When installing the expansion joints of highway bridges, the construction units should lay out the joints according to the width of the drawings of the engineering design units, and use the concrete slotting machine to cut the joints. When cutting the joints, attention should be paid to keeping the vertical and smooth incisions of the pavement without biting edges. The material between the two slits is chiseled with air pick, and the surface of the groove is chiseled with concrete. The original expansion joint filler in the groove is cleaned and washed in time. Attention should not be paid to concrete outside the groove. High-pressure pump is used to flush the residual debris in grooves and structural joints. The construction unit should correct the reinforcing bars and check the embedded reinforcing bars carefully. Because of the rolling of construction machinery and vehicles in past vehicles and paving roads, the embedded reinforcing bars will appear cracks, breaks and missing. The cracked and broken reinforcing bars should be timely corrected and welded or repaired according to the welding requirements. The distorted embedded reinforcing bars should be straightened out to meet the requirements of the size of embedded reinforcing bars and the installation of fur. Welding Requirements of Le Device. In order to ensure the installation quality in actual installation, all anchor rings are welded with embedded steel bars, and the surface of steel bars is derusted before welding.
3, we should insert the expansion joint with the foam board of the corresponding thickness into the joint of the special-shaped steel structure, pay attention to the sufficient depth and tightness, and the above should be level with the bottom of the trough, and there should be no loosening and larger cracks to prevent leakage. 4. Installation and welding of expansion joint products; when expansion joint products are manufactured and assembled in factories, the gap of expansion joint device should be adjusted according to installation temperature before installation, and the expansion joint device should be put into the slot by crane or manual, paying attention to the right and left position before and after installation. When there is a hindered embedded bar, it can be properly bent, and then adjust the top height of expansion joint device from the middle to both ends with the help of aluminium alloy ruler until the top surface is 0-2mm (D80), 0-3mm (D160) lower than the road surface. At this time, if the gap width of expansion joint device meets the requirements of installation temperature, the pre-embedded bar can be pulled close to the anchor ring of expansion joint device for welding. The sequence is spot welding from the middle to both ends, then check and retest, and repair welding from the middle to both ends when meeting the requirements. There are at least two welds on each side of each meter, and the length of each weld is not less than 40 mm. After the welding is completed, the fixed portal frame can be removed in time. If the gap width of expansion joint device does not meet the requirement of installation temperature, one side beam and embedded bar can be welded and fixed by the above method, then the fixed portal frame can be gradually cut from the middle to both ends, and the gap and height can be adjusted before welding.
5, install plug polyethylene foam board, wear tendons, cover nets, cement concrete; after welding, the expansion joint device is in normal expansion condition. At this time, the width of the expansion joint is 50mm wider than the width of the gap, the length is about 200mm, and the foam board with a height lower than the notch depth is 40mm, and the transverse section is cut into V shaped groove. The foam board will sew the gap tightly to prevent leakage. The width of the seam should ensure the smaller width of the expansion joint design, then rinse the notch and clean up the grooves. When installing D160, it is necessary to protect the box and beam from mortar leakage. The steel bars of 12 mm (D80) or 16 mm (D160) are penetrated into the anchor ring according to the requirements of the drawings and covered with the steel mesh of 6-80 mm and fastened with wire respectively. Before pouring concrete, check again whether the flatness (deviation less than 2 mm), the position of the middle line and the gap of the expansion joint device meet the requirements. If there is any change, the concrete can be poured only after correcting. According to the design label, symmetrically pouring concrete, the key parts of vibration are inside and below the expansion joint device. Those who fail to vibrate and cause void or fail to discharge air bubbles are not qualified, especially at the junction of bridge deck and profiled steel top surface, they should be strictly controlled. When concrete is poured into the groove, it needs to be vibrated by inserting vibrating rod. When vibrating, the compactness of concrete under the side beam of expansion joint, anchor ring, anchor plate and support box should be paid attention to. Small stone concrete should be used under support box. When pouring concrete, attention should be paid to the repair of the anti-collision wall. After concreting, polishing machine, three-meter straight board and mud knife are used to wipe the surface. When wiping surface, three-meter straight ruler is used to detect the smoothness of the concreting connection zone, so as to ensure the smoothness of the concreting connection zone. At this time, the relative height of the concrete above should be between the surface of the pavement and the plane of the expansion joint device, and the height of the cement concrete should be well controlled.
6. For the maintenance and protection of bridges; the curing of cement concrete should cover waste felt or sacks in time after initial setting, sprinkle water after final setting, keep wet, and remove the plug template the next day at room temperature. When the strength of concrete reaches 50% of the design strength, V-shaped rubber seals can be installed. Under the protection of side beams, V-shaped rubber seals are not directly crushed by wheels. They can not only resist tension, but also displace vertically and laterally. They can also remove sediment and prevent water by themselves. They can be replaced or repaired by vulcanization on bridge deck with simple tools. When installing, clean up the foam board and other sundries that are used as templates in the seams, and apply a layer of lubricating oil (liquid wax or butter) in the groove of the expansion joint, then insert the special crowbar into the rubber bar to complete the expansion joint installation. The construction site should be cleaned up in time after completion of construction. No vehicle shall be allowed to pass until the strength of concrete reaches 90%. Maintenance period should be no less than seven days. If it is really necessary to pass, the suspension pedal should be installed, and a special person should be responsible for ensuring the quality of concrete.
