Type or paste a DOI name into the text box. 9 LFD Seismic presents the very latest information, but this pdf rankine formula for columns pdf may be helpful for those wanting to easily print the LFD seismic information as it was in April 2010.
Seismic design of bridges shall conform to AASHTO Division I-A, 1996 and Interims thru 1998. Refer also to the 1998 Commentary for Division I-A. Seismic retrofitting of existing bridges shall conform to the Seismic Retrofitting Manual for Highway Bridges, FHWA-RD-94-052, May 1995. Seismic isolation systems shall conform to AASHTO Guide Specifications for Seismic Isolation Design, 1999. 9 supplements the above documentation and does not apply to culverts, movable bridges, bridges with spans greater than 500 ft.
There are special considerations for single-span bridges, temporary bridges and bridges with stage construction. Bridges may suffer damage but should have a low probability of collapse. Hazard to human life should be minimized, and essential bridges should continue to function after an earthquake. Bridges are designed for good ductility and displacement control and are allowed to suffer minor, acceptable damage in order to prevent major, unacceptable damage. 0 for soil profile type I, II, III, and IV respectively. The elastic design acceleration spectra shown in Fig.
2 is a plot of structural period T versus the maximum acceleration quantity of the structure. 1, it can be seen that the acceleration of soil is larger than the acceleration of rock by an amplification factor S. Soil type is important to the evaluation of ground acceleration. 2, stated briefly, the design acceleration spectrum is a plot of the maximum acceleration to a specified seismic load for all possible single degree-offreedom systems. System in order of increasing complexity. Pi corresponding to the ith mode of the structural component.
A, the above mentioned analysis procedure is not required. For a regular bridge in SPC B, C, or D, procedure 1 and 2 are the minimum required analysis methods, procedure 3 is strongly recommended. A regular bridge, as described in AASHTO Division I-A, 4. Multi-mode spectral analysis is recommended for most bridges. Time History analysis is generally not recommended because its application requires considerable engineering judgement and experience. SPC A, B, C and D, see Fig. 50-year lifetime of the bridge, corresponding to a return period of 475 years.