week 3

• What does this week cover?


  • Site specific risk identification, assessment and management
  • Demolition, planning for demolition, introduction to the legislative (Codes of Practice, Licencing) requirements
  • Bulk Earthworks, cutting and filling, soil states, planning excavation works, undertaking excavation works (location of services, angle of repose, zone of influence, erosion and sediment control)
  • Building over or near services (Sewers, water mains, stormwater drains and sanitary drains, working near overhead and underground electric lines)
  • Appendix 1: Description and classification of soils and rocks used in a geotechnical site classification report
• Site investigation and inspection


  A process of collecting information, assessment of the data and reporting potential hazards on a site
• Latent conditions


  Physical conditions which are either on, under or adjacent to a site that cannot easily be identified during a routine site inspection and may also remain hidden even after a certain amount of site investigation
• Examples of latent conditions

  • Contaminated soil/groundwater
  • Rock
  • Mine shafts
  • Major underground service infrastructure

  
• Locating underground services


  1. Dial Before You Dig

  2. Use underground services locators

  3. Potholing
• Dial Before You Dig


  • A free enquiry service for information on underground assets anywhere in Australia
• Underground services locators


  • Consisting of both underground cable and pipe locators as well as Ground Penetrating Radar
• Potholing

  • Involves digging with hand tools or non-destructive techniques such as vacuum excavation to physically locate underground services and utilities to confirm location
• Physical site conditions

  The surface and subsurface conditions of the site that must be considered to ensure the site can support the plant to be used on the site
• Geotechnical investigation


  Provides the subsurface profile of the site enabling assessment of what surface treatment is required to support the construction plant and traffic movements
• Geotechnical investigation methods


  1. Drilling of boreholes

  2. Excavation of test pits
• Soil


  The unconsolidated material in the earth's crust resulting from a weathering or breakdown of rock formations, a comparatively soft, loose and uncemented material that can be excavated by normal earthmoving plant
• Rock


  The solid matter that makes up the crust, or outer part of the earth, a hard, rigid and strongly cemented material that must be ripped or drilled and blasted with explosives so that it can be removed
• Soil and rock descriptions and classifications

  • Soil types
  • Rock strength
  • Soil grading
  • Degree of weathering
  • Soil cohesiveness
  • Degree of fracturing
  • Soil origin
  • Stratification rating
  • Moisture condition - coarse grained soils
  • Moisture condition - fine grained soils
• Test pit/ bore log symbols

  • Example test pit log
  • Example drilled borehole log
• Other site-specific risks


  • Environmental (sediment and erosion, storm water run-off, noise, flora and fauna)
  • Construction traffic (movement of construction plant internal and external to the site in the proximity of workers and public)
• Hazard


  A source or a situation with the potential for harm in terms of human injury or ill-health, damage to property, damage to the environment, or a combination of these
• Risk


  The chance of something happening that will have a negative effect, the level of risk reflects the likelihood of the unwanted event and the potential consequences
• Risk assessment


  A process to identify potential hazards and analyse what could happen if a hazard occurs
• Risk management

  1. Identify hazards

  2. Assess the risks of the hazard

  3. Select appropriate risk controls, or decide not to continue with an activity

  4. Periodically review the process and the risk controls to ensure they are working and preventing harm
• Methods to identify hazards

  • Observation
  • Consultation with stakeholders
  • Site inspections
  • Investigating incidents
  • Audits
• Risk matrix


  A method of deciding priorities, items from the first rank would be prioritised 1st followed by those from the 2nd rank and then those from the 3rd rank
• Hierarchy of controls


  A framework used to select the most effective controls to minimize or eliminate exposure to hazards
• Residual risk

  The remaining risk after controls have been implemented, the level of residual risk will enable a decision to be made to either accept the risk, stop the activity or continue to search for better controls
• Demolition means to demolish or dismantle a structure or part of a structure that is load-bearing or otherwise related to the physical integrity of the structure
• Demolition work


  High risk construction work if it involves demolition of an element of a structure that is load-bearing or otherwise related to the physical integrity of the structure
• Work Health and Safety Queensland have developed the Demolition work Code of Practice 2021 which provides practical guidance on how to manage health and safety risks associated with demolition work
• Demolition planning


  Identifying hazards, assessing risks and determining appropriate control measures in consultation with all relevant persons involved in the work
• Things to consider in demolition planning

  • Method (manual, mechanical, induced collapse, explosives)
  • Type of equipment to be used
  • Public safety (access and protection)
  • Existing services and their location
  • Hazardous chemicals and materials (asbestos, lead, PCBs, synthetic mineral fibres)
  • Removal of debris
  • Securing the demolition area (exclusion zones)
  • Procedures to deal with emergencies
• Demolition licence


  Required if the structure contains pre-tensioned or post-tensioned structural components, demolition involves use of load shifting equipment, or demolition involves use of explosives or another induced collapse method
• Asbestos removal licence


  Required for removal of friable asbestos (class A) or non-friable (bonded) asbestos (class B)
• Hiring an experienced licensed and insured demolition contractor will streamline the entire demolition process
• Bulk earthworks involves the removal, moving or adding of large quantities of soil or rock from a particular area to another, also referred to as excavation
• Bulk earthworks methods


  • Excavating (cutting)
  • Depositing and consolidating (filling)
• Soil states


  Undisturbed (bank), Loose, Compacted
• Excavation work is 'high risk construction work' as it is generally carried out using tools, machinery or explosives
• Work Health and Safety Queensland have developed the Excavation work Code of Practice 2021 which provides practical guidance on how to manage health and safety risks associated with excavation work
• Undisturbed material


  Typically 90% as dense as undisturbed material
• Soil states


  • Undisturbed (Bank) - medium density
  • Loose - least dense
  • Compacted - most dense
• Solid rock can never be compacted as tightly as it existed in bank after moving