Recently I am working on a transition bent which is a multi-column bent. The approaching span is simple span, and the main span is continuous-three-span. I am considering using the 3rd option for live load auto generation since the first two options (one for simple, the other for continuous) are not proper for my case.
Someone please teach me how to use this option 3~ See questions below~ THX
1. The red marked area
This input blocks are always inactivated?
2. The yellow marked area
What are the meanings for each input block? Why there are two trucks and lanes here? The moment input is caused by bearing centerline offset from cap centerline?
3. The blue marked area
What are the physical meanings of these factors?
I tried to find some introduction on this from help file, but I failed. Someone please help~
BIG THX
Let me try to answer one question at a time.
" 1. The red marked area
This input blocks are always inactivated? "
I'm not sure why it is inactivated , I tested in standalone and in Leap Bridge Enterprise in both the cases when I checked "Input already computed Reaction" the input boxes did got activated. So you can still use this option.
1) Run the analysis in Conspan or Conbox.
2) Export the RCpier reaction to a text file . Just note down the Max Truck and Lane load for Pier #1 from the text file.
3) Input the truck and lane load separately and then click on Generate button.
Answer Verified By: Dong Wang
On your second question :
" 2. The yellow marked area:What are the meanings for each input block?
Answer :The Integral Pier heading comes under "Import Superstructure Reaction" . User can import the Integral Pier reaction from Conbox to Rcpier using the IMPORT button or the user can manually input the values. Please see the attached screenshot for more information.
Truck --> Max Load : Maximum Vertical Reaction of Truck Truck --> Moment : Truck Moment Generated for Maximum Vertical Reaction. Lane --> Max Load : Maximum Vertical Reaction of Lane Lane --> Moment : Lane Moment Generated for Maximum Vertical Reaction.
Truck --> Load : Vertical Reaction of Truck for Max Moment Truck --> Max Moment : Truck Maximum Moment Reaction. Lane --> Load : Vertical Reaction of Lane for Max Moment Lane --> Max Moment : Lane Maximum Moment Reaction.
Why there are two trucks and lanes here? There are 2 trucks and lanes is because one if for Max Vertical reaction (truck/Lane) and other is just vertical reaction for Maximum Moment ( Truck / lane ) . Please see the above definition.
The moment input is caused by bearing centerline offset from cap centerline? "
On your third question for integral pier, girders are monolithic with the pier cap and their connection is considered to be at the centerline of the cap. In such pier, moment from the superstructure is also transferred to substructure along with vertical Loads. integral/monolithic piers resist some moment imparted from the superstructure. For detailed information please do refer our user manual.
On your third question
" 3. The blue marked area
What are the physical meanings of these factors? "
Answer :
The Physical meaning of these factors are basically dependent on if you are using Single line of bearing or Double Line of Bearing.
Let me try to explain by taking 2 examples.
1) Integral Pier / Single line of Bearing .
Generally there are no bearing for integral pier but for analysis and design purpose the program considers single line of bearing to transfer the load from superstructure to substructure . If you have continuous Box girder then there are cases wherein only single line of bearing is used.In such cases in order to distribute the superstructure reaction to the bearing the program automatically assigns Reaction factor, which is basically 1 for single line of bearing. But if the user wants to modify that then he/she can do that based on the project requirement. Please see the attached screenshot.
2) Two line of bearing .
If you have continuous Pre stressed I girders then generally 2 line of bearing is used. In such cases in order to distribute the superstructure reaction to the bearing the program automatically assigns Reaction factor, which is basically 0.5 for each line of bearing. Half of the reaction is distributed to one bearing line and the other half will be distributed to other bearing line. But if the user wants to modify that then he/she can do that based on the project requirement. Please see the attached screenshot.