Product Details

I. Project Overview

Within the power plant's industrial area, the chimney is 120 meters tall, and there have been instances of protective layer detachment from several parts of the chimney (already repaired). Now, there is a large-scale detachment of the protective layer and horizontal reinforcement at approximately 45 meters from the top of the chimney. Due to the safety hazard posed by the chimney, the company has decided to dismantle it.

1. Removal Method: Due to the company's no longer needing this chimney and the existence of certain safety hazards, the 120-meter concrete chimney of the power company will be manually dismantled.

2. Key points for the construction organization of this dismantling: This project task is tall and challenging with high difficulty, stringent safety management requirements, and significant time investment. Construction must comply with the factory's requirements at all times.

3. Waste Exportation: The transportation, shipping, and disposal of waste after dismantling.

Compilation Basis

As Per Factory Demolition Plan

"2. The 'Bid and Tender Law of the People's Republic of China'"

3. The "Regulations for the Administration of Construction Quality"

4. "Company Contract Project Bidding and Negotiation Management Regulations"

Demolition Work Content and Requirements

The outer wall is reinforced with a hoop at 45 meters.

Chimney exterior H-shaped environmental protection platform removal

Demolition of refractory bricks and insulating perlite layer on the inner wall of a 120-meter chimney.

Demolition of concrete chimney筒壁, 120 meters in height.

Export of waste after dismantling.

Safety Precautions for Dismantling

Overall project planning demands stringent safety measures, significant fire resistance, and substantial waste transportation and storage after dismantling. It is crucial to ensure ample manpower and coordinate with safety and environmental protection, as well as security guards for timely entry and exit from the facility.

1. First, gain an accurate understanding of this project to ensure timely commencement and smooth construction thereafter. Anticipate various potential issues during construction and develop corresponding preventive measures.

2. Tailor construction schedules based on the actual characteristics of the project, and arrange continuous construction in a reasonable manner.

3. Thoroughly organize the construction team for a technical and safety briefing on the demolition project to address potential safety hazards during the dismantling process.

4. Enhance dynamic management of the construction schedule during the project, adjusting plans promptly based on actual on-site conditions, and implementing a checking system.

5. Ensure proper ground fire prevention and protection, especially the importance of fire prevention for the northern oil tanks.

6. Ensure timely requirements for transporting various debris out of the factory (due to the large volume of debris, storing it all would require substantial space).

7. Conduct a pre-site inspection of the construction section, check and hand over the subgrade, and promptly report any issues to the relevant units. Begin mechanical preparations in advance and promptly organize the construction crew to start work.

Following the analysis, measures to be taken: arrange personnel and prepare for the dismantling in advance. Workload should be assigned based on actual circumstances, considering the overall construction to ensure all projects are completed within the preparation time.

1. Safety Management Policy:

Safety first, prevention-oriented.

Enhance the environment, safeguard health, practice scientific management, and ensure sustainable development.

2. Safety Construction Goals

Zero fatality accidents

Loss incidents: Zero

Accident recordable to zero

Zero environmental accidents

Fire incidents: Zero

3. Construction Safety Assurance System

All personnel on the construction site must strictly comply with the "Construction Site Safety Management Regulations" and the "Construction Site Fire Safety Management System" of the company's Engineering Department, ensuring "adherence to laws and rigorous enforcement." The project department is responsible for safety propaganda and education of workers, diligently implementing and enforcing the relevant safety regulations of the Engineering Department, and assigning specific responsibilities. Self-inspections by work teams, security checks by project专职安保 personnel, inspections by the project manager, and random checks by the company's inspection team all form part of the project's security supervision system.

Our company's staff on construction sites must strictly adhere to the owner's code of civil construction while also complying with this regulation and submitting to the supervision and leadership of the site management personnel.

Construction sites should be clearly marked with prominent signs to delineate the construction area.

(2) Construction personnel should maintain friendly relations with neighboring construction units and residents near the construction site, proactively coordinate issues arising during construction, respect the construction achievements of neighboring units, and project a positive image of civilized construction.

(3) Smoking is strictly prohibited on the construction site.

(4) Prohibited on construction sites.

(5) No sleeping is allowed on the construction site.

(6) Absolutely no chasing and horseplay on the construction site.

(7) Absolutely no fighting or brawling on the construction site.

(8) Absolutely no eating of any food is permitted on the construction site.

(9) Proper attire is required; no bare chests or arms, and slippers are prohibited.

(10) Conduct yourself with civility; no offensive language or behavior is permitted.

(11) Access to the construction site requires wearing a name tag and uniform attire.

(12) Maintain harmonious relationships with other construction companies, always starting with a "please" and ending with a "thank you."

The Civilized Construction Management Regulations serve as the daily conduct guideline for every employee and embody the company's "image."

Construction Procedure and Technical Requirements

Construction Technical Plan and Measures

1. Construction Preparation

(1) Implement construction water supply, electricity, communication facilities, and construction roads.

(2) Arrange for construction staff to stay and live in designated accommodations.

(3) Organize the entry of construction and technical staff.

(4) Organize small machinery and equipment, tools, mobile operation platforms, and the arrival of necessary materials and safety facilities on-site for assembly.

(5) Locate machinery and equipment on-site and establish waste storage points for structures.

(6) Conduct safety education, quality education, safety contract verification, and provide construction technology briefings for employees.

(7) Establish a safety warning line outside the bottom exterior of the chimney within the specified range, set up clear signs, assign a dedicated guardian, and at the north oil tank, place sand and gravel as well as a fire extinguisher, with a designated person responsible for it.

(8) Ensure a safe passage for construction personnel.

2. Construction Process

Construction Preparation → Installation of safety barriers, caution lines, equipment, storage, temporary main power distribution cabinet, and construction of safety sheds → Installation of power lines, water supply pipes, inspection and repair of personnel access ladders and steel platforms → Reinforcement of chimney middle clamps → Demolition of chimney environmental protection platform → Installation of power supply on the chimney, installation of roller machines → Installation of portable operation platforms → Chimney bottom opening, demolition of ash accumulation platforms inside the chimney → Drilling holes in the chimney wall → Crushing reinforced concrete chimney wall with hydraulic machinery → Removal of wall sections → Removal of concrete waste → Demolition of portable operation platforms, removal of safety barriers, equipment removal, and site acceptance and clearance.

Firstly, reinforce at the midpoint of the chimney, 45 meters up.

At the midpoint of the chimney, 45 meters up, where there was a detachment, we first reinforced the middle section of the chimney, which had a potential safety hazard. We used two bands made from 5x50 flat steel, welded them in place, and reinforced at the 45-meter mark to form a fixed structure, preventing further detachment during dismantling. During construction, workers ascended to the platform first, fastened their safety belts, and for added security, a #10 wire rope was wrapped around the outer wall of the chimney, with each worker's safety belt attached to this rope.

Cement Chimney Demolition.png

Once the portable work platform is installed, the construction personnel fasten their safety belts, which are then securely hung around the smokestack on a steel wire rope. By pulling the hand winch, the entire portable platform is raised to the top of the smokestack. The φ22 reinforced bolts are used to connect and tighten the gaps in the clamping band.

Once the entire portable platform is installed, the construction crew begins dismantling the concrete cylinder walls. During dismantling, air is supplied from an air compressor, transported through a flexible hose from the compressor to the construction platform via the chimney ladder. While working, the construction crew secures their safety harnesses around a steel rope encircling the chimney on the construction platform. As they dismantle a section of the reinforced concrete chimney, when reaching the construction platform, they go to the ladder, gradually loosen the reinforcing bolts at the clamp connection, and then slowly release the guide chain. The construction platform, held in place by the clamps encircling the chimney and the weight of the work platform, is slowly lowered using a hand winch. Once the clamp platform reaches its position, the gap at the clamp is tightened with bolts, and the reinforcing bars of the concrete chimney are securely fastened to the guide chain on the work platform, allowing for normal dismantling work to proceed. As the outer cylinder wall of the chimney narrows from top to bottom, with a smaller diameter at the top and a larger diameter at the bottom, additional clamp and triangular support platform box components are added as the construction reaches a certain cross-section.

1) Gas cutting tools need to be connected, mainly used for gas cutting of steel bars, splitting machines, lighting, etc. Equipped with a special power distribution box using a four-core cable, proper grounding and three-level protection measures must be in place.

2) Compressed air from large air compressors is delivered via hoses to the deconstruction work area.

3) Equipped with intercom phones and walkie-talkies for easy communication between levels.

4) Set up temporary lightning rod grounding equipment. The lightning rod must be 3 meters higher than the construction platform. Install the lightning rod with a climbing ladder, and the grounding resistance should not exceed 10Ω. Connect the lightning rod downwards with a 16-square steel wire to the original lightning rod break box on the chimney.

5) Bottom opening of chimney, removal of ash accumulation platform inside the chimney wall

At approximately 30 meters from the top, an opening was made at the bottom of the chimney using a cannon vehicle at the original chimney door at the base. The opening was at the ash accumulation platform, with a height of 4 meters. After the construction opening was prepared, the existing ash accumulation platform was dismantled. Post-dismantling the ash accumulation platform, the waste was not initially cleared for transportation. Instead, a bulldozer was used to pile the waste at the opening to prevent concrete blocks from spilling out during the feeding process inside the chimney. This made it easier to clean up the concrete debris after dismantling. (This method controls the upward flow of dust, as opening the construction opening early could cause dust to rise.)

6) Chimney Tube Bore Holes

Drill holes using a pneumatic drill. First, create a 400mm groove from top to bottom on the intermediate operation platform of the chimney concrete cylinder wall, starting from the top of the chimney. Perform drilling from top to bottom, forming梅花-shaped holes with a width of 400mm. The drilling distance from top to bottom is 300mm to facilitate mechanical crushing.

Construction Workforce Plan

I. Organizational Structure

The organizational setup for the 120-meter chimney demolition project is as follows: Overall Supervisor, 1 Site Coordinator, and 10 Construction Workers.

II. Basic Composition of Maintenance Personnel

A total of 11 personnel are involved in the full dismantling, with the following equipment allocation:

1. Responsible Person: 1

2. Team Leader: 1 position

3. On-site Safety Officer: 1 Position

4. Maintenance Staff: 8

Construction Progress Schedule

Based on the schedule from the factory's relevant departments and the thermal power plant, the detailed schedule and control points are as follows:

Based on actual workload, 50-60 sunny workdays are considered for effective labor allocation.

All pre-construction preparations are completed, and safety training and handover will be conducted upon entry.

Equipment installation and reinforcement to be completed in approximately 3 days.

Chimney environmental platform removal takes approximately 2 days.

4. Chimney demolition to 20 meters requires 6 days (including 1-2 days for separating steel and concrete structures, and clearing debris) with debris transportation included.

5. Demolition above 10 meters should be done during the day. Separation of steel and concrete structures, and clearing debris from the chimneys should be conducted at night, with an estimated duration of approximately 35 days.

6. Below 10 meters, mechanical demolition is used, which takes approximately 3 days with the use of a cannon truck.

7. Site clearance and acceptance: 1 day

Quality Goals and Assurance Measures

Quality Assurance System

Jiangsu Xindagao High-altitude Engineering Co., Ltd. has established a comprehensive quality assurance system based on the philosophy of construction quality management. The company passed the ISO9002 quality system certification as early as 2008.

2. Quality Objective:

(1) Pursue excellence, offer dedicated service, uphold integrity, ensure customer satisfaction

(2) High pass rate for maintenance engineering, high pass rate for anti-corrosion engineering

(3) High coverage of quality assessment

3. Quality Assurance System

1 set: 7 personnel assigned for dismantling.

2 sets: Responsible for ground maintenance and night cleaning, with 3 personnel involved.

3 sets: Logistics support should provide round-the-clock services to all personnel's logistics supply teams: ensure normal drinking water and reasonable meal arrangements. Assign 1 person.

Significant Risk Control Measures

Electrician operations, certified staff in place, to prevent on-site electric shocks.

2. Ground fire prevention: ensure dedicated supervision.

3. Cross-operation, wear a safety helmet, properly equip labor protection, ensure the functionality of safety belts and secondary restraints, securely fasten and secure each person's tools, and strictly prevent injuries from falling objects from heights.

4. Robust supervision, emphasizing the importance and achieving the "No harm to the four aspects."

Note construction safety measures

Safety is of utmost importance during construction. Prior to starting, check and secure safety harnesses, wear hard hats, and put on work clothes. Based on the chimney condition, first reinforce the hazardous middle section with a tie箍 made from 5x50 flat steel (2-3 layers), and strengthen it at 45 meters to form a fixed structure. During construction, when workers climb to the platform, they must first secure their safety harnesses. For added safety, use #10 wire rope to encircle the exterior of the chimney, and attach each worker's safety harness to this rope.

Environmental Protection Measures for Construction

Environmental protection against pollution is also crucial during the construction process.

Firstly, environmental protection for dust during the upper chimney removal: During the removal process, a ground-high-pressure pump and water hose are used to directly deliver water to the top of the chimney. The water hose is inserted directly into the insulating layer between the chimney wall and the refractory bricks, allowing a continuous flow of water. This ensures that the refractory bricks on the outer and inner walls of the concrete chimney structure do not generate dust during removal.

Two, Environmental Protection for Demolition Debris and Dust Separation: During the removal, when high-altitude debris falls to the inner wall of the chimney, an environmental-friendly dust removal fog cannon is used to continuously spray water into the discharge opening at the bottom of the chimney. This way, the debris removed will no longer produce dust.

Three, Environmental Hygiene During Transportation: Minimize loading during the loading process. During transportation, it is crucial to prevent any debris from falling onto the road; mesh nets must be used for protection. If cleaning is required, it must be carried out promptly. It is necessary to sign an environmental protection contract with the transportation vehicle during transportation. The supervision is conducted by the factory.

Four: Waste Disposal: Sign a disposal agreement with the storage waste area to ensure environmentally-friendly disposal is confirmed.

Winter Construction Safety Measures

As the project is approaching winter, in order to ensure the implementation of all measures for winter construction and to ensure the project is completed safely and of high quality as soon as possible, a comprehensive construction plan for all indicators is proposed.

Arrange construction personnel, organize coordination, inspect, and supervise the implementation of all measures. Ensure the availability of labor during the winter construction period. Responsible for proposing the overall construction schedule of the project, coordinating all management positions and construction teams to prepare for construction activities, and supervising the implementation of regulations and measures. List winter construction projects based on the specific circumstances of this project and the overall construction schedule, propose safety measures for construction personnel, participate in inspections of the implementation of winter construction plans, and propose corrective measures. Provide specific technical guidance for construction operations, promptly feedback and record any issues found in the construction operations area. Coordinate the overlapping processes in the construction operations area, propose the schedule for materials required for construction, assist safety officers in conducting safety briefings and inspections of safety facilities, and urge teams to promptly rectify issues found during inspections. Strictly adhere to national, local, and Huafang Company's specifications, organize inspections and acceptance of each process, and promptly reflect and propose corrective measures for any issues found. Responsible for the safety education of operation personnel in all teams, and in charge of the implementation and inspection of winter construction safety measures. Stop any measures that do not meet requirements, propose corrective measures, and supervise their implementation.

In accordance with regulations, construction at heights should cease when wind speeds exceed 6 levels, and work should halt during rain or snow. When frost forms or ice accumulates on ladders after rain, anti-slip measures must be taken before climbing. Only after cleaning can climbing be done safely. Construction personnel must be equipped with appropriate cold-weather gear, and safety belts must be worn during high-altitude work, with the lanyard securely fastened to a sturdy anchorage point. It is strictly prohibited to drop objects from heights during dismantling.