Program provides four options for the computation of bearing loads due to dead load from superstructure. This generation internally accounts for the pier view direction and then generates loads as per the view direction.

When generating loads for multiple column pier or hammerhead pier, any of the four available options can be used. However, for integral piers, it is recommended that either option 3 (input longitudinal reaction) or option 4 (import reaction from CIP RC/PT Girder) be used. This is important because integral/monolithic piers resist some moment imparted from the superstructure, which is not generated when first two options are used.

The first option uses the simple span distribution to compute bearing loads. For slab and girders you will specify material unit weight. The program will use the girder cross sectional area, bridge width and slab thickness and determine the load on each bearing location. For barriers, the load should be the total load for two barriers (when two barriers are present, one on each side.) The load from the slab, barriers and wearing surface is distributed among bearings based on each bearing/girder tributary width. If you want to distribute barriers differently, please specify loads as manual input.

The second option lets the user specify a computed superimposed DL reaction on the pier. If the pier supports double bearing lines, program first computes the load that will be supported by each line. If the spans supported by two bearings are not equal, user should change the factors for correct distribution of load between two bearings. For single bearing line, all loads are supported by the bearings on this line. Once total load to be supported by each bearing is computed, program then distributed this load among bearings using their corresponding tributary width. When this option is selected, user can still at the same time choose to generate girder and slab load based on simple span approach (this may be helpful for pre-stressed concrete superstructures made continuous). For steel bridges, the entire reaction can be specified including the slab and girder acting on composite and no slab or girder loads generated.

The third option lets user specify a computed superimposed DL reaction on the pier. If the pier supports double bearing lines, program first computes the load that will be supported by each line. If the spans supported by two bearings are not equal, user should change the factors for correct distribution of load among two bearings. For single bearing line, all load is supported by the bearings on this line. Once total load to be supported by each bearing is computed, program then distributed this load among bearings using their corresponding tributary width. When this option is selected, user can still at the same time choose to generate girder and slab load based on simple span approach (this may be helpful for pre-stressed concrete superstructures made continuous). For steel bridges, the entire reaction be specified including the slab and girder acting on composite and no slab or girder loads generated. When the pier type is integral, program distributes the input reaction equally to all girder location as cap loads.

The fourth option lets user read the composite dead load reactions from Precast/Prestressed Girder or CIP RC/PT Girder. In order to do that, you must first export the analysis results from within Precast/Prestressed Girder/CIP RC/PT Girder to a text file or be in a LEAP Bridge session. Afterwards, you can import that in Substructure. If flared girders are defined in Precast/Prestressed Girder, then user can only generate the dead loads if he exports the girder reaction from Precast/Prestressed Girder. Precast/Prestressed Girder computes separate reactions for DL and ADL and supplemental composite load on each pier. When imported into Substructure, program first determines total reaction and then distributes among bearing lines and bearings using a very similar approach explained earlier in this section for a manually input reaction. Please note that in Precast/Prestressed Girder, slab and girder loads act on simple span. For that reason, those are not imported. In this case, it is suggested that you generate the girder and slab loads within Substructure in addition to importing the reaction from Precast/Prestressed Girder. When the pier type is integral, the reactions from CIP RC/PT Girder can be imported. In a number of instances all permanent loads are lumped together and applied together as dead loads. Therefore when reactions are read from CIP RC/PT Girder, DC, DW, PT and shrinkage loads may be imported. Please see section, Import Reactions from CIP RC/PT Girder Screen.

If you have a continuous bridge and you generate loads using the simple span approach, you can apply a continuity factor to the dead load and live load generated by the program.