Lack of maintenance compromises tunnel structural safety, by Sadek & Hamad (2007)

Title:

Authors:

Salah Sadek, Professor of Geotechnical Engineering, Department of Civil and
Environmental Engineering, Faculty of Engineering and Architecture, American
University of Beirut, Bliss Street P.O. Box 11-0236, Beirut, Lebanon, Tel.:
+961-1-350000 x3472, Fax: +961-1-744462 (website, e-mail)
Bilal Hamad, Professor of Structural Engineering, Department of Civil and
Environmental Engineering, Faculty of Engineering and Architecture, American
University of Beirut, Bliss Street P.O. Box 11-0236, Beirut

The Chekka tunnels represent a critical section of the Northern Lebanon Highway. The
approximately 350 m long twin tunnels are the most important such structures in the
country. They are used by regular and freight traffic and are a vital link to the capital,
Beirut. The tunnels were completed in the early 1970s on the eve of the Lebanon civil
war. Given the state of affairs in the country for about two decades of strife, the
tunnels were not maintained nor did they undergo any regular inspection. This unique
condition of near-abandonment continued up until recently, when the first signs of
distress were documented. These consisted of severe and extensive cracking,
particularly in the portal approach of the southbound tunnel, along with significant
deterioration of the tunnel lining and radial section joints. The danger to the traffic and
potentially to the structure itself was evident. In this paper, the results of an extensive
site inspection and evaluation program are presented. The underlying causes of the
observed damage are analyzed and discussed using a modeling approach of the evolving
loading conditions. Remedial measures are discussed along with a summary of the
actual repair and rehabilitation works which have just been completed.