The widening of motorway overbridges and county road bridges is considered in relation to using as much as possible of the existing infrastructure. Some general possibilities for and limitations of bridge widening are summarised, and some specific illustrative examples are presented. Reasons for bridge widening include: (1) those required by highway improvement schemes; (2) improvements local to a bridge; and (3) widening to enable future road or bridge maintenance to be done without a road closure. There are many approaches to bridge widening that can be useful in some circumstances; seven methods of widening underbridges and lengthening overbridges are listed. Sometimes it is better to reconstruct an existing bridge instead of widening it. Nine technical bridge widening problems are considered, and three other influences on the choice of solution are mentioned. The following problem areas are discussed: (1) changing design standards; (2) varying characteristics; (3) settlement; (4) planning constraints; (5) inspection and maintenance; (6) utilities; and (7) hidden difficulties with old bridges. Four case studies of bridge widening are given, which show that the many problems and pitfalls can be resolved. For the covering abstract see IRRD 873097.


  • English

Media Info

  • Pagination: p. 104-24

Subject/Index Terms

Filing Info

  • Accession Number: 00712421
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Oct 24 1995 12:00AM