DFI Traveling Lecturer

Viaduct No. 1, on what is formally known as the L-2 highway in Venezuela, was originally built in the 1950s as part of the construction of a vital highway linking the capital city of Caracas with the country’s most important maritime port. By the late 1980s the viaduct was experiencing severe movements, which were found to be product of lateral thrust from a re-activated macro-landslide on its southern abutment, which is likely associated with an active fault zone crossing the viaduct.

The study of the macro-landslide and repeated attempts to mitigate it over two decades became a dominant topic of geotechnical forums in the country. Ultimately, the macro-landslide won, the battle ending with the dramatic collapse of the original viaduct. A replacement viaduct, much longer to bypass the unstable area, was built in record time, with significant construction time savings afforded by the utilization of high-capacity micropiles. This was the first utilization of high-capacity micropiles in Venezuela. It may have also been the first case of large-scale and exclusive utilization of micropiles for foundation of a viaduct of this size in Latin America.

This presentation generally discusses the geotechnical history of Viaduct No. 1 until its collapse and explores its significance within the social framework and the impact of its closure on the economy and the people. More specifically, the presentation covers the micropile foundation design and construction, including details of the micropile design to support the significant compressive and tensile axial loading, shear, and bending product of the substantial seismic motions in the area. The presentation also covers the challenges encountered, such as presenting a new technical concept for an extremely sensitive project, the extremely difficult site and access, poor availability of material and equipment, and political and social pressure behind the project.