Method Statement for Crosshole Sonic Logging for Bored Piles

method statement for crosshole sonic

What is Crosshole Sonic Logging?

Crosshole Sonic Logging (CSL) is carried out on drilled shafts/bored piles to inspect the structural integrity, and extent and location of defects, if any, by sending ultrasonic pulses through the concrete from one probe to another (probes located in parallel tubes). The CSL is carried out as per ASTM 6760. Both the time between pulse generation and signal reception (“First Arrival Time” or “FAT”) and the strength of the received signal give a relative measure of the quality of concrete between transmitter and receiver. Dividing the distance between transmitter and receiver by the FAT value yields the approximate concrete wave speed which also is a relative indicator of concrete quality. For equidistant tubes, uniform concrete between the test tubes yields consistent arrival times with reasonable pulse wave speed and good signal strengths. No uniformities such as contaminated or soft concrete, honeycombing, voids, and inclusions exhibit delayed arrival times with reduced signal strength.

pile sonic cross logging test
Setting up of the testing equipment for sonic cross logging test for a pile.

Method Statement for Crosshole Sonic Logging for Bored Piles

TABLE OF CONTENTS

I. Description of Works

  1. Introduction
  2. Definitions
  3. Reference
  4. Responsibilities
  5. Interfacing with Other Operations
  6. Duration, Phasing with the Subcontractors
  7. List of Subcontractors

II. Resources

  1. Plant and Equipment
  2. Workforce
  3. Light Tools

III. Materials

IV. Site Planning

  1. Preparation
  2. Site Clearance
  3. Traffic Management
  4. Pre-construction Safety Meetings
  5. Methodology

V.1 Mobilization

V.2 Equipment

V.2.1 Access Tubes

V.3 Timing of the CSL Test

V.4 Methodology

V.5 Analysis and Report

VI. Risk Assessment

VII. Permit and Licensing Requirements

VIII. Drawings, Diagrams, Maps and Survey Data

IX. Pre-Start Safety Briefing Arrangements

  1. Protective and Safety Equipment
  2. Information to Personnel
  3. Special Safety Requirements
  4. Emergency Contact Numbers

X. Supervision and Monitoring Arrangements

XI. Environment and Quality Issues

  1. Precautionary Measure
  2. Disposal Requirements
  3. Inspection, Test, and Sampling
  4. Quality Assurance Requirements Table

XII. Attachments

APPENDIX A: CSL Logs
APPENDIX B: Risk Assessment
APPENDIX C: Calibration Certificate

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Method Statement of Bored Piles

1. Introduction

The purpose of this method statement is to describe the mobilization plan and execution of the Crosshole Sonic Logging on selected piles.

Crosshole Sonic Logging (CSL) is carried out on drilled shafts to inspect the structural integrity, and extent and location of defects, if any, by sending ultrasonic pulses through the concrete from one probe to another (probes located in parallel tubes). The CSL is carried out as per ASTM 6760.

  1. Definitions
  • Name of Client
  • Project Management Team
  • Supervising Consultant
  • Third-Party Testing Laboratory
  • SE Site Engineer
  • QC Quality Control Engineer
  • SF Site Foreman
  • PM Project Manager
  • SA Site Agent representative from the Lab
  • HSE Manager Health, Safety & Environmental Manager
  • HSE Officer Health, Safety & Environmental Officer
  • Main Contractor
  • Project Specifications
  • MMUD Ministry of Municipality and Urban Planning
  • GIS Geographical Information System
  • Project Specifications
  • CEMP Construction Environmental Management Plan
  • QCP Quality Control Plan
  • HSE Plan Health, Safety and Environment Plan
  • GWL Ground Water Level (meter)
  • NGL Natural Ground Level (meter)

Note: All dimensions are in mm unless specified.

  1. Reference
  • ASTM D6760- Standard Test Method for Integrity Testing of Concrete Deep Foundations by Ultrasonic Crosshole Testing
  • Health and Safety Plan
  • Overall Construction and Environment Management Plan
  • CEMP (Construction and Environment Management Plan)
  • Construction of Bored Piles
  1. Responsibilities

Project Manager

Responsible for accomplishing the stated project objectives which include creating clear and attainable project objectives, building the project requirements, and managing the constraints of the project management triangle, which are cost, time, scope, and quality.

Construction Manager

Responsible for overall construction activities ensuring that all quality and safety procedures are implemented and required approved permits are obtained.

QA/QC Engineer

Ensure the proper implementation of the Quality system and monitor the overall quality of the work is maintained. Conduct inspection and monitor tests. Determine and report any non-conformance and recommended corrective actions. Ensure that all personnel is aware of the quality requirement. Training of relevant personnel. Conduct surveillance and inspection duties at various stages to ensure compliance with QA/QC Plan.

HSE Manager

Health, safety, and environmental (HSE) managers generally plan, coordinate and implement issues and directives within the organization. They ensure safe environmental working conditions for all employees.

HSE Engineer

Ensure enforcement of safety procedures in accordance with the approved HSE Plan. Will be closely monitoring the site engineer’s strict implementation of the MS and Risk Assessment, the use of proper tools and equipment to maintain safety, certifications of equipment and their adherence to safety regulations, reporting of any unsafe work or stopping work that does not comply with ES&H procedures. Will advise for Health & Safety requirements and monitor the Hazard controls implemented on-site as per the Method Statement/Risk assessment.

Instrumentation Engineer

Manage, update and supply collected data. Analyze and ensure to standardize equipment on return. Supervise current equipment service contracts. Maintain and update instrumentation systems and electronic control.

Geotechnical Engineer

The head of the Geotechnical Division will have direct responsibility for the work. The Head of the Geotechnical Division and his team will ensure that all equipment conforms to the specifications and that the work and documentations are according to required standards.

Surveyor

Carry out a pre-construction survey to fix the locations and corresponding elevations as per the approved shop drawings. Ensure the quality and compliance during phases of surveying works and the regular checking of the surveying equipment or periodic calibration from the third party. Ensure the validity and the serial number of calibration certificates are available and posted in the survey equipment. Ensure proper safety guarding of surveying equipment. To maintain the records of all surveying equipment handled.

Data Encoder
Enters various pieces of information or data in the mainframes. Maintain accurate records and even complete data that is necessary for the project. Provide assistance to one’s superior by encoding the right information or data needed.

  1. Interfacing with Other Operations
  • Excavation Works
  • Dewatering Works
  • Shoring Works
  1. Duration, Phasing with the Subcontractors
  • The duration of work is indeterminate but will not critically affect the progress of the project.
  1. List of Subcontractors
  • Main Contractor:

Name of Main Contractor here

  • Sub-Contractor:

(Third-Party Approved Testing Agency)

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