FAQ’s FP

Can Floor Pro and MAT run an unlimited number of load combinations?
For punching shear check, the program can run up to 50 strength combinations.

How can I make the program calculated top reinforcement “grouped” rebar centered over the support instead of “distributed” over the tributary width?
When working in ADAPT-Floor Pro RC or MAT-RC, the program will automaticlly distribute all calculated reinforcement over the tributary width.  To change this, select the desired reinforcement and from the “Modify Item Properties” input, go to the “Rebar” tab and change the bar distribution to grouped. 

Can applied displacements be applied in ADAPT-Floor Pro?
Applied displacements cannot be explicitly applied in the program, however, there are two methods whereby this behavior can be modeled.

(1) Apply a point spring with a given stiffness at the location of support.  Note that the spring should replace the physical member (i.e. column). 

(2) ADAPT-Floor Pro accounts for axial shortening of columns.  You can determine a force which cause the shortening in the column to equal the displacement given the area and modulus of elasticity (P = Displacement*A*E / L).  Apply this force as its own load case in association with those combinations which should consider the displacement.

How does ADAPT-Builder set the depth of mesh reinforcement or other base rebar when a model contains more than one slab region of different depths?
The cover of reinforcement is taken relative to the first slab input into the model.  Any mesh reinforcement assigned will be located in depth relative to the dimensions of this slab.  If mesh reinforcement is required at different depths, assign individual meshes to different slab regions and modify the cover to the proper value.  Note that negative covers are acceptable to shift a mesh downward.  See the video “Bulder 1010 Mesh Reinforcement Placement” on the ADAPT-Floor Pro/MAT video page for an example.

In ADAPT-Floor Pro RC how can I change the density or spacing of design sections for automatically generated middle strips?
Go to C:/Program Files/ADAPT/Builder 2010/Initialize_Builder.txt and modify the following lines.  These allow you to control the spacing and number of sections for middle strips.  The program will create the number of sections as input unless it is less than spacing interval….if spacing interval controls, it will create sections at this spacing.

“Spacing_Of_Middle_strip_design_sections_m”  1.0
“Minimum_of_middle_strip_design_sections” 36

In ADAPT-Floor Pro RC, why is the reinforcement in beam bottoms shown as distributed?
In ADAPT-Floor Pro RC, all reinforcement is shown as distributed, regardless of support line design designation.  If beams are included on a support line, design sections will include the beam depth (stem) as part of the design section and the flexural capacity is based on the depth of the beam.  Any rebar shown as “Bottom” bars should be located and detailed such that they are located off the bottom fiber of the stem.   

Are point and line supports automatically deleted if a column or wall is moved?
 There are two instances when a point or line support WILL NOT be deleted and automatically regenerated when the model is re-meshed and analyzed.  These are: (1) When the user makes any modication to the support, either fixity or relocating/shifting the support, and (2) When the column or wall is offset downward or made longer. 
 
If you allow the program to generate the default supports or if you change the support type in CRITERIA and then mesh, the supports will be regenerated each time. 
 
What is the best way to carry out distrubited or uniform tendon design in ADAPT-Floor Pro.  It can be very time consuming inputting all of the tendons for the distributed direction and then having to modify to complete a design? 
 
There are two ways of modeling distributed tendons that may help in making the process more efficient.  
When the % balanced load exceeds 100% what can be done to reduce this and does it mean that the geometry or tendons should be modified?
The % limit for balanced loading is not code-stipulated.  The recommended range is typically somewhere between 50-100%.  This is the level where you will see the most economical design.  Values greater than this range may be an indicator of the economy of the design, or lack thereof.  If drape heights are being maxed out to control stress and as a result there is too much uplift then that could mean several things.
 (1) The LL/TL ratio is high…meaning….you have plenty of PT to balance the dead load, but due to the magnitude of LL your total force and positioning of tendons is required to control the allowable tensile stress.  Reducing the LL may not be practical and is seldom the solution.
(2) You may have a condition where the PT is at max heights and a high balanced load % occurs, increasing the depth of slab may help in decreasing the total required force and %balanced load.

(3) To reduce % balanced load for a design that is not controlled by allowable tensile stress, either reduce the force in strands and/or shift the low points up or lower the CGS over support. 
Note that Floor Pro accounts for uplift from tendons in both directions that are tributary to the span.  So shifting tendon forces or profiles in both directions would be helpful. 

How is serviceability reinforcement calculated for prestressed beams in ADAPT-Floor Pro?
Where beams are present in Floor Pro PT, the program uses 0.004*Act (ACI318 Section 18.9.2).  The program will internally calculate the effective flange based on the minimum of (a)0.25*span length, and (b)16*h + b where ‘h’ is the slab thickness and ‘b’ is the width of beam stem.  Section properties related to the effective width are used in calculating the centroid of section for Act. 

 
Why does ADAPT-Floor Pro assume 0.3*LL for the Sustained service load combination?
Many international codes assume higher live loads than those prescribed by ASCE or IBC.  For designs carried out using these codes, a value greater than 0.3 can be justified. 
Do the assumptions made between unbonded tendon systems and the “Effective Force” method apply for bonded tendons as well?
The effective force assumption for post-tensioned tendons has been the primary method of design in North America for many years. Both ACI and PTI have been discouraging its use in favor of using the “Variable Force” method, but the practice is still common. The method applies to both bonded and unbonded systems. The application of the method is tied to a maximum tendon length for stressing. For unbonded tendons the practice is to limit the length to 38m (125 ft). For bonded tendons, this length is shorter. The practice is to select 33 to 35m (100 -115 ft) as maximum length. The shorter length for bonded tendons is due to a greater friction loss, which impacts the in-service performance for cracking and deflection. This, however, is compensated in part in greater increase in stress of bonded tendons at ultimate limit state. 
 
What is the proper way to model a drop cap/panel at a corner of slab?  If the drop cap/panel extends beyond the slab edge, will it be considered properly in the Punching Shear check?
When a drop panel or cap is present, the program checks critical sections with respect to the column face, inside the drop, and outside the drop where slab region occurs.  In a case where a column overhangs the slab (as shown in the image below on the left) the program will correctly check the punching shear  inside the drop panel/cap depth for the left image below, however the check outside the face of the drop is checked differently as compared to the image on the right.  Outside the slab, for the condition where the cap/panel is centered on the column and extends outside the slab on two sides, the program uses the entire drop width in determining the critical sections (b1 and b2).  This results in allowable concrete shear stress values that are greater than actual.  In the second case, the program uses the entire drop width also, but the width is reduced to only account for that portion inside the slab boundary.  This is the proper way to model the condition.  The same can be applied to “End” and “Edge” conditions. 

 

 

How does ADAPT-Floor Pro 2009/2010 treat openings near columns with respect to punching (tw0-way) shear?
The program makes a check of two lines or “sections” which extend from the column centroid in each direction a distance c/2 + 4h; where c = the column dimension in the direction of section and h = the slab thickness.  If the line is intersected by any opening, the program categorizes the opening as an “End” or “Edge” condition depening on the axis of bending.  Where openings occur on two sides and intersect the line, the column is categorized as a “Corner” condition.  The concrete located between the face of column and opening edge is discounted in the calculation of allowable concrete shear strength. The following is a sketch of each condition.

ADAPT-Floor Pro 2009/2010 P.S. classifications

When using the EC2 code in ADAPT-Floor Pro 2009, the punching shear reinforcement appears to be excessive when compared with other third-party software, why is this?
There are a couple of reasons the results in ADAPT-Floor Pro may differ, specifically to the EC2 code.  These are:  (1) The program categorizes columns per ACI classifications.  That is, the column will be categorized as an interior, edge, end or corner condition.  For edge, end and corner conditions, the program will conservatively take the slab dimension to the column face rather than some overhanging slab edge for the determination of the critical area for punching.  Note that ACI 318 is ONLY used to classify a column and is not used in any other punching shear calculation with respect to the EC2 code,  nor is it used in determining critical sections. (2) The program does not include the contribution of precompression or longitudinal reinforcement in determing the punching shear resistance of a slab. 

 
NOTE:  ADAPT-Floor Pro 2010 has been improved to include the contribution of precompression and longitudinal reinforcement for punching shear resistance so long as the user designs design sections prior to running the punching shear check. 

When the program calculates L/deflection ratios, what length is used?
The L/deflection ratios in Floor Pro are a function of the spans of each support line and their lengths.  For example, if you run a support line from one slab edge to the opposite edge without any intermediate spans (i.e. “clicks”), the value for L/deflection ratio would be calculated based on the entire length of the support line. 

When designing a PT slab, can the entire bay width be used in determining moment-capacity for a T-section at negative moment regions (i.e. drop panel at a column location)?
This response is specific for ACI-318.  The question could be asked if there is any code provision that prohibits the used of full design section width in determining the design capacity?  We are unaware of any such provision.  

Since the precompression introduced into the system due to the PT is deposited over the entire tributary cross-section, most engineers will base the design capacity on the same section, which is typically defined as the most logical load path along support lines.  ACI-318 clearly excludes provisions found in Chapter 13 (two-way conventially-reinforced concrete slabs) in the design of prestressed structures, unless clearly stated.  Furthermore, Section 18.12.1 clearly states that factored moments and shears in prestressed slab systems “shall be determined” in accordance with the Equivalent Frame Method (EFM).  Our interpretation would be that this means the full tributary.  

The same provision excludes sections 13.7.7.4 and 13.7.7.5 which calls for the total negative moment to be distributed to column and middle strips.  Some may apply column/middle strip design to PT structures or some similar line of thinking with respect to distribution of moment, etc.  This does not apply to prestressed slabs and is explicitally excluded in ACI-318 Section 18.

 Does disregarding column/middle-strip methodology as defined by ACI-318 when using a finite element analysis violate the code?  Even when using FEM analysis, should I still proportion reinforcement based on code percentages?
ACI-318 specifically states that “column strip/middle strip” distribution does not apply to post-tensioned floor systems.

When using the program  for conventionally reinforced two-way slabs, the program gives the user the option to distribute the reinforcement based on “column strip/middle strip.”  The program DOES NOT apply the code-prescribed percentages to each strip, but geometrically sub-divides design strips based on the code provisions and designs each strip according to the nodal integration method.   

The intent of the ACI recommendation for breakdown of reinforcement between column strip and middle strip has been for improved crack control in service condition. For the safety of the structure (Ultimate Limit State) the distribution is immaterial, as long as the tributary of each support line is provided with the associated rebar.

In summary, for better crack and deflection control, it is advisable to place most of the reinforcement of a design strip near the column when designing a conventionally reinforced concrete, regardless of the method of analysis. It is our opinion that this is the intent of ACI-318, although it is not explicitly stated in the code for designs based on FEM analysis.  Since, using the reinforcement disposition, specified by a user, ADAPT-Floor Pro can calculate the cracked deflection of a conventionally reinforced two-way floor system, one can logically argue that the ACI’s column strip/middle strip disposition need not be adhered to, if cracked deflections meet the code’s deflection limit.

When calculating shear capacity of two-way prestressed slabs, does the program include the average precompression, fpc, as shown in ACI318-05/08 Equation 11-36?
Yes, however, the program conservatively assumes the minimum value of 125 psi regardless of the actual precompression in the slab.  If a single tendon is included in a model, the program will apply Equation 11-36 for each column, regardless of its location with respect to the tendon location. 

When a slab is overlaid on another slab region, does the program count the self-weight twice? 
No, the program calculates the self-weight according to the true, three-dimensional representation of the model as input by the user. 

How do I move a drop cap or drop panel such so that it is not centered on the column?
If you click on a drop and then select the handle (X in center) you can move it to any location away from center of column.  This may require that you include some construction lines.  The easiest approach is to highlight the component and then use the Copy/Move toolbar where you can enter the distance in X and Y directions. 

If I modify the mesh after designing rebar do I have to run the analysis and rebar design again? 
Anytime a change is made to the mesh, we recommend the analysis and design is rerun. 

After I design the reinforcement for a slab and change “Grouped” rebar to “Distributed” can I change the extents of the rebar distribution over the entire design strip width?
When “Grouped” rebar is changed to “Distributed,” the program defaults to extents of 0.5 m (0.5 ft) on each side of the rebar.  This results in very short spacing dimensions.  Currently, there is no automatic option to change this to extend the rebar over the entire tributary width.  You can manually change the extents by double-clicking on any rebar and changing the extents in the property input screen OR you can click and drag the extent handles if you click on rebar graphically.   

Why do I get the warning “Contours Not Possible.  Values are Identical” when I try to view the stiffness ratio (Ieff/Igross) in the View Results Screen?
If no cracking occurs in the slab, the displacement values for the cracked and uncracked conditions are equal, therefore the results cannot be displayed for cracking. 

Why are my design sections shown Green and “OK” as design status for initial stress when the stress values exceed allowable values?
ACI 318 allows mild reinforcement to be added to slabs and beams to account the tensile force resulting from the overstress.  Since the program adds this reinforcement, the design sections and status are shown as “OK.”  The same is true for international codes where mild reinforcement is required where overstress occurs. 

How does Floor Pro determine effective depth for two-way slabs in each direction?
When a support line is tagged as “Two-way Slab” the program determines the CGS as follows:

For Top and Bottom bars at outer layer: Cover (as defined in Criteria) + 1/2* outer bar diameter

For Top and Bottom bars at inner layer:  Cover (as defined in Criteria) + outer bar diameter + 1/2 inner bar diameter bar

If you double-click on any support line and go to the “Design” tab you have the option (for two-way slab designated support lines) to define the design based on outer layer or inner layer for top and bottom bars.  By default all support lines in the X and Y directions are designated as “outer layer” for top and bottom.  Our recommendation is to define X direction as “outer layer” and change Y direction to “inner layer” to account for the different depths in analysis. 

Note: Inner and outer bar diameters are the same for top or bottom

How does Floor Pro calculate Mcr (cracking moment)?
The default values that Floor Pro uses in determining the cracking moment are:

Beams & One-Way Slabs:  S*7.5sqrt(f’c)
Two-Way Slabs:  S*6sqrt(f’c) 

Note that the user-defined input for allowable tensile stress (Total Service condition) is used in determining Mcr in ADAPT-PT.  ADAPT-RC uses S*7.5sqrt(f’c) for beams and slabs. 

In calculating cracked deflections for two-way slabs in Floor Pro RC, Ieff will be based on the default value shown above.  For the program to calculate Mcr based on 7.5*sqrt(f’c) in lieu of 6*sqrt(f’c) the user can open in Floor Pro PT, save the model and then re-open in Floor Pro RC. 

Note: For post-tensioned slab designs carried out in ADAPT-PT or Floor Pro, Mcr also includes the effects of pre-compression such that:

Mcr = S*(P/A + fr); where fr is based on criteria listed above

Why are my results different when I compare a design strip in Floor Pro and PT?  
When comparing results between the two programs, there are several things to consider in order to make an adequate comparison.

-Make sure that the load combinations include Prestressing or Hyperstatic actions.  If you open a project in ADAPT-Floor Pro RC and later open in Floor Pro PT, the auto-generated load combinations from RC will remain.  These do not include prestressing effects.  To include prestressing, you can modify the combinations manually or you can go to CRITERIA>General>Analysis/Design options and toggle between codes.  This will auto-generate the combinations and include the prestressing effects.   

-When you import tendons from ADAPT-PT, they are automatically “disregarded” in the FEM analysis.  To include the PT in the design, you must click on each tendon that has been imported and in the FEM tab, change from “Disregard” to “Consider.”  You can also do this for all tendons by selecting all tendons and using the MODIFY ITEM PROPERTIES tab.  On the left hand side you will see FEM and here you can also change to “Consider.”

 -Make sure that the design criteria and other variables match in the Floor Pro and PT.  Note that for Loading, Material and Criteria input there are options for both FEM and Strip Method.  If the results are to compared, make sure that the design parameters are similar for each model. 

-Results between Floor Pro and PT will not be exactly the same for such a structure, regardless of having identical input parameters.    The analysis methods are different (FEM vs. Equivalent Frame Method) and variation in results is to be expected since in one method (EFM) general approximations are used in equating a 2D frame to exhibit some two-way slab action through torsional members.

Why does ADAPT-PT and ADAPT-Floor Pro uses 0.3*LL for the Sustained Load service combination?
ACI-318 refers to “sustained” loads, but does not specify a percentage. We used 0.3 as default since the European Code EC2- EN1992-1-1:2004(E) that is currently governing structural design in Europe recommends 0.3. I am told the corp of engineers in the US uses 0.5. Also, using other codes, some designers in Dubai use 0.2.

How do I include pattern loads in load combinations?
Skipped live load patterns and envelopes (max and min) in and of themselves cannot be factored unless they are (a) added to an existing load combination or, (b) added to a new load combination created by copying and modifying an existing combination.  If you select the patterns individually you can only change the Analysis/Design Options to Strength, etc. Once you have changed this setting (after highlighting the specific pattern) select “Save” and the design option should change and remain.

To illustrate this, see the examples below.

1. Adding a pattern to an existing load combination

        a. Select “Total Load”
b. From the “Load Cases” pull-down menu select the pattern or envelope you wish to include.
c. Set the load factor
d. Under the “Combination Parts” box, select “Add” or “Update” if the pattern is replacing the Live Load component.
e. Beneath the combinations list, press “Save” and the combination is updated.

2. Creating a new combination from an existing

        a. Select any existing load combination.
b. Make changes to the combination parts.  This can include patterns or envelopes.
c. Change the combination Label and press “Save.”  The combination will be added to the list.

3. Creating a combination for a pattern with a load factor greater than 1.0

        a. Select any pre-defined load combination.
b. In the combination parts, add a pattern with the load factor
c. Delete all other components
d. Rename the combination and press “Save”

Does ADAPT-Floor Pro design for torsion?
ADAPT-Floor Pro reports torsion and twisting moments (Mxy).  The user has the option of designing for Mxy based on the Wood-Armer Method.  This is an option in the Criteria-General-Analysis/Design Options input screen.  If this option is not selected, twisting moments are not accounted for in the general design of Floor Pro and must be carried out manually if a user wished to design for such actions. 

For punching shear calculations what does ADAPT use as Vu and Mu?
ADAPT-Floor Pro conservatively uses the column reactions as Vu and the sum of upper and lower column moments for Mu.  Note that if upper and lower columns are not concentric, only the moment from the lower column will be used for Mu.  As a workaround, you can align columns as an approximation or manually calculate the shear stress from the contribution of the upper column moment and compare with the excess shear capacity (PhiVn – Vu). 

Does Floor Pro consider effective width when beams are integral with slabs?
No, the concept of “effective flange” is not necessarily applicable to FEM-based solutions.  The effective width concept was introduced to equate the maximum stress from simple beam theory to that of an elastic solution recognizing plate action of the flange.  Floor Pro considers the true composite action between beam and slab/flange and is inherent in its solution.  Technical Notes #228 and 276 provide additional detail.

Why are the % Dead Load Balanced values not equal for symmetric spans?
ADAPT-Floor Pro does not use equivalent loads when determining balanced dead loading percentage as is the case for ADAPT-PT and other commercial design programs.  The vertical force component, due to prestressing at each cell node and tributary to the span in question, is determined and compared to that from self-weight and dead load.  If the finite element mesh is “sparse” and non-uniform, the % reported will be slightly different.  Note: Floor Pro reports % balanced dead load as a function of self-weight plus superimposed dead load.


Why are my design stresses shown Green when overstressed areas are present when viewing BuilderSum?
If the design of sections is executed prior to tendons being input in the model, the program sets the default view to enveloped bending moments.  This is not reset after tendons are added.  You can change the view from the Result Display Settings in the Support Line Results toolbar.  If you design the sections after tendons have been input, the default view will be Service (Total) Load.

Does Floor Pro show stresses in ADViewer in RC-only mode?
No, but there is a “trick” to do this.  If you use the RC&PT mode and include at least one tendon in the model, you can view stresses in ADViewer.

Does Floor Pro account for user-identified reinforcement when checking rebar spacing requirments for mild-reinforced slabs?
No.  Floor Pro independently checks reinforcement against spacing requirements as specified by the user in the “Criteria” menu.  Reinforcement shown on plan is the envelope of requirements from Service, Strength or spacing criteria.  If user-defined reinforcement (mesh or otherwise) is input, the program only checks this against Service and Strength conditions.  Where additional reinforcement is required at any design section, the program would then apply the spacing check.

How are punching shear reinforcement results to be interpreted for shear studs and shear links?
The results show the distance at each layer away from the face of column and drop panel where applicable.  For shear studs, the total number of studs at the column perimeter is a function of the number of layers specified by the user.  For shear links (stirrups) the program reports the distance from face of column and the number of vertical shear legs to be distributed at the column perimeter at the particular layer.

Is Builder 2009 compatible with Windows 2000?
Although ADAPT does not claim compatibility of Builder 2009 with Windows 2000, you can install Builder 2009 on most Windows 2000 operating systems.
If you have Builder v3 currently installed on your Windows 2000 system, you can simply uninstall Builder v3 and install Builder 2009 without any issues.
If you plan to newly install Builder 2009 on your Windows 2000 computer, you will receive an error message when opening Builder saying that MFC80.dll is missing in several folders. You can go to Program Files/ADAPT/Builder 2000/Microsoft.vc80.mfc where the MFC80.dll file resides and copy it into the locations mentioned in the error message. Builder 2009 will then start without error messages.

Does Builder 2009 run on a 64bit computer?
Builder 2009 comes in two versions: the 32bit setup can be installed on 32bit machines running Windows XP and Windows Vista.  The 64bit setup can be installed on a 64bit machine running Windows Vista.  Ensure that you have the appropriate setup for your computer.

1.  Use the tools built into Builder for partial tendon optimization instead of designing in PT first and having to manually input several tendons equal to the total force from PT.  The program has some distributed tendon mapping tools in the Tendon Toolbar.  If you create a “master” tendon first, you can then map this over a range of area in the slab and the program will determine the required spacing and profile based on precompression and %balanced loading.  You will still likely need to make design modifications since the program does not consider allowable tensile stress for the optimization algorithm.

2.  In Builder, instead of modeling one direction banded and the other distributed, model both directions banded.  Once the design is final, break those out into distributed for one more check and be done with it.  In ADAPT-PT, the program is always assuming some force over a cross-section that is uniform and doesn’t differentiate between banded or distributed.  You simply enter the force.  Builder is more sensitive to this since a localized effect will occur if all strands are banded, but it is a good starting point to move you along in a design.