Construction report

According to the initial on-the-spot report from Liftech’s Feroze Vazifdar accompanied by a geotechnical engineer from Harza, Peter Kaldveer, the berths at Kobe are contained within pe­rimeter quay walls and filled with reclaimed granular fill material hydraulically placed over natural sea bottom clay. The walls are made from 10m wide x 13m deep hol­low concrete caissons filled with granular material. Girders for the waterside crane rails are placed over the caisson wall. The caissons were designed for a lateral coeffi­cient of 0.lg while a seismic co­efficient of 0.2g was usually speci­fied for the container cranes.

Graphical cross-section summary of Kobe port construction, with 50ft and 100ft gauge

crane rails, and earthquake consequences (Source Liftech Consultants)

A lateral force of 0.1g is lower than would normally be specified today in earthquake zones. The Pier J expansion area at Long Beach, for example, is designed to 0.2g while the structures will re­spond to a force of 0.33g. The wharf structure uses the so-called “structural fuse” design developed by Dames & Moore in conjunc­tion with the port’s engineers.

The main seismic event at Kobe had a duration of 20 sec­onds and produced peak effective lateral accelerations near the port of 0.8g (north-south) and 0.6g (east-west) while peak vertical ac­celeration was 0.3g.