Abstract

The present study examines the performance of concrete modified with different percent of epoxy resin under various curing conditions. Different grades of concrete (M20, M25, M30) with different epoxy (resin hardener) - cement ratio were analyzed to determine the impact on the mechanical properties of the mixed concrete.72 specimens (36 cubes and 36 cylinders) for all the three grades (M20, M25, M30) with varying epoxy (resin hardener) - cement ratio by weight for each grade that is 5%, 7.5% and 10% were testified. Compressive strength as well as splitting tensile strength are evaluated for 7, 14, and 28 days. The results were then compared with the conventional concrete specimens for each grade at the respective ages. Results showed that the strength of samples depend on the amount of epoxy used and showed that the strength of Epoxy Mix Concrete (EMC) is having more strength than conventional concrete at the corresponding ages. Results also showed that there is a considerable decrease in slump and workability with the increase in epoxy -cement ratio and that the workability of conventional concrete is more than that of EMC.

Abstract

This paper presents the transient load analysis of an existing stone masonry arch bridge. The bridge is analyzed to study its stress and deformation behavior. Three cases, namely, original bridge subjected to MG (Meter Guage) or BG (Broad Guage) loading, retrofitted bridge subjected to BG loading was analyzed. The analysis indicated that retrofitting is required to launch BG loading in the existing bridge. A retrofitting by concrete jacketing on the pier and intrados of arch was suggested. The adequacy of the suggested retrofitting to carry the increased load due to the gauge up-gradation is evaluated. The finite element analysis is carried out to determine the stress, crown deflection, and spread of the arch. Three dimensional models of the stone masonry arch bridge in its original form and strengthened form are generated in CATIA V5 (Computer Aided Three Dimentional Interactive Application Software). Transient analysis of the bridge is carried out in ANSYS (Analysis System Software). The 3D finite element analysis indicated that the crown deflection in the original structure is more than the limiting value specified in the Arch Bridge Code. The provision of 450 mm thick concrete jacket for the arch was found to be sufficient to mitigate the excessive crown deflection. The strengthening work is progressing in the work site.

Abstract

The production of cement generates large amount of carbon dioxide. Normally, conventional concrete is manufactured with Portland cement, which acts as a binder. The production of cement emits CO into the atmosphere, 2 which is a greenhouse gas and causes environmental pollution. In view of this, there is a need to develop sustainable alternatives to Portland cement utilizing the industrial by-products, such as fly ash, Ground Granulated Blast furnace Slag (GGBS) which are pozzolonic in nature. It has been established that fly ash can replace the cement partially. In this context, a new material was developed known as “Geopolymer”.

In this study, various parameters on the short term engineering properties of fresh and hardened properties of Geopolymer Mortar were studied. In the present investigation, cement is replaced by geopolymer source material (fly ash and GGBS) and water is replaced by alkaline activator consisting of Sodium Silicate and Sodium Hydroxide of molarity (12 M). The ratio of sodium silicate to sodium hydroxide adopted was 2.5. The test results showed that final setting time decreases as the GGBS content in the mix increases and also these is increase in compressive strength.

Abstract

Seismic design is followed in different countries on force based design with a final check on displacement. Linear elastic analysis is performed and the comparison of Response Reduction factor is calculated based on the National and International codes. Response reduction factor reflects the capability of structure to dissipate energy through inelastic behavior which accounts for the damping and ductility requirement. Building codes define R-factor based on type of structural system, material configuration, and detailing. Codes also differ in calculation of drift and allowable drift limit. R-factor from many developing countries are obtained from well developed countries which makes them more vulnerable towards earthquake and thus provides a false representation and thereafter it turns to be unrealistic. A parametric study involves modeling a dual system in ETABS and response spectrum analysis is carried out. This paper focuses on study of variation of base shear with R factors and its effect on membrane forces considered in design of members. A comparison of results is made using building codes IS 1893 and ASCE 7-10. The performance of building is verified using displacement modified approach.

Abstract

Neo-Deterministic Seismic Hazard Analysis is an innovative method for seismic hazard analysis in India, based on realistic earthquake scenario. This paper shows a comparative study on methodology of neo-deterministic seismic hazard analysis over DSHA and PSHA. Deterministic seismic hazard analysis and Probabilistic seismic hazard analysis provides only peak ground acceleration, but Neo-deterministic seismic hazard analysis provides also other ground motion parameter like peak ground displacement and peak ground velocity that can play key role in developing seismic hazard maps. The objective of this research and use for seismic microzonation purposes were also discussed.

Abstract

In the recent past, Geopolymer concrete has emerged as a potential alternative to the OPC concrete in the light of global warming, which is a major environmental concern all over the world. A considerable work has been reported on the development and poperties of Fly-ash based Geopolymer concrete, but only a little work can be seen in the past literature on blended geopolymer concrete. The present work investigates the strength properties of Ternary blended geopolymer concrete with different combinations of fly ash, GGBS, and Wallastonite in which 50% of fly ash was kept constant in all the mixes and remaining 50% with Wallastonite and GGBS in the ratios of 15%:35% , 25%:25%, 35%:15% respectively were taken. All the mixes are designed for 40 Mpa and the strength properties, such as compressive strength, split tensile strength, and flexural strength tests were determined on all the mixes. Strength tests reveal that a mix with combination of 50% fly ash and 25% Wallastonite and 25% GGBS has shown better performance over other mixes and chosen as Optimal mix.

Abstract

In this paper, the authors present an illustratived step by step approach to perform Isogeometric analysis (IGA). The existing literature does not have any solved problems in a stepwise procedure, which can be useful to explain in a classroom. This paper should serve as a benchmark example to refer the stepwise procedure to learn IGA. The focus is on the illustrative stepwise analysis and Isogeometric analysis using NURBS basis functions (Non-Uniform Rational), which can represent the Geometry of the structure more precisely over the finite element method. In this paper, a two dimensional plane plate structure carrying in-plane loading is analysed using Isogeometric analysis. The problem is also solved using Marc Mentat®, a finite element package and the results are compared and presented. The results show that the nodal displacements calculated using Isogeometric analysis are in close agreement with the nodal displacements found using a standard finite element package.