REDUCING NEGATIVE FRICTION WITH BITUMEN SLIP LAYERS

Recently developed ways of reducing negative friction are mentioned. One method involves a telescopic pile containing a gravel fill inside. Downdrag effects on the upper section are counteracted by the development of positive friction in the inner face which transfer the load to a lower section resting on a firm stratum. Negative friction is produced by the relatively larger settlement of the sorrounding soil in comparison with the movement of the pile. The settlement of soil is caused by an increase in load. It can also be due to remoulding of sensitive clays which may be provoked by pile driving, earthquake or landslide. For the reduction of negative friction with bitumen, a special type with a certain viscosity is needed. Since the viscosity is a function of the sorrounding soil temperature, the specifications of the bitumen must be modified in accordance with the soil temperature of the region, which can vary considerably with geographical location. The results are reported of subsurface investigations for the Caracas Metro when soil temperatures were recorded at several points in the city. It is noted that soil temperatures between the depths of 16.4 ft. and 49.2 ft. in the city of Caracas, are considerably higher than the soil temperature (50 deg. F) at the test locations in the Netherlands.

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Filing Info

  • Accession Number: 00099104
  • Record Type: Publication
  • Report/Paper Numbers: ASCE #11398 Proceeding
  • Files: TRIS
  • Created Date: Oct 18 1975 12:00AM