This report summarizes the results of international parallel test on the measurement of the elastic shear modulus at very small strains, Gmax, using bender elements which was carried out from 2003 to 2005 by technical committee, TC29 (Stress-strain and Strength Testing of Geomaterials) of the International Society of Soil Mechanics and Geotechnical Engineering. The purpose was to evaluate the consistency of the bender element test results obtained by applying the exactly similar test material as well as the test method besides identifying the various existing hardware and software being used in this test. It was decided that the domestic TC29 group of Japanese Geotechnical Society (TC29-JGS) was expected to lead this international co-operation. By 2005, reports of the test results were obtained from 23 institutions from 11 countries. This report has been prepared by TC29-JGS taking a leading role from the beginning. A standard test method is proposed here in order to obtain more accurate data from the bender element test by examining various test methods adopted at diŠerent institutions worldwide and the eŠects of various factors on the test results.

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Exterior tile cladding can suffer debonding or adhesive failures as it ages. Failures that result in cladding tiles falling from the building are highly dangerous for people passing beneath, and consequently, it is vital to be able to identify debonding defects at an early stage to prevent tiles falling. This study was performed to develop high-precision apparatus for efficient detection of debonding. This paper presents the results of investigations into detection methods using impact acoustics. Initially, eight exterior-tile wall specimens were prepared with artificially debonded areas. The type of tiles, bonding materials, debonding interface and debonding depth were different for each sample. Percussion tests were carried out by three professional testers, and diagnostic tests were also performed using two types of existing debonding detecting apparatus. The results of these tests revealed several issues that need to be addressed to achieve objective and accurate diagnosis of debonding. A prototype apparatus with a highly-efficient impact mechanism and a microphone was manufactured. Suitable analysis method using impact acoustics, criteria for detecting debonding and an effective method for predicting depth of the debonding were investigated using the apparatus. 2008 4 3 10 1 2) 8) 9) 12) 13)14) 15) 18)Exterior tile cladding can suffer debonding or adhesive failures as it ages. Failures that result in cladding tiles falling from the building are highly dangerous for people passing beneath, and consequently, it is vital to be able to identify debonding defects at an early stage to prevent tiles falling. This study was performed to develop high-precision apparatus for efficient detection of debonding. This paper presents the results of investigations into detection methods using impact acoustics. Initially, eight exterior-tile wall specimens were prepared with artificially debonded areas. The type of tiles, bonding materials, debonding interface and debonding depth were different for each sample. Percussion tests were carried out by three professional testers, and diagnostic tests were also performed using two types of existing debonding detecting apparatus. The results of these tests revealed several issues that need to be addressed to achieve objective and accurate diagnosis of debonding. A prototype apparatus with a highly-efficient impact mechanism and a microphone was manufactured. Suitable analysis method using impact acoustics, criteria for detecting debonding and an effective method for predicting depth of the debonding were investigated using the apparatus. 2008 4 3 10 1 2) 8) 9) 12) 13)14) 15) 18)Exterior tile cladding can suffer debonding or adhesive failures as it ages. Failures that result in cladding tiles falling from the building are highly dangerous for people passing beneath, and consequently, it is vital to be able to identify debonding defects at an early stage to prevent tiles falling. This study was performed to develop high-precision apparatus for efficient detection of debonding. This pa...