Innovations in material characterization and structural configuration of link slabs
Expansion joints included in bridges to accommodate thermal expansion and contraction provide an easy route for water to pass through to the underlying substructure, thus, causing corrosion of the substructure. These expansion joints accumulate debris and require frequent repair and maintenance. Link slabs provide a potential solution to eliminating these expansion joints. The research presented in this thesis explores the structural behavior of link slabs through experimental tests and finite element simulations. The study presents a novel non-proprietary ultra-high performance concrete, which can also be a potential replacement for materials used in the link slabs.
The first part of this thesis consists of testing two full scale link slab specimens in the laboratory. The link slabs were made of fiber-reinforced concrete (FRC) with steel and GFRP rebars. The link slabs were carefully designed so that the stresses from the concrete deck are effectively transferred to the link slab. The designed link slabs were tested to evaluate the detailing of the transition zone and to understand the overall performance of the structural setup. A comparison was then made between the results obtained from the two link slabs. A set of finite element models were developed for the link slabs tested and the parameters, such as rebar spacing in debonded length, rebar spacing in bonded length and depth of link slab, were evaluated.
In the second part, an experimental setup was tested to find out the effect of support condition on the stresses in the link slab. The effect of support condition was further evaluated by developing a set of finite element models for a case study bridge to explore the possibility of installing a link slab on existing bridge structures. The finite element study not only evaluated the response of link slabs, but also determined its effect on the substructure of the existing bridges. In the final part, a nonproprietary UHPC was developed with the properties that are important for link slabs. The non-proprietary UHPC was tested for transport properties, volume stability, and frost resistance. The non-proprietary UHPC mixes tested showed characteristics comparable to the proprietary UHPC mixes, thus, making it a competitive alternative to be used in link slabs.