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原文传递 Study of Long-Term Pavement Performance (LTPP): Pavement Deflections.

题名：	Study of Long-Term Pavement Performance (LTPP): Pavement Deflections.
作者：	stubstad, r. lukanen, e. clevenson, l.
关键词：	load deflection, database, data errors, manual input
摘要：	This report presents the results of a study of pavement deflections. The study covered all level E falling weight deflectometer (FWD) deflections and associated data in LTPPs database from Data Release 9.0, November 23, 1998. Although the limited amount of data from unbound material testing was also provided, these data were not screened due to the large variations in the recorded deflections in comparison with bound layer tests. The report covers the screening techniques developed and used to identify data errors and anomalies in the FWD loaddeflection database, along with a description of each category of data errors identified. Contrary to prior expectations, the vast majority of these data errors were related to manually input data elements, not the deflections themselves. Approximately 8 percent of the 4.4 million lines, or records, in the pre-autumn 1998 load-deflection database were affected by manual input data errors alone, while less than 0.2 percent appear to be affected by actual load-deflection data anomalies generated by the FWD. Out of the approximately 8 percent of manual input data errors found, around 7 percent were associated with nonprotocol and unreported placement of the deflection sensors along the FWDs raise-lower bar. Other types of manual data entry errors, each occurring at a rate of less than 1 percent, included incorrect lane designation, station number, date- or timestamp, test site, drop height, and configuration of the sensors for joint testing on portland cement concrete (PCC) pavements. Deflection reading data errors included deflection basin anomalies and sensor malfunctioning errors. A universally applicable deflection basin screening tool called SLIC was also developed for use on select FWD data file formats. The overall quality of the pre-autumn 1998 FWD database can be characterized as good to excellent. / NOTE: Final rept. Apr-Sep 01. / Supplementary Notes: Sponsored by Federal Highway Administration, McLean, VA. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
报告类型：	科技报告