C FISSU     SOURCE    CHAT      05/01/13    00:01:48     5004           
C FISSU     SOURCE    INSL       24/10/96    
      SUBROUTINE FISSU(S1X,STRNX,TANG,RTM,PENT)
C
C         BETON FISSURE : COMPORTEMENT ADOUCISSANT
C                        ---> TENSION-SOFTENING
C
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8(A-H,O-Z)
C
      TANG=PENT
      S1X = RTM-PENT*STRNX     
      IF(S1X .LE. 0.D0) THEN
        S1X = 0.D0
        TANG = 0.D0
      ENDIF
C
C       ACTUALISATION DE LA RESISTANCE EN TRACTION
C
      RTM=S1X
      RETURN
      END