CSM Bridge Design AASHTO - Superpositioning

Description

The task CSM Bridge Design AASHTO - Superpositioning supports the input of combinations of transient actions acc. Table 3.4.1-1 AASHTO - 2014 in a tabular way.

The following combinations can be considered, with the number and the name of the limit state being fixed:

Number	Limit State	Description
1	STRENGTH I	Basic combination relating to the normal vehicular use of the bridge without wind.
2	STRENGTH II	Load combination relating to the use of the bridge by Owner-specified special design vehicles, evaluation permit vehicles, or both, without wind.
3	STRENGTH III	Load combination relating to the bridge exposed to wind velocities exceeding 55 mph.
4	STRENGTH IV	Load combination relating to very high dead load to live load force effect ratios in bridge superstructures.
5	STRENGTH V	Load combination relating to normal vehicular use of the bridge with wind of 55 mph velocity.
11	SERVICE I	Load combination relating to normal operational use of the bridge with a 55 mph wind and all loads taken at their nominal values. Also relating to deflection control in burried metal structures, tunnel liner plate and thermoplastic pipe, to control crack width in reinforced concrete structures, and for transverse analysis relating to tension in concrete segmental girders. This combination should also be used for investigation of slope stability.
12	SERVICE II	Load combination intended to control yielding of steel structures and slip of slip-critical connections due to vehicular live load.
13	SERVICE III	Load combination for longitudinal analysis relating to tension in prestressed concrete superstructures, with the objective of crack control and principal tension in the webs of segmental concrete girders.
14	SERVICE IV	Load combination relating only to tension in prestressed concrete columns with the objective of crack control.

Larger of the two load factors for action TU (force effect due to uniform temperature) acc. Table 3.4.1-1 needs to be taken into account when checking the deformations. Therefore, for each combination from the previous table an analogue type is available:

Number	Limit State	Number	Limit State
6	STRE_DEFO I	15	SERV_DEFO I
7	STRE_DEFO II	16	SERV_DEFO II
8	STRE_DEFO III	17	SERV_DEFO III
9	STRE_DEFO IV	18	SERV_DEFO IV
10	STRE_DEFO V

The following transient actions are supported by the task:

Action	Description	Action	Description
BL	Blast loading	LL	Vehicular live load
BR	Blast loading	LS	Live load surcharge
CE	Vehicular centrifugal force	PL	Pedestrian live load
CT	Vehicular collision force	SE	Force effect due to settlement
CV	Vessel collision force	TG	Force effect due to temperature gradient
EQ	Earthquake load	TU	Force effect due to uniform temperature
FR	Friction load	WA	Water load and stream pressure
IC	Ice load	WL	Wind on live load
IM	Vehicular dynamic load allowance	WS	Wind load on structure

Note

Each cell in the task’s columns “Action 1-10” contains a drop-down list of the allowed actions. The list will only show actions, which loadcases have been previously calculated.

Additionally, Combinations 4 and 9, i.e. STRENGTH IV and STRE-DEFO IV, require a modified value of the safety factor for the dead load of structural components and nonstructural attachments. Therefore, the allowed list of actions for these two combinations also includes the actions D_1 and D_2, i.e. structural dead load and nonstructural components, and only if the corresponding load cases have been previously calculated (usually with CSM Construction Manager).