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3 Vehicle structure

3-1 Structure

Reasons for rejection

Mandatory equipment

1. A sliding chassis is not fitted with both:

a) an effective locking device to prevent inadvertent extension or separation, and

b) endstops at the end of the slideway to prevent separation of the sliding parts if the primary locking device fails.

Condition and performance

2. Refer to general trailer pages.

3. The chassis (Note 1), body or other load-bearing structure of a vehicle, including a monocoque construction body, has any of the following damage so that the vehicle is no longer of adequate strength for all conditions of loading and operation for which the vehicle was constructed:

a) deformation from original shape that has affected the vehicle’s structural integrity, or

b) cracking, or

c) significant corrosion or delamination, or

d) significant rust heave that exceeds the limits in Figure 3-1-3, or

e) poor repairs that have not returned the structure to within safe tolerance of when it was manufactured eg:

i. filler has been used to conceal corrosion damage or deformation of a component, or

ii. a high-strength steel component has been heated, or

iii. a component has been strengthened.

f) loose, broken or missing fasteners or rivets, or

g) damage that affects the integrity, operation or mounting of the following components:

i. steering and suspension system, or

ii. load anchorages, or

iii. brake system, or

iv. mandatory lighting equipment, or

v. towing connections, or

vi. vehicle body.

4. A body-to-chassis attachment, such as a weld, fastener, hinge, body guide or locking device, is:

a) missing , or

b) loose, or

c) broken, or

d) cracked, or

e) otherwise in poor condition.

5. A tipping body hinge, body guide or locking device has deteriorated so that it is not effective in securing the body to the chassis.

6. The locking of a sliding chassis locking device is not readily verifiable by visual inspection.

7. A sliding chassis locking device has wear or damage, such as a worn or bent pin, so that it is not effective.

8. A sliding chassis locking device does not operate correctly.

9. A sliding chassis end stop is:

a) missing, or

b) insecure, or

c) damaged.

Modification and repair

10. A modification or repair affects the vehicle structure and:

a) is not excluded from the requirements for HVS certification (Table 3-1-1), or

b) the modification is not for the purpose of law enforcement or the provision of emergency services, or

c) is missing proof of HVS certification, that is:

i. the vehicle was modified or repaired before the last CoF inspection and no LANDATA record has been entered, or

ii. the vehicle was modified or repaired since the last CoF inspection and no valid LT400 form from an HVS certifier of category HVEC, HVMC or HVIC has been presented.

Note 1

Body means that part of the vehicle that is designed for the use and accommodation of the occupants or to hold any goods.

Chassis means the structural lower part of a vehicle to which the running gear and, as applicable, engine, transmission, steering system and body may be attached.

Chassis assembly means a chassis with running gear attached and, as applicable, engine, transmission and steering system attached.

Note 2

Rust stains can indicate fretting or movement between two components, for example as a result of loose fasteners or cracking.

Note 3

Chassis cracking is most likely to occur in the following areas:

  • where there are abrupt changes in chassis section
  • adjacent to welds
  • body mounting points
  • adjacent to loose fasteners
  • notches.
Note 4

Corrosion is most likely to occur in areas where moisture is retained, or when the vehicle is used to carry stock, fertiliser or corrosive cargo.

Table 3-1-1. Requirements for HVS certification

HVS certification is required

HVS certification is not required

1. Repairs to a structural component of a monocoque body.

2. Repairs to a chassis cross member that is:

a) the first or last cross member of the chassis, or

b) a cross member that is fitted within 500mm of an engine mount, transmission mount or suspension support, or

c) a cross member to which a driveshaft centre bearing is fitted, or

d) a cross member that supports any of the following:

i. ball-race turntable, or

ii. fifth wheel, or

iii. kingpin, or

iv. bolster attachment, or

v. hoist, hydraulic cylinder of a tipping body or any other device that may place a concentrated load on the chassis.

3. Repairs to a coaming rail that supports a load anchorage point or J-hook, or that secures a load-rated curtain.

4. Modifications carried out on or after 1 April 2005 that may result in increased stress to a localised area of the chassis or significant redistribution of the load over the chassis (eg fitting of a hoist, crane, tipping body or other special equipment, etc.).

For modifications carried out before 1 April 2005 it is up to the vehicle inspector to determine if certification is required. Individual certification is only required when the vehicle inspector determines, on reasonable grounds, that the component presents a safety risk.

1. Repairs to a non-structural component of a monocoque body (eg a body panel).

2. Repairs to a first failure of a chassis cross member except a repair listed in the left-hand column.

3. Repairs to a coaming rail that does not support a load anchorage point or J-hook or does not secure a load-rated curtain.

4. Any modification or repair likely to have been carried out before 1 January 1997 (modifications and repairs before this date generally required certification but for inspection purposes no evidence of this is required).

5. Any repair or modification not listed in the left-hand column unless the vehicle inspector considers that certification is required because the modification or repair has affected the vehicle’s safety performance (a second opinion from an expert may be needed).

Figure 3-1-3. Rust heave limits

rust heave limits

Rust heave beyond the limits described above is acceptable only if an HVS certifier
has confirmed this in writing. The vehicle may continue without repair until an expiry
date specified by the HVS certifier. Where no expiry date is specified the vehicle
must be referred to an HVS certifier for another assessment at the next CoF inspection.

Regardless of any expiry date, an inspector may refer the vehicle to an HVS certifier if
he/she suspects that the safety of the vehicle is compromised, for example due to
excessive corrosion or chassis cracking. If the chassis is repaired, an LT400 is required.

Summary of legislation

Applicable legislation
Mandatory equipment

1. A sliding chassis must be fitted with:

a) an effective locking device to prevent inadvertent extension or separation, and

b) endstops at the end of the slideway to prevent the separation of the sliding parts if the primary locking device fails.

2. The body of a vehicle, such as a tank body for transporting bulk liquid; a tipping body for transporting sand, grain or other bulk goods; or other types of body that are constructed to contain the transported goods without the use of lashings, chains or other devices, must be specifically designed to contain that type and size of load.

Condition and performance

3. The following must be of adequate strength for all conditions of loading and operation for which the vehicle was constructed:

a) the chassis and body of the trailer, and

b) the body of a trailer of monocoque construction, and

c) any other load-bearing structure.

4. The locking of a sliding chassis locking device must be readily verifiable by visual inspection.

5. A sliding chassis locking device must be effective.

6. If a sliding chassis locking device incorporates a system that provides energy for its operation, the device must remain fully engaged in the locking position, or the locking action must be initiated immediately, if the energising system fails.

7. Load-securing equipment that is fitted to a vehicle must be constructed to ensure that the load can be securely contained on the vehicle under all conditions of loading and operation for which the vehicle was constructed.

Modification and repair

8. A modification or repair that affects the vehicle structure must be inspected and certified by an HVS certifier of category HVEC, HVMC or HVIC, unless the vehicle:

a) is excluded from the requirement for HVS certification (Table 3-1-1), and

b) has been inspected in accordance with the requirements in this manual, including those for equipment, condition and performance.

Page amended 1 June 2018 (see amendment details).