Moving Load Cases
Use the entered vehicle load classes and the traffic lanes to create moving load cases. Define type of vehicle, number of lanes, and the method to be used in moving load analysis
From the Main Menu select Load > Moving Load > Moving Load Cases.
To enter
new or additional moving load cases
Click
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.
To modify
previously entered moving load cases
Select
the moving load case to be modified in the dialog box and click
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.
To delete
previously entered moving load cases
Select
the moving load case to be deleted in the dialog box and click
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.
Data
entry method when is
clicked.
When AASHTO Standard is selected from Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Multiple Presence Factor
Enter the scale factors for multi-lane vehicle loads.
AASHTO specifies 1.0 for loading up to two lanes, 0.9 for loading 3 lanes and 0.75 for loading 4 lanes or more.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
To
enter new or additional vehicle load class
Click .
To
modify previously entered vehicle load cases
Select the vehicle load case
to be modified in the dialog box and click .
To
delete previously entered vehicle load cases
Select the vehicle load cases
to be deleted in the dialog box and click .
Data
entry method when is clicked. [Details]
Load
Case Data
Vehicle Class
Select the vehicle load class or directly enter the vehicle load.
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Scale Factor
Enter the scale factor for the application of the vehicle load class.
Min. Number of Loaded Lanes
Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes
Enter the maximum number of lanes to be loaded by the vehicle load class.
Note
The maximum and minimum numbers of loaded lanes must be
smaller than the number of selected lanes.
Assign
Lanes
Select the lanes to be loaded by the vehicle load class.
Assign the lanes to be loaded
by the vehicle load class in the traffic lane list with
the mouse and click .jpg){kind=small}
to select. If previously selected lanes are to be removed
from the selection, assign the lanes with the mouse and
click .jpg){kind=small}
to delete.
Note
The number of lanes selected to be loaded is limited to
10.
When ‘Moving Load Optimization’ is selected:
Multiple
Presence Factor
Enter the scale factors for multi-lane vehicle loads.
AASHTO specifies 1.0 for loading up to two lanes, 0.9 for loading 3 lanes and 0.75 for loading 4 lanes or more.
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog. 4 ft is recommended as per AASHTO Standard.
Load Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Min. Number of Vehicles
Enter minimum number of vehicles to be loaded within the carriageway width.
Max. Number of Vehicles
Enter maximum number of vehicles to be loaded within the carriageway width.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicles. If more than two vehicles are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in a Moving Load Case, then this function does not consider the cases where different vehicles are applied simultaneously.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
Example: To find the critical results between HS20-44 and HS20-44L
When
AASHTO LRFD is selected
from Moving Load Code.
Load
Case Name
Enter the moving load case name.
Description
Enter the description of the moving load case
Multiple Presence Factor
Enter the scale factors for multi-lane vehicle loads.
AASHTO LRFD specifies 1.2 for loading up to one lane, 1.0 for two lanes, 0.85 for 3 lanes and 0.65 for 3 lanes or more.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
To
enter new or additional vehicle load class
Click .
To
modify previously entered vehicle load cases
Select the vehicle load case
to be modified in the dialog box and click .
To
delete previously entered vehicle load cases
Select the vehicle load cases
to be deleted in the dialog box and click .
Data
entry method when is clicked. [Details]
Load
Case Data
Vehicle Class
Select the vehicle load class or directly enter the vehicle load.
Scale Factor
Enter the scale factor for the application of the vehicle load class.
Min. Number of Loaded Lanes
Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes
Enter the maximum number of lanes to be loaded by the vehicle load class.
Note
The maximum and minimum numbers of loaded lanes must be
smaller than the number of selected lanes.
Assign
Lanes
Select the lanes to be loaded by the vehicle load class.
Assign the lanes to be loaded
by the vehicle load class in the traffic lane list with
the mouse and click
to select. If previously selected lanes are to be removed
from the selection, assign the lanes with the mouse and
click to delete.
Note
The number of lanes selected to be loaded is limited to
10.
Note
When midas Civil envelops maximum and minimum results, two
design truck scenario is considered for the negative moment
and reaction only. In other words, although the maximum shear
or axial force effects are found under two truck loading,
midas Civil will disregard them and present the force effects
from a single truck scenario. For example, if a single truck
results in the maximum axial force -240 kips and double trucks
result in the maximum axial force of -450 kips, midas Civil
will report -240 kips in the min/max envelope results.
When ‘Load Case for Permit Vehicle’ is selected:
Load Case for Permit
Vehicle
Select this option if Permit Vehicle is defined from AASHTO LRFD Code User Define option. When this option is selected the dialog box changes to a number of input fields for Permit Vehicle.
Permit
Vehicle
Vehicle
Choose the vehicle to be used. The user can only choose the vehicle that has been defined as Permit Vehicle Type.
Ref. Lane
Select the reference lane to provide the location where Permit Vehicle travels.
Eccentricity
Input the distance of the Permit Vehicle to the Ref. Lane. By looking towards the direction the vehicle travels, the right side is considered positive and the left side is considered negative.
Scale factor
Enter the scale factor for the application of the vehicle loads.
When ‘Moving Load Optimization’ is selected:
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog. 4 ft is recommended as per AASHTO LRFD specification.
Load Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Min. Number of Vehicles
Enter minimum number of vehicles to be loaded within the carriageway width.
Max. Number of Vehicles
Enter maximum number of vehicles to be loaded within the carriageway width.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicles. If more than two vehicles are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in a Moving Load Case, then this function does not consider the cases where different vehicles are applied simultaneously.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
When Canada
is selected from Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Multiple Presence Factor
Enter the scale factors for multi-lane vehicle loads.
CAN/CSA SA-06 specifies 1.0 for loading for one lane, 0.9 for loading 2 lanes, 0.8 for loading 3 lanes, 0.7 for loading 4 lanes, 0.6 for loading 5 lanes and 0.55 for loading 6 lanes or more.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
To
enter new or additional vehicle load class
Click .
To
modify previously entered vehicle load cases
Select the vehicle load case
to be modified in the dialog box and click .
To
delete previously entered vehicle load cases
Select the vehicle load cases
to be deleted in the dialog box and click .
Data
entry method when is clicked. [Details]
Load
Case Data
Vehicle Class
Select the vehicle load class or directly enter the vehicle load.
Scale Factor
Enter the scale factor for the application of the vehicle load class. It is recommended that scale factor should not be used for taking into account dynamic load allowance as it is taken as per the code by midas Civil, automatically.
Min. Number of Loaded Lanes
Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes
Enter the maximum number of lanes to be loaded by the vehicle load class.
Note
The maximum and minimum numbers of loaded lanes must be
smaller than the number of selected lanes.
Assign
Lanes
Select the lanes to be loaded by the vehicle load class.
Assign the lanes to be loaded
by the vehicle load class in the traffic lane list with
the mouse and click
to select. If previously selected lanes are to be removed
from the selection, assign the lanes with the mouse and
click to delete.
Note
The number of lanes selected to be loaded is limited to
10.
Note
It is
recommended that scale factor should not be used for taking
into account dynamic load allowance as it is taken as per
the code by midas Civil, automatically.
When ‘Moving Load Optimization’ is selected:
Multiple
Presence Factor
Enter the multiple presence factors as per CSA S6-14.
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog. 1.2 m is recommended as per CSA S6-14.
Load
Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Min. Number of Vehicles
Enter minimum number of vehicles to be loaded within the carriageway width.
Max. Number of Vehicles
Enter maximum number of vehicles to be loaded within the carriageway width.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicles. If more than two vehicles are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in a Moving Load Case, then this function does not consider the cases where different vehicles are applied simultaneously.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
Example: To find the critical results between CL-625 Truck and CL-625 Lane.
When
BS is selected form Moving
Load Code
Standard Load (BD37/01, BS5400)
Auto Live Load CombinationIn the case of HA&HB(Auto), combination of the live loads is automatically organized based on the selected code. Partial factors for HA and HB loads are applied in the moving load analysis. Thus, partial factors for live loads should be 1.0 in the load combination. In the case of HA, HB or HA&HB, this option should be checked off and partial factors for live loads are not taken into account in the moving load analysis. Thus, partial factors specified in the code should be applied in the load combination.
Type
of Design Combination FactorSelect a limit state to determinate load factors to be applied to the moving load analysis results.
Ultimate Limit State: Applies the load factor at ultimate limit state
Serviceability Limit State: Applies the load factor at serviceability limit state
Combination
of LoadsSelect a combination to determinate load factors to be applied to the moving load analysis results.
Combination 1: Applies the load factor for combination 1
Combination 2 or 3: Applies the load factor for combination 2 or 3
Sub
Load Case When Vehicle is HA&HB (Auto)
If a number of Sub-Load Cases are defined in a Load Case, Min/Max result values from all the Sub-Load Cases are generated. That is, analysis is separately performed for each Sub-Load Case, and the Sub-Load Cases are not combined for analysis.
Load Case Data
Scale Factor: Enter the scale factor for the application of the vehicle loads.
Number of Loaded Lanes: Enter the number of lanes to apply for Moving Load Cases. The selected lanes and the number of lanes inputted should be the same.
Vehicles: Enter the type of vehicle to consider for Moving Load Cases
Assign Lanes
Assign the selected vehicles to lanes
List of Lanes: Displays the list of lanes
Selected Lanes: Select the lane
HB Straddling Two Lanes: Select the two adjacent lanes on which HB loading shall occupy any transverse position. To use this function more than two Cross Beam Type lanes should exist.
When Vehicle is HA, HB, HA&HB, Pedestrian.
Load Case Data
Scale Factor: Enter the scale factor for the application of the vehicle loads.
Number of Loaded Lanes: Enter the number of lanes to apply for Moving Load Cases. The selected lanes and the number of lanes inputted should be the same.
Vehicles: Enter the type of vehicle to consider for Moving Load Cases
Assign Lanes
Assign the selected vehicles to lanes
List of Lanes: Displays the list of lanes
Selected Lanes: Select the lane
HB Straddling Two Lanes: Becomes activated only in the case of HA&HB(Auto)
-
Auto
Live Load Combination
The application of combined SV/SOV and HA vehicle is automatically organized based on the BD 86/11. In order to apply SV/SOV without HA, this option should be checked off.
Type
of Design Combination FactorSelect a limit state to determine partial factors to be applied to the moving load analysis results. In this case, partial factors for moving load case should be entered as 1.0 in the load combination.
Ultimate Limit State: Applies the partial factor at ultimate limit state
Serviceability Limit State: Applies the partial factor at serviceability limit state
Combination
of LoadSelect a combination to determinate partial factors to be applied to the moving load analysis results.
Combination 1: Applies the partial factor for combination 1
Combination 2 or 3: Applies the partial factor for combination 2 or 3
Load Case DataStandard Load: Select HA vehicle.
Special Load: Select SV or SOV load model.
Assignment
LanesList of Lanes: Display all the lanes defined.
Selected Lanes: Select the lanes on which HA or SV or SOV will be applied.
Straddling Lanes: Select the two adjacent lanes on which SV or SOV shall occupy any transverse position. Straddling lanes are supported only for the ‘Cross Beam’ type as a vehicle load distribution.
CS 454 Assessment (ALL Model 1)
In this version, applying ALL model 1 alone is supported. Combination of ALL model 1 and special vehicle will be available in the next release.
Load Case DataALL Model 1 Load: Select a vehicle corresponding to ALL model 1.
Assignment LanesSelect lanes to be applied to find the most unfavorable effect.
Selected Lanes: Select lanes where ALL model 1 is applied.
Remaining Area for UDL Load: Select lanes where UDL of 5 kN/m2 is applied. Once ALL model 1 is defined in the Vehicle dialog box, it is not necessary to define any vehicle corresponding to UDL which will automatically be applied to the lanes selected as remaining area.
CS 454 Assessment (ALL Model 2, Special Load)
Auto
Live Load CombinationCheck on to automatically apply partial factors (gamma_fl) for the combined ALL model 2 and special vehicle.
Check off to get assessment results (adequacy factor, reserve factor) for the special vehicle alone. The appropriate partial factor for live load can be applied in the 'Rating>Load Combination for Assessment' menu.
Type of Design Combination
FactorSelect a limit state to determine partial factors to be applied to the live loads.
Ultimate Limit State: Applies the load factor at ultimate limit state
Serviceability Limit State: Applies the load factor at serviceability limit state
Combination of LoadsSelect a combination to determine partial factors to be applied to the live loads.
Combination 1: Applies the load factor for combination 1
Combination 2 or 3: Applies the load factor for combination 2 or 3
Assignment LanesSelect lanes to be applied to find the most unfavorable effect.
Selected Lanes: Select lanes where ALL model 2 is applied.
Straddling Lanes: Select two lanes where a special vehicle straddles within the two lanes. When more than one set of straddling lanes are selected, the program finds only one set of straddling lanes which will give the worst effect. The 'Straddling' option is only activated for the auto live load combination.
When ‘Moving Load Optimization’ is selected:
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog. For HB loads and special vehicles, only one vehicle is applied on the carriageway at the same time. Thus, 0 m is recommended for HA loads as per BS.
Load
Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Number of Loaded Lanes
Enter the number of lanes to apply for Moving Load Cases.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
Example: To find the critical results for the combined HA and AB.
Note. Optimization with ALL model 1
Optimization with ALL model 1 is not fully automatic. The location of remaining area should be defined by the user and the optimization
will be performed for the area left. Here are the recommended steps to follow:
1. Create moving load case 1 (without optimization) for remaining area only.
2. Create moving load case 2 (with optimization) for the optimization area.
3. Combine two moving load cases using load combination.
When
EUROCODE
is selected from Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Load Model
When Vehicle is LM 1, FLM 1/ Footbridge
Load Case DataVehicle: Select the vehicle to be used. The user can only choose Load Model 1 or FLM 1.
Footway: Select the Footway uniform load to be used. The footway load can be specified in Load tab > Moving Load > Vehicles > Add Standard > EN 1991-2:2003 Footway and FootBridge > Uniform load (Road bridge footway).
Ignore ψ FactorCheck on to neglect ψ factor. If the traffic load is considered as Leading Variable Action in the load combination as per Eurocode 0, the moving load case for which the Ignore ψ factor option is checked on will be used. In this case, the ψ factor entered for the vehicle used in the corresponding load case will not be used. (That is ψ factor is considered as 1.)
Assignment
LanesList of Lanes: Display the list of defined lanes.
Selected Lanes: Select the lane to be loaded by the vehicle load.
Footway Lanes: Select the lane to be loaded by the footway uniform load.
Remaining Area: Select the lane to be used as the Remaining Area as set forth in Eurocode.
When Vehicle is LM 2,3,4 / FLM 2,3,4 / Footbridge / Permit Truck
VehicleSelect the vehicle to be used. The user can only choose Load Model 1 or FLM 1.
Ignore ψ FactorCheck on to neglect ψ factor. If the traffic load is considered as Leading Variable Action in the load combination as per Eurocode 0, the moving load case for which the Ignore ψ factor option is checked on will be used. In this case, the ψ factor entered for the vehicle used in the corresponding load case will not be used. (That is ψ factor is considered as 1.)
Sub-Load CasesEnter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect: Assign the method of combining vehicle loading conditions.
Combined: If more than two vehicle classes are assigned in a Sub-Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Sub-Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
To enter new or additional vehicle load class, click
and enter
the following data.To modify previously entered vehicle load cases, select the vehicle load case to be modified in the dialog box and click
.To delete previously entered vehicle load cases, select the vehicle load case to be deleted in the dialog box and click
.Load Cases DataVehicle Class: Select the vehicle load class.
Min. Number of Loaded Lanes: Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes: Enter the maximum number of lanes to be loaded by the vehicle load class.
Assignment LanesSelect the lanes to be loaded by the vehicle load class.
List of Lanes: Display the list of defined lanes.
Selected Lanes: Select the lane to be loaded by the vehicle load.
Assign the lanes to be loaded by the vehicle load class in the List of Lanes with the mouse and click
to select. If previously selected lanes
are to be removed from the selection, assign the lanes
with the mouse and click to delete.-
This load case considers the combined placement of Load Model 1 vehicle and Load Model3 vehicle. The simultaneous placement of LM1 and LM3 vehicles is done with the clearance prescribed in the Eurocode and is shown below: These LM3 vehicles cannot straddle between the lanes so only the longitudinal clearance in a particular lane is taken care of in this load case.
Simultaneous placement of LM1 and Standard LM3 special vehicles
Ignore ψ FactorCheck on to neglect ψ factor. If the traffic load is considered as Leading Variable Action in the load combination as per Eurocode 0, the moving load case for which the Ignore ψ factor option is checked on will be used. In this case, the ψ factor entered for the vehicle used in the corresponding load case will not be used. (That is ψ factor is considered as 1.)
VehicleLM1: Only Load Model 1 can be selected.
LM3: Only the Standard Load Model 3 can be selected.
Assignment LanesList of Lanes: Display the list of defined lanes.
Selected Lanes: Select the lane to be loaded by the vehicle load.
Remaining Area: Select the lane to be used as the Remaining Area as set forth in Eurocode.
When Vehicle is LM1 & 3 Multi (Straddling)
Selecting the Load model:-LM1 and Special multi, a load combination corresponding to the Load Model 1 and LM3(Special) is defined. These straddling vehicles have been discussed in Eurocode vehicles in EN 1991-2:2003 - Road Bridges as Load model3 Special vehicles. This load Model will consider the combined effect of LM1 and Special LM3 vehicles in which the LM3 vehicle can straddle between the lanes with a defined longitudinal spacing from the LM1 vehicles as shown below.The longitudinal placement is taken care of in the program. The transverse clearance of the straddling vehicle from the kerbs should be taken care of manually by the user.
Longitudinal placement of LM1 and LM3(SV/SOV)
Transverse placement of LM1 and LM3(SV/SOV)
The details of the input data is described below:
Ignore ψ FactorCheck on to neglect ψ factor. If the traffic load is considered as Leading Variable Action in the load combination as per Eurocode 0, the moving load case for which the Ignore ψ option is checked on will be used. But if the traffic load is considered as Accompanying Variable in the load combination then the Load case corresponding to the one in which ψ is not ignored will be considered. To have all the required load combinations as per Eurocode 0, both the load cases should be made. The value of ψ is input in the definition of the vehicles.
Load Case DataLM1:Here only LM1 can be selected which will be placed along with the straddling vehicle.
LM3(Special):Here only the straddling vehicles( LM3 SV/SOV) can be selected. The non-straddling LM3 vehicles can not be selected here.
Assignment LanesList of Lanes: All the lanes specified by the user in the model will be displayed here.
Selected Lanes: From the list of displayed lanes, using
the lanes on which the vehicle load
will be applied are selected.Straddling Lanes: From the list of selected lanes, using
the pair of lanes in which the LM3(SV/SOV)
can straddle are specified.Note: Only adjacent lanes should be selected for a straddling lanes group. For accurate results one lane should be a part of one straddling lane group i.e. the lane composition for two straddling lane groups should be different.
Remaining Area: Select the lane to be used as the Remaining Area as set forth in Eurocode.
Note 1
In the program the straddling nature of the vehicle is considered by different horizontal placements of Straddling vehicle on the two lanes which have been defined in the straddling lanes group and the placement giving the maximum effect is displayed. In the program several lanes are defined in the combined width of two lanes. The image below shows the centre lines of the lanes being considered for the straddling vehicle placement on one side of the centre line of combined width of two lanes.
Placement of vehicle in two lanes
In the image above the vehicle can straddle in adjacent Lane A and Lane B. The bold black lines represent the wheel spacing edges for Lane A and Lane B. The different lanes considered for the placement of the vehicle are
Centre line of Lane A is donated as Lane1 CL.
Lane 2 CL: Centre line of Lane 2 is at the centre line of combined width of Lane A and Lane B
Lane 3 CL : Centre line of Lane 3 is midway between the Lane 1CL and Lane 2 CL
Lane 4 CL : Centre line of Lane 4 is located midway between the Lane 1 CL and Lane 3 CL.
Similarly the lanes definition is considered on the other side of the center line of the combined width of the two lanes i.e. Lane 2 CL.
Note 2
When the straddling vehicle placement is visualized using the Moving Load Tracer, the transverse wheel spacing is same as defined in the lanes definition. But this is not the actual transverse wheel spacing corresponding to the straddling vehicles. The transverse wheel spacing for straddling SV and SOV as defined in UK National Annex is shown below:
The transverse wheel spacing for LM3 SV 100(same for other SVs ): 2.65m centre-centre.
The transverse wheel spacing for LM3 SOV vehicles.
On conversion of a vehicle placement in Moving Load Tracer to a static vehicle placement using
.jpg)
in moving Load tracer( refer to Moving
Load Tracer), the vehicle with the above shown transverse
spacings can be considered.When Vehicle is Railway Bridge
Define Moving Load Case dialog box (when Railway bridge is selected)
Ignore ψ1 FactorThe combination factor, psi1 can be considered in the moving load analysis by checking off the Ignore psi1 Factor option as the values of psi1 factor depend on the number of loaded lanes. In case this option is checked on, the psi1 factor will not be applied to the moving load analysis, which means that psi1 factor is considered as 1.
Note
The psi1 factor can take value as 0.8 or 0.7 or 0.6 depending on the number of loaded lanes. For the number of loaded lanes greater than 3, a value of psi1 - 0.6 is applied. The psi1 value is reflected on the vehicle loads while the psi0 value is reflected when the load combinations are generated using Auto Generation function (Refer to Combinations for more details on the combination generation).
Multiple Presence FactorEnter the scale factors for multi-lane vehicle loads. This factor will be applied for the LM71 and SW/0 rail models depending on the number of loaded lanes.
Note:For the determination of the most adverse load effects from the application of Load Model LM71 and SW/0, these load models shall be applied to any one track, any two tracks or 0.75 times the load model to three or more tracks.
Sub-Load CasesEnter the loading method and the traffic lanes to be loaded by the vehicle load class in a moving load case.
Loading Effect: Assign the method of combining vehicle loading conditions.
Combined: If more than one vehicles are assigned in the Sub-Load Cases, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in the Sub-Load Cases, then this function does not consider the cases where different vehicles are applied simultaneously.
To enter new or additional vehicle load class, click
and enter
the following data.To modify previously entered vehicle load cases, select the vehicle load case to be modified in the dialog box and click
.To delete previously entered vehicle load cases, select the vehicle load case to be deleted in the dialog box and click
.Load Cases DataVehicle: Select the vehicle load class.
Min. Number of Loaded Lanes: Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes: Enter the maximum number of lanes to be loaded by the vehicle load class.
Assignment LanesSelect the lanes to be loaded by the vehicle load class.
List of Lanes: Display the list of defined lanes.
Selected Lanes: Select the lane to be loaded by the vehicle load.
Assign the lanes to be loaded by the vehicle load class in the List of Lanes with the mouse and click
to select. If previously selected lanes
are to be removed from the selection, assign the lanes
with the mouse and click to delete.
When ‘Moving Load Optimization’ is selected:
Ignoreψ
Factor
Check on to neglect ψ factor. If the traffic load is considered as Leading Variable Action in the load combination as per Eurocode 0, the moving load case for which the Ignore ψ option is checked on will be used. But if the traffic load is considered as Accompanying Variable in the load combination then the Load case corresponding to the one in which ψ is not ignored will be considered. To have all the required load combinations as per Eurocode 0, both the load cases should be made. The value of ψ is input in the definition of the vehicles.
Load Case Data
LM1: Here only LM1 can be selected which will be placed along with the straddling vehicle.
LM3 (Special): Here only the straddling vehicles (LM3 SV/SOV) can be selected. The non-straddling LM3 vehicles cannot be selected here.
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog. For LM3 or special vehicles, only one vehicle is applied on the carriageway at the same time. Thus, 1 m is recommended for LM1 loads as per Eurocode.
Assignment
Lanes
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Num. of Loaded Lanes
Enter the number of lanes to apply for Moving Load Cases.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
Note: In Civil 2018 (v1.1), the remaining area for LM1 vehicle is not included in the moving load optimization. For now, it is recommended to define a lane separately for the remaining area and locate it on the carriageway and select the lane into the ‘Remaining Area’ box. This will be improved in a future release.
Example: To find the critical results for the combined LM 1 and LM 3 (Special vehicle).
When Australia
is selected from Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Select Load Model
General: Select General to apply AS 5100.2 Road Traffic Loads (M1600, S1600, etc), AS 5100.2 Pedestrian and Bicycle Path Loads or AS 5100.7 Rating Vehicles (T44, L44).
Fatigue: Select Fatigue to apply AS 5100.2 Road Traffic Fatigue Loads, i.e. A160, M1600 without UDL.
Heavy Load Platform: Select Heavy Load Platform to apply AS 5100.2 Heavy Load Platform, i.e. HLP 320, HLP 400.
Rail Traffic Load: Select Rail Traffic Load to apply AS 5100.2 Rail Traffic Loads, i.e. 300LA, 150LA.
1) When General or Fatigue is selected:
Accompanying Lane Factor
Enter the scale factors for multi-lane vehicle loads. If more than one lane is loaded, the A160, M1600, S1600 or M1600 tri-axle load applied to the additional lanes will be multiplied by the accompanying lane factors.
AS5100.2 specifies 1.0 for the loaded lane giving the largest effect, 0.8 for the loaded lane giving the second largest effect, 0.4 for the loaded lane giving the third largest effect.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
To enter new or additional vehicle load class
Click .
To
modify previously entered vehicle load cases
Select the vehicle load case
to be modified in the dialog box and click .
To
delete previously entered vehicle load cases
Select the vehicle load cases
to be deleted in the dialog box and click .
Data
entry method when is clicked. [Details]
Load
Case Data
Vehicle Class
Select the vehicle load class or directly enter the vehicle load.
Scale Factor
Enter the scale factor for the application of the vehicle load class.
Min. Number of Loaded Lanes
Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes
Enter the maximum number of lanes to be loaded by the vehicle load class.
Note
The maximum and minimum numbers of loaded lanes must be
smaller than the number of selected lanes.
Assign
Lanes
Select the lanes to be loaded by the vehicle load class.
Assign the lanes to be loaded
by the vehicle load class in the traffic lane list with
the mouse and click
to select. If previously selected lanes are to be removed
from the selection, assign the lanes with the mouse and
click to delete.
Note
The number of lanes selected to be loaded is limited to
10.
2) When Heavy Load Platform is selected:
Type of Load Factor for Design Combination
Load factors for design road traffic loads specified in AS 51000.2 will be applied to each loading. Thus, load factors should be entered as 1.0 for the moving load case in the load combination.
Ultimate Limit State: Moving load analysis results will be multiplied by load factors as follows.
Heavy Load Platform (HLP): 1.5
Half of SM1600 traffic load in unobstructed lanes when applied in conjunction with HLP loading: 1.8
Serviceability Limit State: Moving load analysis results will be multiplied by load factors as follows.
Heavy Load Platform (HLP): 1.0
Half of SM1600 traffic load in unobstructed lanes when applied in conjunction with HLP loading: 1.0
Unobstructed Lane Scale Factor
For bridges with three or more standard design lanes, the unobstructed standard design lanes will be loaded with half of either M1600 moving traffic load or the S1600 stationary traffic load to create the worst effect.
Load Case
Data
Heavy Load: Select Heavy Load Platform.
M1600 or S1600: Select M1600 or S1600 or None. If None is selected, only Heavy Load Platform will be applied.
Assignment Lanes
Min. Number of Loaded Lanes: Enter minimum number of lanes loaded M1600 or S1600.
Max. Number of Loaded Lanes: Enter maximum number of lanes loaded M1600 or S1600.
List of Lanes: Display all the lanes defined.
Selected Lanes: Select the lanes on which M1600 or S1600 will be applied.
Heavy Load Lanes: Select the two adjacent lanes on which Heavy Load Platform will be applied.
The HLP 320 and HLP 400 heavy load platform shall be positioned within two standard design lanes. The Heavy Load Platform shall be positioned up to 1.0 m laterally from the center of two standard design lanes to create the worst effect. Note that these two lanes should be adjacent and the two lanes should not be away from each other. The two adjacent lanes should meet each other at the boundary lines of the lane width.
3) When Rail Traffic Load is selected:
Multiple Track Factor
When loading a number of tracks simultaneously, the multiple track factors shall be used. Enter the multiple track factors.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
When ‘Load Case for Permit Vehicle’ is selected:
Load Case for Permit Vehicle
Select this option if Permit Vehicle is defined from User Define Vehicles. When this option is selected the dialog box changes to a number of input fields for Permit Vehicle.
Permit
Vehicle
Vehicle
Choose the vehicle to be used. The user can only choose the vehicle that has been defined as Permit Vehicle Type.
Ref. Lane
Select the reference lane to provide the location where Permit Vehicle travels.
Eccentricity
Input the distance of the Permit Vehicle to the Ref. Lane. By looking towards the direction the vehicle travels, the right side is considered positive and the left side is considered negative.
Scale factor
Enter the scale factor for the application of the vehicle loads.
When ‘Moving Load Optimization’ is selected:
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog.
Load Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Min. Number of Vehicles
Enter minimum number of vehicles to be loaded within the carriageway width.
Max. Number of Vehicles
Enter maximum number of vehicles to be loaded within the carriageway width.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicles. If more than two vehicles are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in a Moving Load Case, then this function does not consider the cases where different vehicles are applied simultaneously.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
When India is selected from Moving Load Code
Load
Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Auto Live Load Combination
Check on this option to define the Live Load Combinations according to the clause 207.4. of IRC: 6-2000. Check off this option for a user-defined Live Load Combination.
Multiple Presence Factor
Enter the scale factors for multi-lane vehicle loads.
Number of Loaded Lane
Enter the number of lanes to be loaded by the vehicle load class. This option will be activated only when Auto Love Load Combination option is selected.
Sub-Load Cases
• When Auto Live Load Combination is selected
(When the Number of Loaded Lanes is '1')
Scale factor
Enter the scale factor for the application of the vehicle loads.
Number of Loaded Lanes
Vehicle Class Selection
-Class I: The user can select either Class A, Class B or user-defined wheeled vehicles.
Footway Loading
Enter the load which will be applied to the remaining width of the carriageway when the number of loaded lanes is 1.
(When the Number of Loaded Lanes is more then '2')
Scale factor
Enter the scale factor for the application of the vehicle loads.
Number of Loaded Lanes
Vehicle Class Selection
-Class I: The user can select either Class A, Class B or user-defined wheeled vehicles.
-Class II: The user can select either Class AA, Class 70R, Class 40R or user-defined wheeled/tracked/bogie vehicles.
• When Auto Live Load Combination is not selected
Scale Factor
Enter the scale factor for the application of the vehicle load class.
Min. Number of Loaded Lanes: Enter the minimum number of lanes to be loaded by the vehicle loading.
Max. Number of Loaded Lanes: Enter the maximum number of lanes to be loaded by the vehicle loading.
Vehicle: All of the defined vehicles can be selected.
Note
If more than two vehicle classes are assigned in a Sub-Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
• Load Case for Permit Vehicle
Select this option if Permit Vehicle is defined. When this option is selected the dialog box is changed to a number of input fields for Permit Vehicle.
Vehicle
Choose the vehicle to be used. The user can only choose the vehicle that has been defined as Permit Vehicle Type.
Ref. Lane
Select the reference lane to provide the location where Permit Vehicle travels.
Eccentricity
Input the distance of the Permit Vehicle to the Ref. Lane. By looking towards the direction the vehicle travels, the right side is considered positive and the left side is considered negative.
Scale factor
Enter the scale factor for the application of the vehicle loads.
To enter new or additional vehicle
load class
Click .
To modify previously entered vehicle
load cases
Select the vehicle load case to be
modified in the dialog box and click .
To delete previously entered vehicle
load cases
Select the vehicle load cases to
be deleted in the dialog box and click .
When Russia
is selected from Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When 'Independent' is selected, we can check the envelope results for each vehicle class. When 'Combined' is selected, we can check the envelope results for the combinations of each vehicle class.
To enter new or additional vehicle load class,
click
.
To modify previously entered vehicle load cases,
select
the vehicle load case to be modified in the dialog box and
click .
To delete previously entered vehicle load cases,
select
the vehicle load cases to be deleted in the dialog box and
click .
Data entry method when
is clicked.
[Details]
Load Case DataVehicle Class
Select the vehicle load class or directly enter the vehicle load.
Scale Factor
Enter the scale factor for the application of the vehicle load class.
Min. Number of Loaded Lanes
Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes
Enter the maximum number of lanes to be loaded by the vehicle load class.
Note
The maximum and minimum numbers of loaded lanes must be smaller than the number of selected lanes.
Assign LanesSelect the lanes to be loaded by the vehicle load class.
Assign the lanes to be loaded by the vehicle load class in the traffic lane list with the mouse and click
to select. If
previously selected lanes are to be removed from the
selection, assign the lanes with the mouse and click
to delete.Note
The number of lanes selected to be loaded is limited to 20.
When Poland is selected
from Moving Load Code
Load
Case Name
Enter the moving load case name.
Description
Enter the description of the moving load case
Select Load Model
Select one of the vehicle type.
Vehicle S / Vehicle 2S / Permit Type
Vehicle K Type
Military Load Type
Sub-Load Cases
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading Effect: Assign the method of combining vehicle loading conditions.
Combined: If more than two vehicle classes are assigned in a Sub-Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Sub-Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
To enter
new or additional vehicle load class, click
and enter the following data.
To modify
previously entered vehicle load cases, select the vehicle
load case to be modified in the dialog box and click .
To delete
previously entered vehicle
load cases, select the vehicle load case to be deleted in
the dialog box and click .
Load Cases Data
Vehicle Class: Select the vehicle load class.
Min. Number of Loaded Lanes: Enter the minimum number of lanes to be loaded by the vehicle load class.
Max. Number of Loaded Lanes: Enter the maximum number of lanes to be loaded by the vehicle load class.
Assignment
Lanes
Select the lanes to be loaded by the vehicle load class.
List of Lanes: Display the list of defined lanes.
Selected Lanes: Select the lane to be loaded by the vehicle load.
Assign the
lanes to be loaded by the vehicle load class in the List of
Lanes with the mouse and click to select.
If previously selected lanes are to be removed from the selection,
assign the lanes with the mouse and click
to delete.
When ‘Load Case for Permit Vehicle’ is selected:
Load
Case for Permit Vehicle
Select this option if Permit Vehicle is defined from User Define option. When this option is selected the dialog box changes to a number of input fields for Permit Vehicle.
Vehicle
Choose the vehicle to be used. The user can only choose the vehicle that has been defined as Permit Vehicle Type.
Ref. Lane
Select the reference lane to provide the location where Permit Vehicle travels.
Eccentricity
Input the distance of the Permit Vehicle to the Ref. Lane. By looking towards the direction the vehicle travels, the right side is considered positive and the left side is considered negative.
Scale factor
Enter the scale factor for the application of the vehicle loads.
When ‘Moving Load Optimization’ is selected:
Optimization
Min. Vehicle Distance
Enter the minimum vehicle distance in the transverse direction. The minimum distance between vehicles is determined as the larger between ‘Min. Vehicle Distance’ and ‘2 times margin’ entered from the ‘Moving Load Optimization’ dialog.
Load Case Data
Loaded Lane
Select a carriageway defined in the ‘Moving Load Optimization’ dialog.
Min. Number of Vehicles
Enter minimum number of vehicles to be loaded within the carriageway width.
Max. Number of Vehicles
Enter maximum number of vehicles to be loaded within the carriageway width.
Loading Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicles. If more than two vehicles are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicles are applied simultaneously.
Independent: Apply the vehicles independently. If more than two vehicles are assigned in a Moving Load Case, then this function does not consider the cases where different vehicles are applied simultaneously.
Assignment Vehicle
Selected Vehicle: Select a vehicle to be applied for the moving load optimization.
Scale Factor: Scale factor for vehicle loads
When South
Africa is selected from Moving Load Code
NA/NB/NC Type
Load
Case Data
Select
a corresponding vehicle defined in Vehicles option.
Assignment
Lanes
Assign the selected
vehicles to lanes
List
of
Lanes: Displays the list of lanes
Selected
Lanes: Select the lane
NC
+ 2/3 NA Type
Load
Case Data
Select a corresponding NC and NA vehicle
defined in Vehicles option.
Assignment Lanes
Assign
the selected vehicles to lanes
List of
Lanes: Displays the list of lanes
NC Lanes:
Select the lane for NC vehicle
NA
Lanes: Select
the lane for NA
vehicle
User Defined (Sub-Load Cases)
Enter the loading method and the traffic lane to be loaded by the vehicle load class in a moving load case.
Loading
Effect
Assign the method of combining vehicle loading conditions.
Combined: Combination of vehicle classes. If more than two vehicle classes are assigned in a Moving Load Case, then this function considers all combinations, including the cases where different vehicle classes are applied simultaneously.
Independent: Apply the vehicle classes independently. If more than two vehicle classes are assigned in a Moving Load Case, then this function do not consider the cases where different vehicle classes are applied simultaneously.
Note
When
'Independent' is selected, we can check the envelope results
for each vehicle class. When 'Combined' is selected, we can
check the envelope results for the combinations of each vehicle
class.
Moving
Load Optimization
Moving Load Optimization is only applicable for NA, NB and User Defined vehicles.
Note
Each
vehicle type acts individually (i.e., NA, NB and NC can’t
act together). NA can be applied to multiple notional lanes
at the same time but NB and NC loads could be applied to only
one lane at a time in the carriageway.
When
Transverse
is selected from the Moving Load Code
Load Case Name
Enter the name of a moving load case.
Description
Enter the description of the moving load case.
Vehicle
Select the vehicle for analysis. In case of inputting a vehicle that has not been defined, click on [...] tab and define any vehicle load.
Scale Factor
Enter the scale factor for the application of the vehicle load class.
Line Lane
Select the lane to be analyzed.
Multiple Presence Factor
Enter the scale factors for multi-lane vehicle loads.
A1. Theoretically, the maximum possible moment due to a group of wheel loads does not occur at the center of simple span. We can find the location of maximum possible moment in the simple span by applying two things.
1. The maximum possible moment will occur at the wheel load which is closest to the resultant load of group of wheel loads. In case where the amount of the wheel load closest to the resultant load is small, the maximum possible moment can occur at the second closest wheel load. In your case, the group of loads consists of just two wheel loads with the same amount. If we denote it as P1 and P2, the closest wheel load can be either P1 or P2. If we take the closest wheel load as P1, the maximum possible moment will occur at P1.
2. If we denote the distance between the closest wheel load (P1) and the resultant load (R) as ‘d’, the location of P1 which causes the maximum possible moment will be d/2 away from the center of span as shown below.
