SOFiSTiK Forum

Which modul is the best way to dimensioning prestressed concrete (with creep and shrinkage). I try with AQB but it doesn't work property when I use EC2 as design.

Thank You!

AQB is the modul to deal with sections and has the most elaborated tretement of creep and shrinkage.

If your results are doubtfull, the most common error is to specify wrong humidity and/or age for first loading t0.

Otherwise please provide a detailed problem report to support@sofistik.de

Thanks!



For instance I create simple input for dimensioning!



+PROG AQB urs:376

HEAD Reinforcement

ECHO COMB

NORM EC



BEAM (1 100 1) CS0 1000 CS1 2001

LC TYPE G CST CS0 REF IDEA

LC TYPE P CST CS0 REF IDEA

LC TYPE C CST CS1 REF IDEA

LC 501 TYPE L CS1 REF IDEA



COMB MAXD MY LC1 G LC2 P LC3 C LC4 L

COMB MIND MY LC1 G LC2 P LC3 C LC4 L

COMB MAXD QZ LC1 G LC2 P LC3 C LC4 L

COMB MIND QZ LC1 G LC2 P LC3 C LC4 L

COMB MAXD MY LC1 G LC2 P LC3 L

COMB MAXD QZ LC1 G LC2 P LC3 L

COMB MIND QZ LC1 G LC2 P LC3 L



DESI STAT ULTI SMOD

COMB MAXR MY LC1 G LC2 P LC3 C LC4 L

NSTR S0 KSV SLD CRAC EC2 CW 0.2

END



The problem is…

AQB gives section forces for combinations of LC1, LC2 (originally prestressing force, without steel relaxation), LC3 (creep and shrinkage, steel relaxation), and LC4.





Section forces are zero (LC3) for creep and shrinkage, steel relaxation (statically determinate system), so the required reinforcement (EC2 design) is also zero…it’s relevant for serviceability.

But, steel relaxation underrates initially prestressing force. How to take it into consideration???

Thank You!