Lessons Learned in the Launching of Steel Girder Bridges
Launching of steel girder bridges is a construction method that is implemented when the terrain conditions allow the assembling of the structure behind one of the abutments. This methodology may be safer, faster, and more cost effective than other traditional erection procedures since most of the operations are conducted on firm soil. This paper presents the details of the launching operations of two bridges recently constructed by incremental launching. The first case study, the Los-Pajaros Bridge, is a three-span continuous I-girder structure with a total length of 639'-6" that was originally designed as three independent simple spans and was converted to continuous spans in a value engineering improvement to facilitate launching. The second case study is the Villorita Bridge, a two-span continuous tub-girder structure with span lengths of 171'-4" and 304'-3". The paper focuses on three aspects of bridges erected with launching methods: the implementation of the incremental launching method and its benefits, the design calculations and the limit states that apply to girders in cantilever, and the expected versus real structural behavior in terms of girder stresses and cantilever displacements.
- Date: 4/3/2019 - 4/5/2019
- PDH Credits: 0
T. Andres Sanchez, PhD; Michael LaViolette, PE