4.4 Small Building Site on Port Island
4.4.1 Location and Treatment
The ground at the site of a small pile-supported building at the southeast corner of Port Island Phase I, Figure 3.4, was improved by the vibro-rod method in 1981. The building is across the street which parallels, and is directly adjacent to, the sea wall that bounds Phase I on the south. The vibro-rod treatment extended a distance of 10 m around the building.
4.4.2 Observations Outside the Treated Area
The sea wall across the street displaced to the south a distance of 20 to 30 cm, accompanied by settlement and the development of a large parallel crack in the pavement, as shown in Figure 4.20. The building in the left background of Figure 4.20 is located directly across the street to the east of the treated area. A close-up view of that pile-supported building is shown in Figure 4.21. The settlement of the adjacent untreated ground is large.
Figure 4.20: Displaced sea wall and cracked pavement at the southeast corner of Port Island Phase I.
Figure 4.21: Large settlements of untreated ground adjacent to pile-supported building, southeast corner of Port Island Phase I.
4.4.3 Observations Within the Treated Area
The post-earthquake conditions at the treated site are shown in Figure 4.22. The building itself appeared undamaged, and the settlements around it were considerably smaller than observed in the untreated areas.
Figure 4.22: Limited settlement of treated ground adjacent to pile-supported building, southeast corner of Port Island Phase I.
Figure 4.20: Displaced sea wall and cracked pavement at the southeast corner of Port Island Phase I.
Figure 4.21: Large settlements of untreated ground adjacent to pile-supported building, southeast corner of Port Island Phase I.
Figure 4.22: Limited settlement of treated ground adjacent to pile-supported building, southeast corner of Port Island Phase I.