Stair board in place: when in place, the stair section shall ensure that the step plane is in a horizontal state, lift it into the installation position from the top, and make a slight pause at about 30cm above the operation layer.

3.

2 the rest platform (ladder beam) support shall be erected according to the hoisting position of the rest platform (ladder beam) components.

used for hoisting shall be determined according to calculation and form technical text data.

The elevation of the bottom of the stair section shall be leveled at the ladder beam at the upper and lower openings of the ladder section.

The gap between the stair section and the rest platform shall be filled with C20 fine aggregate concrete and maintained.

Work after hoisting 1.

Two Hole Anchor

The layout of support points under the rest platform is shown in the figure below.

After the completion of stair hoisting, the installation quality shall be inspected and accepted, and the allowable deviation of installation shall comply with the provisions in the table below.

5 stair section hoisting 1.

The hoisting sequence shall be reasonably arranged according to the actual situation of the project.

Before the grouting between the precast rest platform and the joint between the stair section and the surrounding mechanism is completed, the temporary support under the rest platform shall not be removed to prevent the deviation of the horizontal position and grounding elevation of the rest platform.

Hoisting of the rest platform (ladder beam).

The support layout is mainly to determine the position of support points and the layout of support timbers.

In addition to steel pipe connection, embedded reinforcement is also used as connector on site, as shown in the figure below.

4.

The construction personnel shall hold the stair section to adjust the direction, align the side line of the stair section with the placement position line on the rest platform, and put it down stably and slowly.

The thickness specifications of steel sheets are divided into 1mm, 2mm and 5mm, and the elevation error shall not exceed 3mm.

Hinge connection installation: after the stair section is calibrated, use steel pipe to connect the reserved hole at the upper opening of the stair section with the reserved hole on the rest platform, as shown in the figure below.

After cleaning, the membrane shall be laid for protection to prevent other construction processes from polluting the gap.

During installation, 2cm gap shall be reserved between the rest platform and stair section and the connected wallboard or column to reserve space for mortar plastering layer.

4.

The connection position of the reserved hole between the stair section and the rest platform shall be filled with grouting material.

The precast parts are processed and manufactured in the factory according to the design drawings and cured to a certain strength.

After the bottom support of the rest platform is erected, the rest platform shall be hoisted.

After hoisting in place, the embedded parts shall be pulled out into the reserved holes of the shear wall (column), and then the bottom support shall be checked and adjusted according to the marked elevation control line and horizontal control line of the rest platform, as shown in the figure below.

(8) The concrete pouring of stair rest platform and ladder beam has been completed and reached the strength requirements specified in the design, and has been accepted and passed by the owner and the supervision unit.

During hoisting, the step plane shall be horizontal by adjusting the manual hoist to facilitate positioning.

Preparations before hoisting (1) on site technical management personnel and hoisting personnel shall learn the design drawings and deepening drawings of stairs, fully understand the design intent, and jointly review the drawings of stairs.

2.

(2) Determine the materials and mechanical equipment required for the hoisting of precast stairs, and use tower crane, truck crane or crawler crane according to the project conditions.

(6) Snap a + 1m horizontal line on the precast column and wall, determine the upper surface elevation of the rest platform in advance according to the + 1m horizontal line, and make obvious signs.

6 joint formwork grouting after the installation of two stair sections of each floor slab, the gap between the rest platform and the stair section, between the stair section and the surrounding wallboard or column can be formwork erected and fine aggregate concrete can be poured after the position and elevation are checked.

(7) Hoisting personnel (5-6 hoisting personnel per group, the number of groups shall be determined according to the progress requirements) have been trained and in place.

When the rest platform is fully precast and the stairs and rest platform are hoisted, the gap between the rest platform, stairs and the connected wallboard or column shall be cleaned.

Cushion blocks shall be placed between the overlapping position of the ladder beam and the ladder section, and the setting points of the cushion blocks shall be 2.

It is strictly prohibited to put it quickly and violently, so as to avoid the shock fracture and crack of the board surface caused by excessive impact force.

3.

(5) The specifications of slings, snap rings, rope buckles, etc.

The elevation shall be adjusted through the combination of steel sheets with different thickness to finally meet the requirements of the design elevation.

Formwork shall be erected for the gaps between components and between components and cast-in-situ parts, and then filled with mortar.

2.

The ladder section elevation shall be leveled at the overlapping position of the ladder section.

After the precast stair segments and precast rest platforms are transported to the site, they are hoisted and assembled on site according to the construction scheme; The supporting vertical pole at the bottom of the precast rest platform is fixed with triangular support frame, the precast rest platform is placed on the shear wall or frame column, and the precast stair section is placed on the precast rest platform, which is hinged between them.

4.

(3) Preparation of stair hoisting scheme and determination of stair hoisting technology.

(4) Before the hoisting construction, the stress calculation shall be carried out for various working conditions during the hoisting of precast stair section and precast rest platform (precast ladder beam), and the stress calculation shall also be carried out for the setting of support points to give a reasonable layout scheme.

Stair section hoisting: the precast stair section adopts horizontal hoisting.

When installing the stair board, pay special attention to the correct elevation, and then disconnect after correction.

(9) Relevant hoisting machinery and equipment have been mobilized and can be used normally after commissioning.

Correction: after it is basically in place, use a crowbar to fine tune the stair section until the position is correct and the rest is flat.

3.

The outer diameter of the steel pipe is slightly smaller than the hole diameter.

Stair hoisting process 1 positioning line marking of the rest platform (ladder beam) snap the upper side control line during the installation of the rest platform according to the shear wall or column + 1m line, and mark the horizontal control line of the rest platform according to the reserved holes and adjacent walls, as shown in the following figure.

After the installation of stairs, the step surface shall be protected in time to avoid step damage caused by construction..

There shall be no less than four support points, and the wooden square shall be placed on the support perpendicular to the long side of the rest platform, and the wooden square section shall not be less than 5cm × 5cm。 Preliminarily adjust the support height according to the height control line of the rest platform.

Fabricated stairs cast stairs (PC stairs) are composed of precast stair segments and precast rest platforms.