Deadly Descent: Concrete Pump Topples, Claiming One Life

 

A Concrete Pump overturns on a construction site and kills one worker in the Houston area

My geotechnical firm investigated the soil conditions under the crane and the timber that was placed under the outriggers. 

 

They conducted a geotechnical investigation of the soil.

The soil conditions under the crane were sufficiently compacted for the weight of the crane. Based on their calculation, the soil bearing capacity was 2,100 psf for a safety factor of 3.

They measured and analyzed the support timbers under the crane’s outrigger and found that they were insufficient in size. 

 

Based on the results of the field explorations, laboratory testing, and engineering analysis, it was the Geotechnical opinion that the potential causes of the concrete pump truck outrigger failure are as follows:

1)     The concrete pump truck outrigger failure occurred at the rear outrigger leg.

2)    The significant presence of plastic trash beneath the rear outrigger leg support area is attributed to one of the main reasons that resulted in the rear outrigger leg support failure.

3)    It is likely that this area is a disposal site for waste materials. Thus, the on-site soils in this area were disturbed and poorly compacted.

4)    The presence of gasoline crossing the rear outrigger leg support area could contribute to the rear outrigger leg support failure due to soil disturbances and poor compaction by the construction of the gas line.

5)    The presence of the hidden voids near the rear outrigger leg support area could contribute to the rear outrigger leg support failure.

6)    Rainfall contributed to the rear outrigger leg support failure by increasing the subsoil moisture and decreasing the soil shear strength.

 

Perform a bearing capacity check of the staging area by a geotechnical engineer for any crane or concrete pump truck outrigger used on the project.

Meet with your crane operator and review a lifting plan before work commences.

Consider all the aspects of the lift;

1)     Weight

2)    Center of gravity

3)    Lifting points on the load

4)    The path that the load will travel during the lift.

5)    The capabilities of the crane, review the load tables or the instrument of loading.

6)    Consider the wind

7)    Communication during the whole process of the lift.

8)    Are the outrigger pads a sufficient size?  

Shettig Construction Management provides Professional Construction Management services from the inception of your project through completion. www.shettig.com

mshettig@gmail.com