# Design and Simulation Analysis of a New Type of Assembled UHPC Collision Avoidance
###### Abstract  
Ship-bridge collisions are one of the most common types of accidents, and bridge anti-ship collision devices are of great importance for bridge protection. First, a new type of assembled ultra-high performance concrete (UHPC) collision avoidance is proposed in this paper. The main components of the device are double-deck, two-way, densely reinforced ultra-high performance concrete floating boxes that are connected by high-strength bolts to form the whole structure and are equipped with steel supporting elements to form a collision energy dissipation device. The device is self-floating in water, is strongly energy absorbing due to plastic deformation, has a high degree of toughness, is corrosion resistant, and so on. This device also benefits from modular manufacturing, efficient installation, and easy replacement of damaged parts. Then, in this paper, the main parameters of the new collision avoidance, such as the material of the internal supporting elements, the wall thickness of the floating box, and the reinforcement ratio of the floating box, are optimized. Finally, a performance analysis and evaluation of the UHPC collision avoidance for the Honghe Bridge in Zhuhai City are carried out by using LS-DYNA program. The numerical results show that the new collision avoidance has significant advantages in reducing the ship-bridge collision force, prolonging the ship-bridge collision time, and protecting the ship. The results show that the assembled UHPC collision avoidance system is very effective for protecting ships and bridges in the event of a ship-bridge collision. ship-bridge collision; UHPC; collision avoidance; buffer energy consumption; finite-element models +
Footnote †: journal: Applied Soft  
collision avoidances in the world are artificial islands, double-wall steel cofferdams, steel floating boxes, suction pile [7], FRP(Fiber Reinforced Plastics) fenders, wood fenders, etc. [8]. However, artificial islands require a large amount of engineering, entail high costs, and occupy a large amount of navigable area, and steel collision avoidance systems have great stiffness and result in a hard contact with the pier. Additionally, the corrosion resistance of the whole system is poor, the maintenance process is complex, the damage scope is large when an impact occurs, and the maintenance costs are high. Since the strength of the material itself is low, fiberglass reinforced plastics and wood are able to meet the requirements. There are great limitations in terms of energy absorption. At present, the applications of ultra-high performance concrete materials are gradually being promoted, as reported by [PERSON] et al. [9]. The compressive strength of UHPC with different fiber contents was studied by a splitting test using a Hopkinson compression bar (SHPB). It was found that the impact resistance, compressive strength, and flexural strength of UHPC increased with the the fiber content and with increases in the strain rate. [PERSON] et al. [10] found that the compressive strength and splitting tensile strength of UHPC under dynamic loads are sensitive to the strain rate and the stress rate. [PERSON] et al. [11] studied the dynamic characteristics of UHPC under bending and shear loads and gave the variation law of the dynamic growth coefficient. [PERSON] and [PERSON] [12] found that UHPC materials have strong resistance to chloride ion erosion, according to the test methods found in American specifications. [PERSON] and [PERSON] [13] carried out chemical erosion-related durability tests and found that super high performance concrete made with fly ash shows excellent durability. It can be seen that the UHPC material has the advantages of high strength, good corrosion resistance and ultra-high durability [14] and that it is very suitable for anti-ship collision structures in water.