OH & S

Duty of care responsibilities

Responsibilities for safety and health are placed on all parties at the workplace.

Employer’s general ‘duty of care’ obligations for safety and health under the Act include:

Providing a workplace and safe system of work so employees are not exposed to hazards;

Providing employees with information, instruction, training and supervision to enable them to work in a safe manner; and consulting and co-operating with employees and safety and health representatives (where they exist) in matters related to safety and health at work.

Employees also have obligations under the Act. They must take reasonable care to ensure their own safety and health at work and avoid putting other’s at risk by anything they do or don’t do.

Employees must also report any situations that may be hazardous.

The employee’s duty for safety and health is complementary to the employer’s duty, and employees must receive adequate information, instruction, training and supervision to meet their obligation.

Employers who, in the course of trade or business engage contractors (and contractors employees,) have the same responsibilities of an employer towards the contractor in relation to matters over which they have control or the capacity to have control.

Tilta Industries recommends where possible, the operator apply and release load restraint whilst the Tiltip tray is extended in tilt mode, allowing the operator via drop-sides to access the pop-up load restraint rings from ground level, avoiding the requirement to climb up and dismount from elevated tray bodies

TILTIPLoad Restraint Ring 4 Ton SWL Certification

TiltipLoad Restraint Rings 4 Ton SWL Certification

Engineering report No.: JBLCKT-004

Structural linear static FE analysis of a Tie Down assembly
For
Tilta Industries

Prepared by:Tomas Pisko, M. Mech. Eng
Approved by:James Blacket, Sundevices

LINEAR STATIC ANALYSIS OF A TIE DOWN ASSEMBLY.

Objective:
Calculate maximum allowable load for the given tie down assembly. This load must not generate stresses beyond maximum design stress, calculated from Yield strength and using FOS=1.5 for all materials.

Supplied information:
Client has supplied 3D models of the Tie down assembly, material properties and position of the load attachment.

Test description:
Analyzed Tie down assembly consisted of truck tray deck section which was treated as a rigid body, tie down top plate, pin welded to the top plate and a load attachment plate. The load is usually transferred onto the load attachment plate via a shackle which wasn’t included in the analysis. Nominal load of 5t was defined over a 6mm wide area inside the load attachment hole using a definition of a bearing load with parabolic profile. The direction was defined along the connecting line of the pin hole and load attachment hole. This corresponds with real case where the loading plate is free to swivel around the pin.

The load attachment plate was free to slide/rotate on the pin.

Following material properties were applied to tie down parts:
The truck tray deck – GR250 steel (with yield strength of 250 MPa)
Tie down top plate – GR250 steel (with yield strength of 250 MPa)
Pin – GR350 steel (with yield strength of 350 MPa)
Load attachment plate – BISPLATE 400 (with tensile strength of 1320 MPa)

Based on material properties, following maximum design stresses were defined:
Maximum design stress for GR250 steel: 166MPa
Maximum design stress for GR350 steel: 233MPa
Maximum design stress for BISPLATE 400 steel: 880MPa

Test procedure:
Mesh was refined in all key areas – mainly around the pin contact area and around the load definition. Over 250 000 elements (350 000 nodes) were generated for this study. This ensured high quality, dense mesh with high level of accuracy.

Test results:
Maximum stress of 1345 MPa was recorded in the load attachment plate – in the load bearing face. Compressive stress from the pin contact was 864 MPa and 885 MPa was recorded on the sides of the load attachment hole due to part’s extension.

Tie down top plate recorded 290 MPa of stress and 319 MPa was recorded in the pin welds.

Maximum deformation of 0.66 mm was recorded in the load attachment plate, in the location of the bearing face. Deformation of the pin was only 0.2 mm.

Conclusion:
The design of tie down plate assembly experienced stresses higher than allowable design stress when subjected to load of 5 tons.

Load attachment plate experienced stress of 1345 MPa, in the area of the bearing face – area of the smallest cross sectional area. This is more than defined allowable design stress of 880 MPa and even more than tensile strength of the BIS 400 material. During the calculation was assumed that the shackle aligns with the axis (connection of two holes) of the load attachment plate and results in tensile load only. No bending moments acting on the plate were assumed.

Load attachment plate also experienced compressive loads (from pin contact) with maximum magnitude of 864
MPa.

Maximum stress in the pin was 200 MPa and 319 MPa was recorded in the welds and tie down top plate recorded
290 MPa which is above our design stress of 233 MPa.

156 MPa is less than our design stress for GR350 steel.

Based on the results we need to lower the maximum allowable payload to 4 tons for current design.

All results in this document are only theoretical, calculated using a linear solver and based on available information and ma thematical model, with a few simplifications and assumptions made during the FEA process. Real tests should be conducted before production, con firming these results and parameters from FEA simulation.

LINEAR STATIC ANALYSIS OF A TIE DOWN ASSEMBLY.

Supplied information:
Client has supplied 3D models of the Tie down assembly, material properties and position of the load attachment.

The load attachment plate was free to slide/rotate on the pin.

Tie down top plate recorded 290 MPa of stress and 319 MPa was recorded in the pin welds.

Maximum deformation of 0.66 mm was recorded in the load attachment plate, in the location of the bearing face. Deformation of the pin was only 0.2 mm.

Conclusion:
The design of tie down plate assembly experienced stresses higher than allowable design stress when subjected to load of 5 tons.

Load attachment plate also experienced compressive loads (from pin contact) with maximum magnitude of 864
MPa.

Maximum stress in the pin was 200 MPa and 319 MPa was recorded in the welds and tie down top plate recorded
290 MPa which is above our design stress of 233 MPa.

156 MPa is less than our design stress for GR350 steel.

Based on the results we need to lower the maximum allowable payload to 4 tons for current design.

Discussion Points For Tip Truck Operators

Tip Truck Operators must acknowledge all tipping activities may involve an element of risk requiring the operator to make informed judgements based on sound corporate OH&S procedures, WorkSafe and Road Legislation, acknowledging his / her operator responsibilities towards workmates and the general public on a daily basis.

Elevated tipping bodies will have a heightened centre of gravity, when combined with adverse conditions the vehicle can become unstable during discharge operations jeopardising safety. The operator must remain vigilant and always assess site conditions prior to discharging loads or manoeuvring on site.

Influences such as; evolving technology, equipment design capacity, age and serviceability, industry & corporate demands & expectations, load / materials characteristics, terrain and climatic conditions, varying sites conditions all impact on operations, which the operator must identify, understand and then compensated for during load or discharging procedures.

Any proactive corporate OH&S policy review must incorporate State Road and Workplace Legislation; Insuring a well targeted and professional training and risk assessment, seeking and encouraging team involvement, whilst adopting a commonsense approach to operations.

The following points are not designed to supersede or replace existing corporate OH&S procedures or State and Federal WorkSafe legislation guidelines, but rather provide topics for team consideration and discussion during OH&S reviews.

Driver Operator must received adequate equipment induction training and be judged competent to operate the vehicle and ancillary equipment by recognised training personal, and hold the relevant driving / operating licences.
Driver / operators / crews must be familiar with, and comply with all corporate OH&S procedures, adhering to State Road Legislation and understand individual WorkSafe / Workplace OH&S Responsibilities, and be prepared to assume those responsibilities the moment he takes charge of the vehicle.
Operators must wear appropriate protective equipment for the activity at hand for example; coloured safety vest, steel capped boots, safety glasses and face dust mask if considered appropriate, sun or safety hat, apply sunburn creams regularly, wash and dress any abrasions or cuts as they can easily get infected by contaminated loads, seeking medical treatment and report accidents as required.
The Driver / Operator is responsible for all equipment he / she operates, prestart-up vehicle inspections are necessary to insure roadworthiness and road readiness, that the load is correctly distributed, does not exceed OEM or State regulations axle load limitations, and is covered and restrained as required by legislation.
Maintaining correct tyre pressures is essential for safe breaking, cornering and tipping operations. Tyres, water, batteries and oils should be checked weekly or as directed by management or operations manuals.
The Driver / Operator must familiarize himself with the task at hand, and the materials to be loaded, transported, and tipped, paying strict attention to those materials characteristics. For example determine is the sand wet / dry? Does the load consist of demolition rubble which could protrude beyond the parameters of the body, and or sticky clay, as each of these materials will have different load, restraint and discharge characteristics which must be assessed to understand their potential affect on vehicle stability during transport and tipping activities.
Avoid tipping across the face of an incline, this is a dangerous practice. Because as the body and load are raised the centre of gravity elevates and moves towards the downhill side eroding vehicle stability, if combined with slippery or uncompacted surfaces and incorrect tyre pressures, add strong side winds, you now have serious OH&S exposure putting the operator and bystanders at risk.
Tipping the load downhill can result in the centre of gravity falling behind the rear axle group during the tipping operation once again adding to vehicle instability and jeopardising safety.
Driver / Operator must inspect site conditions; consider Ingress and exit on and off project site, consider road traffic conditions, site congestion, other onsite project activities and service crews sharing limited space, soil compaction and surface condition ie. wet or dry, site incline profile.
“Look Up and Live” Automatic operator reaction when entering a site, register hazards such as overhead obstruction; building awnings, trees, powerlines and any other obstacles which may impact adversely on safety.
Weather conditions may also influence tipping activities, high winds combined with surface incline will erode vehicle stability during tipping operations especially if materials such as sticky clays which require excessive tipping height and angles to dislodge and release. Avoid reversing back and hitting the brakes to dislodge loads, that energy backlash will destabilize a vehicle further as the backlash will exaggerate any instability already caused by high centre of gravity issues , especially if that centre of gravity has shifted off centre and fallen to leeward.
Having assessed the site, plan the activity, communicate your activity and intentions to associated crews and bystanders, if personal are available appoint a ground observer to provide guidance and keep bystander’s at bay , maintain visual and verbal communications at all times with appointed observers.
When ready to discharge load, disembark and make required equipment adjustments such as releasing the tail gate, securing it to the side of the vehicle, releasing load restraint and load covers if applied, reaffirm the tipping area and surface is fit to receive the load.
Insure all personal are informed and remain at a safe distance, standing away from the vehicle during tipping / loading operations, check to make sure there are no other site activities about to impact adversely on your pending activity.
After tipping or loading material conduct a pre start-up vehicle walk around inspection, returning and securing all equipment and fittings to the correct transit settings prior to departing site.
Operators must conduct regularly vehicle inspections and maintain all ancillary equipment such as load restraint and winch cables, keep windscreen and mirrors clean, check vehicle and trailer lights and electrical connection & fittings are functioning correctly.
Report all vehicle service issues and insure the vehicle and ancillary equipment are booked in for preventive maintenance services in accordance with OEM recommended intervals and or when vehicle defects which can adversely affect safety are detected.
Do not operate equipment if fatigued, under the influence of drugs, or suffering illness which could impair your judgment or ability to perform tasks professionally.
Never allow complacency to enter the workplace, Operator failure to comply with State or Federal WorkSafe and or Road Legislation, or follow corporate operation procedures and OH&S policies could expose themselves to repercussions which would adversely impact on careers, health, lifestyle, including that of the family, work associates, and the general public. There are severe penalties for those who fail to understand or assume operator responsibilities associated with plant and equipment.
Take pride in your ability and workplace responsibilities, the vehicle and equipment you operate requires specific skills, so display your professionalism at all times.