Eriksson Girder automatically computes the self-weights of the beam and deck slab. These loads are computed based on the cross sectional area and concrete density of each. The load types in this dialog box are externally-applied loads.

For convenience, dead load is divided into non-composite and composite types. In the case of a bridge with no composite slab, the group box surrounding the composite loads will dim, indicating that those loads will be applied to the non-composite section.

Non-Composite

Loads that act on the bare precast section (or on the bare precast section + transformed strands if “Transform steel” was checked in the Analysis Options dialog box).

Self-Weight Multiplier

Eriksson Girder computes the self-weight of the bare beam based on the area of the precast beam and density of the concrete. This value is then multiplied by the self-weight multiplier to arrive at the effective girder weight with units of either KLF or kN/m. The default value of the self-weight multiplier is 1.0, which implies that the full self-weight of the girder is to be used. Entering a value less than 1.0 means that less than the full self-weight of the girder will be considered. Entering a value greater than 1.0 means a value of self-weight greater than what is calculated by the program will be used. A typical case where a value greater than 1.0 might be used is where there is additional girder concrete that is not reflected in the area of the cross section, such as a series of internal diaphragms in a box beam. In such a case, if there are several evenly spaced diaphragms, the equivalent additional self weight of the diaphragms can be computed as the diaphragm weight divided by the diaphragm spacing. That weight should them be added to the default beam self-weight and the result divided by the default self weight to arrive at the effective self-weight multiplier.

Diaphragms

Diaphragms are modeled as point loads at the sections selected.

Weight

If at least one diaphragm location is checked, then the diaphragm weight edit box will be enabled. All diaphragm loads are assumed to be equal to this value. 

Weight Multiplier

An optional multiplier used to scale up or down the weight analysis results.

Location

Four possible locations may be specified for diaphragms: L/4, L/3, L/2, and one user-specified location., where L is the design span (measured from the centerlines of bearings). If L/4 or L/3 is checked, then symmetric diaphragm loads will be placed at L/4 and 3L/4, and at L/3 and 2L/3. Symmetric loads are also assumed for the user-specified location. However, if L/2 is checked, only a single point load will be placed at midspan of the beam.

Composite

Composite loads are those loads that act on the fully composite section. If the deck includes an (optional) overlay, then all composite loads act on the full composite section, except the weight of the overlay itself, which acts on a composite section consisting of the beam, haunch, and deck.

Barriers

The barrier load is that portion of the total weight of the barriers that is assigned to the girder under design. The barrier load can be entered as a constant value or as a variable quantity. If entered as a variable quantity, select one of the methods available. Equal distribution means the total barrier weight is computed (number of barriers x weight per barrier) and distributed equally to all girders. The variable method is useful for situations when the number of girders in the bridge cross section can vary. When load tables are generated, the variable option should be enabled.

Future Wearing Surface

Future wearing surface load. A fixed amount can be assigned to the girder or the amount can vary according to two different methods. If entered as a variable quantity, select one of the methods available. For the Beam Spacing case, the pressure entered is converted to a linear load by multiplying the pressure by the girder spacing. For the Curb to Curb method, the assigned pressure is multiplied by the curb to curb width and then divided evenly to all girders.  When load tables are generated, the variable option should be enabled.

Additional Dead Load

Additional dead load can be entered as point load or line load.