10-04-2017, 08:39 PM
paper in iee format of underwater concreting pdf
Abstract
Acoustic emission testing technique is a dynamic testing technology. In this paper, the relationship between the cumulative energy of acoustic emission and lower cycle reversal loads is studied based on results of the experiments on underwater concrete columns, and waveform acoustic emission signal of different destruction states is picked up. Spectrum analysis is carried out, the results of which are compared with those of parametric analysis. The comparison shows that the waveform acoustic emission signal can be used to disclose the characteristics of the concrete materials under loading in real time.
Introduction
Our main objective is to address the risk analysis of the water ingress to underground concrete structures. The reliability level of the safety measures accounted for in the design process, to ensure optimal water resistance and durability of concrete structure, is evaluated. The ingress of water into concrete elements is mainly through cracks and joints. Performance functions related to cracks induced in concrete are formulated. Limit state functions related to early age and long term shrinkage cracks, flexural cracks, and combined long term shrinkage and flexural cracks are then formulated. To acquire the true reliability of the water barriers designed for the raft and boundary walls of an ongoing design of an underground structure located in the Middle East is studied. The mentioned structure will be subjected to salty ground water present in the site. The structural elements will also be subjected to high hydrostatic pressure of the ground water in the range of 20 meters. In order to achieve the above objective, it is necessary to identify the water barriers. The multibarrier strategy comprises of a reliable thickness of the raft foundation and the basement walls and dual layer of waterproofing membrane system which will provide a reliable system to block the water ingress to the underwater structures. Finally, the reliability of the water barriers was calculated, and found that the provided design approach will ensure a safe structural system