Masters Theses


Stephen Eads


"The objective of this study was to develop an economical solution for the seismic retrofit of existing highway bridges in low occurrence seismic zones, such as in the Central and Eastern United States. To achieve this objective, metallic dampers were introduced to protect bridge structures from being damaged by dissipating a significant portion of the seismic energy that is traditionally stored in structural members in the form of strain energy. The scopes of this study included a) select and test small-scale, low carbon steel rods for their ductile behavior and material strength; b) test large-scale, tapered rods for their energy dissipation capability and fatigue strength under regular, irregular, and earthquake loads; c) validate the system performance of a full-scale damper made of five tapered rods, d) address the implementation issues such as the performance of joints and connection members, and e) develop a hysteretic model of existing rocker bearings. In addition, the previously-proposed step-by-step procedure is examined and applied into the retrofit design of a three-span continuous steel-girder bridge in southeast Missouri.

Test results indicate Hot Rolled AISI/SAE1018 can be used as damper materials for the development of an economic retrofit solution. The damping ratio of tapered rods is independent of loading frequency and specimen size; it rapidly increases at small displacements and approaches a value of 0.35~0.40 in the range of over 1.8". Even at a displacement of 2.4”, the steel rods can survive over 100 cycles of loading with little degradation of damping property. The full-scale, five-rod damper has been demonstrated to reveal a progressive failure mode that is desirable for earthquake applications"--Abstract, page iii.


Chen, Genda

Committee Member(s)

LaBoube, Roger A.
Dharani, Lokeswarappa R.


Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering


The author thanks the Missouri Department of Transportation and the University Transportation Center at the University of Missouri--Rolla (UMR) for their financial support that made this project possible.


University of Missouri--Rolla

Publication Date

Fall 2004


xii, 123 pages

Note about bibliography

Includes bibliographical references (page 122).


© 2004 Stephen Alan Eads, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Earthquake resistant design
Energy dissipation
Bridges -- Earthquake effects
Bridges -- Design and construction

Thesis Number

T 8689

Print OCLC #


Link to Catalog Record

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