GB/T 30561-2014Cranes -- Stiffness -- Bridge and gantry cranes (English PDF)

Foreword

This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard uses redrafting method to adopt and modify ISO 22986.2007 "Cranes --

Stiffness -- Bridge and gantry cranes" (English version).

The technical differences between this Standard and ISO 22986.2007, and the reasons

therefor, are as follows.

- Regarding normative references, this Standard has made adjustments with technical

differences to adapt to Chinese technical conditions. These adjustments are

mainly reflected in Chapter 2 "Normative references." Specific adjustments are

as follows.

- Replace ISO 4306-1 with GB/T 6974.1, which is equivalent to ISO 4306-1;

- Replace ISO 4306-5 with GB/T 6974.5, which is equivalent to ISO 4306-5.

- Annex A includes a stiffness index formula (A.2) for the trolley located at the

effective cantilever length;

- In Annex A, Table A.1, it adds "Scope of application" and "Trolley position" to the

header, and adds "Mid-span" and "Effective cantilever length" to the "Trolley

position";

- Annex A includes Figure A.1, which shows the stiffness index of the main beam at

different positions of the crane trolley;

- In Annex B, the coefficient "0.4857" in the formula is changed to "0.492";

- An informative Annex C "Guidance values for minimum vertical natural

frequencies of bridge and gantry cranes" has been added. The dynamic vibration

of the entire crane, in addition to the main beam, shall also include the fully loaded

trolley, hoisting wire rope pulley blocks, lifting equipment, and hoisting load.

Annex B of ISO 22986.2007 only provides guidance values for minimum natural

frequencies for beams with free supports at both ends, and does not provide

guidance values for the minimum natural frequencies of the entire bridge and

gantry crane.

To facilitate use, the following editorial modifications have been made to this Standard.

- The description of delta1 in Figure 1 shall be changed to "the static deflection caused

by the self-weight load of the main beam minus the preset camber";

- Figure 1 is supplemented with illustrations to show the cases where the trolley is

located at the positions of maximum and minimum slope of the main beam,

Cranes -- Stiffness -- Bridge and gantry cranes

1 Scope

This Standard provides recommended values and requirements for the stiffness

characteristics of bridge and gantry cranes (hereinafter referred to as "cranes")

structures -- deflection and natural frequency.

2 Normative references

The following referenced documents are indispensable for the application of this

document. For dated references, only the edition cited applies. For undated references,

the latest edition of the referenced document (including any amendments) applies.

GB/T 6974.1, Cranes -- Vocabulary -- Part 1.General (GB/T 6974.1-2008, ISO

4306-1.2007, IDT)

GB/T 6974.5, Cranes -- Vocabulary -- Part 5.Bridge and gantry cranes (GB/T

6974.5-2008, ISO 4306-5.2005, IDT)

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 6974.1

and GB/T 6974.5 apply.

4 Requirements

5 Preset camber of main beam

The preset camber has no effect on the strength of the main beam and no specific

requirements need to be made.

To help meet the requirements of 4.2b), the slope range of the crane main beam (the

difference between the maximum and minimum slopes) can be divided into two parts

with approximately equal positive and negative values, or a preset camber method can

be adopted to reduce the maximum slope value (see Figure 1).

The slope of the main beam shall take into account the position of the unloaded trolley

that gives it the maximum slope. It shall take into account other possible unloaded

trolleys and their own weight loads.

Other possible reasons for the pre-set camber are the appearance requirements of the

crane or to compensate for certain permanent deformations of the welded main beam

after load testing.

6 Natural frequency of crane's main beam vibration