Concerns about chassis strength

The Caravan Council of Australia has invested in a mobile chassis strength testing rig, as it raises concerns about some caravan chassis not complying with the latest safety laws.

The CCA’s Colin Young pinpointed chassis welds as a particular area of concern, citing the relevant ADR 62/VSB-1 regulations that apply not just to A-frame members, but also the welding of those members to both the chassis and the coupling mounting plate.

“Concerns have been raised regarding the use of calculations or FEA (finite element analysis) as a means of reliably demonstrating compliance with the legal requirements,” Young said. 

The RV consumer advocacy group also raised questions about whether manufacturers have changed the dimensions and grades of steel used for A-frames and chassis members to comply with the latest rules, and if all existing Engineering Certificates remain valid.

Operated by CCA-accredited engineers, the mobile unit can be towed to a manufacturer’s premises, to enable physical strength tests to be conducted.

The chassis assembly is secured to the high-strength mobile chassis rig via a series of fully-adjustable securing clamps.  Hydraulic rams with calibrated force transducers then apply forces in various directions to a number of critical areas to test for compliance.

“The structural members and welds are then examined to determine if they have satisfactorily withstood the tests,” he said. “If desired, the forces can then be increased until there is a structural failure, so as to confirm the ‘safety factor’ provided.” 

Young said the strength tests are conducted on a "worst-case" chassis assembly which includes the highest ATM rating, the longest, lowest-grade and slimmest members, and the smallest welds.  

To enquire about the ADR 62/VSB-1 strength test, visit the CCA website.