Experimental study on transverse flexural performance of thin UHPC bridge deck structure with cavities

To address the durability deterioration of steel bridge decks caused by chloride-induced corrosion in marine environments, the thin UHPC bridge deck structure with cavities was proposed based on the superior durability and mechanical properties of ultra-high performance concrete (UHPC). Four full-scale transverse bending tests were conducted to systematically investigate the effects of fiber type and concrete cover thickness on the mechanical performance and cracking behavior of thin UHPC bridge deck structure with cavities. The experimental results revealed that steel fiber-reinforced UHPC specimens significantly outperform basalt fiber-reinforced specimens in enhancing the mechanical properties of thin UHPC bridge deck structure with cavities. Specifically, under positive and negative bending moments, the cracking loads increased by 380 % and 225 %, cracking stresses improved by 298.6 % and 224.2 %, and ultimate bearing capacities were elevated by 80 % and 140 %, respectively. Similarly, increasing the concrete cover thickness and utilizing steel fiber reinforcement effectively suppressed crack initiation and propagation. A finite element model of the temporary bridge structure under staged loading conditions was developed to validate structural safety in practical engineering scenarios. Furthermore, predictive equations for cracking load and ultimate bearing capacity of thin UHPC bridge deck structure with cavities were formulated, incorporating the unique mechanical characteristics of UHPC, the numerical results demonstrate close agreement with experimental data. • The bending tests of four thin UHPC decks with cavities were carried out. • The influence of fiber type and loading method on transverse bending properties was analyzed. • A finite element model of thin UHPC deck with cavities is established and analyzed. • Equations are developed to estimate the cracking stress and ultimate load and of the thin UHPC deck with cavities.