Live Load Case (Highway) [SIG]

General

Influence Surface: The influence surfaces defined in the previous section must be assigned to the Live Load case.

Max for Stress Range(Fatigue) [Yes/No]: If this is not a fatigue case, the maximum negative stress and maximum positive stress can be generated from different lane placements. However, when dealing with a fatigue case, a distinct methodology must be employed to calculate stress ranges from single lane placement. Please confirm by responding "Yes" if this is a fatigue case.

Multiple Presence Factor: Per AASHTO, the multiple presence factors are 1.2 for a single lane, 1 for two lanes, 0.85 for three lanes, and 0.65 for four lanes and more. For fatigue loads, use a single lane and select a multiple presence factor of 1, according to AASHTO 3.6.1.1.2.

Maximum Number of Lanes[No Limit/Number Of Lanes]: If no limit is imposed, the maximum number of lanes that can be placed in the transverse direction is based on the dimensions of the roadway. For instance, a 55-foot roadway can accommodate up to 4 lanes, with each lane measuring 12 feet. Generally, there should be no limit, but in some cases, such as fatigue or permit loads, restrictions may apply even if the roadway geometry allows for it. For fatigue trucks, a single lane should be used, and it is important to set the maximum number of lanes to 1 per AASHTO.

Design Lanes

Different placements can be made for each design lane, such as HL93 case, HL93 2 truck case, and HL93 tandem case. These options can be entered as Design Lane Option 1, 2, and 3, respectively.

Design Lane Option 1:

Design Lane Option 2:

Design Lane Option 3:

Design Lane Option 4:

Magnification Factors

The Advanced Influence Surface-Based Live Load (LL) Analysis supports the LADV-11 magnification factor table. This advanced feature includes a critical vehicle position-finding algorithm that dynamically incorporates the Magnification Factor Table. The table can account for variations based on span length and inflection points, ensuring a more precise analysis of live load effects across different structural configurations.

Magnification Factor for Fx (Pos): This parameter can be used to define the factor for positive Fx values.

Magnification Factor for Fy (Pos): This parameter can be used to define the factor for positive Fy values.

Magnification Factor for Fz (Pos): This parameter can be used to define the factor for positive Fz values.

Magnification Factor for Mx (Pos): This parameter can be used to define the factor for positive Mx values.

Magnification Factor for My (Pos): This parameter can be used to define the factor for positive My values.

Magnification Factor for Mz (Pos): This parameter can be used to define the factor for positive Mz values.

Magnification Factor for Fx (Neg): This parameter can be used to define the factor for negative Fx values.

Magnification Factor for Fy (Neg): This parameter can be used to define the factor for negative Fy values.

Magnification Factor for Fz (Neg): This parameter can be used to define the factor for negative Fz values.

Magnification Factor for Mx (Neg): This parameter can be used to define the factor for negative Mx values.

Magnification Factor for My (Neg): This parameter can be used to define the factor for negative My values.

Magnification Factor for Mz (Neg): This parameter can be used to define the factor for negative Mz values.