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Prefabrication of 1. section

1. Template system

The system consists of bottom mold system, side mold system, end mold system, internal mold system and embedded system. Among them, the bottom mold system includes the bottom mold trolley, the bottom mold support, the bottom mold, and the bottom mold hydraulic system; the side mold system includes the side mold, the side mold support, the angle mold, the platform, and the side mold hydraulic system; the end mold system includes the mobile end mold, Fixed end mold; the embedded system includes embedded parts such as sliding track, side mold and end mold.

2. Prefabricated construction

The first is formwork adjustment, adjusting each system of formwork in place according to the size of the design drawing; the second is steel skeleton installation, lifting and placing the bound steel skeleton in place, and reviewing and adjusting the position of each component of the formwork system; the third is pouring concrete according to the sequence of first bottom plate, back web plate and top plate. The pouring process adopts the insertion vibrator as the main part and the attached vibrator as the auxiliary part to ensure the concrete pouring quality; the fourth is formwork removal and maintenance. When the concrete is cured to the formwork removal strength, check whether the hydraulic system of the formwork is normal, and remove the moving end formwork, inner formwork and outer formwork in turn. Fifth, the beam section shall be hoisted and transferred. When the strength of section 1 meets the design requirements, it shall be matched with section 2. After section 2 is poured and maintained to reach the formwork removal strength, section 1 can be lifted and transferred. In addition, the Hebei segment assembly construction can be moved to the designated beam storage area by the lifting device using vertical lifting and longitudinal shape separation, and the circular prefabrication of all segments can be completed in turn.

2. segment transportation

The segmental box girder is transported to the installation site by a special transport vehicle via Hangu and Baishiyi Town, with a transport distance of 10 kilometers, during which the roads are smooth and the road conditions are good, meeting the traffic standards for large transport vehicles. At the same time, in order to ensure uninterrupted segment transportation during Hebei segment assembly construction, the project department has set aside another transport vehicle to ensure the supply demand for segment installation in the front yard. In order to ensure the safety of segment transportation, all safety measures shall be fully taken before the transport vehicle leaves the factory, and the segment binding, fixing, support, etc. shall be checked in detail and recorded before leaving the factory, and special vehicles shall be equipped to warn in front of and behind the transport vehicle during driving, and full-time commanders shall be equipped.

Installation of 3. section

1. Pier top block installation

The top section of the first span pier is installed by truck crane, and the other top sections of the pier are installed by bridge erecting machine. During installation, the pier top segment shall be accurately positioned according to the monitoring instructions, and the segment shall be anchored on the cover beam with finish rolling thread steel, and the support and temporary anchoring leveling layer shall be filled with high-strength cement and support mortar to ensure the stability of the pier top segment.

2. Installation of bridge erecting machine

Before the installation of the bridge erecting machine, the temporary support and reinforcement of the large cantilever of the cover beam shall be completed. The top section of the pier shall be installed with a truck crane. The middle leg of the bridge erecting machine, the main box girder of the bridge erecting machine, the crane crane, the front and rear guide beams, the front auxiliary leg, the electromechanical system and the monitoring system shall be installed in turn. The acceptance of the bridge erecting machine shall be completed after inspection, commissioning.

3. Hanging assembly of whole hole segment

Install longitudinal temporary steel tooth blocks of segments in advance, and use special lifting tools to hang them one by one. After the suspension of all segments is completed, accurately collect the coordinates and elevation of the pier top segment and feed them back to the monitoring party, and position them according to the installation instructions of the first suspension segment issued by the monitoring party. The position of 1# wet joint adopts the type steel plug pad; at the same time, tension the longitudinal finish rolling threaded steel anchor to complete the accurate positioning of the first suspension segment; collect the data of the first suspension segment and feed them back to the monitoring party, pre-assembly shall be carried out according to the installation instruction of the second suspension segment. After the coordinate and elevation pre-assembly and adjustment are in place, the segment shall be retracted and lifted, the matching surface epoxy splicing glue shall be applied manually, the formal assembly of the second suspension segment shall be carried out, and the longitudinal finish rolling thread steel shall be tensioned to ensure the effective bonding and accurate positioning of the first and second suspension segments, thus completing the assembly of the remaining segments of the span in this process cycle. After the whole hole segment is assembled, install the wet joint formwork and pour the concrete, and after the concrete strength reaches the design requirements, carry out external cable threading and tensioning. According to the same process, complete the assembly of the whole segment, tension the negative bending moment prestressed steel bundle, remove the support lock, and complete the conversion of the whole system.

4. External prestressing construction

The external cable of Hebei segmental assembly project adopts the filled epoxy coated steel strand system, which is composed of epoxy steel strand, anchor, steering gear, crossing pipe, shock absorber, anti-corrosion device, etc. The steel strand is laid with felt and geotextile for blanking and threading, and the steering wheel and PE sleeve are set at the corner position to avoid coating damage and scratches. After the beam threading is completed, two special front jacks are used for synchronous, step-by-step single-end tensioning, and anti-corrosion treatment is carried out on the exposed part of the anchor, such as oil filling, waxing, installation of protective cover, and finally installation of steel beam shock absorber.

5. The whole bridge erecting machine traverses and spans

The luffing traverse adopts the innovative technology of new single slide rail and multi-functional middle outrigger mechanism combined with step-by-step traverse, I .e. the luffing traverse of the bridge erecting machine is completed through the relative sliding movement between the lower single slide rail and the outrigger beam, thus realizing the function of fast installation of double-width segmental beams. The longitudinal traverse adopts the innovative technology of leg leapfrog conversion combined with step-by-by-by-by-by-by-by-by-step longitudinal traverse, I .e. temporary support of front and rear auxiliary legs, the middle and rear legs span directly to the previous span cover beam, and the longitudinal movement of the whole machine is realized by the longitudinal movement oil cylinder combined with the longitudinal movement track.

6. Refurbishment of beam body

Hebei segment assembly construction can be carried out through the special external modification frame operation platform of the bridge erecting machine, the installation segment can be polished and trimmed, and the anchor hole can be filled with grouting to complete the trimming work of each span beam.
In the construction of Hebei segmental assembly, the company adheres to the concept of "science and technology leading, ingenuity and creation", and takes operation standardization as the driving force to conduct in-depth research, analysis and summary of each process. Through the research and development of advanced equipment, optimization of process details and other measures, to achieve the segment smooth, sharp edges, color homogeneity, assembly linear smooth, beautiful appearance, entity generous, for the creation of market excellence, competition for national excellence has laid a solid foundation.