vicroads worksite safety update newsletter

Worksite Safety UpdatePromoting safety in road construction

No 108 June 2011

Will Your Plant SWMS Prevent Rollover.Do the Controls Include Construction Method?

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In this Edition: West Gate Bridge Strengthening – Traffic Management Challenges Solved

with Multiple TMAs and Shadow Vehicles Page 1 The Prevention of Plant Rollovers Page 3 Working Near Overhead Services – Height Warning System Page 6 The Safe Use of Temporary Safety Barriers Page 7

West Gate Bridge Strengthening – Traffic ManagementChallenges Solved with Multiple TMAs and Shadow Vehicles

The upgrade of the M1 West Gate Bridge has presented many safety challengesand has included significant high risk works. Work on the bridge railing hasbeen protected from traffic by utilising temporary safety barriers and screensfor the majority of the project while Truck Mounted Attenuator (TMA)protection was provided for short term works where barriers were notpractical. Speed limits were reduced to 60 km/h to reduce barrier deflectionsunder impact, because of the narrow clearance behind the barriers, and to 40km/h when pedestrian workers were present and not protected by barriers.Concrete and steel barriers were deployed, with anchored steel barriers inareas where weight restrictions were necessary.

As the project neared completion, and in preparation for the opening of five traffic lanesin both directions, it was necessary to remove the temporary barriers. To protectconstruction personnel during the removal of the barriers and the additional works toprepare for the opening of the five lanes, the mobile barrier ‘line of steel’ approach wasemployed.

Line of TMAs protecting adjacent works in left lane.


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View closer to works zone.

This innovation was first deployed on the South East Metro Eastern Freeway permanentbarriers installation project, where it was not practical to deploy safety barriers in thelong term due to the need to maintain traffic and transit lanes open in peak periods.

The concept was further enhanced by the West Gate Bridge Strengthening Alliance andVicRoads Road Services across the bridge with up to 6 TMAs deployed with works andincident response vehicles acting as shadow vehicles for additional protection.

This approach provided a line of vehicles on the bridge to protect and isolate pedestrianconstruction personnel working in the adjacent left lane from passing traffic. Two laneswere closed to facilitate the line of steel and a lateral buffer zone of 3 metres betweentraffic and actual work zone.

The Lane Utilisation Management System (LUMS) and VMS Displays were used to adviseapproaching traffic that the two left lanes were closed and to merge right. The LUMSclearly showed the closed lane with flashing red crosses and the 40 km/h signs showedthe open lanes and required speed limit. Police were enforcing compliance with the lanesigning – it is an offence to travel in a closed lane (Red Cross displayed above the lane).

Works were conducted off-peak and primarily at night to reduce traffic congestion andpublic inconvenience. The reason for the reduced speed limit was obvious to drivers andspeed compliance was excellent in general. The reduced speed limit improved safetyand Police and TSS speed enforcement was also available when necessary.


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Congratulations to the West Gate Bridge Strengthening Alliance for seeking on-goingsafety innovation during road construction works on a challenging site.

The Prevention of Plant Rollovers

Plant Rollovers continue to be a significant concern on projects. The followingfeedback is provided as the result of recent roller incidents:

1. The wearing of seat belts has increased on all sites and this has protected plantoperators from serious injury in recent incidents. Without wearing the belts injuries willresult when the operator is thrown from their seat and collide with fittings inside theircabin, or are thrown out of their cabin and crushed by their own machine.

2. Two projects have decided to construct over width batters from bottom layer up andtrimmed back to the design width. This removes the need to roll close to the edge andreduces the risk of the roller going over the edge.

3. General agreement that rollers should not roll closer than 1 metre to batter edges.

4. Experienced Plant Operators and Trainers, such as Jim Gascoigne, DirectorGascoigne Training & Assessment, have advised that when the verges were constructedwith the outside edges of formation layers sloped towards the centre of fills (so thatrollers lean inwards and away from the edges), rollovers were not an issue. The middleareas of fill can be topped up after edges are compacted. Other experienced operatorshave also explained that this was the practice in the past when VicRoads constructedverges and rollovers were not encountered as frequently as they are today. Thedefinitive ‘best practice’ is still to be identified.

Diagram illustrating verges sloping towards centre as described in 4 above.

5. The Anthony’s Cutting Alliance Project has fitted a rollover warning device to one of itsarticulated dump trucks. This Inclinometer Device provides audio and visual warning towarn the operator when the incline of the dump tub or the turning inertia / centrifugalforces acting on the tub are such that a rollover is imminent.

Many of these devices use mercury to dampen instrument reaction so as to avoid toomany false alarms from relatively minor movements of rough terrain. If too many falsealarms occur, there is a danger that operators will ignore the alarms and a rollover willoccur. Fine tuning the device is necessary so that it does not provide unnecessarywarnings such that the operator will ignore them.

The commercial devices that exist are in use around the world and are suitable for devicessuch as tip / dump trucks and rollers – the latter being the most common machineinvolved in plant rollovers.


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The photographs below illustrate the location of the detector and the operator warningdevice within the cabin of the articulated dump truck.

Articulated Dump Truck to which the warning device has been fitted.

Sensor attached to the dump tub.


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Flashing warning light and audible alarm in operators console.

Warning system within driver’s primary field of view.


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6. There is an increasing application of remote control devices to earthmoving plant inlocations where operator safety may be compromised. For example, if a rolleroperator should be fatigued or lose concentration, it is possible that they couldapproach the edge of a batter and the machine rollover the side.

The mining industry is using remote control devices for earthmoving plant and hasmore experience in this area. It is an area which should be investigated by the roadconstruction industry, particularly where high batters are present and the risk andconsequence of a rollover significantly increased.

Ergonomically designed controls in portable carry harnesses are available for line ofsight operations, as well as more sophisticated caravan type control panels.

Examples of the type of equipment may be found at: www.rct.net.au

Working near Overhead ServicesHeight Warning System for Excavators / Backhoes

Work near overhead and underground services still depends significantly onbehavioural / administrative controls. Most of the larger construction contractorshave introduced procedures which follow the WorkSafe Framework and include workpermits for excavations to ensure all of the necessary controls are in place.

Some contractors also require work permits for the movement of plant such asexcavators and backhoes on site. This is a wise precaution because trackingexcavators in particular have a high enough reach (movement envelop) to makecontact with overhead power lines, particularly when tracking with the boomelevated. Indeed, based on the editors own experience, tracking excavators are themost frequently use plant that make contact with overhead services and often aspotter is present when it happens.

What is indicated is an engineering control which warns and /or stops the machine ifthe boom reaches a preset height limit. This will reduce the behavioural risk whereoperators or spotters are distracted and the machine is tracked into an overheadservice with significant potential for fatalities and community inconvenience.

Such devices are available. They usually consist of a boom mounted computersensor and a cab warning display and can be adjusted to limit the height of the boomfor both safe services clearances and restricted headroom areas on site.

One such device is the Prolec Pro safe Heightwatch 6 Height Monitoring System.

Further details may be found at:www.prolec.co.uk/heightwatch_6_height_monitor.html

http://www.rct.net.au/


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The Safe Use of Temporary Safety BarriersThe use of Temporary Safety Barriers is increasing for the protection of worksother than roadworks conducted adjacent to roads. Barriers are a level 2 controlunder the hierarchy of safety controls applicable to worksite traffic managementand have proven very practical to protect the longer term works on or adjacentto roads over recent years.

It is good to see more and more worksites deploying this type of protection but itis necessary to highlight the need for the barrier installations to be fit forpurpose for the intended applications. Otherwise works personnel could beunknowingly exposed to a significant risk behind barriers which are unsuitablefor the application or incorrectly installed.

It is evident that as the use of temporary safety barriers by contractors that are not underthe supervision and control of VicRoads the risk from unsuitable barriers or incorrectlyinstalled barriers will increase. The risk not only potentially includes the workers involvedbut also road users.

The Road Traffic Authority NSW and WorkCover NSW have recently released a joint SafetyAlert ‘Safe Work on or near Public Roads – Issues with Plastic Water Filled Barriers’, a copyof which is appended to this Update. VicRoads already has limitations on the use of WaterFilled Barriers where they are deployed as terminal crash attenuators, reflecting the testresults of these barriers and the US Federal Highway Administration restrictions to avoidhigh speed high angle impacts.

There are a number of issues which have been observed when barriers areinstalled by personnel without the necessary training and experience:

1. Water Filled Barriers in a longitudinal installation typically have large deflectionsunder impact and this sometimes is not being taken into account for worksadjacent to high speed roads.

2. Water filled terminals (barrier end crash cushion) without water or leaking water.3. Water filled terminals which are not installed as per the manufacturer’s installation

specifications.4. Insufficient numbers of barrier units are sometimes deployed which will result in an

unsafe performance and protection for workers and road users.5. End crash attenuator protection is sometimes not in place or insufficient to safely

cushion the impact of an out-of-control vehicle.6. The difference in gating and non-gating terminals is not understood and insufficient

allowance for this is sometimes observed on sites.7. Water filled terminals installed with connecting pin not removed from first unit at

traffic approach end.8. No hazard warning markers on the barrier approaches.

The use of trained installation personnel will ensure that the barriers are fit forpurpose and correctly installed as per the manufacturer’s installationspecifications. This could be achieved through the temporary barrier hirecompanies.

Worksite Site Safety Update is produced monthly by VicRoads Major Projects Division tocommunicate industry safety information and initiatives within VicRoads and to ourcontractors. It is also circulated via the WorkSafe Safety Soapbox to industry. The contentreflects civil road construction and maintenance safety and includes works conducted on orbeside operational roads. The editor may be contacted at: [email protected]

mailto:[email protected]


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