Optimum Strand Arrangement for Suspension Bridge Cable

Paul H. Mueller

Construction Consultant

P.H. Mueller International Inc.

Fort Lauderdale, FL, USA

paulhmueller@bellsouth.net

Paul H. Mueller, born 1928, received engineering training in Germany, gained bridge construction know-how while working with Phoenix Bridge Co. and American Bridge Division (US Steel) in the USA

There are two methods to install suspension bridge cable; Air-spinning method and PPWS installation. Whichever method is taken, one cable is composed of many numbers of wire-bundles which are called “Strands”. After those strands are installed, they are compacted together using a compacting machine to form the cable round cross section and to the diameter as specified. Conventionally those strands are arranged in a “Staggered Arrangement”. However, recently cables for some bridges have been designed and/or constructed in a “Matrix Arrangement”. We strongly oppose this idea. For the reason that this arrangement will cause many wires to cross during compacting, which would lead to stress corrosion cracking and eventually to many wire failures during long term operation and consequently shorten the lifetime of the cable.