Bridge Pier Protection Research Articles

Manufacturing and evaluation of Large-scale Composite Bumper System for bridge pier protection against ship collision

An innovative Large-scale Composite Bumper System (LCBS) for bridge piers against ship collision was recently proposed at Nanjing Tech University. The modular segment of LCBS is made of Glass Fiber-Reinforced Polymer (GFRP) skins, GFRP lattice webs, Polyurethane (PU) foam cores and ceramic particles in which Vacuum Assisted Resin Infusion Process (VARIP) is adopted in the manufacturing process. This novel bumper system offers several remarkable advantages, such as: self-buoyancy in water, modular fabrication of segments, efficiency for on-site installation, excellent corrosion resistance, as well as ease in replacing damaged segments. In this paper, the manufacture procedures as well as the installation process of LCBS were introduced. An in-depth analysis of performance evaluation of LCBS was then conducted for a real cable stayed bridge using a nonlinear explicit dynamic finite-element analysis program (LS-DYNA). The simulation results indicated that LCBS can effectively increase the impact time of ship-bridge collision, and reduce the peak collision forces to a non-destructive level, leading to a good effect in energy dissipation. The results suggest that LCBS is an effective bumper system for protecting bridges and ships in ship-bridge collisions.

Case Study: Evaluation of a Floating Steel Fender System for Bridge Pier Protection against Vessel Collision

AbstractVessel collisions with bridges occur frequently worldwide and have the potential to cause enormous casualties, substantial property loss, and environmental destruction. Physical protection systems designed for bridge piers against vessel collisions are viable solutions to alleviate/prevent those disruption costs. This paper introduces a floating steel fender system for bridge pier protection and evaluates the performance using an explicit dynamic finite-element analysis code. The analysis method is validated against available drop-weight impact tests of a steel box module, because the steel fender system is constructed by repeatedly stacking and aligning a similar subassembly. The introduced fender system noticeably reduced the peak impact force applied on a bridge pier by approximately 55.3% and on the colliding vessel by approximately 56.2% while extending the impact duration approximately 273.1% as compared to the head-on collision without any protection. It was also shown that the initial kine...

Advances for studying the effect of viscosity in riprap sizing for bridge pier protection

En la experimentación sobre dimensionamiento de enrocados de protección de pilas de puentes es habitual el considerar despreciables los efectos de la viscosidad del agua sobre los resultados y excluir del análisis dimensional al grupo adimensional representante de dichos efectos. Sin embargo la experiencia en ensayos de laboratorio de diques de escollera marítimos ha demostrado que para ciertas escalas el flujo entre las capas de enrocado puede variar de régimen introduciendo efectos de escala significativos. En ese marco el objetivo de este trabajo fue el de realizar avances en el estudio de la influencia de la viscosidad para ensayos de enrocados de protección de pilas de puentes. Se realizaron en el canal sedimentológico del IMFIA tres pares de ensayos. En cada par se mantuvieron constantes los grupos adimensionales que influyen en el problema a excepción del representante de la viscosidad. En dos de los tres ensayos se constató un cambio significativo en el tirante necesario para el movimiento del enrocado al variar el representante de la viscosidad, por lo que se concluyó que su influencia no debería ser descartada a priori. Se remarca la necesidad de continuar la línea de investigación ampliando los ensayos a mayores tamaños de enrocado.

Evaluation of a New FRP Fender System for Bridge Pier Protection against Vessel Collision

Physical protection systems typically are used to reduce vessel impact loads to nondestructive levels or redirect vessels away from bridge piers. An efficient physical protection system is critical for the safe operation of bridges and vessels. A new fender system, referred to as a floating fiber-reinforced plastic (FRP), can meet the design needs to protect both bridge piers and vessels. In addition, the floating FRP fender system, which is composed of FRP box modules filled with rows of FRP tubes, offers high-performance energy dissipation capabilities, modular construction, and easy replacement benefits. This paper focuses on a performance evaluation of this new fender system, used in a prestressed concrete bridge, by using a nonlinear explicit dynamic finite-element analysis program. The study included a vessel collision analysis with material properties calibrated by experimental data. The authors concluded that this new fender system has excellent energy-absorbing capabilities, significantly reduces collision forces, and increases collision duration imposed on the bridge pier and colliding vessel. Therefore, the new protection system is worthy of consideration for locations where a vessel-bridge collision is a concern.

A Mechanical Calculation of the Flexible & Floating Anti-Ship Collision Device for Bridge Piers

This study conducts simulation analysis of collision processes between a ship and a pier with the finite element software ABAQUS. It aims to compare peak values of impact forces, stresses and strains of the anti-collision device, and energy changes of the system when with or without the bridge pier protection buffer, so as to verify the device’s role in buffering impact and greatly improving the pier’s resistance to impact.

Impact Model Tests and Simplified Analysis for Flexible Pile-Supported Protective Structures Withstanding Vessel Collisions

Flexible pile-supported protective structures have been used extensively in the protection of bridge piers against vessel collisions. Their success is dependent on their ability to absorb impact energy through large deflection and yielding. A large soil tank (15×5×6 m) was used to conduct large-scale model tests on protective structures in silt. A lateral static load test on a single pile was carried out to derive p-y curves for the piles on the basis of the measured bending moment of the pile shaft. Impact tests with different initial impact energies were then conducted on the protective structures and on a single pile to study the energy transfer mechanism during a collision. Soil damping and the inertia force of the pile shaft have obvious effects on the load-displacement curves of single piles, especially in the initial phase of impact. However, their influence on the maximum bending moment of the pile shaft was weak. Compared with protective structures that consist of free-standing piles or a pile row, a novel protective structure with two rows of piles has a relatively larger lateral stiffness and a much larger energy-absorbing capability. A simplified energy-based analysis method is proposed to estimate the lateral deflection of the flexible pile-supported protective structures that are subjected to a given impact energy. Comparison of the calculations with the test results shows that this simplified analysis method gives conservative results approximately 30% for the energy-absorbing capability.

Protection of bridge piers against scouring with tetrahedral frames

Abstract Armoring countermeasures, such as riprap stones, are the primary method used to protect bridge piers against scouring; however, these methods have not had definitive success. Recently, flow-altering countermeasures, such as sacrificial piles, have been tested as an alternative to armoring countermeasures. This study investigated the mechanics of an innovative flow-altering countermeasure device, frames in the shape of tetrahedrons that act as a pier-scour countermeasure. Results of measured characteristics for turbulence flow showed that the flow around the tetrahedral frames can be divided into three regions: (1) a deceleration region near the sediment bed; (2) an acceleration region in the middle of water depth region; and (3) a restoration region near the water surface. The velocity magnitudes, turbulent intensities and vorticities decreased in the deceleration region, increased in the acceleration region and reverted to that of the unprotected condition in the restoration region. This pier-scour countermeasure is innovative because of its ability to dissipate energy associated with the downflow and the horseshoes vortex generated around the bridge pier. The scour tests revealed that the frames protected the foundation of bridge piers against scour. The experimental results showed that the percentage reduction of scour depth decreased as the velocity ratio, U/U c , decreased, reaching a value of 50% for the range of parameters tested in this study. Moreover, its efficiency was dependent on the placement density of the frames. The data showed that the frames were more effective when η was larger. However, their influence becomes less significant when η ≥ 0.16.

Protection of bridge piers against ship collision

AbstractThis article outlines the development of pier protection against ship collision over the last 25 years. The calculation of impact forces is developed from general formulas for equivalent loads, based on collision tests, to numerical FEM simulations. Comparisons between the results are given. Examples of the structural protection of 18 bridges are described.

Durable Roadside Protective Structures for Low-Volume Roads

Data compilations on accidents nationwide show that 30% of all traffic fatalities and 16% of all injuries occur when a vehicle goes into a ditch or strikes a fixed obstacle on the roadside. Highway traffic barriers and crash cushions are not economical for use on low-volume roads, even though they could be helpful in reducing fatalities and injuries. Sand-filled barrels and metal barriers that undergo controlled deformation are relatively expensive and require significant investments in placement, inspection, maintenance, and repair. A crash cushion design based on scrap tires encased in foamed, fiber-reinforced concrete is being developed and can provide a versatile, low-maintenance safety barrier that is also resistant to vandalism. The composite scrap tire–and–concrete protective barrier uses a skeleton of scrap tires as an attachment point that can serve to lift, place, and anchor a mass of foamed, fiber-reinforced concrete in place on the roadside. The foamed, fiber-reinforced concrete crushes like wood under impact from tools or projectiles, so the modules are difficult to vandalize and can survive scrapes from graders or snow removal equipment. Module array can be developed on the basis of weight distribution in sand-filled barrel arrays. Potential uses for the barrier modules include protection of bridge piers, bridge railings, and obstacles on curves. The durability and economy of these units make them a practical option for use in improving safety on low-volume roads, especially in remote areas.

Retrofit Analysis of Bridge Fender Systems

Several accidents in which vessels impacted bridges have led to significant improvement of design procedures for impact protection of bridge piers. However, the guidelines usually call for such expensive solutions as piers that can withstand a design force derived from local waterway standards. This paper presents an idea for retrofitting a certain class of existing bridge fenders to serve more efficiently as protective structures against such impacts. Computational analysis was conducted using the nonlinear, dynamic computer code LS-DYNA. The research concentrated on analysis of a collision of a Jumbo Hopper barge with a bridge fender consisting of concrete piles. Several impact scenarios were considered, and four different retrofit solutions were compared with the original design. The analyses performed were used to assess the crashworthiness performance of the fender system, and specific retrofit recommendations, allowing for more efficient kinetic energy absorption, were developed and compared with the original design. The numerical results from 3D computational mechanics were also compared and interpreted using a simple special-case, two-body analytical approach.

Dynamic analysis of dolphins subjected to ship impact

The protection of bridge piers is an important facet of structural engineering, as without such protection major disasters and fatalities can result. It is therefore the intention of this paper to provide the details of a computer program which considers the dynamics of ship/dolphins/soil interaction and the design of dolphins, clusters and platforms or caps.