1 Abstract- In this paper, a sandwich composite bridge deck made of fibre-reinforced polymer (FRP) as face layers and closed-cell semi-rigid PV foam as the core is investigated. First, Finite element model sandwich composite deck panel is developed and free vibration analysis of the deck panel models are performed to obtain the dynamic responses such as natural frequencies, mode shapes. The objective of the present research is to perform the sensitivity analysis considering different material properties of the different layers of the composite sandwich deck panel. The sensitivity analysis is carried out on the basis of modal properties of the panel with respect to different material parameters such as Ex, Ey, Ez, Gxy, Gxz, Gyz and Poisson’s ratio of face layers and modulus of elasticity (E) of the core of the sandwich plate. The sensitivity analysis is repeated for the various sandwich deck panels with different elastic material properties. The comparative study is performed for all the sandwich deck models analyzed. Keywords- Sandwich Composite; Mode Shape; Bridge Deck; Sensitivity; Frequency I. Introduction The sandwich FRP structure is made of a special type of composite materials which is manufacture by stacking two thin face plates and a thick core layer. The faceplates are thin but very stiff and the core material is basically low in strength, but the bending stiffness is high and low density to the structure for its higher thickness. In core layer synthetic foams, honeycombs, polyethylene are commonly used as core material. In the open and closed-cell-structured, foams are * Corresponding author Subhajit Mondal Department of Civil Engineering, NIT Rourkela, India, mondalsubhajit@nitrkl.ac.in mainly used as core material. Glass laminated or carbon laminated fibre-reinforced thermoplastic or thermoset polymers like unsaturated polyesters, epoxies etc. are commonly used as face materials. The face sheets are bonded with the core with an adhesive or with metal components by staking together. The surface of the bridge is known as bridge deck. The bridge deck is a structural component which transfers and distributes the loads to the corresponding piers and abutments. Nowadays, the pre-cast concrete plates are widely used as bridge decks. The structural failure of a bridge deck is due to various environmental conditions, fatigue and dynamic loadings, heavy vehicle traffic. There are various problems arisen in the replacement and repair of a concrete bridge deck for their heavyweight. Because of the heavy traffic volume in bridge, speed of construction and replacement of heavy deck are very critical. The sandwich composite deck is light in weight as compared to the concrete bridge deck. So, it becomes easier to replace and handle where necessary. The sandwich composite deck advantageous because of their high strength, ease of handling, replacing, repairing and also less time consuming in construction. Liu [1] conducted a sensitivity analysis on the composite laminated structures considering the mode shapes and frequencies obtained from the free vibration analysis. Kulpa and Siwowski [2] investigated the bridge deck panel made up of novel FRP sandwich to evaluate strength and stiffness for redecking bridge deck by experimentally. Sahoo and Singh [3] investigated composite laminates sandwich plate with periodic compressive and in-plane static load to observe the dynamic stability. Ji et al. [4] analyzed the sandwich composite bridge deck which was made up of GFRP as face layer and steel core to observed static and fatigue performance. Mondal et al. [5] studied the composite sandwich plate with hole/cut out and observed the dynamic performance in the mix of experimental and numerical study. Mondal et al. [6] used the gradient base Second ASCE India Conference on “Challenges of Resilient and Sustainable Infrastructure Development in Emerging Economies” (CRSIDE2020) March 2-4, 2020 Sensitivity Analysis of Bridge Deck Panel Made of Fiber Reinforced Plastic Sandwich Composite Chandan Kabat #1 , Suryamani Behera *2 , Bibhuti Bhusan Mukharjee #3 , Subhajit Mondal *4 #1 Department of Civil Engineering, CAPGS, BPUT Rourkela, India, chandan.kabat.ck@gmail.com * 2 Department of Civil Engineering, NIT Rourkela, India, suryamani1014@gmail.com #3 Department of Civil Engineering, CAPGS, BPUT Rourkela, India, bibhuti.2222@gmail.com * 4 Communicating author, Department of Civil Engineering, NIT Rourkela, India, mondalsubhajit@nitrkl.ac.in