Economic Construction of an Extradosed Bridge
The Chao Phraya River Crossing Bridge is part of an infrastructure project in the Province of Nonthaburi 30km north of Bangkok. The 460m long two pylon bridge is Thailand’s widest bridge with a width of 32.4m, and also the first extradosed bridge in the country.
Context
The Bridge is part of Nonthaburi 1 Road, together with new intersections and a new 6 lane road, the new bridge spans the Chao Phraya River, relieving three highly frequented bridges in its vicinity.
The bridge structure’s main span measures 200m, and the two side spans are 130m long. On both sides of the bridge deck, 48 stay cables are evenly arranged parallel to each other in 12 layers.
Scope
DYWIDAG supplied a total of 96 stay cables for this project:
48 Type DG-P 31 Dyna Grip Stay Cables
48 Type DG-P 55 Dyna Grip Stay Cables, with a maximum stay cable length of 87m
Solution
310t of galvanized, waxed and PE coated 1,770N/mm2, 0.62" strands were required for the stay cables. External dampers were installed on the Type DG-P 55 Stay Cables. The Dyna Grip Anchorages were sealed against water and air to ensure long-term corrosion protection.
Furthermore, the new Dyna Link Anchor Box System was used for the first time on the Chao Praya River Crossing Bridge. The DYWIDAG Dyna Link Anchor Box System replaces conventional saddle systems and is based on a steel structure in which stay cables are anchored using standard Dyna Grip Anchorages.
Due to the single-plane cable-stayed span with a width of 32.8m, rigidity of the cross section was required. Therefore, 1.2m deep ribs with a spacing of 2.5m were included as part of the design. In order to speed up construction progress, Sumitomo Mitsui fabricated the ribs as precast elements on the deck.
Afterwards, the ribs were installed using a form traveler. This way, the time needed for assembling and disassembling the formwork could be reduced. Furthermore, the precast ribs were used for supporting the side spans. Sumitomo Mitsui also optimized some pre-cast elements for the foundations and the bridge substructure. These segments functioned like a wall at high tide, thus permitting a fast and safe construction progress in the river.
Comprehensive quality conformance tests of the materials that were installed and the components that were needed were continuously carried out and documented by the joint venture consisting of Italian-Thai Development Public Company Limited, Thailand and Sumitomo Mitsui Construction Co., Ltd., Japan, who carried out the contract.
After its completion, the bridge was named Maha Jessada Bodin.
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