ISO 8686-4:2005 pdf download – ranes – Design principles for loads and load combinations 一 Part 4: Jib cranes.
4.2 Simultaneous accelerations
In general, the effects of two accelerating drives. e.g. travelting. traversing, slewing or luffing or telescoping. are assumed to act simultaneously with hoisting acceleration: only two drives are assumed to accelerate simultaneously in the absence of hoisting. Stewing inertia force with the accompanying centrifugal force shad be considered as otis load effect in this context However, no simultaneous accelerations shall be considered iMien specthcalty prevented by design features.
4.3 Side loading
Certan design features may have the effect o( inducing side loading on js. When those features are present Wi a design, they shall be included with al applicable load combinations for which calculations are performed, combined so as to maximize side loading. In addition to stewing and wind effects, an example of a feature affecting side loading would be a reeving arrangement that causes the host line to deviate from the j centrebne.
4.4 Emergency actions
4.4.1 Manually initiated actions
For manual emergency stops, caused by engaging an emergency stop controL calcidations shall be corned
out under emergency cut -out on line 16 of Table I or Table 2.
4.42 AutomatIcally Initiated actions
When jib cranes are fixnished with controls or devices that cut out &tves and apply brakes under emergency condeions without an rwtiating action by the dnver, or are furnished with brakes that automatically engage on loss of power or control function, calculations reflecting those effects shall be caTied out under emergency cut-out on line 16 or fa4ure oImechansrns on Ins 17 of Table 1 or Table 2.
5 Loads from acceleration of crane drives
5.1 Hoisting effects
Inertial effects due to hoisting, except for hoisting an urwestrained grounded load (see ISO 8686-1:1989, depend on the change In hoist drive force s.F. The change in force shall be cculated from hoist dnve or brake characteristics using the highest drive/brake torque actualy generated by the system.
5.2 Effects from other than hoist drives
In practice, acceleration and deceleration rates can vary depending on the attachment fItted, the operating radais. the control scheme employed, and the chactenstics of the drive and braking mechanisms. For proof-of-competence calculatIons. the changes In dnve forces F causing acceleration or deceleration shall be calctdated from the highest drive/brake torque actually generated by the systeni
5.3 Application of changes in drive force, AF
The values of AF for hoisting e amplified by an appropriate value for (see ISO 8686-1:1989. Table 1) taken from Table 3 to male up the load for use on line 5 of Table 1 or Table 2.
The values of F for dnves other than holstlng are amplified by an appropriate value for 5 talcen from Table 3 to make up the load for use on line 4 of Table 1 or Table 2.
6 Proof-of-competence calculations for steel structures
6.1 General
Proof-of-competence catadations shal be carried out ustg either the allowable stress method or the limit
state method, see ISO 8686-1 –
6.2 Allowable stress method
Table 1 gives loads and load combinations for the allowable stress method together with pbcabIe alowable stress coefficients and damc aniplification factors 4. Table 3 gives vthin for the factors Ø and other pertinent load wifcmiabo& Table 4 describes the motions that are to be combined, in consideration of Clause 4, and the conditions to be included within the load combinations listed m Table 1.
For members under axial compression, the ellowable stress coefficients j ven in Table I are applicable only when used m conjunction with a cdumn formula selected m accordance with Annex A.
6.3 Limit state method
Table 2 gives loads and load combinations for the limit state method together with appicable partial bad factors and dynamic ampkfication factors Ø,. Table 3 gives velues for the factors and other perttient load information. The resistance coefficient y,,, shal be ten as ii for ad load combinations. The limi strength shall be divided by 7m to reflect statasticel vanabons ii material strength and locel imperfections. Table 4 descnbes the motions that are to be combined, In consideration of Clause 4, and the conditions to be included vAthm the load combinaticns bsted In Table 2.
For members under axial compression, the resistance coefficient Tm and the partial load factors y, ven in Table 2 are applicable only when used in conjunctmn with a cobimn formida selected ii accordance with Annex A.