Lead rubber abutment
CLRB abutment design
The CLRB series lead core spacer rubber abutment is according to the current national and industry standard GB 20688.2-2006 Rubber Abutment section 2: Bridge Vibration rubber Abutment JT/T 822-2011Highway Bridge Lead Isolated Rubber Abutment , and refer to international standard ISO 22762 -2 The design of Elastomeric seismic‐protection isolators‐Part 2: Applications for bridges‐Specifications has improved for the relevant standard recommended model parameters.
CLRB abutment type
Common abutment : CLRB series ordinary lead-core spacer rubber abutment is composed of support body and upper and lower connecting plate and anchoring device, and its body shape is divided into two types: rectangular and circular. Self-reset support: CLRB series has a reset function (self-reset support), on the basis of a common rectangular seat, between its body and the upper connecting plate, a sliding surface and displacement adjustment locking device is provided. The mounting height (H) of the support with the reset function is 10 mm, (8 mm PTFE plate and 2 mm stainless steel plate) compared with the corresponding common rectangular support, and the parameter table is not listed separately. One-way shear support: CLRB series anti-shear support (also called one-way support), is an anti-shear device on one side of the common support body. The actual shear force of the shear device is 10% of the vertical abutment capacity, which ensures the function of one-way function during normal operation of the support and does not affect the seismic isolation effect at the time of the earthquake. The mounting dimension is increased in the ordinary seat corresponding to the limit direction. This parameter table is not listed temporarily.
CLRB abutment selection
Scope of application: CLRB series supports are suitable for earthquake acceleration 0.2 g, and the road bridge in the following areas.
Shear modulus: The shear modulus is selected according to the ambient temperature of the bridge site.
when the average monthly average temperature for the coldest month is -10 ℃. Taking G=0.64MPa;
when the average monthly average temperature for the coldest month of the year is -10~5 ℃. Taking G=0.80MPa;
when the average monthly average temperature for the coldest month of the year is 5~20 ℃. G=1.0 MPa;
when the average monthly average temperature for the coldest month is more than 20 ℃. Taking G=1.2MPa.
Vertical abutment capacity: The actual load shall not be greater than the vertical abutment capacity specified in the parameter table.
Horizontal rigidity: the abutment of the continuous beam center pier should be selected from the support with a relatively high degree of rigidity, so that the bridge is extended symmetrically and telescopically.
Horizontal displacement: horizontal displacement due to temperature, concrete shrinkage, bridge twist, etc. shall not be greater than the design displacement specified in the parameter table.
When the maximum temperature in the cold area is lower than 14 ℃, the displacement quantity caused by the daily temperature difference shall not be greater than the front displacement of the support (Qy/K1).
Self-reset function: The abutment of continuous beam side pier should be selected with support with reset function, but it may not be considered when the ambient temperature is close to the reference temperature at the time of construction.
One-way shear function: if the lateral horizontal load of the bridge exceeds the yield shear of the abutment lead core, the lateral displacement of the abutment shall be limited, and a coaxial abutment of each pier shall adopt the shear one-way support.
Rotation angle: CLRB series support turning angle of 0.008rad.
Other requirements for the type specification and the above conditions listed in the parameter table can be specially designed.
CLRB abutment installing
(1) The height difference between the four corners of the cushion stone concrete shall not be less than C40, and the height difference of the top surface of the cushion stone shall not be greater than 2 mm, and the height of the cushion stone shall not be less than 100mm in consideration of the convenience of installation and replacement of the support.
(2) Embedded plate (adjustment plate) shall be provided on the bottom of the bridge to eliminate the influence of the longitudinal slope of the bridge and the horizontal slope on the mounting of the support. The bottom surface of the embedded plate (leveling plate) shall be horizontal and flat, and the horizontal plane shall not be more than 1 mm/m.
(3) The grouting material complying with the design requirements shall be adopted at the installation of the abutment, and the strength shall not be lower than the strength of the cushion stone.
(4) After the bridge placement is completed, the displacement amount of the seat with the reset function is adjusted and locked.
(5) The ambient temperature of precast concrete beam, steel beam installation and beam falling beam shall be sufficiently close to the reference temperature, otherwise the displacement amount of the support shall be adjusted in consideration of the beam falling beam.
CLRB abutment MARKING EXAMPLE
|特殊功能，kj：抗剪；F:自复位||Special function, kj: shear; F: self-reset|
|橡胶剪切模量||Rubber shear modulus|
|支座本体高度||Height of support body|
|Shape of support body
The rectangular lead-core holder is JQ, and the circle is YQ
|铅芯橡胶隔震支座||Lead-core rubber septum support|
Example 1, CLRB‐JQ320×420×145 G1.0‐F
Description: Rectangular lead-core spacer rubber abutment, support body width of 320mm, length of 420mm, the body abutment height of 145mm, rubber shear modulus 1.0 MPa with reset function.
Sample 2 CLRB‐YQ920×240 G1.2‐KJ
Description: Circular lead core spacer rubber abutment, support body diameter 920mm,the body abutment height 240mm, rubber shear modulus of 1.2MPa with one-way shear function.
Type selection parameters for CLRB abutment
Installation dimension drawing of lead-core spacer rubber abutment
|1、预埋钢板||1. Embedded steel plate|
|2、连接钢板||2. Connecting steel plate|
|3、矩形（或圆形）支座本体||3. Rectangular (or circular) support body|
|4、锚固螺栓||4. Anchor bolt|
|5、锚固套筒||5. Anchor sleeve|