CONTROL AND QUALITY OF PILES BY NON-DESTRUCTIVE EXPRESS METHODS: LOW STRAIN METHOD AND CROSS-HOLE SONIC LOGGING

Abstract

This paper described using Low Strain Method and Cross-Hole Sonic logging (CSL) for identify of integrity of bridge foundations of LRT in Astana, Kazakhstan. The CSL is a method prescribed by ASTM D6760 - 08, Standard Test Method for Integrity Testing of Concrete Deep Foundations. This method is considered to be more accurate than sonic echo testing in the determination of soundness of concrete. The sonic access tubes do not contribute to the structural capacity of the pile. The bored piles of LRT are 1.0^1.5 m of diameters and 10^55 m of lengths. Design bearing capacity of piles is more than 4500 kN. At the testing period were founded defects in foundation bodies. To check of integrity were conducted by static load tests. The CSL test is based on the length of time for an ultrasonic wave to be propagated between any two of the selected tubes. The velocity of the propagated wave depends on the material through which the wave is transmitted. The aim of this paper is to discuss the advantages and disadvantages of Low Strain Method and CSL methods by analysis of field testing. For checking integrity applying two methods - Low Strain Method and Cross-Hole Sonic Logging. The aim of this paper is to discuss the advantages and disadvantages of each method using the examples of a real application.