Tiêu chuẩn quốc tế

• Số hiệu / Standard Number: AASHTO BSG:2011
• Năm ban hành / Publication date: 2011
• Tình trạng / Status: A - Còn hiệu lực
• Tên tiếng Anh / Title in English: Bridge Security Guidelines
• Số trang / Page: 62

Phạm vi áp dụng / Scope of standard

An assessment of the importance of a specific bridge should be
conducted during the planning of new bridges, rehabilitation of
existing bridges, or both.

For bridges deemed important, a formal vulnerability study
should be conducted and measures to mitigate the vulnerabilities
should be incorporated in the design.

This article presents a broad view of the issues that need to be
considered during the planning and design of bridge projects to
address bridge security. Bridge owners should establish criteria
for the size and location of the threats to be considered when
analyzing bridges for security as specified in Article 1.2. These
criteria should take into account the type, geometry, and
importance of the structure being considered.

Bridge owners are responsible for establishing the procedures by
which bridge importance is assessed and by which formal
vulnerability studies are conducted. This work can be carried out
by bridge owners with appropriate experience or by retaining the
services of a qualified security consultant.

Currently, there are no uniform procedures for assessing the
importance of a bridge. Accordingly, it is up to the discretion of
the bridge owner to establish the procedures required to assess the
importance of a bridge. Factors common to many of the proposed
procedures include the following:

• Social and economic impact of bridge loss,

• Role played by bridge in defense or security of region, state,
and nation,

• Average daily traffic,

• Average daily truck traffic,

• Distance to nearest detour, and

• Symbolic importance.

Work is being done to produce a uniform procedure to prioritize
bridges for security. In the absence of uniform procedures, some
states have developed their own, incorporating security
prioritization methods that, while similar, differ in the details.
In addition, state procedures to assess bridge importance have been
developed by departments of transportation to assist in
prioritizing seismic rehabilitation. These procedures also may be
used in conjunction with security considerations.

Guidance on security strategies and risk reduction may be found
in the following documents: Design of Critical Bridges for
Security against Terrorist Attacks (27), A Guide to Highway
Vulnerability Assessment for Critical Asset Identification and
Protection (21), Improving Surface Transportation Security: A
Research and Development Strategy (10), Protecting Public Surface
Transportation against Terrorism and Serious Crime: An Executive
Overview (15), and Recommendations for Bridge and Tunnel
Security (7), as well as in the ASCE Journal of Bridge
Engineering articles "Analysis and Design of Critical Bridges
Subjected to Blast Loads" (26), "Risk-based Prioritization
of Terrorist Threat Mitigation Measures on Bridges" (17),
and "Risk Management and Design of Critical Bridges for Terrorist
Attacks" (25).

Though not specific to bridges, the Federal Emergency Management
Agency (FEMA) has published a series of reports that provides
valuable information on risk management to mitigate potential
terrorist attacks, including FEMA 426 (12) and FEMA 452
(13). Unified Facilities Criteria (UFC) 4-020-01, a
publically available U.S. Department of Defense publication
(32) addressing facilities planning, also has guidance
that may be relevant for bridges.