Inspection method and inspection apparatus of reinforced concrete pipe

• US 7,426,879 B2
• Filed: 01/31/2008
• Issued: 09/23/2008
• Est. Priority Date: 05/08/2002
• Status: Expired due to Term

• Current Assignee: Sekisui Chemical Company Limited (Sekisui)
• Original Assignee: Sekisui Chemical Company Limited (Sekisui)
• Inventors: Minagi, Takushi, Nozaki, Yoshiharu
• Primary Examiner(s): Rogers; David A.
• Application Number:
  US12/010,999
• Publication Number:
  US 20080134790A1
• Time in Patent Office: 236 Days
• Field of Search: 735/84, 735/88, 735/92, 738/658, 73/120.8, 73/120.9
• US Class Current: 73/865.8
• CPC Class Codes: F16L 2101/30 Inspecting, measuring or testing
• CPC Class Codes: G01M 3/005 using pigs or moles G01M3/246, G01M3/2823 take precedence
• CPC Class Codes: G01M 3/246 using pigs or probes travelling in the pipe
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0232 Glass, ceramics, concrete or stone
• CPC Class Codes: G01N 2291/2636 cylindrical from inside
• CPC Class Codes: G01N 29/045 by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks measuring resonant frequency G01H13/00; measuring strength properties by application of mechanical stress G01N3/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G01N 33/383 Concrete, cement

Abstract

Deterioration of reinforced concrete pipes is checked and the deterioration progress level is classified. Based on the inspection result, a portion to be inspected in detail in an inspection area is selected. With respect to the selected portion to be inspected in detail, the pipe thickness and the diameter of reinforcing bars are measured and the location of reinforcing bars in the portion to be inspected in detail are checked. Using the data of the thickness of a pipe, the diameter of the reinforcing bar and disposition of the reinforcing bars, structural analysis is carried out and the strength of the reinforced concrete pipe is calculated. The calculation result is used as information for evaluating the deterioration state of the reinforced concrete pipe.

Claims

1. An inspection method for reinforced concrete pipes for inspecting the deterioration state of a reinforced concrete pipe inside the pipe, comprising the steps of:

measuring propagation waves of a pipe to be inspected by carrying out an impact elastic wave test;

analyzing the resonant frequency spectrum of the propagation waves; and

determining the deterioration level based on the strength ratio between the top peak strength in the high frequency range and the top peak strength in the low frequency range in the resonant frequency spectrum.