T.Y. Lin International provided a seismic engineering evaluation for the Tren Electrico (Electric Train), Lima-Callao Line 1. The team conducted several checks of existing bridge modules and a check of the recently constructed elevated viaduct guideway which runs along a north-south alignment over two medians of Aviacion and Tomas Marsano Avenues in downtown Lima. The guideway will cross Expresa Javier Prado, a major freeway.
- T.Y. Lin International successfully met an aggressive 18-month, fast-track design and construction schedule.
- Recommendations for retrofit concepts saved the contractor a significant time and money by as much as one third for some structures.
Lima-Callao Line 1 consists of ballasted dual rail transit guideways, approximately 6.5 miles in total length. The new structure features precast girders and reinforced concrete piers on spread footings and, in few cases, on piles. Typical spans are 65 feet long and 4.2 feet deep; they are made continuous up to six spans by the reinforced concrete deck and post-tensioned cast-in-place diaphragms. Precast girders are also used in modules with spans up to 114 feet. Single-cell post-tensioned concrete haunched box girders spanning up to 147 feet are used over the major avenues and freeways, and where the alignment is on a curve.
The existing elevated structures are approximately 1.8 miles long. The design of the modules consists of multi-span, dual post-tensioned box girders supported on two piers, framed monolithically in the transverse and longitudinal directions. There are also six elevated train stations and a number of at-grade stations.
T.Y. Lin International provided preliminary results and findings of the seismic resistance design check. The firm also provided recommendations for retrofit concepts to be incorporated by the designer, when deficiencies were observed for the structural components. T.Y. Lin International’s seismic retrofit recommendations were for 4km of existing viaducts and the firm provided a seismic evaluation and redesign of 8km of new viaducts.
The team successfully met an aggressive 18-month, fast-track design and construction schedule, providing a redesign of the substructures addressing seismic requirements while construction took place! For the seismic retrofit of the existing structures, new technology was required including carbon fiber wrapping to make the footings, columns, and joints ductile.
By applying state-of-the-art design methodology and latest AASHTO LRFD code requirements, construction costs were reduced up to as much as one-third by reducing the footing size and the amount of reinforced steel in the substructure. The footprint around the footings was reduced thereby requiring less excavation. As a result, traffic maintenance was alleviated as two additional lanes were not necessary.