Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

The Niger Delta is situated in the southern-most section of Nigeria and forms the major crude oil reservoir of Nigeria. However, it is in most parts devoid of transportation routes. A proposed Trans-Kalabari Highway is expected to connect some of the communities located within the Mangrove (“Transition”) hydro-meteorological zone of the delta that is characterized by a network of rivers, creeks and rivulets. The left abutment of one of the bridges across a 400-meter wide river indicates that the sub-surface down to a depth of 30.00 meters at a distance of about 40.00 meters from the edge of the river channel has six (6) different soil layers as against four (4) at a comparative distance on the right abutment. These soil layers are basically dark-gray organic silty clays (OH) underlain by grayish silty clayey sands (SC) which are further underlain by poorly graded silty sands (SP). A dark, highly plastic, grayish silty clay layer (SC-SM) underlies the above strata at a depth of between 12 to 18 meters. Well-graded sands and gravel (SW) layer further underlies the above and extends to depths in excess of 30.00 meters. Borings situated between 40.00 meters and the edge of the shoreline of the river channel all have five layers with poorly graded sands (SP) and well-graded sands and gravels (SW) underlying the organic silty clays and silty sands. Steel piles for the bridge support are expected to be borne at depths of between 20 and 25 meters corresponding to the well-graded sands and gravels (SW) layer. This paper describes the detailed geotechnical engineering properties of the sub-soils at both abutments, gives a bathymetric profile of the river bed at the bridge crossing and recommends the design parameters for the piles such as the end-bearing-capacities for the piles to be used for the bridge support.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 11th, 12:00 AM Aug 16th, 12:00 AM

An Evaluation of the Geotechnical Characteristics of the Abutments of a Proposed Bridge Across a 400-Meter River Channel in the Lower Niger Delta, Nigeria

Arlington, Virginia

The Niger Delta is situated in the southern-most section of Nigeria and forms the major crude oil reservoir of Nigeria. However, it is in most parts devoid of transportation routes. A proposed Trans-Kalabari Highway is expected to connect some of the communities located within the Mangrove (“Transition”) hydro-meteorological zone of the delta that is characterized by a network of rivers, creeks and rivulets. The left abutment of one of the bridges across a 400-meter wide river indicates that the sub-surface down to a depth of 30.00 meters at a distance of about 40.00 meters from the edge of the river channel has six (6) different soil layers as against four (4) at a comparative distance on the right abutment. These soil layers are basically dark-gray organic silty clays (OH) underlain by grayish silty clayey sands (SC) which are further underlain by poorly graded silty sands (SP). A dark, highly plastic, grayish silty clay layer (SC-SM) underlies the above strata at a depth of between 12 to 18 meters. Well-graded sands and gravel (SW) layer further underlies the above and extends to depths in excess of 30.00 meters. Borings situated between 40.00 meters and the edge of the shoreline of the river channel all have five layers with poorly graded sands (SP) and well-graded sands and gravels (SW) underlying the organic silty clays and silty sands. Steel piles for the bridge support are expected to be borne at depths of between 20 and 25 meters corresponding to the well-graded sands and gravels (SW) layer. This paper describes the detailed geotechnical engineering properties of the sub-soils at both abutments, gives a bathymetric profile of the river bed at the bridge crossing and recommends the design parameters for the piles such as the end-bearing-capacities for the piles to be used for the bridge support.