Bridge Design Manual by ETHIOPIAN ROADS AUTHORITY

1 INTRODUCTION

These Standards deal with small and medium sized structures and shall be used for all
structures within the Ethiopian Roads Authority (ERA) throughout the country.
These Standards are based mainly on the American Association of State Highway and
Transportation Officials (AASHTO) LRFD Bridge Design Specifications, 2nd edition,
1998, with modifications to Ethiopian conditions, requirements and applicable laws of the
Federal Democratic Republic of Ethiopia.

As a supplement to these Standards for structures not mentioned here (such as prestressed
bridges, large bridges, certain steel bridges, composite bridges, aluminum bridges, etc.),
the AASHTO LRFD Specifications, 2nd edition 1998 or later editions may be used but
only together with Chapter 3: Load Requirements in these Specifications.

The Bridge Design Manual is written for the practicing engineer and describes current,
mandated and recommended practice in selected aspects of bridge engineering. These are
based on mathematical calculations, and the Ethiopian terrain, experience and research,
and have the support of the Ethiopian Roads Authority. It closely follows American
practice and is based mainly on the LRFD Bridge Design Specifications, 1998 Second
Edition, SI Units, of the American Association of State Highway and Transportation
Officials.

These Specifications are based primarily on the AASHTO LRFD Bridge Design
Specification 2nd Edition 1998 which replaces the AASHTO Standard Specification for
Highway Bridges, 16th ed. 1996. The latter specs may however be used during a transition
period of 3 years up to December 31, 2003, after which this Bridge Design Manual
(LRFD Code) shall govern.
The LRFD method was introduced by AASHTO in the USA in 1994. A similar method
has been used for bridge design in parts of Europe since 1988, and, without load reduction
factors, for building design at the Addis Ababa University since 1985.

These Specifications shall govern over the Ethiopian Building Code Standard (at present
EBCS Nos. 1,2,3,5,7 and 8, 1995). EBCS shall be used as a compliment to these
Specifications.

Required loads, dimensions and methods are summarized generally in Chapters 2, 3, and
6-11. The remaining chapters are generally concerned with recommended practices. It is
the purpose of this manual to provide all the necessary procedural guidance, dimensions,
and materials advice to enable a civil engineer with some field experience to prepare
appropriate preliminary and detailed designs for small and medium sized bridges.

Bridge Design Manual by ETHIOPIAN ROADS AUTHORITY