Betar

Save river’s bridges

• Location: Vila Franca do Save, Govuro district, Inhambane Provoince
• Solution: Bridges, Infrastructure and Transport
• Type: Road bridges, Rehabilitation, Management and construction inspection, Roadways and railways, Management and construction inspection
• Promoter: ANE - ADMINISTRAÇÃO NACIONAL DE ESTRADAS
• Client: ANE - ADMINISTRAÇÃO NACIONAL DE ESTRADAS
• Scope: Desgin project reviewing of Structures and Road Access, including the rehabilitation design project of the suspension bridge and the design project of the new structures, Onsite and resident supervision of works
• Area: New bridge: 13621.5 m2 (1.009m x 13.5m); Suspension bridge: 9222 m2 (870m x 10.6m)
• Project: 2018/2019
• Construction: 2018/2022
• Contractor: China Road & Bridge Corporation
• Dimension: New bridge: 1009m (120m max span); Access viaducts: 245+275m (30m max span): Suspended bridge: 870m (210m max span); Road access: 2400m
• Ver no Google Maps

The river crossing of the N1 over the Save River was achieved in the late 1960's by a Suspension Bridge with multiple spans (3 central spans with 210m each and 2 lateral spans with 100m, on a total length of 830m). This bridge has several uncommon structural characteristics, such as the adoption of a hanger system composed by inclined hangers in a triangulated configuration, anchored on the top on funicular cables, and 2 pre-stressed cables to increase the global stiffness located under the deck. The platform is composed by reinforced and prestressed concrete isostatic modules each one with 10m long and 10.6m wide.

Due to its advanced age and to the limited maintenance since its construction the Bridge revealed several pathologies that compromised its safety, such as, advanced level of corrosion of the hangers; concrete damaging and exposed reinforcement; damages at bearings and at expansion joints; among others. Due to these problems some weight limitations were imposed to the traffic creating huge constraints to the users.

In this context, the Government decided to built a new Bridge designed in accordance with the most updated bridge standards and adequate to the high importance of this road corridor. In addition, and considering the unique characteristics of the older Bridge, the Government also decided to implement Retrofit and Rehabilitation Works in the existing Suspension Bridge to keep it as a landmark of the Bridge Engineering in the Country.

The new Bridge led to the need of execute a new paved road (bituminous standard) along 2.4km and 11.2m wide. The new Bridge is more than 1.000m long and is 13.5m wide which embraces a 9.6m carriageway and 1.2m walkways in each side of the platform. Structurally, it can be divided into 3 sections: i) Main Bridge, with 490m long and max. spans of 120m, whose deck is a concrete prestressed box girder with variable height on a parabolic way (and whose construction is by the cantilever method); and ii) the north and south access viaducts, with 240m and 270m respectively, and deck solution by prestressed pre-cast T beams with 30m as regular span.

The Retrofit and the Rehabilitation Works on the Suspension Bridge included the integral replacement of the hangers; the repairing of damaged concrete and its reinforcements; the replacement/repair of the bearings and expansion joints.

BETAR was awarded the Design Checking and validation (the design was performed by the Contractor under the FIDIC Turnkey framework contract for design and built) and also contributed for the solutions definition and optimization along with the role of on-site Supervisor/Engineer in behalf of the Employer.