In civil engineering projects such as bridge and viaduct construction, pier columns, as important load-bearing structures, their construction quality is directly related to the stability and safety of the entire project. As a key tool for shaping the appearance of pier columns and ensuring the quality of concrete pouring, pier column formwork often encounters various problems during use due to improper operation, material loss, or environmental impacts. The following is a detailed introduction to the common problems in the use of pier column formwork and corresponding solutions.

Common quality problems in pier shaft construction include: misalignment, pockmarked surface, honeycombing, excessive air bubbles, and chipped edges/corners, etc.

1. The first common problem is severe pier column misalignment: uneven concrete surfaces at formwork joints, with unsmooth curves.

Preventive measures:

① Select plates that are not easily deformed and have a smooth surface for formwork materials, so that the formwork has sufficient strength and rigidity to prevent significant deflection and deformation of the formwork during concrete pouring. After the formwork is processed, first check whether the specifications and geometric dimensions of the formwork materials are consistent with the design drawings; second, check whether the structural dimensions of the formwork meet the design requirements; finally, check whether the flatness, misalignment, and formwork joints meet the design and specification requirements.

② Before installing the formwork, conduct a trial assembly, set positioning pins at the trial assembly positions, check the formwork joints and flatness, and number them at the same time to ensure the accuracy and fit of the formwork and ensure that the misalignment does not exceed 2mm. Then, derust, polish, and grind each formwork. Apply formwork paint or release agent.

③ When installing the formwork, the connecting positioning pins of the upper and lower formworks must be aligned to ensure the flatness of the joints. The connecting seams between formwork panels must be sealed with 2mm thick and 30mm wide double-sided tape. Specifically, first stick the double-sided tape to the bolt connection of the side of the first installed formwork, then tear off the anti-adhesive paper on the double-sided tape before the next formwork is about to be closed, align the two formworks to make them stick together, and tighten the connecting bolts. After the connecting bolts are stressed, the double-sided tape is squeezed to play a sealing role, ensuring that the formwork does not leak grout. After the formwork installation is completed, it should be calibrated to ensure the quality of formwork splicing. Before pouring concrete, debris such as garbage, wood chips, shavings, sawdust, mud, and peeling iron sheets in the formwork must be thoroughly cleaned.

2. The second problem is pockmarked surface on the pier column appearance: local lack of grout and roughness on the concrete surface, or many small pits, but no exposure of steel bars or stones.

Preventive measures:

Clean the formwork surface thoroughly, ensuring no adhesion of dry and hard cement mortar and other debris.

Before pouring concrete into wooden formworks, fully moisten them with clean water, clean them thoroughly, and leave no standing water. Ensure tight splicing of formwork gaps; if there are gaps, fill them tightly to prevent grout leakage.

Apply the release agent evenly on steel formworks without missing any areas.

Concrete must be vibrated evenly and densely in layers according to operating procedures, strictly preventing missed vibration. Each layer of concrete must be vibrated until air bubbles are completely eliminated.

3. The third problem is honeycombing on the pier column appearance: local looseness of concrete, with less mortar and more stones, and gaps between stones forming honeycomb-like holes.

Strictly control the mix ratio during concrete batching, conduct frequent inspections, and ensure accurate material measurement. Adopt electronic automatic measurement. Concrete must be mixed evenly with consistent color, and the minimum continuous mixing time meets the specified requirements.

The free fall height of concrete should generally not exceed 2m; if it exceeds, measures such as chutes should be taken for feeding. Concrete vibration should be done in layers. The thickness of the pouring layer should not exceed 1.25 times the length of the working part of the vibrator. When compacting concrete mixtures, the moving distance of the inserted vibrator should not be greater than 1.5 times its radius of action; for fine aggregate concrete mixtures, it should not be greater than 1 time its radius of action. The distance from the vibrator to the formwork should not be greater than 1/2 of the effective radius of action of the vibrator. To ensure good bonding between the upper and lower layers of concrete, the vibrator rod should be inserted into the lower layer of concrete by 5cm. When vibrating concrete, the vibration time at each point must be properly controlled. The appropriate vibration phenomenon is: the concrete no longer sinks significantly and no more bubbles appear.

During concrete pouring, constantly observe the formwork, supports, and joint sealing, etc. If formwork movement is found, immediately stop pouring and repair it before the concrete initial setting.

4. The fourth problem is chipped edges/corners of the pier column. Possible causes: early formwork removal, impact by external forces, or poor protection, resulting in chipped edges and corners.

Preventive measures:

When removing column formworks, the concrete should have sufficient strength; do not use excessive force or rush during formwork removal, and pay attention to protecting the edges and corners.

Strengthen the protection of finished products. For concrete corners in passages with heavy pedestrian traffic or material transportation, corresponding protective measures should be taken.

In summary, the problems that occur during the use of pier column formwork are mostly related to links such as material selection, installation operations, and maintenance management. Construction personnel need to enhance their quality awareness, strictly follow the specifications and requirements for formwork selection, installation, use, and maintenance, take preventive measures in advance for common problems, and promptly handle emerging issues to ensure the construction quality of pier columns, thus laying a solid foundation for the safety and stability of the entire project.