2.1 Beam Cross-Section

Vertically offsetting sections upwards towards midspan can be used to simulate an arched or haunched soffit.

2.3 Concrete Materials

The user can also specify whether the precast concrvete is flowable (i.e. self-consolidating concrete) or steel-fibre reinforced.

Hollow-Core Fill

The weight of the fill is accounted for in the load analysis but not considered to be composite with the section and does not carry any prestress or add to the composite section. The fill is only considered effective in resisting transverse shear.

2.4.3 ShoringThe cast-in-place pour (CIP pour) can be placed with the beam shored so that it's weight is carried by the composite section. The weight of the beam can also be jacked so that it is also carried by the composite section, as in thin slab construction.

The "Beam Shored During Cast-in-Place Pour" option has the effect of causing the weight of the cast-in-place pour and the DL (before CIP) to be carried by the composite section. This would be the case if shoring was placed tight to the underside of the erected beam without it carrying any of the beam's weight. The additional "Shoring is Jacked or Wedges to Carry Beam Weight" option has the effect of causing the beam's weight, as well as the CIP pour, to be carried by the composite section. The eccentric effects of any prestressing are also restrained by the composite section. This additional option is intended for thin-slab prestressed construction or non-prestressed beams which have a downward deflection at erection if not shored (including the effect of any prestress camber). The shoring is assumed to hold the erected beam in a neutral position (zero stress due to self-weight).

2.5 Simulating ContinuityYou may be able to simulate continuous beams in Concise Beam using one of two approaches.

The first approach, which is appropriate for semi-continuous beams (continuity formed by a cast-in-place deck), is to consider a single span and add fixed end moments to the continuous end. This requires an external analysis to get the fixed end moments. You also need to anchor the continuity steel at the end of the beam to avoid having a development length. The example file "Continuity Example - Fixed End Moments.con" in your Problem Files directory quickly illustrates this approach.

The second approach, for continuous precast beams, is to apply interior prop loads (negative point loads) where the interior supports would be. In each load case you will need to add prop loads of sufficient magnitude to give an immediate deflection of zero at the support for that load case. You can balance the prestre

ss camber and beam weight together in the Beam Weight (additional) load case. You find the prop load through iteration by guessing at the prop load, looking at the immediate deflections, and then adjusting the prop load, etc. The long term deflections for prestress and beam weight will be a bit off since each load has a different long-term deflection modifier. Also adding a prop load to the Beam Weight load case will throw off the transfer and lifting stage results. You'll need a different model for them. The example file "Continuity Example - Prop Load.con" in your Problem Files directory quickly illustrates this method.

2.7.1 Material

If the CPCI curve is used the maximum usable strand stress is limited to 0.98 fpu.