ULARC

[JohnNichols]

DO 211 N=1,NUMSFT
        Read (sr,*, end = 1005, err = 1005)N_DUM, AA(N), XI(N), YBAR(N), E(N),SKII(N),SKJJ(N),SKIJ(N),nsfsci(n),NSFSCJ(N)
        AA(N) = AA(N) * (1.0+0.05*R1A)
        XI(N) = XI(N) * (1.0+0.05*R1B)
        E(N) = E(N) * (1.0+0.05*R1C)
        write (sw,220)N,AA(N),XI(N),E(N),YBAR(N),SKII(N),SKJJ(N),SKIJ(N),nsfsci(n),nSFSCJ(N)
        
211 CONTINUE

210 FORMAT(I5,6F10.0,2I5)
215 FORMAT(/////' STIFFNESS TYPE TABLE'//' STIFF.',3X,'SECTION',2X,'MOMENT OF',3X,' YOUNGS    Y',6X,' STIFFNESS COEFFICIENTS' ,3X,'STRENGTH TYPES'/,' TYPE' ,3X,'    AREA' ,2X,'  INERTIA' ,2X,'   MODULUS',2X,'BAR',6X,'KII',5X,'KJJ',5X,'KIJ',5X,' END I  END J'//)
220 FORMAT(I4,2X,2E11.3,E11.3,1X,F5.3,2X,3F8.3,3X,I4,2x,I6)

    !
    !     SECTION STRENGTH TYPE TABLE
    !
    READ (sr,*, end = 1006, err=1006) (N,YMP(N),YMN(N),ROTCP(N),ROTCN(N),M=1,NUMCST)
    write (sw,240) (N,YMP(N),YMN(N),ROTCP(N),ROTCN(N),N=1,NUMCST)

ULARC developed by Powell's group at UCB in the late 1960s, is a good program for quick and dirty analysis.  I am using it to look at some quick and dirty problems in a place a long way away where there is limited information.  

I was making some minor amendments to look at Structural Reliablity problems, just playing, and I noticed for the first time the difference in the input method in line2 and line 19, one is wrapped in an external do loop and one in an internal do loop.   Will they generate equivalent assemby code?  

[JohnNichols]

Neat and thank you - a fun read, would have made an interesting textbook, a bit like my fluid mechanics in Physics 2. 

[jimdempseyatthecove]

Jim Dempsey

[JohnNichols]

 do M=1,NUMCST
        READ (sr,*, end = 1006, err=1006)N_dum,YMP(M),YMN(M),ROTCP(M),ROTCN(M),A2(m),A1(m),A0(m),LIMIT(m)

        write(sw,240)N_dum,YMP(m),YMN(m),ROTCP(m),ROTCN(m)
        write(sdd,245)N_dum,YMP(m),YMN(m),ROTCP(m),ROTCN(m)
        YMPStart(m) = YMP(m)
        YMNStart(m) = YMN(m)

        YMP(M) = YMP(M) * (1.0+(FPM*R1D))
        YMN(M) = YMN(M) * (1.0+(FPM*R1E))
        write (sdd,245)N_dum,YMP(m),YMN(m),ROTCP(m),ROTCN(m)
    end do

I fixed the error when you first found it.  

If you are doing Structural Reliability analysis, you have the standard equation,   Z = R - S.  where Z is the excess capacity, R is the capacity and S are the loads. 

Of course we do this the long way with design,  S is factored up to allow for the mean + some factor * standard deviation and the reverse for R. 

A program like Ularc is great for getting the ratio of R/S quickly and determining an overall lambda, the trick is to transform lambda into Z.  Two things that help, a stack of standard solved problems that can be done by hand and ULARC, and a extremely bright Russian stat professor, of the two they are about equal.

The problem is when R is a slowly decreasing function of time and people want to take heavier loads down the roads and bridge, so S is increasing. 

ULARC will do 100000 runs in a few minutes and give you Z, STRAND7 will do one in four hours and not give you Z. 

We can measure the change in frequency with time and hence change in stiffness.   

The usual bridge loses about 15 microHz/day and the bad bridges say 1000.  

So thanks again.

[jimdempseyatthecove]

>>The usual bridge loses about 15 microHz/day

!?

So if a bridge has a initial frequency of 1 second

is stays ringing for 66666.666 seconds?

Jim Dempsey

[JohnNichols]

Well, if it is a steel bridge with a first natural frequency of 1 Hz right now and the current loss rate is 15 microHz/day then it is 

0.005475 

Hz/year change multiply by the required years, say 80 => 0.4 Hz, knowing the traffic has quadrupled in intensity, the loss rate when new is probably close to zero, it is a parabola and you estimate the original frequency at 1.2 Hz.  The middle of the bridge has degraded more, and you can estimate the loss in stiffness with the harmonic equations, so the likely etc... pick a forward year to estimate the loss.

The problem is not 15 it is 1000+ 

If you have 4 million measurements, you have highly accurate means and stdevs. 

[JohnNichols]

The method uses thermal vibration, and it is based on a method developed by Kappler in 1934, which we can now apply to any structure. 

I would upload the text from him, but it is in German and whilst I read German most people do not, but it is funny all the things he had to deal with in his work.