Topping slab for Bridge

[Structures33]

I have an existing bridge in a high-end residential neighborhood - Kiawah Island, SC - that was constructed in 1993. The bridge was never used following construction because development of the area stopped. The client now wants to put a topping on the bridge and finalize for vehicular traffic. The bridge is made of 1'-5" deep prestressed hollowcore panels, supported by concrete piles/caps at 34' spacing (total of 510' long). The panels are 4'-3" wide and overall bridge width is 34' (total of 8 precast panels across).
After construction they never installed the wearing surface on the bridge so all the joints are visible. They want to revise the bridge to have a 2-lane road down the middle of the bridge with walkways on the outside.
The original design had a 2.5" thick concrete topping slab for wearing surface (which wasn't installed). If we're trying to avoid seeing the joints, what is the best material - concrete or asphalt? What is the best method for installation to ensure an adequate bond of the topping to the existing? What should the minimum thickness of topping be?

Thanks very much for any advice you can provide.

 

[ishvaaag]

The different hollowcore elements when having a point load at one side the interface will cause substantial stress in the overlay; so I first would examine how the initial design dealt with this issue. Maybe it was not dealt with, but then you want a durable finish and so want to examine the question.

A FEM model of whatever in the end to place is very recommendable. The overlay needs to be durable to wear and weather, stout and hardly breakable, and maybe not to exceed some given thickness or weight. This points more to some specialty overlay product than asphalt mixes; however one could examine a structural (slab) topping plus a wearing surface.