Meilin Bridge (Jiangxi) – Prestressed Engineering Case Study
Meilin Bridge is a key highway bridge located in Jiangxi Province, China, spanning a major river valley with a total length of approximately 780 m. The main bridge adopts a prestressed concrete continuous rigid‑frame structure with a typical span arrangement of 85 m + 3 × 130 m + 85 m. The bridge is designed to withstand heavy traffic loads and seismic activity in the region.
The prestressed system plays a vital role in ensuring the bridge’s long‑term performance, with tendons placed in the box girder webs, top and bottom slabs, as well as in the bridge piers for additional vertical prestressing.
| Construction Challenge | Description | Prestressed Solution |
|---|---|---|
| Long cantilever casting span Main span 130 m, balanced cantilever \ construction | Large cantilever spans induce high tensile stresses at segment joints, risking cracking during construction. | Use multi‑strand bonded post‑tensioning (19‑strand tendons, 1860 MPa); place tendons in top and bottom slabs to resist both positive and negative moments. |
| High pier flexibility Pier height up to 45 m |
Tall piers are sensitive to temperature gradients and shrinkage, prone to longitudinal cracking. | Apply vertical prestressing using threaded bars inside the pier shafts; impose pre‑compression to control cracking. |
| Curved tendon layout Bridge alignment includes a horizontal curve |
Curved duct alignment increases friction and makes strand threading difficult. | Pre‑bend ducts in factory; use strand puller with lubricant; pre‑assemble strand bundles to reduce field friction. |
| Grouting quality assurance Voids lead to corrosion & bond loss |
Incomplete grouting compromises strand protection and structural durability. | Adopt vacuum‑assisted grouting with high‑performance corrosion‑inhibited grout; perform post‑grouting inspection by impact echo. |
| Asymmetric tensioning Uneven strand elongation |
Uneven force distribution among multiple strands may cause structural distortion and unbalanced prestress. | Deploy synchronous multi‑jack tensioning system with digital monitoring; real‑time adjustment of oil pressure per strand. |
| Anchor zone bursting stress High local stress under anchor plates |
Concentrated force at anchor heads may cause concrete cracking or spalling. | Install dense spiral reinforcement around anchor heads; increase bearing plate area; apply staged tensioning to reduce peak stress. |
Achieved zero cracking, 30% reduction in threading time, void‑free grouting, full compliance with JTG 3362‑2018
✅ Achievements & Summary
Through the systematic application of advanced post‑tensioning technology:
· Achieved zero cracking in the box girder webs during cantilever construction.
· Reduced strand threading time by 30% using pre‑assembled bundles and lubricant.
· Completed grouting inspection with zero voids on all tendons.
· Fully compliant with Chinese highway bridge design code (JTG 3362‑2018).
Meilin Bridge demonstrates how modern prestressed solutions enable long‑span continuous rigid‑frame bridges to be built safely, efficiently, and durably in complex terrain, serving as a reference for similar projects across China.
