OPAC Consulting Engineers

Gibraltar Bridge

Strait of Gibraltar, Spain-Morocco


Prof. T.Y. Lin, San Francisco, California


Study completed 1996

Scope of work:

Feasibility Study

Construction cost:

US$ 15 Billion (estimated)

Services Performed:

  • Developed global computer models
  • Performed structural configurations and stiffening systems studies
  • Performed aerodynamic performance study


  • Hybrid stayed-suspension bridge design
  • Deep water construction
  • Wind analysis of long span bridge

One of the great challenges to the bridge and structural engineering profession is the design and construction of a fixed bridge spanning the Strait of Gibraltar. Its significance is evidenced by UNESCO's studies of the crossing in conjunction with the UN Economic Commissions for Africa and Europe, and the Morroccon and Spanish government agencies SNED and SECEG that were set up to study and manage the development of the project.

Several engineers have advanced designs for the Gibraltar Bridge on various alignments and with differing structural configurations. Professor T.Y. Lin's proposal for a crossing between Point Oliveros and Point Cires captured the attention of the world, however, with its 14km length, deep piers, and unprecedented 5000 meter spans.

OPAC was engaged by Professor Lin to study structural configurations, stiffening systems, and aerodynamic performance issues for the Oliveros-Cires crossing's 5000 m spans. Several bridge configurations were dimensioned, computer models were developed, and were analyzed for static and dynamic characteristics and relative aerodynamic feasibility. The bridge types that were studied included classic suspension bridges, cable-stiffened suspension bridges, and Professor Lin's proposed hybrid stayed-suspension bridge concept. The hybrid stayed-suspension bridge was developed into the most suitable alternative, with greater rigidity and better aerodynamic characteristics than competing systems with much smaller spans.