The Application Of Steel Corrugated Pipe Culverts In The Reinforcement Of Old Culverts

According to the investigation and verification of the construction and design units, the old culvert on Jinshan Avenue is located on the main roadbed of Guangming Expressway and needs to be demolished, rebuilt or reinforced.

There are a total of 5 old culverts, including D1.5m reinforced concrete circular pipe culverts, (2 × 2) and (4 × 2.5) m reinforced concrete slab culverts of three structural and size types. After comprehensive comparison , the old culvert is repaired and reinforced with lined steel corrugated pipes.

D1.5m reinforced concrete circular culvert and (2 × 2) m reinforced concrete slab culvert are respectively lined with D1.25m steel corrugated pipe and D1.7m steel corrugated pipe, using integral pipe type. The (4 × 2.5) m reinforced concrete slab culvert is lined with D3.5m steel corrugated pipe,and it is a semi-circular pipe.

The assembled pipe type is used segmented connection form is plate overlap, using M20 high-strength bolts. Q235 hot-rolled steel plate is used. The parameters of corrugated steel plate are as follows: wave spacing 1=200mm; Wave height d=55mm; Peak and valley radius r=53mm; The thickness of the steel plate is 4mm for the overall pipe type and 5.5mm for the assembled pipe type. Anti corrosion treatment method: hot-dip galvanizing ≥ 63 μ m);Taking into account the factors such as force and construction convenience, steel wave and sections of the corrugated tube are connected in a cone shape.

(1) Desilting and repairing. Remove debris, silt, and water from the old culvert cavity, inspect for defects, remove flaking concrete debris, remove rust and corrosion on exposed steel bars, and repair cracks and split expansion joints on the culvert platform.

(2) Installation of corrugated pipe culverts . Lift the corrugated pipe culvert sections to the culvert opening, use the winch to drag the sections to the designated position, and after installation is completed according to the "JDHG Metal Corrugated Pipe Installation Operation Rules" and the design drawings, set uniform support pads on both sides and the top of the bottom of the pipe section. The pads can be made of mortar bricks or concrete prefabricated blocks. Then install the next pipe section. After connecting it to the previous pipe section, set pads to fix the pipe section. Install the corrugated pipe in this way. When installing steel corrugated pipes, the joints must be cleaned. The sealing material can be square natural rubber, chloroprene rubber, polyethylene foam or weather-resistant sealant with good durability to ensure that the joints are dense.

End sealing. After all pipe sections are installed, the gap between the corrugated pipe culvert and the old culvert is sealed. Use cement mortar brickwork to seal the ends, lay 3 layers of bricks (thickness not less than 36cm), and use concrete mortar to seal the surface (mortar thickness not less than 3cm).The larger side is reserved for pumping and exhaust holes. After the end is sealed, let it stand for 48 hours and then grouting can be carried out after it reaches a certain strength.

1) Pumping cement mortar,Until pumping is no longer possible; insert the grouting steel pipe, block the pumping port, and reserve the grouting port and exhaust port of the steel pipe. 2) Inject mortar through the steel pipe under pressure, the pressure value should be 0.8~1.2MPa, and grout until the concentration of slurry discharged from the exhaust hole is consistent with that of the inlet. 3) Check the grouting quality. If there are large gaps or bubbles, use pressure injection cement slurry. Finally, close the slurry outlet and maintain a stabilization period of not less than 0.8MPa for 5 minutes. Use cement slurry M20, and its mix ratio (weight ratio) is cement: HL-80 grouting agent: water = 1435:159:446. Use P. 042.5 cement, drinking water or clean groundwater.

(5) Adjust drainage. C20 fine stone concrete is used to connect the two ends of the steel corrugated pipe culvert and the opening to ensure smooth drainage.

(6)Regular inspection. Within 2 years after the completion of construction, a dedicated person shall conduct regular inspections on the reinforced steel corrugated pipe culvert every month and keep detailed records. After 2 years, routine maintenance can be performed like other culverts. The inspection and maintenance focus shall be on the deformation and rust of the steel corrugated pipe.

(1) Inspection of materials upon arrival. Before construction, check whether the corrugated pipe has any bending deformation or cross-sectional deformation caused by impact, wear or other reasons during transportation. Damaged steel corrugated pipes should be replaced, and the parts where the galvanized layer has been scraped off should be painted with asphalt for corrosion protection.

(2) The ends of the corrugated pipe should be firmly sealed, with a smooth surface and no gaps. The reserved pipe should be firm and not loose to ensure that there is no leakage during the grouting process.

(3) If grouting points are found at the joints of the corrugated pipe or on the surrounding slope (ground) during the grouting process, the grouting should be suspended and the grouting points should be sealed with water glass cement mortar before continuing the grouting.

(4)Avoid overloaded vehicles passing during the health preservation period.

(1) High strength, good axial flexibility, and both rigidity and flexibility. The strength of steel corrugated pipes is 1.5 to 3 times that of cement pipes. The "Highway Culvert Design Regulations" points out that steel corrugated pipe culverts are suitable for roadbeds with low foundation bearing capacity or large settlement and deformation. It is beneficial to improve the misalignment phenomenon at the junction of soft soil foundation structures and embankments, and improve driving safety and comfort.

(2)Convenient construction and short construction period. Steel corrugated pipes are produced in a factory-standard scale, with stable and reliable quality. The pipe wall is thin and light, which is convenient for transportation and storage. It is easy to install on site without the need for large equipment. It is not affected by seasons and geological conditions and is convenient and fast. The steel corrugated pipes lined in the old culvert are repaired and reinforced without affecting road traffic.

The application of steel corrugated pipe culverts in the reinforcement of old culverts is widely used in many projects, we can provide the detailed scheme for the project with professional designing of corrugated pipe culverts.