1.2.1 Division of construction sections

1. Divide the whole construction region into several construction sections according to the principles listed as follows:

(1) The quantities are roughly equal;

(2) The dividing line should be set at a place where the shear force is small and the construction is convenient;

(3) The area of each construction section is roughly 400~500 m².

2. Start position and flowing direction should be indicated in the schematic diagram.

1.2.2 Calculate the quantity of each construction section

(1) Unit component quantities

Calculate unit component quantities according to the task drawings given. Table- 1 can be referenced.

Table- 1 Unit engineering quantities

 

 The location of structural members is shown in Figure 1

 

 

 

Figure 1 Location of structural members

 

(2) Construction section engineering quantities (standard floor)

Construction section quantities (standard floor) shall be calculated according to the division of the construction section and production quota requirements. Table- 4, and Table- 5 can be referenced.

Notice:

Generally, the amount of any horizontal structural member’s formwork and steelwork will be always the same, but their concrete work might be different from that of formwork and steelwork. The reason is listed below:

The concrete work should stop at the middle one-third of the secondary beam where there exists a construction joint, but the corresponding formwork and steelwork have already been done before the concrete is placed at the span.

The counting methods are shown in Figure 2.

 

 

Figure 2 Amount of the horizontal structural member

 

1.2.3 Determination of the construction sequence

There are two available construction sequences: Formwork 1 time and concrete casting 2 times (1F2C), Formwork 2 times, and concrete casting 2 times (2F2C).

Write out the technological processes of the two construction sequences, analyze their advantages and disadvantages, and choose one of the construction sequences.

 

(1) Sequence of 1F2C:

Column steel --->column, beam, and slab formwork--- >column concrete; beam and slab steel ---> beam and slab concrete----> column, beam, and slab formwork dismantle.

(2) Sequence of 2F2C:

Column steel--->column formwork---> column concrete--->column formwork dismantle; beam and slab formwork--->beam and slab steel--->beam and slab concrete--->beam and slab formwork dismantle.

Notice:

For columns, the top part of their formwork and concrete placement will be constructed together with the beams and slabs.

1.2.4 Selection of the vertical transport machinery

There are many kinds of vertical transportation methods: Tower crane + hopper; Winch or derrick + trolley; Self-propelled rod crane, winch, derrick + trolley; Concrete transportation pump.

Select suitable vertical transport methods and their machinery.

1.2.5 Selection of construction method of main works

(1) Formwork: Preparation; Configuration of the column, beam, and slab formwork; Necessary drawings of the column, beam, and slab formwork; Installation sequence and key points of component formwork system; quality requirements of formwork installation; formwork dismantling. 

(2) Steelworks: Steel bar processing; Preparation before steel bar binding; Binding methods, connection type, and concrete cover controlling of the column, beam, and slab; Acceptance of reinforcement works, etc. 

(3) Concrete work: The preparation of concrete should include the calculation of the concrete mix ratio, the problems in preparation and selection of the mixer; Concrete distribution methods; Casting of concrete: including preparation before casting, and vibrating methods of the column, beam, and slab; selection of vibrating machine; Arrangement and treatment of concrete construction joints; Curing methods and requirements for concrete.