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PGSuper™ Known Problems
No matter how hard we try, no software is perfect. In order to keep you informed of problems that might effect your designs we publish this list of known problems. However, we don't stop here. Interim (or preview) updates to the software are published as quickly as possible to provide you with the latest enhancements and fixes. Be sure to check out the download area to get the latest version of the software.

Topic: Span by span girder spacing
Version: 2.8
Date: July 17, 2014
Version Corrected: 2.8.1
Description:

When girder spacing is defined span-by-span, the spacing information at the start and ends of the span will be switched each time the Span Details window is closed.

This problem only occurs if editing of the span details is initiated by either double clicking on the span or selecting Edit > Span from the menus.

This problem does not occur when editing the span details from the Framing tab of the Bridge Description window.

Resolution:

This issue will be fixed in the next release of PGSuper.

Edit span-by-span girder spacing through the Bridge Description window.


Topic: Warning for PGSuper users upgrading to Windows 8.1
Version: 2.7.4
Date: January 10, 2014
Description:

There was a bug in the PGSuper Version 2.7.4 installer published prior to November 20, 2013 that prevents PGSuper from being installed or uninstalled from Windows 8.1.

If you downloaded and installed PGSuper Version 2.7.4 prior to November 20, 2013, you must uninstalled the software prior to upgrading your computer to Windows 8.1

If you downloaded and installed PGSuper Version 2.7.4 after November 20, 2013 you will not be afflicted by this problem.

Resolution:

If you downloaded and installed PGSuper Version 2.7.4 prior to November 20, 2013 and you are upgrading your computer to Windows 8.1 follow these steps to get around the problem:

  1. Uninstall PGSuper before upgrading to Windows 8.1
  2. Install Windows 8.1
  3. Download and install the latest version of PGSuper. (DO NOT USE THE INSTALLER PACKAGE DOWNLOADED PRIOR TO 11/20/2013)

If you have already upgraed to Windows 8.1 and cannot uninstall or update PGSuper open a command window as Administrator and download the latest version 2.7.4 installer run the following command

msiexec /fv PGSuper_2.7.4.msi

This will repair the installation and replace the installer package cached by Windows with the corrected installer package.


Topic: Problem computing maximum shear when the live load vehicle is longer than the structure
Version: 2.5.2
Date: December 09, 2011
Description: For the vary rare cases when the live load vehicle is longer than the bridge length, and the heaviest axles are at the rear of the vehicle, the maximum live load shear is not computed correctly.
Resolution:

This issue will be resolved in PGSuper Version 2.5.3

As a temporary work around, create a user defined vehicle that consists of the only axles that are known to produce the maximum shear. Ensure that this vehicle is shorter than the bridge length. Envelope the results of this vehicle with the other design live loads. It is also prudent to validate these live load results with an independent calculation.


Topic: Service III Tension Stress computed incorrected when analysis method is "Envelope"
Version: 2.5.0
Date: August 16, 2011
Version Corrected: 2.5.1
Description: The service III tension stress is computed incorrectly when the analysis method is "Envelope". The service III tension is computed correctly for Simple Span mode and Simple Span Made Continous Mode. An updated version will be released this week (8/15/2011). In the interm, it is suggested that you use Simple Span mode.
Resolution: This problem was correct in Version 2.5.1 (8/17/2011)

Topic: Live Load Deflections
Version: 2.4.2
Date: January 18, 2011
Version Corrected: 2.5
Description:

The bridge stiffness, EI, for the Optional Live Load Deflections Check is computed incorrectly in some situations. This may result in live load deflections that are incorrect. Also, the deflections that are reported are for a full lane of live load and not for a girder.

For bridges where different girder types are used in each span, or when a different number of girders is used in each span, the overall stiffness of the bridge cross section is computed incorrectly. The stiffness in the first span is generally used and this is incorrect.

The live load distribution factor that should be used is (multiple presence factor)(number of design lanes)/(number of girders). The comparison of the allowable live load deflection and the computed live load deflection is based on a full lane of live load. That is, the live load distribution factor is not applied.

Resolution:

To correct the live load deflections by hand:

  1. Compute the correct EI for the full bridge section.
  2. Compute the live load distribution factor as (multiple presence factor)(number of design lanes)/(number of girders)
  3. Compute the correct live load deflection by multiplying the deflection reported by PGSuper by the live load distribution factor and the ratio of (bridge EI reported by PGSuper)/(correct bridge EI).

This calculation has been fixed in version 2.5.


Topic: Incorrect minimum moment capacity computed for negative moments
Version: 2.3
Date: May 12, 2010
Version Corrected: 2.3.1
Description: When evaluating minimum reinforcement for LRFD 5.7.3.3.2 for negative moment, PGSuper uses the full negative moment for Mu (girder + slab + traffic barrier + live load, etc). The correct negative moment is that from superimposed dead loads and live loads after continuity.
Resolution: Version 2.3.1 resolves this issue

Topic: Negative moment yield stress ratio incorrect for load rating
Version: 2.3
Date: May 05, 2010
Version Corrected: 2.3.1
Description:

The check for reinforcement yielding for negative moment yields incorrect results due to two issues with PGSuper.

  1. The additional stress transfered to the reinforcement due to cracking, fbcr, has the wrong sign. This is always a tensile stress and should always be a positive value regardless of the value of Mbcr.
  2. The cracked moment of inertia is computed incorrected for negative moments

Resolution: Version 2.3.1 resolves this issue

Topic: Effective flange width incorrect when overhang exceeds S/2
Version: 2.2
Date: April 02, 2010
Version Corrected: 2.3
Description: In the Girder Details Report, PGSuper lists a warning "The slab overhang exceeds S/2. The overhang is taken to be equal to S/2 for purposes of computing the effective flange width and the effect of structurally continuous barriers has been ignored. (LRFD 4.6.2.6.1)". However, when reviewing the details of the effective flange width computation, the full overhang is used.
Resolution: This problem was fixed in version 2.3.

Topic: Negative moments for deck analysis
Version: 2.2
Date: February 22, 2010
Version Corrected: 2.3
Description: The Strength I and Strength II negative moments computed for evaluating the capacity of the deck include moments from simple span components.
Resolution: This issue was fixed in version 2.3

Topic: WSDOT Girder Schedule - P and Theta incorrect for splayed girders
Version: 2.1
Date: March 06, 2009
Version Corrected: 2.1.1
Description:

The P and Theta parameters in the WSDOT Girder Schedule report are computed incorrectly for splayed girders or girders on curved alignments.

Resolution:

The correct values of these parameters can be obtained using the following calculations

Theta can be computed as (180 deg - (Bearing of Pier - Bearing of Girder)).

P = N/sin(Theta)

This problem will be fixed in the 2.1.1 release


Topic: Bearing Design Parameters Report - Live load reactions and rotations should not include impact
Version: 2.1
Date: March 06, 2009
Version Corrected: 2.1.1
Description: The live load reactions and rotations given in the Bearing Design Parameters report include impact. Paragraph 3 of LRFD 14.4.1 says

"The influence of dynamic load allowance shall be included for MBJS, but need not be included for bearings".

Resolution:

This problem will be fixed in version 2.1.1.

In the interm, the live load reaction without impact can be obtained from the Details and Bridge Analysis Reports


Topic: Overlay load applied incorrectly
Version: 2.1
Date: March 06, 2009
Version Corrected: 2.1.1
Description: The overlay load is applied as a series of trapazoidal load segments. The first load segment is not applied to the bridge model. The effect of this may be seen in the reactions caused by the overlay.
Resolution: The problem will be fixed in Version 2.1.1. The missing load segment is relatively short. In all but very short spans, the influence of this error is minimal. The reaction and shear at the start of the girder will be slightly underestimated. The influence on mid-span moment is virtually negligible.

Topic: Design and Permit Live Load Reactions and Rotations labeled incorrectly
Version: 2.1
Date: February 11, 2009
Description:

The Design and Permit Live Load Reactions and Rotations listed in the Load Responses - Bridge Site section of the Detail Report are labeled incorrectly. This values are listed as being per lane, however the values reported are per girder.

To make the values per lane, divide by the live load distribution factor.

Resolution: This problem will be fixed in the next maintenence release.

Topic: Problems evaluating horizontal interface shear
Version: 2.0.7
Date: January 08, 2009
Version Corrected: 2.1.0
Description:

There are two problems related to the evaluation of horizontal interface shear (LRFD 5.8.4).

The parameter dvi (distance between mid-thickness of the slab and the centroid of the tension resultant) is computed as
dvi = tslab/2 + Ytop Girder + Strand Eccentricity

The strand eccentricity is measured with respect to the centroid of the non-composite girder section. However, PGSuper is using Ytop for the composite section. It should be using Ytop of the non-composite section.

The minimum area of interface shear reinforcement (LRFD 5.8.4.4) is not being evaluated correctly. Avf min is correctly computed by equation 5.8.4.4-1 and by the procedure given in the first bullet of 5.8.4.4 (also see Equation 5.8.4.1-3). The minimum area of interface shear reinforcement should be the lesser of these two values. However, PGSuper is using the greater of these two values.

Resolution: The Details Report provides adquate information to easily hand calculate the horizontal shear demand and minimum shear reinforcement requirements.

Topic: Incorrect maximum moment values plotted in the analysis results view.
Version: 2.0.7
Date: August 28, 2008
Version Corrected: 2.1
Description: The maximum moments plotted in the Analysis Results View, when the analysis type is set to Simple/Continuous Envelope are incorrect. The maximum moments plotted are those from the continuous analysis when they should be from the simple span analysis. The maximum moments listed in the reports are correct. PGSuper uses the correct moments for design and analysis. This is simply a plotting issue.
Resolution: This problem will be corrected in the version 2.1 release.

Topic: Lifting Analysis Calculations
Version: 2.0.5
Date: January 17, 2008
Version Corrected: 2.0.6
Description:

The total mid-span camber at lifting is computed incorrectly. The cantilever deflection is not included in the computation. This results in an underestimation of yr and thus an underestimation of FScr.

The resulting error is small when the cantilever overhangs is less than approximately 20% of the girder length.

Resolution:

For a more accurate analysis, compute the deflection at the ends of the cantilever and add it to the mid-span deflection. In the lifting analysis, substitute this value for Dself and finish the computation by hand.


Topic: Prestress losses at temporary strand removal stage
Version: 2.0.5
Date: January 15, 2008
Version Corrected: 2.0.6
Description:

The prestress losses at the temporary strand removal stage are computed incorrect. PGSuper is taking the loss to be DfpR0 + DfpES + DfpSR + DfpCR + DfpR1 + Dfptr.
The correct loss is DfpR0 + DfpES + DfpSRH + DfpCRH + DfpR1H + Dfptr. This error will impact the allowable stress check at the temporary strand removal stage.

To work around this problem, create a Details Report and find the correct loss value, given as DfpH. Using this loss, hand calculate the actual stress demand and compare it to the allowable values.


Topic: The composite area for sections with composite decks is incorrect
Version: 2.0.3
Date: December 31, 2007
Version Corrected: 2.0.4
Description:

The composite area for girder sections with composite decks is reported incorrectly.

This is a problem with a conversion factor and not the actual value. To get the correct composite area, multiply the reported value by 0.00064516 (US units) or 10^6 (SI units).

This problem will be corrected in Version 2.0.4

Resolution: This problem is corrected in Version 2.0.4

Topic: Incorrect stresses at Temporary Strand Removal Stage
Version: 2.0.3
Date: December 31, 2007
Version Corrected: 2.0.4
Description:

The "Stress Check for Service I for Temporary Strand Removal" stage has a few glitches.

Losses

PGSuper is using the total losses at time of deck placement to calculate stresses due to prestress (i.e. f = fpj - DfpRO - DfpES - DfpLTid - Dfptr). It should be using the total losses at time of hauling, plus losses due to temporary strand removal, for this stage (i.e. f = fpj - DfpRO - DfpES - DfpLTH - Dfptr). This is based on the assumption that the girders are shipped, erected, braced and the temporary top strands are removed all in one day, which is the worst case scenario.

Service I Stresses

PGSuper is using the total dead load on the bare section to calculate Service I stresses for this stage (i.e. Girder + Diaphragm + Slab). This stage should only be using the Girder dead load on the bare section to calculate Service I stresses since the temporary top strands must be cut prior to placing the Diaphragms and Slab.

Resolution:

This problem is corrected in Version 2.0.4


Topic: Incorrect capacity reduction factor used for negative moment
Version: 2.0
Date: August 13, 2007
Version Corrected: 2.0.1
Description: PGSuper is using the wrong capacity reduction factor for negative moment. PGSuper is using 1.0 which is the factor for prestressed concrete. In negative moment regions, we have a reinforced concrete beam and the reductino factor should be 0.9
Resolution: Manually multiply the computed negative moment by the correct capacity reduction factor.

Topic: Deflection due to removal of temporary prestressing strands is incorrect
Version: 1.12
Date: May 09, 2007
Version Corrected: 1.13
Description: The deflections due to the removal of the temporary prestressing strands are incorrect. This deflection is always computed to be 0.0. This error will impact the camber at time of slab casting ("D" Dimension) and subsequently impact the camber, Slab Haunch ("A" dimension), loading, and prestress losses.
Resolution: This problem will be fixed in Version 1.13

Topic: The V/S ratio is incorrect for voided slabs and box beams.
Version: 1.9.0
Date: April 24, 2006
Version Corrected: 1.9.1
Description: When computing the drying surface area, S, for creep coefficients (LRFD 5.4.2.3.2), only the exterior surface area is used. 50% of the surface area of the internal voids should be added to S.
Resolution: This omission should not have a significant impact on the creep coefficient, camber, or prestress losses. If you feel that it does, use hand methods to adjust the computations accordingly.

Topic: User defined loads
Version: 1.8.0
Date: February 01, 2006
Version Corrected: 1.8.1
Description:

If user defined loads are applied to "All Girders" or "All Spans", the loading may be applied to the structure twice. Check the user defined load section of the details report to confirm how many times the load is applied.

Resolution: Install PGSuper Version 1.8.1 or later

Topic: Losses in Deck Bulb Tee girders
Version: 1.8.0
Date: February 01, 2006
Version Corrected: 1.8.1
Description:

The losses for Deck Bulb Tee girders is computed incorrectly.

Resolution: Install PGSuper Version 1.8.1 or later


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