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原文传递 Post-Tensioning the Inverted-T Bridge System for Improved Durability and Increased Span-To-Depth Ratio.

题名：	Post-Tensioning the Inverted-T Bridge System for Improved Durability and Increased Span-To-Depth Ratio.
作者：	noureddin nayal, r. m. peterman, r. j. esmaeily, a.
关键词：	durability, highway construction, traffic control, concrete structures, beams, cracks, span, design, loads(forces)
摘要：	Possibly the most pressing need in highway construction today is the repair or replacement of existing bridges. Due to increased needs and growing traffic, in addition to aging and extensive use, more than 2000 bridges in Kansas alone need to be replaced during the next decade. The majority of these bridges have spans of 100 feet or less, and have relatively shallow profiles. It is becoming increasingly important to implement a standard method for replacement in which the process is expedited and accomplished in a cost-effective manner. Requirements for design and construction of concrete bridges have drastically changed during recent years. A main change in design is live-load requirements. The Nebraska inverted-T (IT) bridge system has gained increasing popularity for its lower weight compared to I-girder bridges. However, there are some limiting issues when using IT system in replacing existing cast-in-place (CIP) bridges. Implementation of a post-tensioned IT (PT-IT) system, which is the focus of this project, is believed to be one excellent solution for the IT deficiencies. Post-tensioning is added by placing a draped, post-tensioning duct in the stems of the IT members. Post-tensioning will lead to a higher span-to-depth ratio than IT system, and will reduce the potential transverse cracks in the CIP deck. Finally, the undesired cambers of pretensioned beams will be reduced, because fewer initial pre-stressing will be needed. This study was intended to explore the behavior of the a PT-IT system, identify major parameters that control and limit the design of this system, and investigate different construction scenarios. This was achieved by conducting an extensive parametric study. / NOTE: Final rept. / Supplementary Notes: Sponsored by Kansas Dept. of Transportation, Topeka. / 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.
总页数：	u0809；262p
报告类型：	科技报告