Designing Seismic Resilient Railway Structures Combining Japanese Seismic and ASHTO Design Standards

This paper introduces the seismic design conducted for the railway viaducts in a highly seismic region in Metro Manila, Philippines, in accordance with the local bridge seismic design standard (DPWH-BSDS, 2013), AASHTO Guide Specifications for Load Resistance Factor Design Seismic Bridge Design (LRFD-S) and the Japanese Seismic Design Standard for Railway Structures and Commentary (JDSRS) for making reference to the anti-derailment check under Level 1 Earthquakes (1:100 return period).

The authors concluded that for level 1 earthquakes the seismic design for short piers (h<10m) and piers located in stiff soils, the seismic design was governed by the DPWH-BSDS and AASHTO LRFD-S due to its larger seismic coefficient for structures with short natural periods. Therefore, the initial structural sizes, reinforcement arrangement and number of piles did not need to be modified. On the other hand however, tall piers (h>10m) located in soft soils, the design is governed by the JDSRS due to its stipulated larger seismic coefficients for structures with a longer natural periods. In this regard, in order to limit the transverse natural period requirements of the JDSRS as part of the anti-derailment check, the sub-structural members needed to be increased in size by approximately 20% - 50%, re-arrange the pier steel reinforcement, and to increase the number of bored piles.