At present, the steel plant are widely used in plant construction. Because of its short construction period, the construction process is relatively simple, low cost and other advantages, except for some special occasions, the steel plant is always preferred. And installation of reinforced concrete factory building cranes in different tests, steel crane inspection otherwise within the plant should pay attention to several issues.
A vibration, noise, sound, easy to loose coupling
Because steel plant vibration absorption effect is poor, crane operation, especially when running carts have a greater vibration and noise. Damping method is currently used in the crane rails and carts bearing rail beam diagonally into the rubber gasket between the pads.manual hoist These rubber pads can absorb vibration noise, but also regulate the level of rail carts levelness. However, this structure reduces the carts with the rail beam orbit coupling stiffness asked. In the crane truck operations, the rubber gasket compression and rebound the intermittent cause carts orbit coupling (eg orbit coupling plate, hook bolts, etc.) are more loose. In the inspection, found several inter-orbit coupling bolts loose carts or track hook bolts loose. Therefore, it is recommended to take the following measures when installing the track: (a) strictly control the height of the rubber gasket in the rail beam height difference between the larger, should be leveled using iron gaskets, rubber mat last; (2) on the bend hook bolt with a larger preload, compression rubber gaskets, increase joint stiffness, torque wrench should be used at the same time evenly distributed between rail fixing bolt preload; (3) using the double nut sturdy other more reliable anti- loose measure.
Two lateral stiffness of the rail and the beam instability
Steel plant bearing rail beam, the use of "I"-shaped self-contained steel surface, the rail beam itself fixed commonly used methods are as follows: the rail beam mounted on a steel column bracket on the lower edge of the beam plate with bolts and bracket connection, beam edge board through the plate and column connection. When the crane trolley or hanging objects swing longitudinally along the main beam, its large wheels to the rail through applying a lateral variation of the beam load; time if not enough lateral stiffness of the rail beam severe vibration occurred, or is not firmly fixed bearing rail beam and instability, the safe operation of the crane will be adversely affected. For some large span the rail beam, when the crane girder span in the rail when unloaded from the car, the brake will cause a greater bearing rail beam transverse vibrations. Currently crane rail beam inspection regulations Chengdui Cheng lateral stiffness is no clear standard requirements and the corresponding test methods, making inspection judgment difficult. Recommended test can be used when no load, the amount of 1.1 times the amount of load and load up under braking the car simply to authenticate the rail beam lateral stiffness.
3 crane girder stiffness measurement
Girder stiffness discrimination law traditionally used water level in the main beam span suspension ruler, ruler hanging under heavy preload, with the water level in the main beam were measured in the no-load and rated load corresponding cross tape readings, calculates Elastic deflection under the main beam main beam stiffness values to determine eligibility. In fact, the main beam in the amount of reading under load, both actual elastic deformation of the main beam, as well as the rail beam deformation, cart wheel assembly space, car assembly ask gap, cart track and trolley track deformation, deformation
lift hoist rope and so on. Plant for the installation of the concrete structure of the crane, the elastic deformation of the main beam other than said several larger, assembly gap and the track deformation is negligible; but the crane of steel plant, which the rail beam, in its amount of wheel load reduction will have a greater flexibility under torsion (measured about 2 ~ 3 mm), will be added to the crane girder deformation measurement values, resulting in large errors. Therefore, the conventional method to measure close to or exceeds the threshold value when the S/800 (S span of cranes), especially for the rail span crane beam span where a small tops should be considered under the rail resilient deflection of the beam . The following methods can be used to verify and then measured again: each of the two ends of the crane beam and the main beam span inside hanging in three scales, respectively,hoist equipment with heavy preload, with the water level were measured cranes at no load and rated load under The three gauge readings, and then calculate the amount set under the main beam deflection under actual elasticity values, l = H a (H1 + Day 2) / 2. Where day, H1, respectively, across the main beam, the left-side and right-side beam beam scale at no load and rated load down the reading difference.