SC Tech Talk: Seismic Zones

This week we are taking you back to revisit our great blog on stable staging for seismic zones!

By: Tony Barnes P.E., Senior Structural Design Engineer

Staging Concepts continues to invest in R&D that delivers the most highly engineered staging systems to our customers. The engineering department at Staging Concepts represents over 15% of the company’s overall headcount and remains the cornerstone of the added value Staging Concepts delivers to its customers.

Notable seismic events have occurred across the globe over the past few years and earthquakes of magnitude 4.0-6.0 occur with a surprising frequency of approximately 35 per day (USGS- United States Geological Survey).  Whether events cause significant damage and risk to life and property or simply discomfort to people, Staging Concepts has responded to the need for increased safety by conducting a study on the performance of our staging products in seismic conditions. As expected our SC90 platforms, SC90 legs and SC9600 bridging understructure perform well when subjected to even the most severe seismic forces typically prescribed by building codes used in the United States.

More specifically, the platform systems were analyzed using the American Society of Civil Engineers (ASCE) and National Earthquake Hazard Reduction Program (NEHRP) recommendations by applying a seismic load equal to 2.5 times the weight of the structure plus a 150 psf vertical live load.  The seismic load of 2.5 times the weight of the structure is derived under the assumption that the platform is constructed near a fault zone and in low stability soil.

Under these conditions, we calculated the performance of a 21’ x 30’ overall stage system. The stage system was constructed using 35 (qty), 6’ x 3’ SC90 platforms attached to one another using roto-lock devices. Our simulation compared the performance of three heights and configurations:

a)     14” height using legs and no bracing

b)     30” height using legs and perimeter bracing

c)      48” height using our bridging understructure and alternating bracing

Using structural analysis software, we were able to calculate the anticipated sway and the degree to which each configuration resists instability and collapse. In each case, our staging met the recommended requirements and achieved factors of safety as high as 13.9. Our technical summary is attached and a more detailed report is available upon request.

We are committed to bringing facts and data to our industry, so our customers can make informed decisions. We hope this study helps our customers construct the safest staging structures possible.