The installation of bolted corrugated steel culverts requires strict adherence to established procedures to ensure a tight connection and reliable leak prevention. The following is a detailed breakdown of the steps:
1.Positioning and Layout
Before installation, accurately mark out the centerline of the culvert and the axis of the foundation. Verify the flatness and elevation of the foundation; proceed with laying out the pipe sections only after confirming that all parameters are correct.
2.Preliminary Docking
Begin installation by positioning the first pipe section, ensuring its centerline is parallel to the longitudinal centerline of the foundation. Gently push the second pipe section into place, maintaining a gap of 3–5 cm between the adjacent flanges of the two sections to facilitate subsequent adjustments.
3.Aligning Bolt Holes
Use a small pry bar to align the bolt holes on both flanges, ensuring they match up perfectly. If any misalignment exists, use a larger pry bar at the opposite end of the second pipe section to make fine adjustments, thereby correcting the longitudinal position.
4.Inserting Bolts and Pre-tightening
Once all bolts have been inserted, thread on the nuts and perform a preliminary tightening (snugging them up). Be careful not to fully lock them down at this stage, as further adjustments may be required later.
5.Inserting Sealing Gaskets
Insert an asbestos gasket between the two flanges to serve as a sealing layer. If the gap is too narrow, use a hammer or chisel to carefully create a gap of approximately 1 cm, then insert the gasket using a screwdriver. If the gap at the top is wide, use wire to tie the gasket to the bolts to hold it in place.
6.Symmetrical Bolt Tightening
Workers should tighten the bolts gradually, working symmetrically and in a crosswise pattern from both sides of the flange. This prevents uneven stress distribution that could lead to flange deformation. Finally, inspect the gap between the flanges; an optimal gap of 2–3 mm should be maintained.
7.Overall Alignment
Use hydraulic jacks to perform a final alignment of the entire culvert structure, ensuring it sits precisely on the designed centerline to prevent any lateral displacement that could compromise drainage performance.
8.Anti-Corrosion Treatment
Apply a uniform coating of hot asphalt or emulsified asphalt to both the interior and exterior surfaces of the pipe wall. The coating thickness should be no less than 1 mm to enhance both corrosion resistance and sealing effectiveness.