conditions, strength reduction factors associated with various independent environmental conditions are proposed. In addition, the failure modes and physical changes of the beams exposed to various independent environmental conditions were also examined. It is concluded that the long-term exposure to humidity is the most detrimental factor to the bond strength between CFRP plates and fabrics and RC beams. Beams strengthened with CFRP plates and exposed to 10,000 hours of 100% humidity (at 38 ± 2 °C) experienced an average of 33% reduction in their strength. The onset of delamination was the primary mode of failure for all of the test beams. Finally, a durability-based design approach is presented. The design approach appropriately demonstrates the evaluation of nominal and design moment strengths of the beam strengthened with CFRP plates and exposed to a 100% humidity condition.Item Mechanical properties of Recyled Coarse Aggregate (RCA) Concrete(Research India Publications, 2014-01) Singh, Shamsher BahadurThis study deals with experimental investigation of mechanical properties of recycled coarse aggregate (RCA) concrete. The scope of the investigation programme is defined to generate detailed material properties for concrete of M25 grade made with various percentage of flyash, GGBS (Granulated blast furnace slag), recycled coarse aggregates with replacement percentage of 100, 90, 80, 70, 60, 50. The experimental programme consisted of thirty two batches of casting and testing of sustainable concrete elements in compression, tension and in flexure. The stress-strain relationship for concrete Recycled Coarse Aggregate concrete under uniaxial compression has been evaluated. The influence of replacement ratio of recycled coarse aggregate, flyash, GGBS on RCA concrete properties were also studiedItem Mesoscale Modelling of Concrete: Need of Including Rheological Parameters(INSA, 2017) Singh, Shamsher BahadurConcrete is a highly complex and heterogeneous material which limits the characterization prediction reliability of the concrete by experimental investigations. To obtain a deeper knowledge about the behavior of the concrete, better understanding of mesoscale constituents of the concrete need to be analyzed. Interaction of different constituents and their parameters manipulating the microstructure is not strictly considered for computing macroscopic performance of the concrete. For realistic simulation of macroscopic performance of concrete, those disregarded parameters need to be examined and included for computational analysis, since mechanical behavior and characterization of concrete are highly influenced by mesoscopic structural arrangement of the concrete ingredients. Characterization of different components of the concrete is made by finite element meshing the individual component with desired approach to vitalize effective computational analysis. This paper reviews different mesoscale modelling approaches and recommends the need and inclusion of rheological parameters in mesoscale models