The basic standard measurement adopts the total station instrument of not less than 1d class to re-test the control foundation pile provided by the design unit, observe two rounds of horizontal angle observation, and conduct joint measurement with the construction control network to overcome the accumulation error. After the control pile retest meets the design requirements, an encryption base is set every 5m. The encryption base can be set between two lines outside the range of the floating board. The distance error of the encryption base is <5mm, the lateral deviation is <2mm, and the base top and design elevation are less than <1mm.
The base plate of the vibration isolator is repaired or polished according to the basic standard to ensure the installation position of the isolator bottom plate is less than 5mm, and the flatness of the beam surface is 2mm/m2. The beam surface is released according to the design drawings. The accurate installation position of the vibrator is detected by a steel bar detector to avoid the anchor bolts of the vibration isolator floor and the bridge reinforcement. After drilling the beam on the beam surface with a hammer drill, the anchor plate is anchored with anchor bolts.
Under special circumstances, the installation position of the vibration isolator bottom plate can be adjusted appropriately. The lateral deviation is Z50mm in the direction of the center of the line, and Z10mm in the outer direction of the line. After the installation is completed, the level of the vibration isolator is measured by the level gauge to ensure that the bottom plate is in a horizontal state.
After the anchoring of the vibration isolator bottom plate is completed, the waterproofing layer construction of the beam surface can be carried out. The top surface of the waterproof layer should be flush with the top surface of the vibration isolator bottom plate, and the flatness error is 2mm/m2. Laying the isolation layer and installing the isolator casing After the strength of the waterproof surface of the tubular beam meets the construction requirements, a PVC rubber sheet with a thickness of 1 mm is laid in the floating plate as the isolation layer between the floating plate and the beam surface, and the seam of the isolation layer is sealed with a plurality of layers of plastic tape to When the concrete is poured, the slurry is caused to adhere to the beam body.
Install the outer sleeve of the isolator on the installed base of the isolator. The outer sleeve should be placed between two adjacent fasteners, and the installation angle should be consistent with the drawing to facilitate the vibration isolator inspection after operation. After the outer sleeve of the vibration isolator is installed, the positioning plate is installed in the outer sleeve of the vibration isolator to prevent the sleeve from moving. The gap between the outer sleeve and the separator is sealed with a silicone gel to prevent leakage of the cement slurry when the track bed is poured. The outer sleeve installation accuracy is 3mm.
The track assembly and adjustment adopts the under-support rail support frame to erect the rails, and the fasteners are installed according to the design requirements. According to the measured base mark, the rail geometry is finely adjusted by the rail support frame. The standard should meet the following requirements: the deviation between the track center line and the design center line is <2mm, and the track direction is 10m string measurement tolerance <1mm.
Reinforcement lashing and concrete pouring shall be carried out according to the steel bar layout drawing, such as steel bar tying and welding. The construction shall pay attention to protect the insulation layer from damage. Install the shearing hinges as required. A small concrete block is placed under the reinforced mesh net to ensure that the thickness of the protective layer of the steel meets the design requirements. Finally, the transverse steel bars are welded to the outer sleeve of the floating plate according to the regulations to prevent the outer sleeve from moving.
Before the concrete is poured, the track should be inspected and adjusted to ensure that the orbital direction, gauge distance, level, height and other geometric dimensions meet the requirements of the specification. The height of the rail top when pouring concrete should be lower than the design height of 40 mm. The bed can be poured after the supervision of the concealed inspection. The floating slab bed is made of C40, and it is vibrated with a plug-in vibrating rod during casting, especially near the casing. Ensure that the concrete is filled sufficiently near the iron pad and nylon casing of the fastener. Finally clean the isolator cover to ensure that there is no concrete on the outer sleeve cover.
The floating plate rises when the concrete reaches the design strength, and the floating plate is lifted by the special hydraulic jack provided. In order to measure the horizontal and static deformation of the floating plate, eight measuring points are arranged on each floating plate.
First, remove the cover on the outer sleeve, clean the outer sleeve, cut off the isolation layer at the installation position of the damping spring, and install the damping spring according to the design requirements. The damper spring is placed in the outer sleeve by the mounting rod until it rests on the bottom plate of the vibration isolator, and the rotating spring group has the three corners of the triangular upper support plate with the hole in the middle and the inner wall of the outer sleeve welded The retaining rings are parallel.
Some suggestions: Because the floating slab bed adopts the WJ-2 type fastener directly buried in the overall cast track bed type, the underside of the insulating rubber pad under the iron pad should be the same height as the top surface of the concrete track bed. Since the thickness of the rubber pad is only 5 mm, it is very difficult to control the height of the floating concrete. The rubber pad is buried in the concrete at a slightly higher level, and the gap is formed under the rubber pad. It is recommended to add a steel backing plate under the original rubber backing plate and directly bury it in the concrete. The bottom surface of the steel backing plate can be arc-shaped to facilitate the discharge of air bubbles when pouring concrete.
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