Friday, November 2, 2007

Just How Safe are Monopole Cell Towers?

Industry Investigating Monopole Failures

July 28, 2007 - There have been multiple monopole failures this year such as this Sprint/Nextel monopine that fell in California in early May.

Although some of the structure failures can be attributed to winds in excess of jurisdictional design requirements, some monopoles reportedly failed at wind speeds that should not have caused the poles to collapse.

One commonality is that numerous failures were directly above the base plate or above flange locations.

In an industry where the speed of rumors, misstatements and misunderstandings can make the highest ASCE three-second gust blush with envy, industry observers are quick to fault poor engineering, manufacturing and/or metal fatigue as the usual suspects.

Some structural engineers believe that design aspects of monopole engineering should require a closer look, and the TR14.7 TIA-222 committee agrees since they will be reviewing base plate design methodologies and weld details of the base connection on monopoles. They’ll also be investigating fatigue categories on welded joints. Their findings and recommendations will be included in Revision H of the tower standard. However, it could be a year or two until this area of concern is fully explored.

Would you want this in your backyard?

Read the entire article here.