| Popis: |
On the basis of a preliminary evaluation, it was determined that a high degree of variation in specifications for horizontal earth boring, pipe jacking, and utility tunneling projects exists across the United States. It was also recognized that many designers and highway department representatives were not familiar with current methods, materials, and equipment being utilized. Since the contract documents, detailed plans, and specifications are the primary instruments of communication for the contractor, then it is understandable why "incomplete, inaccurate, and faulty construction specifications often result in a large number of field problems" (ASCE News, "Construction Technical Activities News," ASCE, Vol. 13, No. 2, New York, New York, February, 1988). Designers and highway departments have a professional responsibility to insure that their specifications are accurate and complete. This report is a result of in-depth research into the development of specifications for the rapidly evolving area of trenchless excavation construction (TEC). A summary description of the various methods, equipment, and materials commonly utilized in the United States is provided. The design principles and practices for various conditions and materials are presented. Recommended guidelines and specifications have been developed and are presented in this report. This is the Executive Summary of the final report. |
