Vertical load impact factor -- vertical impact load as percentage of max.
wheel load
From Table 2.1 of CISC Guide for the Design of Crane-Supporting Steel
Structures 2nd Ed, different operated type of crane has different impact
factor, ranging from 5% to 25%.
For Pendant operated crane, user can select 10%
For Cab operated crane, user can select 25%
User can select 25% if crane operated type is unknown.
From CISC Guide for the Design of Crane-Supporting Steel Structures
2nd Ed Table 2.1
