10, To prevent the vertical and horizontal deflection while the gantry crane is lifting the box-girder, also requiring the maximum deflection angle of no more than 2.

11, The crane spreader installation should be done by hand pulling on the bit. When the bottom of the poles approach the surface of the box girder, slowly decline the spreader in low speed, manual traction the boom aims for the holes for lifting the girder.

Note: If the boom does not fall into the holes for lifting girder, or already fell into the holes and be struck. Prohibit continue to fall the spreader. In this case it will cause rope loosen and slip from the pulley slot.

The steel rope prolapses from the pulley slot can cause serious consequence. The occurrence of the above mentioned situations require operator or command staff immediately check the rope. After the spreader has installed well, ensure that the spreader and rope are in a vertical state. And each boom is in the stress state, meanwhile they are in the state of stress simultaneously, and it will damage the concrete around the lifting beam holes.gantry crane

12, When the crane are lifting the concrete box girder from the girder pedestal, ensure that the beam has torn off from the side and bottom of the template. There is no adhesion between the concrete girder and template or other additional vertical loading. While lifting the girder, guarantee the spreader and steel rope are in perpendicular state. Lift it slowly with the low-speed gear to avoid the beam violent shaking to damage the template.

Note: It is very dangerous that the steel rope can not follow the direction of the rope on the drum groove and compact arranged orderly or the steel rope prolapse from the pulley slot. Therefore somebody required to be on the top working platform to observe the order condition of steel rope when the crane is working. At the same time, the operating and directing staff should check and guarantee the two aspects well before allowing the machine operating.

13, Continue to fall the hook after the spreader has contacted the concrete girder of the ground. The installed spreader should be lifted but declined by misusing. The two above-mentioned situations will cause loose rope or prolapse from the pulley groove which is strictly prohibited matter. In case it happens like the description, an immediate stop to inspect the steel rope situation.

The operation can continue to carry on when the pulley slot has restored the normal condition.

14, In order to guarantee the beam-lifting construction safety, prevent causing the partial extrusion when lifting the box girder from the beam pedestal to damage the girder flange or the template.

Given the possibility of the above-mentioned situations exists, it needs to take the following measures to prevent accidents:

a, Before lifting the concrete box girder, the gap between the flange module and concrete girder should be larger than 5cm.

b, Do the complete test for the spreader before installation.

c, Check the perpendicularity of the installed hook and spreader.

d, Ensure that the steel rope is in the tension state before hoisting the box girder. The spreader must paste densely on the concrete girder.

e, Take advantage of the 4-lifting hook linkage, adopt the slow lifting in low speed gear.

f, While beginning to lift the girder, the specific personnel must be on the winch or both sides of the girder to observe the lifting hook. The personnel need to maintain the effective communication with the operator. Terminate the lifting action once the irregularities happen.

g, If finding a lifting hook doesn’t work or rise slowly, stop it immediately and resolve it before restarting. In the 500cm scope that the girder lifted from the beam pedestal, keep the girder hoisted in the horizontal level. Effectively avoid the edge and bottom of the girder contacts with the side module.