LL Response

The live load response is calculated based on influence line loading algorithms.

The truck is moved forward and backward over the entire length of the bridge.

The lane load is placed on positive or negative patches of the influence line - only for one-lane bridges. It is applied over a width equal to the carriage way width (less than 5.3 m) subtracted by 2.3 m.

Impact	The impact factor can be specified by the user or calculated by the program according to the specifications. The user-specified impact factor can be only one value for the entire bridge. The program-calculated values are based on the code equations, i.e.,IRC6:211.
Distribution Factors	Refer to Loads/Analysis Tab section in the General Operations chapter.
Live Load Response	The truck and lane responses are combined to obtain the total response due to the live load. Each live load can have any number of trucks and only one lane load.
Deflection	All live load deflection responses are calculated by loading deflection influence lines. The vertical deflection and the rotation are adjusted by the following factors: T-beam bridges: The reaction factor. Slab bridges: Bridge width / governing effective width of slab. Box bridges: Live load effect increase factor specified in Loads/Analysis.
Forces	Live load forces (shear, axial, moment) are obtained by loading the force influence lines and applying the appropriate impact and reaction factors.
Stresses	All live load stresses are obtained by calculating the force enveloped (axial and moment) and calculating the stresses from them by using the cross section properties at the POI. Stresses are calculated based on maximum and minimum axial and moment and corresponding values.
Reactions	All live load reactions are calculated by using loading reaction influence lines. Reaction factors are used for vertical and moment reactions.