METHOD OF ASSESING HIGHWAY BRIDGES FOR SUPERLOADS

Technological progress has made it economically beneficial to use larger and heavier industrial components termed "Superloads". These generally involve equipment for electric power and very heavy chemical plants located on coal fields. Because of the absence of inland waterways and the limited capacity of railways in Southern Africa, these loads must travel along the highway network. A current project involves the movement of payloads of up to 400,000 kg (440 tons) over some 500 km (310 miles) of road. In this instance a total of 60 under-bridges of various sizes must be crossed. In order to meet pavement loading restrictions, the transporters carrying these loads may have as many as 288 wheels distributed on 5 m (16 ft) wide axles. The four haulers used to draw these vehicles may give total combination masses of up to 800,000 kg (880 tons) and overall lengths of about 120 m (385 ft). Accurate analytical techniques are required to optimize the effects of these load trains on bridges so that every reserve of strength may be utilised. The multiplicity of structural configurations, construction materials, and original design specifications requires that each structure be assessed individually. Moreover, the variety of vehicle combinations is practically endless. For these reasons the method adopted to make such assessments relies on a load independent computerized influence surface technique involving stresses at critical points. A research program to develop a system termed "Generate-Simulate-Compare" (GSC) is now well advanced and initial analytical results sow good correlation with parallel studies on monitoring techniques in the field. The paper describes the package of analytical programs and field observation methods. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; Maps; Photos; References; Tables;
  • Pagination: pp 212-220
  • Monograph Title: Bridge Engineering. Volume 1
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183767
  • Record Type: Publication
  • ISBN: 0309026962
  • Files: TRIS, TRB
  • Created Date: Dec 3 1978 12:00AM