Main approaches for construction during the rainy season and 21 common engineering protection measures

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Main approaches to construction during the rainy season and 21 common engineering protection measures. The primary approach to construction in rainy seasons is the establishment of a flood control leadership team, which is also responsible for formulating flood prevention plans as well as various emergency response measures. At the same time, the project department should assign dedicated duty personnel to ensure that there is always someone on duty day and night, so as to have a thorough understanding of the weather conditions. At the same time, training for construction workers on working during the rainy season must also be carried out, along with a thorough inspection of the preparations at the construction site. Finally, in addition to the construction site, the drainage systems at the production and living facilities also need to be inspected; drainage water and various types of waste should be cleared regularly to ensure smooth drainage of rainwater. Specific protective measures: I. Drainage in the office area 1. Check the roofs of offices, dormitories, and storage areas for any signs of leaks, and repair any leaking areas promptly. 2. The outdoor ground is fully hardened; the drainage slopes of roads and other areas are correct, and the drains are unobstructed, ensuring that there is no standing water at the construction site. II. Drainage at the construction site
1. Before the rainy season arrives, special attention should be paid to inspecting the underground floors—areas requiring particular precautions in the project. Along the perimeter of the main structure, open drainage ditches measuring 300×500 (b×h) should be constructed. During rainfall, water pumps must be used to drain water from collection pits, and this water should then be channeled into the surface drainage ditches. 2. Organize the construction site to ensure smooth drainage. 3. Inspect the drainage facilities both inside and outside the site to ensure they are in good condition, so that water can be drained quickly after heavy rain. Based on actual conditions, the sump pits at the construction site should be used as centralized drainage points on site, following the principle of proximity. III. Living Area
1. Before the rainy season arrives, project logistics personnel should inspect the temporary buildings in the living area. The inspection should primarily focus on potential hazards such as leaks, structural instability, and risk of lightning strikes. Any issues identified must be rectified promptly. 2. Inspect the drainage channels in the cafeteria, toilets, etc., and clear the sewage pipes promptly. Clean the septic tank before heavy rain arrives to prevent it from overflowing due to the downpour. 3. The foundations of personnel dormitories, fences, etc. at the construction site should be at least 300 mm above the natural ground level, and large footings made of gray sand bricks should be used to ensure the safety of this structural element. The indoor floor should be at least 100 mm higher than the outdoor level to prevent rainwater and other liquids from seeping in. IV. Storage and stacking of raw materials and semi-finished products
1. When stacking steel bars at the construction site, they should be placed in a location with higher ground elevation that is not exposed to rainwater. Additionally, materials such as wooden beams should be used to elevate the bottom of the steel bars by no less than 200 mm. For processed steel bars, they should be placed as much as possible in a rain-proof area within the steel bar processing shed, to prevent them from being corroded and rusted by rain. 2. A warehouse should be built for the cement, and measures should be taken to protect it from rain as well as to keep the floor dry in order to prevent moisture damage. Other materials should be stacked in a manner appropriate to their properties. 3. All materials must be stacked in a safe location at least 3 meters away from the edge of the foundation pit; materials that are prone to scattering should not be stored beside the slope. V. Earthwork and Stonework Projects 1. For the lime-soil that has just been laid but not yet compacted, during the rainy season, strict control must be exercised over the moisture content of the fill soil. Samples should be taken regularly for testing, so as to keep the moisture content within the design specifications. If the moisture content is too high, measures such as loosening the soil, exposing it to sunlight, or mixing in dry soil can be employed ； If necessary, the soil source should be covered in advance to prevent the formation of rubbery soil. 2. If it is soaked by rainwater, the soft ash soil in the waterlogged areas should be removed and replaced with new ash soil, which should then be compacted. The wet ash soil should be allowed to dry before being compacted firmly. Lime and soil should be prepared, along with plastic film to be used for covering in case of rain. VI. Slope Engineering 1. During construction in the rainy season, it is prohibited to pile materials within one meter of the slope. 2. Before construction during the rainy season, check whether there are any displacements or cracks in the slope. Use cement mortar to level the slope so that it slopes toward the drainage ditch, ensuring that no water accumulates around the slope. 3. Keep records of settlement at the slope edges, and conduct measurements whenever there is heavy rain or worse weather. VII. Reinforcement work 1. Reinforcement materials should be delivered to the site in appropriate quantities according to the progress of the project. An excessive amount of raw reinforcement materials should not be stored; at the site, those that were delivered first should be used first, and those delivered later should be used later, in order to prevent severe rusting due to prolonged storage. Rusty or contaminated reinforcement materials must be cleaned before they can be used. The raw reinforcement materials as well as the finished reinforcement products that arrive at the site should be stacked neatly by specification, with a height of at least 200 mm above the ground. In case of rain, they should be temporarily covered with plastic sheets. 2. Welding work is strictly prohibited during thunderstorm weather. In case welding must be carried out under special circumstances, necessary rain protection measures must be taken to prevent rainwater from wetting the welded joints, which could alter the bonding performance of the steel bars and thus affect the quality of the project. 3. If the reinforced bars that have been tied are exposed to rain, they should be rust-removed and cleaned as appropriate after the rain; reinforced bars that are corroded or covered with sludge must not be used in the project. VIII. Formwork Works 1. The formwork and wooden planks stored on site should be arranged neatly, raised at least 200 mm above the ground, and covered with tarpaulins to prevent deformation due to exposure to sunlight and rain. 2. The erected formwork, if concrete has not been poured due to heavy rain, should be covered to prevent the release agent from becoming ineffective as a result of exposure to rain. After the rain, it is necessary to carefully check its levelness, verticality, and the condition of the release agent application; concrete can be poured only if these conditions are satisfactory. IX. Concrete work: It is necessary to keep an accurate track of weather forecasts, and concrete pouring should be avoided on rainy days. If rain occurs, the following measures should be taken: 1. When heavy rain happens during concrete pouring, the already poured concrete should be vibrated to ensure it is compact; construction joints should be created in appropriate locations as required by regulations, after which pouring should be stopped immediately. The area should then be covered with plastic sheeting, which must be secured firmly to the rebar to prevent it from being blown away by the wind. During the pouring of the roof concrete, if light rain occurs, vibration, tamping, and covering should be carried out promptly to prevent the cement slurry from escaping. 2. After the rain, strengthen the treatment of temporary construction joints by removing any residual mortar or weak areas, and clean away any dirt or water accumulation in beams, slabs, and walls. Concrete pouring can proceed only after inspection and approval. 3. To ensure the quality of concrete, during construction in the rainy season, concrete mixers are required to adjust the amount of water used in concrete based on the actual moisture content of sand and gravel, thereby ensuring the quality of the concrete. Regularly send personnel to the mixing plant to inspect the sand and stone storage areas as well as the cement warehouse, checking the mud content in the sand and stone and the condition of the cement against rain. It is strictly prohibited to use sand and gravel with excessive mud content, as well as expired cement, in construction projects. X. Masonry and Plastering Work 1. Before starting masonry work during the rainy season, it is necessary to measure the moisture content of various bricks or blocks. It is necessary to avoid using dry bricks in construction, while also preventing excessive water absorption. To prevent the blocks from getting too wet or soaked by rain, cover them with plastic sheeting during rainy weather. Blocks (bricks) with a high moisture content should be allowed to dry properly before being used again. Construction should be halted in case of moderate to heavy rain, and rainproof measures should be taken for the masonry surface. 2. If mortar flows down the wall surface during construction, it indicates that the moisture content of the blocks (bricks) has reached saturation; in such cases, it is necessary to use a combination of dry and wet bricks for construction, or to employ mortar with a lower consistency. 3. Cement should be stored in a warehouse; the floor inside the warehouse should have brick walls that are 300 mm higher than the outdoor ground level. Scaffolding planks should be laid on these walls, along with asphalt shingles, to prevent the cement from getting wet. The area surrounding the cement storage area must be properly maintained, and drainage ditches should be dug to prevent rainwater from entering the storage area. 4. Sand and gravel storage areas must have proper drainage measures to prevent soil from entering the area during rain. 5. Mortar mixing should be carried out in a centralized manner; mixing stations should be equipped with rain shelters, and vehicles used to transport mortar must have rain covers to prevent rain from entering the mortar. 6. The project tester shall regularly measure the moisture content of sand and gravel based on weather conditions; it is required to measure their moisture content before construction, adjust the mix ratio promptly, and strictly control the consistency of the mortar. 7. Outdoor masonry work is prohibited when it is raining. When masonry must be carried out in light rain, the consistency of the mortar should be appropriately reduced. XI. Roof Works
1. When carrying out roof works during the rainy season, it is necessary to pay close attention to local short-term weather forecasts. Construction should be conducted on sunny days; it is strictly prohibited to perform waterproofing work in the rain. Cover the already constructed areas with plastic sheeting ； When it is found after rain that the waterproof layer has been damaged by rainwater, it must be redone. 2. During transportation and storage, roof insulation materials must be protected from rain and moisture. 3. When laying the insulation layer on the roof, it is advisable to divide the work into smaller sections and complete the upper leveling layer promptly to prevent sudden rainfall from wetting or soaking the insulation layer. 4. For detailed joints such as holes passing through the insulation layer and leveling layer, as well as reserved anchor hooks, temporary sealing and covering should be carried out at all times to prevent rainwater infiltration. 5. When applying the waterproof layer, prior to construction, it is necessary to carefully conduct tests on the moisture content of the leveling layer and adhesion tests in accordance with the technical requirements of the materials used. Construction may proceed only after these requirements are met, so as to ensure the quality of the application of the waterproof layer. 6. Rainwater downspouts and similar components should be installed as early as possible to prevent roof rainwater from flowing along the exterior walls and contaminating the exterior finishes. Before installing interior drainage storm drains, a temporary drainage path should be constructed to prevent rainwater from accumulating inside the pipes due to poor drainage. XII. Waterproofing Works 1. Construction of exterior wall waterproofing works is prohibited on rainy days, and the moisture content of the waterproof base layer must be within the range specified by the standards (≤4%). 2. During the construction of the cushion concrete, ensure that the drainage slope is set as required, and install water collection pits at the edges of the pit to pump out water promptly. 3. For waterproofing work in areas with poor ventilation such as bathrooms and fire pump rooms, ventilation and exhaust measures should be taken to ensure air circulation; personal protective equipment must be used, and fire prevention measures should also be implemented. 4. During the waterproofing work of the exterior walls, close attention should be paid to the stability of the soil on the slopes; the displacement of these slopes should be checked after each rain, and construction should be halted if significant displacement occurs. 13. Decoration Works 1. Interior decoration is best carried out after the roof and floor works are completed, or by first finishing the floors and sealing all holes and gaps to prevent water leakage from the upper layers downward. Seal the window wells and elevator shafts properly, and construct water barriers in the stairwells on each floor. 2. When applying plaster outdoors, it is necessary to ensure proper coverage to prevent it from being washed away by sudden rain; exterior wall decoration work must be stopped during rainy weather. 3. The installed doors and windows should be under someone’s supervision; they should be closed promptly during rain and secured with latches to prevent damage from wind and rain. 4. Various doors, windows, wooden products, as well as other types of keels, decorative materials, glass, fittings, etc., must be protected from rain and moisture during transportation and storage, to prevent adhesion, deformation, or rusting. 5. Gypsum strip boards, gypsum board, gypsum-faced composite panels, and other lightweight partition materials must not be exposed to rain, water immersion, or moisture, in order to prevent material degradation that could lead to quality issues. 6. The application of exterior wall paint should be carried out on sunny days. 14. Curtain Wall Works: 1. Curtain wall construction should not be carried out in conditions of strong winds or heavy rain; sealant application must not take place on rainy days or when the area is still wet after rain. 2. Electrical equipment and power tools used in curtain wall projects must undergo insulation voltage testing. Before construction during the rainy season, check whether the insulation devices are in good condition; any that do not meet the requirements must be repaired promptly. 3. The aluminum panels and aluminum-plastic panels on the upper floor must be securely fixed to prevent them from being blown down by strong winds and causing injury. 15. Safety of temporary electrical installations: 1. During the rainy season, it is necessary to regularly and systematically check the insulation condition of temporary electrical facilities, as well as whether there are any damages to the power cables; any issues found should be addressed promptly. 2. The temporary power supply lines on site use a three-phase five-wire system; the switch boxes for mechanical and electrical equipment as well as the lighting fixtures are equipped with rain protection facilities. All mechanical and electrical equipment must be equipped with a single switch; it is strictly prohibited to use one switch for multiple purposes. Leakage protectors must also be installed. The power supply should be turned off when work is suspended, and the switch box should be locked. Before use, the equipment must be inspected and tested. 3. A qualified leakage protection device must be installed in the distribution box; its sensitivity should be checked regularly, and the door of the box must be kept closed at all times. 4. Personnel engaged in electrical work must hold valid certificates to work, wear appropriate personal protective equipment, and work in pairs—one performs the task while the other supervises. 16. Tower crane foundation and lifting 1. After rain, the electrical circuits and the foundation of the tower crane should be inspected promptly, and the crane should be operated without a load to ensure there are no issues before lifting operations can begin. 2. Observe the basic settlement situation and keep proper records of these observations; if any settlement occurs, it must be addressed immediately to ensure the safety of the tower crane during use. Lifting operations should be stopped during heavy rain, torrential rain, and strong winds. 3. When working at heights after rain, workers must be careful to avoid slipping; they should wear shoes with rubber soles, and it is not allowed to use shoes with hard soles for work at heights. The grounding resistance value of the tower crane must be measured actually, and it should not exceed 4 ohms. 4. Around the tower crane foundation, dig a 200mm × 300mm drainage ditch and connect it to the temporary on-site drainage ditch. The inner surface of the ditch should be plastered, and the bottom of the ditch should have a 5‰ slope leading toward the temporary drainage ditch. 5. Four settlement observation points are installed at the base of the tower; settlement measurements are taken regularly and after rainfall, with any issues addressed promptly. 17. Scaffolding Works
1. Check that the external scaffolds, especially those at higher elevations, have been designed and equipped with adequate lightning protection devices. 2. Anti-slip measures during the rainy season: Install necessary anti-slip facilities in areas where people walk, such as working surfaces and access paths. 3. A drainage ditch should be installed outside the outer vertical poles of the scaffold to allow rainwater to be drained away promptly, thereby preventing the scaffold’s foundation from being soaked by rainwater and causing settlement. Assign a dedicated person to check before rain whether the pole pads are effective and free from collapse ； Check whether the foundation has sunk after the rain, whether the vertical poles have settled, and whether the scaffolding is deformed. If any abnormalities are found, it is necessary to reinforce and repair them promptly. 4. During heavy rain, the erection and dismantling of scaffolding are prohibited ； After heavy rain and strong winds, the scaffolding should be inspected and repaired promptly; it can only be put into use after any safety hazards have been rectified. 5. The scaffold foundation must be solid, and struts should be equipped with wooden pads or blocks that extend throughout their length. 6. The special passageways constructed on the external scaffolding for backfilling operations must be dismantled and reassembled strictly in accordance with the structural requirements for creating openings as specified in the JGJ130-2011 Safety Technical Code for Fastener-type Steel Tube Scaffolds in Building Construction. Additionally, they can only be put into use after being inspected and approved by the on-site safety officer. 18. Road Works 1. Improve the drainage system in the construction area to prevent the roadbed from being soaked by rainwater for extended periods. During rainy weather, assign dedicated personnel to conduct inspections, and promptly clear any water accumulation or blockages. A horizontal drainage ditch is dug every 5–10 meters on both sides of the shoulder to drain rainwater into the side ditches. 2. Concentrate efforts, shorten the sections, and accelerate construction progress; avoid a widespread approach. When constructing lime-fly ash macadam, attention should be paid to weather changes to ensure that tasks such as paving and rolling are completed before it starts to rain, thereby preventing the freshly laid lime-fly ash macadam from being soaked by rain before it can be rolled, which would halt further construction. 3. Adapt measures to local conditions and take necessary rainproofing actions. The compacted lime-fly ash macadam layer has a certain effect in terms of rain resistance. Therefore, after the subgrade is completed, the gravel layer should be laid down as soon as possible. In cases where heavy rain occurs suddenly after the lime-fly ash macadam has been delivered, and there isn’t enough time to spread and compact it, it can be temporarily piled up into mounds, with their surfaces compacted, or covered with tarpaulins. 19. Greening Projects 1. In the event of rain during the construction of the greening soil and salt-exclusion layer, work must be stopped immediately; work should resume only once the moisture level meets the required standards, to prevent the greening soil from being crushed into mud by machinery. 2. When planting trees and grass, care should be taken to ensure that they are not washed away by rain before planting, so as to prevent the soil attached to them from being washed away, which would result in a low survival rate of the plants. 3. Avoid fertilizing the soil on rainy days. 20. Equipment Installation Works 1. Protection of raw materials and semi-finished products: Those that can be stored in warehouses or floors should be placed on elevated surfaces to ensure good ventilation. In particular, insulation materials brought into the site must not be exposed to rain or soaked; measures to protect them from rainwater must be taken promptly. Mechanical and electrical warehouses should have measures to prevent water ingress; exhaust fans should be installed in warehouses that store electrical materials or other equipment that requires protection from moisture, in order to maintain good ventilation inside the warehouses. 2. Materials such as pipes or equipment stored outdoors should be placed on raised platforms, and covered with plastic sheets when it rains. 3. After being unpacked, the mechanical and electrical equipment brought into the site must be protected from rain, and exposure to the open air should be minimized as much as possible. 4. Rainproof measures should be taken for the reserved holes in equipment. If the underground portion of the equipment at the construction site has already been installed, measures must be taken to prevent the equipment from getting damp or being soaked by rainwater. 5. Mechanical processing equipment such as sheet cutting machines and threading machines should be equipped with rain protection facilities. 6. Outdoor welding operations should not be carried out in rainy weather ； When performing indoor welding tasks, care should be taken to ensure that the work area is dry ； It is advisable to dry the electrodes before welding work during the rainy season ； Effective ventilation measures should be in place when welding in confined spaces. 21. Lightning Protection 1. To protect buildings, mechanical and electrical equipment, as well as people and livestock from damage and harm caused by lightning, lightning protection measures such as the installation of lightning rods, lightning conductors, surge arresters, down conductors, and grounding electrodes are generally employed. 2. Temporary sheds, construction work platforms, and dormitories at construction sites must be equipped with lightning protection and grounding measures based on the actual conditions. Install lightning rods, down conductors, and grounding systems for lightning protection. 3. The lightning protection system must have a proper grounding system; it is necessary to regularly check and measure the grounding resistance of this system. The grounding resistance of its independent grounding electrodes should not exceed 4 ohms, otherwise appropriate actions must be taken promptly. 4. Conduct regular inspections of the lightning protection grounding system and enhance daily maintenance, focusing on checking for any damage, breaks, or corrosion in the grounding wires. 5. During the thunderstorm season, it is necessary to monitor thunderstorm activity; on days with frequent thunderstorms, construction workers should be moved indoors, and no work should be carried out in open areas at heights or outdoors. 6. When it is not possible to take shelter in a building equipped with lightning protection, one should stay away from trees and masts. 7. It is not advisable to use an umbrella in open areas at the site, nor to carry steel pipes, shovels, etc. on one’s shoulder. 8. During periods of frequent thunderstorms and intense lightning, people should not approach lightning protection devices such as lightning rods, surge protectors, and down conductors. One should not take shelter from the rain under large trees, and must avoid touching antennas, water pipes, wire meshes, metal doors and windows, as well as the exterior walls of buildings. It is also necessary to stay away from electrical wires and other equipment that carry electricity or similar metal devices, in order to prevent injuries caused by lightning strikes. 9. Lightning protection measures for mechanical equipment: When installing on-site construction equipment such as tower cranes, proper grounding must be ensured. Once the foundation of the building is in place, the tower crane must be connected to the foundation’s lightning protection grounding system. The PE wire of the tower crane’s power supply system is grounded together with the tower crane itself. The top and bottom of the exterior elevator guide rails are grounded respectively. A suitable surge protector (SPD) is installed inside the distribution box.