3、 Key points and measures of supervision and control in the preliminary preparation stage (I) establish a communication mechanism to enable all participants to participate in PC deepening.

Introduction in view of the many advantages of precast buildings in environmental protection, energy conservation and convenient construction, coupled with the strong support of government departments, precast buildings have gradually become the development direction of the construction industry.

2、 Project background (I) project overview the project is a commercial precast concrete building, which is composed of six single buildings and two basements, with a construction area of more than 100000 square meters.

According to order No.

The basement is a cast-in-situ frame shear wall structure; The superstructure is a cast structure, which is composed of precast concrete beams, double T-plates, precast columns, laminated plates and precast stair sections, with an assembly rate of 41%.

（4） Fully consider the relevant construction measures of PC building.

The floor height and span are large.

（2） Analysis of engineering difficulties 1.

If it is arranged outside the building, the lifting distance shall be increased, and a larger tower crane is required).

Tower crane selection and layout.

The qualification of precast component hoisting unit and relevant management personnel shall meet the requirements, and the management personnel shall be on duty.

In order to ensure the hoisting safety and consider the use cost of tower crane, qtz315 tower crane (see Table 1) is selected and arranged in the middle (arranged in the core barrel.

Moreover, the double-T plate is placed on the cattle leg of the beam, so that the converted load of the local beam itself reaches 40kN / m.

The arm length is 36m; The distance between the tower crane center and the farthest component is about 20m, and the distance between the precast component yard and the Tower Crane Foundation Center is within 30m.

The local floor height of the first floor and upper floor of the project is 10.5m.

If the embedded parts of curtain wall need to be accurately embedded in place at one time, the deepening design of curtain wall shall provide basis for the deepening design of PC; In order to facilitate hoisting, whether the component weight and local joints can be optimized on the premise of ensuring the assembly rate (such as solving the problem of reinforcement collision in beam column joints and staggering the beam reinforcement).

Tower crane selection and positioning shall be accurate; Bent erection and component hoisting require high safety control.

The experience and management measures as mature as PC residence have not been formed, and there are many challenges in construction safety.

Curtain walls, doors and windows, fire fighting and other work have an impact on the construction of precast buildings.

The detailed design drawings shall be sealed and confirmed by the original design unit and approved by the qualified drawing review unit before they can be used to guide the construction.

The special construction schemes involved in the construction of commercial cast concrete structures mainly include: special construction scheme for precast component hoisting, special construction scheme for bent erection, special construction scheme for yard and temporary road reinforcement, special construction scheme for PC grouting, production scheme for precast components, etc.

Compared with civil residential projects, the market share of commercial projects is small.

37 of the Ministry of housing and urban rural development, the bent erection of the project is a dangerous divisional and subdivisional project exceeding a certain scale, which is also the focus of control.

2.

3.

37 of the Ministry of housing and urban rural development, experts need to be organized to demonstrate the special construction scheme of divisional and subdivisional works with high risk exceeding a certain scale (special construction scheme for precast component hoisting and bent erection of the project).

Construction supervision ， real-time understanding of construction industry information and more in-depth good articles ， source of concern: construction supervision, issue 11, 2019, author: Tan she Hongyi.

At present, in terms of civil housing, precast concrete precast buildings have begun to take shape, and the relevant technologies and measures in design, construction and management have been mature, which has brought benefits to the market.

（2） Review the qualification of hoisting unit and personnel.

According to order No.

（3） Review relevant special construction schemes and prepare supervision rules.

The design and deepening of precast concrete components is a key link in the preliminary preparation, which is directly related to the smooth development of all work in the construction stage.

This paper analyzes the preparation work before the construction of commercial precast concrete buildings and the supervision control points and measures in the construction process through cases, so as to provide reference for the supervision of similar projects and add bricks and tiles to the promotion of commercial precast concrete buildings.

Table 1 lifting performance of qtz315 tower crane, plus the weight of spreader (lifting shoulder pole, steel wire rope, etc.), the tower crane meets the requirements.

The span of the project is between 11.5m and 12.6m, and the precast floor slab adopts double T-plate.

Prepare targeted supervision implementation rules according to design documents, relevant specification documents and special construction scheme.

In the PC deepening stage, it is suggested that the construction unit convene the design unit, construction unit and relevant supporting units to hold regular coordination meetings to analyze the possible problems in the later stage and deal with them through deepening design, so as to avoid or reduce rework and rectification in the later stage.

Spread Anchor

The heaviest precast component of the project is the precast side beam around, which weighs 13.31 tons, and the plane size of the single building is 39.4 × 38.05m.

1.

Special workers involved in the hoisting of precast components (such as tower crane driver, rigger, etc.) shall work with certificates; Precast component hoisting workers and grouting workers shall go to work with certificates after receiving special vocational ability training and obtaining relevant certificates.

Coupled with some unique characteristics of commercial projects (such as large span, high floor height, heavy components, many supporting units, etc.), precast concrete structures are less used in commercial projects.

The weight of precast concrete members is large, and the maximum weight of a single composite beam is 13.31 tons (all surrounding side beams); The maximum weight of a single precast column is 10.53 tons (arranged around).

There are many supporting units and it is difficult to coordinate.

Determine the model and location of tower crane according to the weight of the largest precast component, the location of the largest component on the floor and the location of precast component storage yard, combined with the specific situation of tower crane rental market.

If the wall attachment point of the tower crane is set on the precast components, the wall attachment setting of the tower crane shall be approved by the design unit..

The first floor is 6m high; The second floor is more than 4.5m high; Local floor height is 10.5m; The building height is 57.15m.