What are the applications of comb plate expansion device in bridge engineering
The comb plate expansion device is a key component used in bridge engineering to adapt to the expansion deformation of the beam and ensure the smooth passage of vehicles. Due to its unique structure (consisting of comb plates, supporting crossbeams, displacement control systems, etc.), it is widely used in various types of bridges. The following are its main application scenarios and characteristi
The comb plate expansion device is a key component used in bridge engineering to adapt to the expansion deformation of the beam and ensure the smooth passage of vehicles. Due to its unique structure (consisting of comb plates, supporting crossbeams, displacement control systems, etc.), it is widely used in various types of bridges. The following are its main application scenarios and characteristics:
1、 Core application scenarios of comb plate expansion device
1. Large displacement bridge
Applicable scenarios:
Large span bridges with a main span exceeding 100 meters (such as cable-stayed bridges and suspension bridges) experience significant beam expansion and contraction due to temperature changes, concrete shrinkage and creep (usually displacement ≥ 400mm).
Multiple continuous beam bridges or bridges with continuous bridge deck lengths exceeding 500 meters need to disperse the cumulative displacement of multiple beam segments through comb plates.
Advantages:
Strong displacement capability (a single set of comb teeth can adapt to a displacement of 500-1200mm, and a combined structure can reach over 2000mm), far exceeding ordinary rubber expansion joints (≤ 120mm).
By interlocking the toothed plates to transfer the load, the displacement jamming problem caused by bolt loosening in traditional modular expansion joints can be avoided.
2. Heavy duty traffic bridges
1. Applicable scenarios:
Highway bridges, urban expressway bridges (such as elevated bridges), especially in sections with dense heavy vehicle traffic such as freight corridors and port connecting lines.
Railway bridges (such as freight dedicated lines and high-speed railway bridges) need to withstand high-frequency and high impact loads from trains.
2. Advantages:
The comb plate is made of high-strength steel (such as Q345D and stainless steel), and its surface has undergone wear-resistant treatment (such as hot-dip galvanizing and shot peening), with excellent fatigue resistance (able to withstand ≥ 1 million load cycles).
The overall rigidity of the structure is high, and the vehicle load is directly transmitted to the beam through the comb teeth, reducing the deformation and loss of the device itself and extending its service life.
3. Landscape bridges and bridges in special environments
1. Applicable scenarios:
Urban landscape bridges (such as irregular structure bridges and pedestrian bridges) need to balance aesthetics and functionality. The comb plate can be designed for concealed installation and integrated with the bridge deck pavement.
In corrosive environments such as cross sea bridges and bridges in acid rain areas, corrosion-resistant materials (such as 316L stainless steel comb plates and epoxy coated steel supports) are used to increase the resistance to chloride ion erosion by 3-5 times.
2. Advantages:
The gaps between the comb teeth can be filled with elastic waterproof materials (such as silicone sealant) to prevent rainwater from leaking into the beam structure and reduce the accumulation of debris (such as fallen leaves and crushed stones).
The surface can undergo anti slip treatment (such as tooth carving), suitable for areas with frequent rain and snow weather, to improve driving safety.
4. Old bridge renovation and maintenance project
1. Applicable scenarios:
The old bridge with severely damaged expansion joints (such as rubber aging and steel fracture) needs to be replaced with a more durable comb plate device.
When widening and renovating bridges, the displacement coordination between new and old beams can be achieved by adding comb plates, avoiding the cracking problem of traditional splicing joints.
2. Advantages:
Modular design facilitates quick replacement and shortens the construction period by more than 50% compared to traditional expansion joints (with less on-site welding and night repair capability).
The comb spacing can be customized according to the actual displacement of the old bridge (commonly ranging from 20~50mm) to meet different deformation requirements.