Mike Robertson - Engistics - Engeneering Investigation Case Studies

10th Chain of Responsibility and Heavy Vehicle Safety Conference

Investigation Case Study Engineering investigations

Mike Robertson BE(Hons), FIE Aust, CP Eng.

MD & Engineering Manager

File name: InformaMR 2Dec15.pdf

Our Ref: E637

Mike Robertson

MD & Eng Mgr

0425 001 086

mike.robertson@engistics.com.au

2 Dec 2015

Disclaimer

This presentation is solely the work and opinion of the Author and is not endorsed or any representation of the opinions of the NSW Roads & Maritime Services

2

The incident

3

Photos from the scene

Unlucky Camry

Very Lucky Camry 4

Liverpool Container Rollover

• Sideloader type semi-trailer engaged to carry the container from first

storage to end user

• Truck turns left from Hume Highway Liverpool into Orange Grove Road,

when it rolled onto a line of stationary cars waiting to turn right

• WHY did it rollover?

• Engistics were engaged to assist NSW RMS’ investigation team

• 19.8 t of freight (melamine planks of “fake wood”) imported in shipping container

5

Key Questions for Engineering Investigation Team

• Speed: Was the vehicle travelling too fast? (cf speed limit and “appropriate cornering speed”)

• Vehicle: Was that truck suitable for the task? (In terms of sufficient rollover stability)

• Load Restraint: Obviously the load moved in the crash but:

– Did the load first move at sea? OR

– Did the rollover cause the load to move? OR

– Did the load movement cause the truck rollover?

• All other matters were covered by the police and RMS investigation teams

6

The Vehicle

• “As Loaded”, this Semi-trailer with its Sideloader had a Static Rollover Threshold of 0.35g

• Assuming the load was well secured, and unmoved before this corner

• This is not ideal, but it did meet a minimum acceptable standard as per Performance Based Standards

• There is little current legal guidance for vehicle loading and stability

7

Conclusion: Truck was suitable but the driver had only the minimum

margin for error

The Load

8

Conclusions: Load was NOT secured to NTC Load Restraint Guide or shipping standardsLoad has NOT moved in the ship (as all bags would fail and packs

splinter under rock and roll)

The load as it left ChinaNote that air bags were ONLY used at the

front door. Nil securing at other end

As found after the incident and recovery.Note the LHS airbag is still intact!

Centre & RHS bags crushedUpper packs to LHS in recovery

RHS Gap 100mm

LHS Gap 100mm

Centre Gap 140mm

The Load Shift

9

Conclusions: The load moved mid-corner when the truck reached 0.16g lateral acceleration. Impact forces would then be very high

The load restraint failure has caused the truck to rollover

RHS packs impact after 100mm

• Airbags at one end only and woefully too small to matter (in size & number)

• Friction testing of packs showed coefficients as low as only 0.16

• This means that the packs slide BEFORE the truck hits the critical SRT of 0.35g

• Even assuming that just far end of upper packs slide 100 -240mm, the impact forces are sufficient to cause the truck to rollover LHS packs

impact after 240mm

Vehicle’s Speed

10

Conclusions: The driver had only a narrow margin, but would probably not have rolled except for the dramatic load shift at only 0.16g

• The site is a 70km/hr zone

• If load was secured to 0.5g, and allowing for radius of cornering truck and banking of corner and vehicle SRT, the estimated speed to rollover was 45-48km/hr

• Load shift would make the critical rollover speed much lower

• Police later advised that ECM showed a speed of 45km/hr

11

Like what you see?Be part of our conversation.

informa.com.au

Join our e-newsletter