Design of beam falling prevention device

The design is based on the Detailed Rules for Seismic Design of Highway Bridges in China and the Seismic Design of Road Bridges issued by the Japan Road Association

Design Data.

1. Design conditions

R: Dead load gravity bearing capacity (KN); Sp: design displacement (mm);

S: Anti falling length (mm)

Allowable shear movement of rubber bearing ≤ Sp ≤ 0.75S ε

S=When using rubber bearings, it is advisable to ensure the allowable shear movement of rubber bearings.

2. Design load

H,=1.5R。

H: Design seismic force of beam falling prevention device (KN

3. Design of connecting cable

(1) Allowable stress of connecting cable

Pa=Py

P: Allowable stress (KN)

P;: Yield load (KN)

(2) Design of connecting cable

P=Hpn≤P。

P: Design seismic resistance of each group of connecting anchor cables

N: Number of groups of connecting anchor cables

4. Design of buffer materials

σ p=1.5x 12=18Mpa

Allowable compressive stress of rubber (MPa)

σ。= P/A≤ σ ba=1 8Mpa

σ p: Compressive stress of rubber (MPa)

A: Compression area of cushion (rubber) (mm2)

5. Design of spring adjustment

B=Spmns

b: Adjustment amount of each spring (mm)

Ns: Number of anchor cable springs in each group

6. Design of production length of spring

N=b+ δ In s+2x+ δ two

N: The fabrication length is designed in 50mm

δ 1: Expansion caused by temperature (mm)

Middle: spring diameter (mm)

δ 2: Minimum compression during installation, designed as a multiple of 100mm