Guidelines for Designing Bridge Piers and Abutments for Vehicle Collisions

Project Description

At a minimum, bridge piers must be designed to support the heavy loads of bridge decks and vehicles. When not protected by barriers, they must also be designed to withstand the immense force created by vehicle collisions — particularly those involving heavy trucks and tractor-trailer rigs. The failure of a bridge pier in such a collision can result in numerous deaths and injuries for vehicle occupants on the bridge, as well as considerable expense for repairs to a collapsed roadway in addition to the pier it was designed to support. The Load and Resistance Factor Design (LRFD) Bridge Design Specifications, published by the American Association of State Highway and Transportation Officials (AASHTO), contains detailed requirements for protecting bridge piers from vehicle collisions and designing the piers to resist impact when collisions do occur. The magnitude of the design force (400 kip, or 400,000 pounds) was determined when the LRFD specifications were published. TTI researchers believed that crash tests conducted since that time, as well as reconstruction analyses of actual collisions would yield new information that could provide further detailed guidance for design engineers. This research effort drew upon that additional information, including analyses of 19 truck/bridge pier collisions, several of which involved partial or complete failure of the bridge pier. In addition, the research staff applied knowledge from additional heavy truck crash tests at TTI's Riverside Campus, including two full-scale crash tests involving 80,000-pound trucks traveling at 50 miles per hour. The researchers recommended revisions to the AASHTO guidelines included: 1) Incorporate crash risk analysis methodology into AASHTO LRFD Bridge Design Specifications; 2) Increase the static force standard from 400 kip to 600 kip; 3) Change the direction of applied force from "any direction" to "zero to 15 degrees to the edge of the pavement; and 4) Change the height of force from four feet above ground to five feet above ground. The recommendations are intended to offer additional guidance to design engineers to ensure greater safety and cost-efficiency of bridge construction.

Project Publications

Analysis of Large Truck Collisions with Bridge Piers: Phase 1. Report of Guidelines for Designing Bridge Piers and Abutments for Vehicle Collisions 9-4973-1

Collision Loads on Bridge Piers: Phase 2. Report of Guidelines for Designing Bridge Piers and Abutments for Vehicle Collisions 9-4973-2

Guidelines for Designing Bridge Piers and Abutments for Vehicle Collisions 9-4973-S

Guidelines for Designing Bridge Piers and Abutments for Vehicle Collisions 9-4973-P2

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