Assessing the choice of a 15m span single bridge: a case study of composite slab bridge deck and solid slab bridge deck.

Abstract

A successful bridge design must be natural, simple, original, and harmonious with its surroundings. Bridge designers are always challenged to provide the most feasible and optimal bridge options for given obstacle. The main objective of this report is to provide a comparative assessment of the cost of construction of a solid slab bridge and a steel composite bridge for a 15m span simple bridge deck using Midas civil software (v2020). This research seeks to provide a material and cost comparison of the two bridge types for a clearcut decision making for bridge design engineers. Finite element analysis software and computer aided design software were used because they are merited to save time, add variations into the software without repeating the design process and decrease error percentage in work. Two bridge decks of span 15 meters and 11 meters wide were analyzed in the software. C32/40 grade of concrete was used for the composite slab and C35/45 grade concrete was used for the solid slab. The steel main girders in the composite slab UB 1016x305x222 and the cross beams were UB 406x140x39. Fixed and free abutments of same properties with a clear height of 5.3m was designed to accommodate the weight of the deck. From Midas Civil, we were able to obtain design results and reports for the different decks from which technical drawings were obtained for costing. Bills of quantities were made for both decks and abutments and from these some conclusions were made as follows • The solid slab bridge deck is preferred especially for shorter spans. • The highest reactions on the abutments occurred un the solid slab bridge • Most materials required for the solid slab bridge are found in Uganda where as the main girder beams used in the composite slab bridge are not locally available. • The field operations associated with construction of steel composite concrete gives a higher degree of ease of construction compared to a solid slab deck