Grillage Analysis of Prestressed Concrete Girder Deck Superstructure for NH-16 Bridge Flyover; Part-1

Abstract

Abstract: The bridge superstructure flyover built on National Highway route 16 (NH-16) near Benz circle in Vijayawada to act as grade separated highway for vehicles to cross over National Highway route 65 (NH-65) is made of precast and post-tensioned concrete girders. This article is the first part of the two phase study that focuses on the structural analyses of concrete bridge girders. The bridge girders are analyzed for vehicular loads considered as per Indian Roads Congress Specifications. The IRC Class of loads of 70R and Class A and their wheel load configurations are discussed. The bridge girders along with deck are modeled as grillage girder-slab members in Staad Pro analysis software. The bending moments and shear forces are computed for each of the IRC vehicular load configurations and the envelope forces for governing load configuration are presented for each of the girders. Finally, the article summarizes the maximum flexural and shear demands on the bridge girders. The pros and cons of grillage analysis modeling for prestressed girders and the alternate superior options for precise but quick modeling are also recommended.