Project to replace the generator was in progress. Accident occurred when they were rigging out the old generator stator (weighs 500 tons,  2x heavier than the Monticello generator stator). Failure occurred when over the railroad bay and the stator dropped 55 feet. Not sure exactly what failed but you can see in the bottom pictures that the stator rotated ~135 degrees before it landed. Have been told that the impact caused the other unit to trip – a check of the NRC website indicates that both are offline, but can’t confirm anything beyond that. Rumor is that the impact could be felt several miles away.  Here are MEMEBR AREA photos of the move before and after the rigging failure. The generator and beams fell 55 feet to the Turbine building ground floor.

Crane 1

Summary: 

About 8:00 am 02/03/03 ***** personal began to set up the 50-ton rough terrain crane at the oil barge dock to unload cargo for the ***** project. After the crane was positioned approximately 8' from the edge of the bulkhead and all pre-lift checks had been made with dry run we proceeded to lift the first piece. The operator lifted up the cargo about 10 to 12 inches high and stopped to insure the load and crane was stabile, at that point the operator felt a shift in the crane and felt the concrete on his left front outrigger cave in. The load came back to rest in its original position on the barge. No one was hurt due to this incident minimal damage done to property.

Root Cause: 

the soil was undermined beneath the concrete where the outrigger was set to stable the rig for lift.

Contributing factors: 

From past experiences of ******** employees and boilermakers present at the time of the incident, that area had not been a problem location. Heavy equipment had been placed there and used in the past to unload barges with no incident prior to this date.

Corrective action: 

******** had the soil tested on 02/03/03 to determine if the undermining was isolated and insure soil stability for future location of equipment as well ******** will have better communication with ******** for other locations that may have possible known undermining prior to setting up equipment in the barge area. ******** has repaired and compacted the undermined area.

Submitted by Casper, our friendly Safety Professional

concre7          concre8


concre8          concre9

Construction Industry Program

Incident Report:

Truck-mounted Concrete Placing Boom Overturns

Category: Cranes & hoists

Sub-category: Concrete placing equipment

Relevant to: All construction sectors, concreting contractors, truckmounted concrete boom pump owners and operators

Date of Issue: 22 January 2003

Reference No: 03: 001

Authorised by: Geoff Thomas, Construction Industry Program Director

Incident

WorkSafe inspectors attended a construction site where a truck-mounted concrete placing boom had overturned onto an adjoining house under construction, damaging the boom and the house1. Fortunately, nobody was injured. 

1 Under the Victorian Occupational Health and Safety (Incident Notification) Regulations 1997, employers must, amongst other things, immediately notify WorkSafe of "the collapse, overturning, failure or malfunction of, or damage to, any item of plant listed in item 2 of Schedule 2 of the Occupational Health and Safety (Plant) Regulations 1995" [Regulation 8 (a)]. Truck-mounted concrete boom pump s are amongst the plant types listed. To find out more about these Regulations, refer to Incident Notification – At a Glance, available free of charge from local WorkSafe offices, or on-line at www.workcover.vic.gov.au.

Preliminary Inspection

WorkSafe’s preliminary inspections indicated the following:

· The concrete boom pump was an imported second-hand Cifa 36, mounted on a truck chassis.

· The owner could not produce evidence that the unit had been registered with WorkSafe Victoria or any interstate OHS regulatory authority2.

· The pump operator held a certificate of competency for truck-mounted concrete boom pump operation that had been issued by WorkSafe Victoria 3.

· Concreting had been completed on the site, and it appears that the boom was being slewed to commence cleaning of the pump’s delivery lines when the chassis tilted to its left side, resulting in the extended boom falling on to a house under construction on an adjoining property. 

· The ground on the left side of the chassis was sunken under the front and rear tyres.

2 Under the Victorian Occupational Health and Safety (Plant) Regulations 1995, a person who has management and control of, amongst other things, a truck-mounted concrete boom pump must not use it, or cause or allow it to be used at a workplace unless it is registered with WorkSafe Victoria or with an interstate OHS authority. [Regulations 1007 (1) and 1001 (1).]

3 Under the Victorian Occupational Health and Safety (Certification of Plant Users and Operators) Regulations 1994, operators of truck-mounted concrete boom pumps must, unless they are trainees under direct supervision, hold a certificate of competency of the appropriate class that has been issued by WorkSafe Victoria or an interstate OHS authority. [Regulation 7 (1), (2) & (4) and Regulation 8 (1) (a).] The class code marked on nationally uniform certificates of competency for concrete placing boom operation is PB.

The sunken ground was backfilled soft soil over an area that had recently been excavated to lay pipes.

The timber pad under the left rear outrigger appeared to have broken during the overturning of the unit.

The attachment points for the slewing cylinders of the two le ft hand outriggers were broken, but it was not clear whether this had occurred prior to or as a result of the incident.

Remedial Action

A Prohibition Notice was issued, preventing any further attempt to salvage the unit until a safe recovery procedure was developed and an engineering assessment had confirmed the suitability of the procedure.

A Prohibition Notice was also issued, preventing the ongoing operation of the unit until it has been recommissioned in a fully serviceable condition. 

The adjoining property was fenced off to prevent unauthorised access pending an assessment of the damaged house by a building surveyor.

Preliminary Findings

Incidents similar to this may be avoided if the advice provided in Australian Standard AS 2550.15, Cranes – Safe Use, Part 15: Concrete Placing Equipment, is fully implemented4.

Clause 4.2 of this Standard sets out rules for the set up of concrete placing equipment, and Clause 7.5 provides advice for safe operation.

The Australian Standard referred to in this incident report can be purchased on- line from Standards Australia at: www.standards.com.au

The Regulations referred to in footnotes to this incident report can be accessed online, free of charge, through the "Victorian Law Today" section of the website:www.dms.dpc.vic.gov.au

Distribution

Posted on WorkSafe web-site Construction Page: 22 January 2003

E-mailed to Foundations for Safety delegates: 22 January 2003

E-mailed to WorkSafe's Construction Safety Circulation Service subscribers: 24 January 2003

E-mailed to interstate OHS regulatory authorities: 22 January 2003

WorkSafe Construction Industry Program field staff: For on-site distribution where appropriate

Disclaimer:

This incident report contains information about WorkSafe’s inspection into the incident as at the date of this report. The information does not necessarily reflect the final outcome of WorkSafe’s actions with respect to the incident. WorkSafe does not warrant that the information in this incident report is complete or up to date and does not accept any liability to any person for the information contained in this incident report or as to its use. 4 The AS 2550 series of Australian Standards forms part of WorkSafe’s Code of Practice for Plant, which provides employers and other persons with obligations under the Victorian Occupational Health and Safety (Plant) Regulations 1995 with advice on recommended ways of achieving compliance with those obligations. The Code of Practice is available, free of charge, from local WorkSafe offices or online at www.workcover.vic.gov.au.

 
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