SYNOPSIS

Leziria Tagus Bridge in Portugal composed by the North Viaduct with 1700 m long, by the main bridge with 970 m long and by the South Viaduct with 9200 m is presented.The observed thickness of the foundation alluvia material varies between 35m and 55m and the maximum observed value is 62m. Hundred eighteen boreholes were performed with a depth between 21m and 71m and eight boreholes were performed from a platform. Standard penetration tests (SPT) were carried out in all boreholes 1.5 m apart. In addition CPTu tests, seismic cone tests, crosshole and downhole tests were performed. In three boreholes continous undisturbed sampling with a triple sampler Geogor S was performed. Related with laboratory tests static tests namely identification tests, triaxial tests, direct shear tests and oedometer tests were performed. In addition for dynamic characterization reasonant columns tests and torsional cyclic tests were performed. One of the most important considerations for designers is the risk of earthquakes since Lisbon was wiped out by an earthquake in 1755 of 8.5 of  Ritcher magnitude. The seismic studies related to the design spectra were performed. The liquefaction potential evaluation was performed only by field tests taking into account the disturbance that occurs during sampling of sandy materials. In this analysis attention was drawn for SPT and CPT tests as the seismic tests have only been used when soil contains gravel particles. The shear values were computed from a total stresses model, that gave results on the conservative side using the program “SHAKE”, For  the North and South Viaducts piles with 1.5 m diameter were used and for the Bridge 2.2 m diameter piles were used. For the construction of the piles metallic casings were driven by a vibrofonceur or a hydraulic hammer and the piles length varies between 20 m to 56 m. Static pile load tests (both vertical and horizontal tests) were carried out on trial piles. In addition pile dynamic tests were performed. The bearing capacity of piles were defined by analytical as well numerical formulations. To assess the integrity of the piles reception tests by sonic diagraphies (crosshole tests) were performed. The bridge was monitored with the purposes of: (i) Validation of design criteria and calibration of mental model; (ii) Analysis of bridge behaviour during his life; (iii) Corrective measures for the rehabilitation of the structure.

BIODATA OF SPEAKER

Prof.  Pedro Simão Sêco e  Pinto is  Full Professor of Geotechnical Engineering of University of Coimbra. Invited Professor of Master Courses "Soil Mechanics" and "Engineering Geology" of New University of Lisbon (1983-1995). He was ISSMGE  President  (2005-2009), ISSMGE Vice President for Europe (2001-2005), United Nations Consultant for Design and  Instrumentation for Dams  (1988-1992). Invited Lecturer of University of California, USA, (1992-1994). Chairman of TC4 “ Earthquake Geotechnical Engineer “ Committee of ISSMFE (1994-2000). President of Portuguese
Society for Geotechnique (1996- 2000). Consulting Engineer of more than 350 major projects on Dams, Power plants, Bridges, Tunnels and Quay Walls, in Portugal, Argelie, Morocco, Tunisie, Angola, Mozambique, Senegal, Guinea, Brazil, Venezuela, Dominican Republic, Ecuador, India, China, Syria, covering field and laboratory testing, dynamic analyses, earthquake engineering, numerical analyses, ground improvement, slopes, special foundations, instrumentation and safety evaluation. He has presented more than 300 State-of-the Art  Lectures and Special Lectures in 76 countries of the 5 Continents. He has received more than 50  international Awards including  American Biographical Institute USA, "Special Volume for the Contributors of Earthquake Engineering, Nagadi Lecture by Indian Geotechnical Society, Széchy Lecture by Hungarian S M Society and Hungarian Academy of Sciences, Nonveiller Lecture- by Croatia Geotechnical Society, Sukle Lecture by Slovenia Soil Mechanics Society, Chin Lecture by Huanzhou University (China), Qian Jia Huan Lecture by Hohai University (China) and 20th Chin Fung Kee Memorial Lecture atThe Institution of Engineers of Malaysia. He is Co-editor of Geotechnical and Geological Engineering Journal, Springer Publisher. Member of Editorial Board of
several Journals, namely "Geotecnia", “Bulletin of Earthquake Engineering”,  Acta de Geotecnia, International Journal of Geotechnical Engineering and Editor of Proceedings of 4 International Conferences. He is author or co-author of 400 technical and scientific reports, more than 150 papers for national and international conferences and journals and has contributed for 10 books.