Monitoring a Pile - Supported Integral Abutment Bridge at a Site with Shallow Bedrock Phase II

Currently, pile supported integral abutments are limited to locations where the depth of overburden can provide fixed support conditions. In Maine, there are often integral abutment bridges site with a shallow depth to bedrock where piles must be drilled into bedrock to obtain fixity. The objective of this research is to expand the use of pile-supported integral abutment bridges bearing on bedrock at sites where the depth to bedrock is considered shallow, less than 4m (13 ft) from the ground surface. The completed Phase 1 of this project (DeLano, 2004) has produced preliminary design guidelines for integral abutment bridges with piles to the top of bedrock at an overburden depth less than that required for developing fixity. The objective of Phase II of this two-part research project is to finalize the design and construction guidelines by incorporating the performance of a constructed, skewed integral abutment bridge on shallow bedrock into the guidelines. Part (a) of Phase II (this report) includes instrumentation installation, construction monitoring, and full-scale live load testing on the Nash Stream Bridge in Coplin Plantation, ME. Observation made during both the construction sequence and live load testing are generally in agreement with those made during Phase 1. Maximum stresses at the end of construction from dead and live load were 59% of the nominal yield stress of -345 MPA (-50ksi). Bending stress was the largest component of the total stress, while axial stress made up an average of 31% of the total stress. There was significant variability in the axial loadings to piles with loads varying from 0.63 to 1.55 of the longer piles were fixed at some depth, while the shorter piles did not develop fixity. The stresses in the short piles were found to be no more severe than the stresses in the long piles. Monitoring of the bridge will continue for more than a full year from the completion of construction to include seasonal thermal loadings. This data will be used to provide a calibration for finite element models developed in Phase 1 and to assess any limitations of the preliminary design guidelines. A final design guideline will be developed for all anticipated conditions in Maine.

Language

  • English

Media Info

  • Media Type: Print
  • Edition: Technical Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 234p

Subject/Index Terms

Filing Info

  • Accession Number: 01055164
  • Record Type: Publication
  • Report/Paper Numbers: ME 01-7
  • Files: NTL, TRIS, STATEDOT
  • Created Date: Aug 3 2007 10:25PM