Old Culvert Reinforcement by Corrugated Steel Structure

The situation of culvert on site

The culvert is a 1-6.0m frame culvert,the net height of 4.5m and length is 12.06m,it is for traffic culvert. There are problem of multiple falling blocks on the existing culvert,missing reinforcement, and the side walls have Multiple cracks.The waterproofing of the culvert is mostly failed, snow and rain may erode the main steel bars.Above problems bring a threat to the safe operation of existing lines, it needs to be immediate reinforcement and repaired.

This culvert is a traffic culvert. If a reinforced concrete lining structure is used, it will compress the overpass clearance of the culvert; And the construction of reinforced concrete lining method requires a long construction period, which can cause inconvenience to nearby villagers After Considering multiple factors, it has been decided to reinforce the culvert with corrugated pipe culverts.

The loading and structure parameter of the corrugated pipe culvert

Checking the loading capacity

Dead load includes the self weight of existing culverts, the self weight of grouting layers, and the self weight of corrugated plate structures The self weight and soil pressure of the track structure.

Live load includes both vertical static load and vertical dynamic load of the train.

Load combination

Main force combination: self weight+vertical static live load of the train+vertical dynamic action of the train.

Additional force combination: main force combination+braking force

structure parameters of corrugated pipe culvert

According to calculations, the structural parameters of the corrugated plate are 200 × 55, Q345 steel, externally galvanized Above 84um.

Considering the length of existing culverts, there are a total of 10 corrugated pipe culverts, each pipe culverts with a length of 10 rings,It is 1.3m in length, and the rings are overlapped, they connected with high-strength bolts, a lap length is 10cm.

Construction process

Survey and measurement → surface treatment of concrete inside the culvert → settlement joint treatment → foundation Excavation of foundation pit → Planting foundation reinforcement → Pouring foundation and fixing angle steel → Installation of corrugated pipe culvert →Gap grouting → Secondary anti-corrosion treatment of corrugated pipe culvert → Monitoring after reinforcement of corrugated pipe culvert.

The installation of corrugated pipe culvert

There are four types corrugated pipe plate ,After transportation to the site, classify and stack them.After the first round of plate assembly is completed, push a section into the culvert, continue to install the second round corrugated plate,after the second round of plate is assembly finished, push section in to the culvert again. Then assembly the third and forth round like this ,Repeat this process until all corrugated pipes are installed.after all corrugated pipe culvert are assembly, Fix the culvert pipe and angle steel with bolts. Before grouting, Lapping per lap and apply sealant to the overlapping part, this can ensure that the cement slurry does not overflow during grouting.

Gap grouting

Set up a blocking wall at both ends of the entrance and exit of the culvert,Reserve one Φ 50 grouting pipes on each upper part of the existing culvert,Reserve two Φ 50 exhaust pipes at the top position.After all pipe culverts are installed, both ends are sealed,Use reserved grouting holes to inject grout from bottom to top,seal the grouting holes and exhaust holes after grouting is completed,Micro expansion cement is used for grouting.

Reinforcement effect

After the reinforcement of the corrugated pipe culvert was completed, through monitoring , it was found that the structural stress and deformation values of corrugated pipe culverts are within the specified limits.

It has been ensuring the existing culvert normal and safety use, and nearby villagers have smooth transportation.

summary

Corrugated pipe culverts have Advantages

Simple construction process,Convenient transportation,Short construction period,Good structural durability.

It is a development direction of reinforcement technology for existing high way and railway culverts ,and it has good prospects for promotion and application.