On the countermeasures inclined tower crane

Because lead to uneven settlement of foundation tilt tower machine phenomena have occurred, does not meet the 4 ‰ verticality of the tower crane safety requirements, such as my company site QT60 a tower crane, lifting height of 40m, the concrete foundation of 5m × 5m × 1.3m,bridge gantry crane its quality Fh is 81.3t. In the non-working state, M = 218.3tm; Fh = 7.8t; Fυ = 108t. Some of its foundation backfill the south, due to heavy rain led to uneven settlement occurs based on measurable at 35m height, tilt to the south side of the 315mm.
      An initial stage of the tower crane tilt safety measures
Tower crane tilted vertical exceeds 4 ‰ safety requirements, they should immediately stop using it. Calculate the tower in the most unfavorable condition (non-operating state), the measurable height, to ensure the tower from tipping machine does the critical maximum inclination amount L. Note that regular observation tower machine tilt speed and the amount of tilt, and make a record. Once you reach the amount of tilt 0.5L, and continues to tilt, you need to take drastic measures such as demolition of the tower.
If the tower crane temporarily can not stop using it immediately, and the deflection of not more than 0.25L, you can take the following safety measures.
      1) based on the increase in the pressure of heavy concrete blocks (tilted in the opposite direction in the appropriate place some more),overhead gantry crane increase in base quality, lower center of gravity height and reduced tower crane e values.
      2) in the appropriate tower height position, additional devices attached to the wall.
      3) In the tower proper height position setting wind cable wire, to prevent tilting tower crane continue.
      2 tower crane tilt correction
Tilt tower machine stopped, in order to return to the verticality of the tower crane within 4 ‰, meet the safety requirements, it would take on the tower crane for correction.
      2.1 Corrective Steps
      A) the use of the principle of similar triangles to calculate the legs of the tower plus the required thickness of the pad.
      2) based on cross-sectional shape of the legs, on the need to top up the two legs to prepare six dimensions slightly larger than the cross-sectional shape of the contour gasket which four thick 6mm, 2 slice thickness of 1.5mm. As can be easily inserted into the gasket to the standard sections and between the legs, each piece can be broken down into four parts washer, Figure 1.
      3) Production lifting iron shoes shown in Figure 2. Iron shoes should be negative for lifting loads without deformation, can be easily mounted on a main limb in the standard section and the section with the standard can provide enough friction.
      4) Adjust the position or lifting the car horn a certain amount of load, so that the tower  bridge crane  balance, to ensure four legs under pressure.
      5) to be installed in the iron shoes of a standard section padded main limb on the standard section bolts loosen a pad thick (6mm) amount of clearance. Loosen both legs advances need to add another bolt, the bolt prestress neither, nor the amount of backlash.

      6) skid pad with a good jack, slowly lifting until the standard section and support legs appear 6mm gap amount, stuffed one (Figure 1, 1,2,3,4 of 4 parts) gaskets, this When the bolt should be no pre-stressed, no margin.
      7) Install the iron shoes to be added to the other side of the main limb pads standard section, and with the skid pad is good jacks, loosen the bolts to a 13.5mm amount of clearance, slowly lifting jacks until the standard section appears 13.5mm When the amount of backlash, into the three pads (6mm, 6mm, 1.5mm). At this point there should be no pre-stressed bolts, no margin.
      8) the iron shoes to install in the first section of the main criteria jacking limb, and add the remaining two spacers (6mm, 1.5mm).
      9) will have two legs padded bolts tightened to the specified preload, and then release the other side of the two legs one by one bolt, legs and if the gap between standard section appears, press Padded amount of backlash after the bolt is good.