1. Rapid seismic damage estimation tool for large bridges

After an earthquake, it is important to be able to assess the extent of damage to all railway structures in order to determine whether it is safe to resume operations.
The Railway Technical Research Institute has previously developed a nomogram for rapid assessment of seismic damage to standard bridges and viaducts following an earthquake.
However the nomogram is not able to accommodate the more complex behaviors of structures such as large bridges.

The Institute has now developed a preliminary estimation tool specifically for large bridges.
The new tool (Figure 1) breaks down the complex behavior of large bridges into multiple motions (modes of vibration) and estimates the extent of motion (response value) for each mode of vibration. The previous nomogram, meanwhile, can be used to estimate response values for each mode of vibration, allowing us to quickly determine the overall extent of damage.

A comprehensive analysis of seismic damage to the 790-meter cable-stayed bridge shown in Figure 2 would take several hours, whereas the new tool can provide a comprehensive safety assessment in just a few minutes (see Figure 3).
The tool can also be used to reliably estimate damage to individual structural members, such as bearings and supports, expressed as response values. In this way, the tool can be used to quickly determine if it is safe to resume operations along railway routes with large bridges.