The Gilberto Borja Navarrete Viaduct, known during construction as the San Marcos Viaduct, carries the Mexico City–Tuxpan motorway across the valley of the San Marcos river in the Eastern Sierra Madre, in the state of Puebla. Its 850 m deck runs over six piers of 33, 76, 166, 208, 121 and 54 m. According to the design team’s paper in Hormigón y Acero, pier 4 was, at the time of construction, the tallest ever built in a balanced cantilever bridge.

The viaduct sits on a 36 km section, from Nuevo Necaxa to Ávila Camacho, that needed six tunnels and 12 viaducts. Design and construction were awarded to CONNET, a joint venture of FCC Construcción and ICA, and FCC’s technical services designed the structure. Work began in March 2009 with the foundations of pier 4. The main structure was completed in November 2012, and the section opened to traffic in September 2014.

208 m
Pier 4 height
850 m
Deck length
180 m
Three main spans
10 m
Box depth over piers
8 days
Mean cycle per segment, pier 4
Phase 1 — The foundation
64 piles before the first test
Pier 4 stands on a meander of the river, on alluvium up to 20 m deep over sloping rock, and is the only pier of the six on deep foundations. Its 64 piles, 1.5 m in diameter, were bored behind a temporary cofferdam 180 m long and 5 m high (described as an embankment in the paper’s English edition). Sonic testing was specified after the first few piles but ran only once all 64 were finished, in July 2009: only 14 of the 64 showed no anomalies on the sonic tests, and after cores and recalculation 53% of the piles built were accepted. Grout injection followed and was completed in March 2010, but could not repair enough piles; in May 2010 the foundation was strengthened with 14 supplementary piles of 1.20 m, permanently cased, completed in June 2010, before the 34 × 34 m pile cap of 6,000 m³ was cast continuously over four days.
Phase 2 — The shafts
Self-climbing to 208 m
The tall piers were built with climbing formwork. On pier 4, a self-climbing system with a 4.5 m lift reached a mean cycle of six days; on piers 2, 3 and 5 the 5.0 m shutters averaged nine.
Phase 3 — The cantilevers
Three pairs of travellers, 20 segments a side
The inner spans were built by balanced cantilever with cast-in-place segments; the two end spans were built on falsework, each together with a 6.5 m cantilever into the adjacent span. Freyssinet México supplied three pairs of form travellers rated for segments of up to 200 t. Each cantilever started from a 13.20 m pier segment and added 20 symmetrical segments per side, from 2.7 m to 5 m long. On pier 4 the best rate was a segment every five days and the mean was eight. Concrete for the pier 4 deck had to be pumped 218 m vertically and then a further 90 m horizontally to reach the segments.
Phase 4 — Wind before closure
A structure that was not yet a bridge
The paper states that wind action governed the dimensioning of the piers. A 1:300 model tested the bridge before the closure segments were cast, and no aeroelastic effects arose during construction. A separate test on an isolated pier, with its maximum cantilever before closure, showed that vortex shedding could not be ruled out; the team judged the conditions for it very unlikely in the valley, and no measures were taken. Section tests on the deck also measured the effect of a wind barrier on lorry overturning; it cut the overturning moment by 22%, and no wind screen was installed.
Four-phase schematic of the Gilberto Borja Navarrete Viaduct: the pier 4 foundation with 64 bored piles and 14 supplementary cased piles under a 34 by 34 m pile cap; the 208 m pier shaft built with self-climbing formwork; balanced cantilever construction with form travellers and 20 segments each side of a 13.20 m pier segment; and wind acting on the free-standing cantilevers before closure, tested on a 1:300 model.
From the foundation to closure at pier 4. Conceptual schematic, not to scale; piles and segments are representative.
Source: Arribas Mazarracín et al., Hormigón y Acero 66(275), 2015. Diagram: EE&HL Network, 2026.
Tap or click the diagram to open it full size.

At 208 m the governing cases moved: the foundation took more than a year to resolve before the pier could rise, and the wind had to be checked on a structure that was not yet a bridge.

The decks were finished in the order the cantilevers allowed: pier 2 in February 2012, piers 5 and 3 in June and July, and pier 4 last, in September 2012, with the closure joints locked between July and November. The design team’s paper notes that the pier 4 deck conditioned the construction time. Read alongside the foundation dates, that suggests the year spent on pier 4’s piles carried through to the end of the programme. That is an editorial reading; the paper does not quantify the delay or say what it cost.

For the commercial reading of the pier 4 test sequence, see Issue 19 of the EE&HL Newsletter. For the method itself, see What Is Balanced Cantilever Construction?; for another record tall-pier cantilever, see the Kochertal Bridge.

Related case studies: Millau Viaduct · Kochertal Bridge · Chenab Bridge

Core concepts: What is erection engineering? · What is heavy lift engineering?

The Gilberto Borja Navarrete Viaduct under construction in a steep, forested valley in June 2012: a concrete deck on very tall rectangular piers, with tower cranes beside the piers and the river on the valley floor.
The viaduct during construction, June 2012. Resized from the original for web display.
Photo: HighestBridges, via Wikimedia Commons, CC BY-SA 3.0.

Sources: Hormigón y Acero 66(275), 2015 — Arribas Mazarracín, D., González Esteban, J. I., Pérez Casas, J. M. and Bernal Sahún, P., “Gilberto Borja Navarrete Viaduct”, the design team’s paper (English edition; Spanish edition): geometry, pier heights, foundation, construction sequence, travellers, cycle times, wind studies and dates; FCC — 2015 Lieberman Prize announcement, naming and participants

Frequently Asked Questions

Pier 4 rises 208 m from the valley floor. According to the design team’s paper in Hormigón y Acero, it was, at the time of construction, the tallest pier ever built in a balanced cantilever bridge. The other five piers are 33, 76, 166, 121 and 54 m tall.

The inner spans were built by balanced cantilever with cast-in-place segments, using three pairs of form travellers supplied by Freyssinet México and rated for segments of up to 200 t. Each cantilever had a 13.20 m pier segment and 20 segments per side. The two end spans, each with a 6.5 m cantilever into the adjacent span, were built on falsework.

Sonic testing of the 64 bored piles, specified after the first few piles, ran only after all 64 were finished in July 2009. Only 14 of the 64 showed no anomalies, and 53% of the piles built were accepted after cores and recalculation. Grout injection was completed in March 2010 but could not repair enough piles; in May 2010 the foundation was strengthened with 14 supplementary cased piles of 1.20 m, completed in June 2010.

Yes. The paper states that wind governed the dimensioning of the piers. A 1:300 model tested the bridge before the closure segments were cast, and no aeroelastic effects arose during construction.

Design and construction were awarded to CONNET, a joint venture of FCC Construcción and ICA, with the structure designed by FCC’s technical services. The owner was Mexico’s Communications and Transport Secretariat (SCT).