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Segmental beam construction technology is gradually emerging in China. Zhuozhou Sanbo Bridge Company has applied segment beam construction technology to urban rail transit section viaducts on a large scale, and has achieved preliminary results. At the same time, the PG-Y prefabricated segmental beam patchwork epoxy structural adhesive is a two-component modified epoxy adhesive, which is suitable for the joint bonding material for the assembly construction of bridge prefabricated segments by the bridge erecting machine.

Characteristics of 1. segmental beam
1. Good thixotropy, convenient mixing and gluing, excellent anti-sagging performance and no dripping;
2, high elastic modulus, low creep, especially high strength, basically does not affect the prestressed tension;
3, the colloid permeability is good, and the concrete bond strength is high, can effectively transfer the load;
4, easy to compact, glue joints without water seepage, and concrete bonding ability;
5. The curing time can be adjusted, and the glue can be selected according to the construction temperature, and the construction can be carried out at 0-50 degrees;
6. The color difference between A and B is large, and it is easy to observe the uniformity of mixing. The color after mixing is consistent with that of concrete;
7. After stirring, the operation time is long, and the high temperature can not be affected within 40 minutes;
8, anti-aging, safe, non-toxic.

Construction of 2. segmental beam
1, according to the design requirements, determine the construction plan, according to the construction environment temperature selection to adapt to the type of structural adhesive;
2. Install the bridge erecting machine, transport the prefabricated segmental beams in place, and sort the prefabricated beams according to the predetermined assembly sequence;
3. Before hoisting the segmental beam, ensure that the splice of the segmental beam is clean and tidy, so as to avoid defects in the later prestress tensioning;
4, single-span integral hoisting prefabricated segmental beam, segmental beam butt joint pre-assembly; After the pre-assembly is qualified, the hoisting segmental beam is moved horizontally about 40cm, leaving a gluing working face; In order to prevent the epoxy structural adhesive of segmental beam from being squeezed into the prestressed pipeline during temporary prestressing, a sponge washer of about 3mm shall be installed at the prestressed nozzle;
5, according to the pre-estimated amount of glue, according to the recommend proportion of glue preparation, the use of low-speed electric mixer stirring, until the color uniform;
6, in the segmental beam splicing surface with tools or gloves directly coating scraping PG-Y prefabricated segmental beam patchwork epoxy structural adhesive, single-sided coating thickness is controlled at about 3mm, to ensure that the seam overflow glue, paste dense and full, after tensioning can be several working surfaces at the same time plastering, plastering should be completed within the time specified in the temperature model of the selected glue;
7, the use of temporary prestress on the two section of the segmental beam tension, temporary tension using 1-2Mpa pre-compression stress, tension should be divided into two times, each interval of 2 minutes, and to ensure that the segmental beam box girder inside and outside each time there is colloid overflow;
8. After temporary tensioning, the structural adhesive shall be cleaned up with a putty knife before curing. Pay attention to the beauty when cleaning. If there is any local colloid that is not dense, the putty knife can be used to repair it;
9. After curing the epoxy structural adhesive for segmental beam patchwork, tension the permanent prestress, release the temporary prestress, and carry out the construction of the next span;
10. For other matters not covered, please consult the manufacturer for technical support.

Precast process quality of 3. segmental beam
1. In principle, it is not allowed to set the bridge prefabricated yard within the red line of the subgrade. If it is really necessary, it should be set in the subgrade section that has reached the standard and must be reported to the supervisor for approval.
2. All kinds of production and living facilities of the prefabrication plant shall be reasonably laid out, all kinds of machines and equipment shall be placed in an orderly manner, the waterproof and drainage system shall be perfect, and the roads in the field area shall be hardened to ensure smooth roads. The prefabrication plant shall set up a project introduction board, construction site layout plan, safe and civilized construction slogan, etc.
3. Before the construction of gantry crane track foundation, the foundation bearing capacity of the base shall be detected, and the width and thickness of the foundation and reasonable reinforcement shall be determined according to the reasonable load weight calculation during construction to ensure the stability of the foundation.
4. The beam body storage site shall be leveled and compacted, and drainage ditches shall be excavated around to ensure that there is no water in the site. The beam storage site shall be arranged first. The beam storage site shall be leveled and compacted, and the drainage shall be smooth to prevent the beam and slab fracture caused by foundation subsidence.