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This paper describes an experimental program of study on the sliding characteristics of Teflonstainless steel interfaces. The effects of normal pressure, sliding distance, normal pressure history, sliding velocity, sliding velocity history, normal pressure rate, and sliding work are identified and interpreted. Test results show that the friction force is independent of the normal pressure history and the sliding velocity history, and is also irrelevant to the normal pressure rate. In addition, the dependence of dynamic friction force on the normal contact pressure and the sliding velocity can be uncoupled. The dynamic friction force can be determined by multiplying the quasistatic friction force by an amplification factor. The reciprocal of the quasistatic friction coefficient is linearly dependent on the normal pressure only, and the amplification factor is solely a function of velocity. Moreover, the dynamic friction force decays during sliding, and the decaying is a function of excess dynamic sliding work.

In this paper, the guide specifications for bridge base isolation published in 1991 by the American Association of State Highway Transportation Officials (AASHTO) are briefly summarized and discussed. The effective stiffness and equivalent damping ratio given in the AASHTO isolation specifications are evaluated. Based on this study, it is concluded that the equivalent damping ratio determined using the AASHTO procedure may decrease with respect to the increase of the inelastic deformation of leadrubber bearings. In addition, the equivalent damping ratios calculated for a singledegreeoffreedom system subjected to a generated AASHTO design earthquake may be larger than 30% for a wide fundamental period range. As a result, a threedimensional inelastic timehistory analysis as required by the AASHTO provisions may be necessary. However, to require a threedimensional inelastic timehistory analysis could be a dilemma for the current bridge engineering design practice. As an alternate approach, an empirical method is proposed for the determination of the effective period shift and equivalent damping ratio.

In the United States, design of steel gable frames normally follows the guidelines prescribed by the American Institute of Steel Construction for assumed wind and gravity loadings. In this study, a pinnedbase steel gable frame structure composed of prismatic members is constructed, and the dynamic characteristics of that structure are investigated using the shaking table. The tests are carried well into the inelastic range so that ultimate lateral strength under seismic excitation can be quantified. It is observed that for such structures the response modification factor adopted by the Applied Technology Council ATC should be assumed with caution. In addition, the excessive elastic and inelastic story drifts, which are attributed to the pinnedbase condition, require careful evaluation to ensure structural safety against large sidesways. The excessive story drift is likely one of the major reasons for the severe nonstructural damage of steel gable frames during the 1985 Chile earthquake and the 1987 Edgecumbe earthquake.

In the United States, design of steel gable frames normally follows the guidelines prescribed by the American Institute of Steel Construction for assumed wind and gravity loadings. In this study, a pinned‐base steel gable frame structure composed of prismatic members is constructed, and the dynamic characteristics of that structure are investigated using the shaking table. The tests are carried well into the inelastic range so that ultimate lateral strength under seismic excitation can be quantified. It is observed that for such structures the response modification factor adopted by the Applied Technology Council (ATC) should be assumed with caution. In addition, the excessive elastic and inelastic story drifts, which are attributed to the pinned‐base condition, require careful evaluation to ensure structural safety against large sidesways. The excessive story drift is likely one of the major reasons for the severe nonstructural damage of steel gable frames during the 1985 Chile earthquake and the 1987 Edgecumbe earthquake.