Check Crack Control for Flexure at Service Loads

 

 

Check crack control of PSC girder at the service loads. For the non-composite box girders, crack control is checked for the top and bottom of the girder. For the precast composite sections, the bottom of the prestressed beam and the top of the slab are checked.

Check the rebar stresses in the slab of composite section under negative moment at service loads. Slab crack control as per clause 8.6.1 of AS 5100.5 is provided for PSC composite beams.

Table Tool in midas Civil offers a variety of powerful built-in functions. Refer to Usage of Table Tool for detail directions.

 

 

 

From the Main Menu select PSC > PSC Design Result Table > Check Crack Control for Flexure at Service Loads .

 

 

 

Upon executing the PSC Design Result Table > Check Crack Control for Flexure at Service Loads

  • Check control for flexure at service (Girder): Crack control checked for the bottom of girder

  • Check control for flexure at service (Slab): Crack control checked for the top of the Slab

Refer to Usage of Table Tool and check the following data:

Elem: Element number

Part: Check location (I-End, J-End) of each element

Top/Bottom: At top of element, at bottom of element

LCom. Name: Load combination name.

Type: Displays the set of member forces corresponding to moving load case or settlement load case for which the maximum stresses are produced. If they are not defined then this field is left blank(-). By default, member forces due to moving load case or settlement load case are not concurrent. In order to consider the concurrent member forces, namely, Fx, Fy, Fz, Mx, My and Mz each having its MAX and MIN value, the program computes FT, FB, FTL, FBL, FTR, FBR for all these twelve sets of concurrent forces.

CHK: Check result

ft: Combined Stress due to bending moment about major axis (My) and axial force at Top fiber

fb: Combined Stress due to bending moment about major axis (My) and axial force at Bottom fiber

s: rebar centre-to-centre spacing

s_max: maximum spacing for transverse shear reinforcement

fs: the stress of tensile reinforcement

fsa: allowable reinforcement service load stress for crack control

ft_PL: stress at top surface (Permanent Load)

fb_PL: stress at bottom surface (Permanent Load)

ft_LL: stress at top surface (Live Load)

fb_LL: stress at bottom surface (Live Load)

fcp: compressive strength of concrete at transfer

 

Elem: Element number

Part: Check location (I-End, J-End) of each element

LCom. Name: Load combination name

Type: Displays the set of member forces corresponding to moving load case or settlement load case for which the maximum stresses are produced. If they are not defined then this field is left blank(-).

Sigma_src: Calculated rebar stress

f_scr: Maximum stress limit in the rebar of the slab.

 

Note. Slab crack control to AS5100.5: 2017

 

Slab crack control is based on Clause 8.6.1 provided for PSC Composite Beams. Load Effect considered for two cases:

a) SLS Load Combination

b) For Beams designed for exposure classifications B2, C1, C2, and U, permanent effects at the SLS. Rebar stress limit based on Table 8.6.1 (A), (B).