Comparative Study of Seismic Analysis of Pier Supported on Pile as per IRC:6-2017 and IRC SP:114-2018
This paper depicts the study of seismic analysis of reinforced concrete bridge piers as per provisions of Indian Road Congress (IRC) guidelines. Bridges are designed having two main structural elements named – “Superstructure” and “Substructure”. Superstructure consists of deck and supporting girder/truss system below deck. Substructure includes Abutments, Piers, Portals and Foundations. Amongst these, Abutments/Piers are crucial part of bridge. Therefore, as per the seismic design philosophy, it is necessary to study the seismic behaviour of bridge piers. With the advancements in technology and subsequent researches in Infrastructure fields, IRC guidelines are updated and revised time-to-time. Introduction of IRC SP:114-2018 guideline for earthquake forces in bridges is an example of such developments. In this research, seismic analysis of Reinforced Cement Concrete (RCC) bridge pier is carried out as per provisions of prevailing guideline IRC:6-2017. Base shear value of IRC:6-2017 is compared with IRC SP:114-2018 which now supersedes seismic provisions of IRC:6-2017. For analysis, different span lengths of 25 m, 30 m and 36 m are used. To assess the impact of height of piers in earthquake analysis, various pier heights such as 10 m, 20 m and 30 m are assumed. The analysis is carried out as per Elastic Seismic Acceleration Method with consideration of different zones and importance of the bridge as per IRC guidelines. Effect of vertical ground motion is also considered in analysis. From analysis, it is observed that base shear and vertical forces have been increased remarkably as per IRC SP:114-2018 compared to IRC:6-2017.