Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

Blasting, in particular underwater rock blasting is the most challenging and least understood source of vibration, which may cause considerable damage to the safety of the adjacent buildings and structures and including berthing structures. Though the blast-induced vibration is best controlled by specification of blasting procedures, it is very essential to measure and monitor the blast-induced vibration of the adjacent structures to access its safety. This paper discusses the measurement and monitoring of underwater blast induced vibration on the berthing structure (berth No.8) at Tuticorin in southern part of India. The vibration is recorded using three acceleration transducers mounted on the deck slab of berthing structure and monitored using a data efficiency system consisting of HBM make multi channel carrier frequency amplifier system with digital storage oscilloscope. It is observed that the peak vertical acceleration is much higher than the longitudinal and lateral peak acceleration, because of vibration of deck slab along with frequency of ground excitation. The peak particle velocity (PPV) is obtained from the time history of acceleration by simple integration. From the spectral analysis, the predominant frequency is found as 26 Hz. For this frequency the allowable PPV value is established from various standards as 25mm/sec. The measured PPV values fro all blasts (31 nos) are well below the limit of allowable PPV value, except in few blasts, which shows the berth is safe against underwater blast induced vibration. Pre and post crack survey also proves that there is no considerable damage to the berthing structure.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Measurement of Vibration in Berthing Structure During Underwater Rock Blasting

New York, New York

Blasting, in particular underwater rock blasting is the most challenging and least understood source of vibration, which may cause considerable damage to the safety of the adjacent buildings and structures and including berthing structures. Though the blast-induced vibration is best controlled by specification of blasting procedures, it is very essential to measure and monitor the blast-induced vibration of the adjacent structures to access its safety. This paper discusses the measurement and monitoring of underwater blast induced vibration on the berthing structure (berth No.8) at Tuticorin in southern part of India. The vibration is recorded using three acceleration transducers mounted on the deck slab of berthing structure and monitored using a data efficiency system consisting of HBM make multi channel carrier frequency amplifier system with digital storage oscilloscope. It is observed that the peak vertical acceleration is much higher than the longitudinal and lateral peak acceleration, because of vibration of deck slab along with frequency of ground excitation. The peak particle velocity (PPV) is obtained from the time history of acceleration by simple integration. From the spectral analysis, the predominant frequency is found as 26 Hz. For this frequency the allowable PPV value is established from various standards as 25mm/sec. The measured PPV values fro all blasts (31 nos) are well below the limit of allowable PPV value, except in few blasts, which shows the berth is safe against underwater blast induced vibration. Pre and post crack survey also proves that there is no considerable damage to the berthing structure.