Seismic Vulnerability of the Highway System

Task D3-2: Seismic Response Modification Strategies for Special Bridges

Subject Area: Seismic Response Modification Devices
Research Year 3

Principal Investigator and Institution

George C. Lee, University at Buffalo


Special bridges are those long-span and spatially curved bridges that require special considerations in their design and construction, in large part due to their one-of-a-kind nature. Typically, complicated nonlinear time-history analyses are involved in their design, which by itself is a challenge to bridge structural engineers. Since relatively little is known about how to design earthquake response modification systems for these special bridges, it is difficult to develop standardized design procedures and specification provisions. To address this need, the ultimate goal of this task is to develop a monograph which will introduce general principles followed by typical case studies of known examples, to benefit those who have to design and retrofit such special bridges. In the first year of this task (Research Year 3), the focus will be on collecting information and knowledge from practitioners and researchers who have been involved in the seismic design and retrofitting of such bridges both with, and without, seismic response modification technologies.


Special bridges are typically one-of-a-kind, and each may have specific dynamic characteristics that require special consideration in analysis and design. To understand these special dynamic properties, experiences from researchers and bridge design professionals will be sought. This will be done in three separate efforts:

(1) Reviewing available literature including journal articles, conference and workshop proceedings, published reports, and other information available in printed or electronic form.

(2) Conducting one major and one small workshop. The first US-PRC Workshop has been planned for September 12-15, 2002 (see Task G3-6) and the results of this workshop will provide information on international practices with respect to special bridges. A small, highly targeted, workshop will be held in California in order to gather and assess information and case studies on the design of special bridges which have recently used response modification technologies.

(3) Meeting with other experts in special bridge design and retrofit, and experts in Seismic Response Modification Device (SRMD) technologies. This will be done by inviting a number of experts to Buffalo, New York for one-on-one meetings, and to a meeting in Portland, Oregon in association with the FHWA National Bridge Seismic Conference.

The small workshop described in (2) will build on and extend the collection of knowledge obtained from the Long-Span Bridge Seismic Research Workshop, which was held in San Francisco, California in December 1994 under the auspices of Task 106-F-5.2.1 of the FHWA Contract DTFH61-92-C-00106 (Project 106). The workshop supported via Task D3-2 will focus on design and retrofit information regarding SRMDs for special and long-span bridges that use SRMDs. Up to ten bridge engineers in charge of actual designs will be invited to share their expertise and experiences at this workshop, which will be conducted in the summer of 2002.

This workshop is expected to result in sufficient information to formulate the basic framework and approach for the development of a manual on the application of SRMDs for special bridges.


The end products for this research task are available targeted by project 094, and the corresponding design approaches.

With such information, we can develop dynamic response modification strategies for the targeted bridges.

The primary product of this task will be information on methods of dynamic analysis to determine specific response characteristics of components and for certain classes of special bridges, and corresponding design approaches. From this, dynamic response modification strategies can be developed for bridge types.

Technical Challenges

The primary challenge will be in synthesizing bridge-specific information and assessments into more generic approaches that can be used for future special bridge studies.

return to Task Statement List