A New Simple Method for Post-tension Strands Friction Coefficient Measurement
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วันที่
2557-08-27
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สำนักพิมพ์
Suranaree University of Technology
เชิงนามธรรม
This article describes a new simple method of measuring the friction coefficients and their values
from construction sites in Thailand. The friction coefficients between prestressing strands and their conduits
are related to both wobble and curvature. The method requires both measured jacking force and elongation
of each strand so the average tensile force along the entire length can be determined from non-linear
stress-strain relationship. Then, the total length and total curvature of each strand were calculated from shop
drawing to simulate the friction calculation in the design process. The determined friction coefficients will
include the effect due to misplace of the conduit layouts from shop drawings. From the experimental measurement
of 624 bonded system strands with spiral galvanized metal sheet conduits in post-tensioned slabs
structures from two construction sites with two different post-tensioned sub-contractors, the wobble coefficient
is 0.0035 per foot and the curvature coefficient is 0.536 per radian for sub-contractor 1 and the wobble
coefficient is 0.0040 per foot and the curvature coefficient is 0.578 per radian for sub-contractor 2. The friction
coefficients significantly differ than those recommended by ACI318-11 and BS8110-1997 standards.
คำอธิบาย
International Conference Paper
คำหลัก
Post-tension, Friction Coefficient, Measurement, Simple Method