Foundation-Soil-Inclusion Interaction Modelling for Rion-Antirion Bridge Seismic Analysis

The Rion-Antirion Bridge in Greece will span a total length of 352 1 m, which includes a five span cable-stayed bridge 2252m in length and two approach viaducts. Upon completion in 2004, the bridge will be the longest cable-stayed bridge in the world. The main factors affecting the foundation design involve high seismicity, poor in-situ soil conditions, deep sea water (65m) and high ship impact force. These factors called for an innovative foundation design for each of the 90m diameter piers by the foundation designer, Geodynamique et Structure (GDS) from France. The proposed design consists of vertical open-ended steel cylinders (called “inclusions”), 25 to 30m long and 2m in diameter, which will reinforce the in-situ soils. The inclusions are to be spaced at 7 to 8m beneath each pier footing supporting a 230m tall pier and pylon structure. These inclusions are not connected structurally to the footing. Beneath each footing is to be placed a layer of gravel in which the inclusion heads are to be embedded. The interface between the pier base and gravel is to serve as a sliding shear fuse under extreme earthquake loading, involving a base isolation concept. This design was checked independently by the Checker - Buckland & Taylor Ltd. (B&T), using nonlinear finite element analyses of the foundation and soil subjected to equivalent seismic or ship impact loading consisting of a horizontal monotonic or cyclic force acting at a representative height (lever arm) above the seabed. The failure mechanisms observed in centrifuge model tests and in field sliding tests of the footing were closely examined and compared with the failure behavior predicted by the finite element soil-structure interaction modeling. The hysteretic damping characteristics of the foundation under horizontal cyclic loading obtained from the above analyses were used in the dynamic global bridge seismic analysis. The Checker’s independent analyses confirmed the viability of the proposed design

Rion – Antirion Bridge Foundations: A Blend of Design and Construction Innovation

This case history discusses the design and construction of the appropriate foundation scheme for the largest cable-stayed bridge in the world. This concession project was financed through a combination of public funds, private equity and bank loans. When completed in 2004, the Rion-Antirion Bridge will connect the Peloponnese, Greece’s southernmost peninsula, with the mainland across the Gulf of Corinth. Alternative foundation concepts that were considered included traditional driven piles, deeply embedded caissons, and soil improvement. The process of how the foundation evolved from schematics to final design, what were the driving forces, how ideas were disseminated among the Design Team, the Design Checker and the Technical Advisors, and the performance of the foundations to date are summarized

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Foundation Engineering

xvii,513hlm.;bib;indek

Foudation engineering

xxiii, 514 p.; 25 cm