Numerical Simulations for Structural Response of Masonry Arch Bridge with Relieving Slab as Upgradation Strategy

Many of the arch bridges built on the railway network are several decades old and were designed according to the loading prevailed in the standards of practice. Most of these bridges are in good state even today and can be upgraded to meet the present demand and for continued usage. In the present paper, an upgradation strategy is formulated for an existing old masonry arch bridge to accommodate the demand for conversion of meter gauge to the broad gage track, and for improvement in structural performance, as well. A three-dimensional numerical finite element modeling and analyses were performed to evaluate the response parameters and to assess the efficacy of upgradation strategy for accommodating the gauge conversion on an existing masonry arch bridge system. Experimental investigations have been carried out on a typical masonry arch bridge to validate the numerical model. The upgradation of the modified arch-slab bridge system is carried out by introducing reinforced concrete relieving slab over the soil fill. To avoid any tension between the fill and the arch masonry (both barrel and spandrel), special contact elements with friction co-efficient is incorporated in the finite element model. From the numerical simulation studies on the modified arch-slab system for the masonry arch bridge, it is found that the proposed upgradation scheme is efficient to meet the need for broad gauge conversion.