Bridges take thousands of vehicle passages every day, so every bolted node works under alternating load. Bridge maintenance also requires road closures and scaffolding at very high cost - which means fasteners must be designed for long-term service without re-torquing. Here is the part-by-part product mapping.
Bearing anchor bolts → DIN 25201 Wedge Lock Washers
Bearings are the load hub of the entire bridge, taking combined vehicle impact and wind load. DIN 25201 generates additional clamping force through cam climb under vibration rather than loosening - it tightens as vibration increases, making it the first choice for bridge locking. Dacromet is recommended (no hydrogen embrittlement, suitable for high-strength bolts).
Expansion joint devices → NFE25-511 M Belleville Washers / DIN 25201 Wedge Lock Washers
Expansion joints take direct repeated wheel impact at high load and high impulse. NFE25-511 French-standard Belleville washers carry higher load than DIN 6796, absorbing impact energy while maintaining high preload; combined with wedge lock washers they deliver both locking and buffering.
Deck-to-girder connections → DIN 6798A External Tooth
High bolt count at moderate per-point load makes this a cost-sensitive area. External tooth washers bite into the substrate for mechanical locking, suitable for high-volume positions where total cost must be controlled.
Parapet and sign gantry posts → DIN 7967 Self-Locking Counter Nuts / Self-Locking Washers
Parapets and sign posts are exposed positions requiring both inspectability and long-term reliability. DIN 7967 is an all-metal self-locking design with no nylon insert, so it is unaffected by high temperature and has no nylon ageing problem - particularly important for long-term outdoor exposure.
Bridge deck ancillary connectors → Custom Stamped Parts
Damper brackets, drainage component connecting plates and similar custom parts can be produced to drawing.
Inland bridges can use Dacromet or hot-dip galvanised carbon steel. Coastal and de-icing salt environments call for A4 stainless or hot-dip galvanising with a sealing topcoat.
Provide the environmental class, node locations and bolt specification, and we will give targeted anti-loosening and corrosion protection recommendations.
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