Moreover, it is highly operational. Sometimes, in order to consider that there is a road under the overpass, it can be easily crossed by using a single pier. Moreover, this kind of engineering quantity is relatively small, especially when the intersection line is inclined, it can be crossed with a smaller span, which is more economical.
To sum up: the construction period is short, the cost is low, and the passability under the bridge is good, which is suitable for sections with small traffic flow and small available space under the bridge.
Disadvantages: Even so, experts say that since 20 19, the design of single pier has been gradually eliminated because of obvious shortcomings, and it is no longer given priority.
Usually, unless the pier beam is reinforced, the pier top has no torsion resistance. Therefore, when the road traffic is saturated and overloaded, we must attach great importance to the design of its lateral anti-overturning system. It is often necessary to adopt the technology of pier beam consolidation to make the pier body have enough strength to resist the bending moment caused by the torsion of the beam.
What is a single-column pier bridge?
Single-column piers belong to the substructure of bridges and are usually used for overpass bridges, overpasses and ramp bridges of expressway Interchange on urban roads. Due to the traffic jam in the city and the limited land requisition for construction in the city and its surrounding areas, it is often necessary to set piers in a limited range. In order to meet the above requirements, people use single-column piers instead of traditional large-area double-column piers or multi-column piers.
Compared with the two-column pier, the single-column pier bridge has the advantages of less land occupation, improved substructure layout, increased vision, beautiful bridge type, shorter span and more economy. But at the same time, there will be problems such as weak torsional capacity of pier top and insufficient lateral overturning resistance. In some extreme vehicle conditions, such as multiple heavy trucks driving in the same lane on the same side of the bridge at the same time, the bridge will be in danger of overturning.
How to reinforce single-column piers in general?
Because of the different topography, geology and construction environment of the bridge, the reinforcement methods are also different. Generally, it can be divided into methods such as strengthening the steel capping beam at the top of pier, adding columns, increasing cross section, adding columns and adding tie rods.
Among them, it is more cost-effective to enlarge the section and reinforce the pier top steel cap beam, which not only has short construction time, but also has ideal price and good reinforcement effect.
There are several points to pay attention to in specific construction.
1, first check the state of the pier, whether there are cracks and other diseases. If yes, use crack repair glue to repair surface cracks or adopt appropriate repair methods according to specific conditions by pouring.
2. When increasing the cross section, use early strength grouting material to ensure the bonding effect of new and old concrete and avoid concrete diseases such as pits, voids, hollowing and cracking as much as possible.
3. In order to ensure the bonding quality between the steel hoop and the bridge pier, high-quality products that meet the national regulations should be selected, and the steel bar bonding adhesive and planting adhesive should meet the specifications.