Hi everyone,
I have modeled a building containing shear walls as well as a moment frame. In modelling the shear walls I used surface entities and applied uniformly distributed loads onto the beams (udls) above them, I've also run the design shear wall command in staad as well. After the analysis of the structure I realized that when I am in post-processing and under the tab surface, the forces are split into surface forces at X (local) and surface forces at Y (local), and are reported as per the division of the surface. I am trying to design the reinforcement for the walls manually so as to confirm the design result from staad, however I am not sure which values to use from the tables in the post processing section. Could anyone help me in deriving the shear, axial and bending moments required for manually designing the wall from these tables.
NOTE: Staad file is attached below.
STAAD SPACESTART JOB INFORMATIONENGINEER DATE 14-Sep-15END JOB INFORMATIONINPUT WIDTH 79UNIT METER KNJOINT COORDINATES1 -8.55 -0.0749998 20.1; 2 -7.63107 -0.0749998 16.9826;3 -6.56933 -0.0749998 13.3808; 4 -5.39593 -0.0749998 9.4001;5 -4.80923 -0.0749998 7.40978; 6 -4.61862 -0.0749998 21.1723;8 -3.70062 -0.0749998 18.0547; 9 -3.7 -0.0749998 0;10 -3.67823 -0.0749998 3.573; 11 -2.67782 -0.0749998 14.5811;13 -1.54273 -0.0749998 10.7262; 17 1.54273 -0.0749998 10.7262;19 2.67782 -0.0749998 14.5811; 20 3.67823 -0.0749998 3.573;21 3.7 -0.0749998 0; 22 4.04664 -0.0749998 19.2298;23 4.61862 -0.0749998 21.1723; 24 4.80923 -0.0749998 7.40978;25 5.39593 -0.0749998 9.4001; 26 6.56933 -0.0749998 13.3808;27 8.55 -0.0749998 20.1; 28 -8.55 4.65 20.1; 29 -7.63107 4.65 16.9826;30 -6.56933 4.65 13.3808; 31 -5.39593 4.65 9.4001; 32 -4.80923 4.65 7.40978;33 -4.61862 4.65 21.1723; 35 -3.70062 4.65 18.0547; 36 -3.7 4.65 0;37 -3.67823 4.65 3.573; 38 -2.67782 4.65 14.5811; 39 -2.625 4.65 0;40 -1.54273 4.65 10.7262; 41 0 4.65 8.3; 42 0 4.65 11.2571;44 1.54273 4.65 10.7262; 45 2.625 4.65 0; 46 2.67782 4.65 14.5811;47 3.67823 4.65 3.573; 48 3.7 4.65 0; 49 4.04664 4.65 19.2298;50 4.61862 4.65 21.1723; 51 4.80923 4.65 7.40978; 52 5.39593 4.65 9.4001;53 6.56933 4.65 13.3808; 54 8.55 4.65 20.1; 55 -8.55 8.3 20.1;56 -7.63107 8.3 16.9826; 57 -6.56933 8.3 13.3808; 58 -5.39593 8.3 9.4001;59 -4.80923 8.3 7.40978; 60 -4.61862 8.3 21.1723; 61 -4.04664 8.3 19.2298;62 -3.70062 8.3 18.0547; 63 -3.7 8.3 0; 64 -3.67823 8.3 3.573;65 -2.67782 8.3 14.5811; 66 -2.625 8.3 0; 67 -1.54273 8.3 10.7262;68 0 8.3 8.3; 69 0 8.3 11.2571; 70 0 8.3 20.4071; 71 1.54273 8.3 10.7262;72 2.625 8.3 0; 73 2.67782 8.3 14.5811; 74 3.67823 8.3 3.573; 75 3.7 8.3 0;76 4.04664 8.3 19.2298; 77 4.61862 8.3 21.1723; 78 4.80923 8.3 7.40978;79 5.39593 8.3 9.4001; 80 6.56933 8.3 13.3808; 81 8.55 8.3 20.1;83 0 -0.0749998 8.3; 84 3.16507 4.65 16.2359; 85 -3.16506 4.65 16.2359;86 0 4.65 16.9071;MEMBER INCIDENCES1 29 28; 2 55 56; 3 30 29; 4 56 57; 5 28 33; 6 55 60; 7 31 30; 8 57 58;9 35 29; 10 62 56; 11 31 4; 12 58 31; 13 32 31; 14 59 58; 15 30 38; 16 57 65;17 37 32; 18 64 59; 19 35 33; 20 62 60; 21 10 37; 22 37 64; 23 38 85; 24 65 62;25 39 37; 26 66 64; 27 31 42; 28 58 69; 29 41 32; 30 68 59; 31 40 38; 32 67 65;34 70 61; 35 39 45; 36 47 37; 37 66 72; 38 74 64; 40 76 70; 41 44 46; 42 71 73;43 41 51; 44 68 78; 45 52 42; 46 79 69; 47 45 47; 48 72 74; 49 46 84; 50 73 77;51 20 47; 52 47 74; 53 47 51; 54 74 78; 55 53 46; 56 80 73; 57 51 52; 58 78 79;59 52 25; 60 79 52; 61 52 53; 62 79 80; 63 54 50; 64 81 77; 65 53 54; 66 80 81;67 84 50; 68 85 35; 76 85 86; 77 86 84;SURFACE INCIDENCE2 29 28 1 SURFACE 1 29 35 8 2 SURFACE 2 35 33 6 8 SURFACE 3 28 33 6 1 SURFACE 4 56 55 28 29 SURFACE 5 56 62 35 29 SURFACE 6 62 60 33 35 SURFACE 7 55 60 33 28 SURFACE 8 30 38 11 3 SURFACE 9 30 57 65 38 SURFACE 10 38 40 67 65 SURFACE 11 40 38 11 13 SURFACE 12 59 68 41 32 SURFACE 13 68 78 51 41 SURFACE 14 41 83 5 32 SURFACE 15 51 41 83 24 SURFACE 16 63 75 48 36 SURFACE 17 36 48 21 9 SURFACE 18 49 50 23 22 SURFACE 19 76 77 50 49 SURFACE 20 77 81 54 50 SURFACE 21 50 54 27 23 SURFACE 22 80 81 54 53 SURFACE 23 53 54 27 26 SURFACE 24 79 80 53 52 SURFACE 25 52 53 26 25 SURFACE 26 19 46 53 26 SURFACE 27 73 80 53 46 SURFACE 28 46 44 71 73 SURFACE 29 19 17 44 46 SURFACE 30 4 31 30 3 SURFACE 31 31 58 57 30 SURFACE 32 DEFINE MATERIAL STARTISOTROPIC CONCRETEE 2.17185e+007POISSON 0.17DENSITY 23.5616ALPHA 1e-005DAMP 0.05TYPE CONCRETESTRENGTH FCU 27579END DEFINE MATERIALMEMBER PROPERTY AMERICAN1 TO 10 13 TO 20 23 TO 32 34 TO 38 40 TO 50 53 TO 58 61 TO 68 76 -77 PRIS YD 0.5 ZD 0.4MEMBER PROPERTY AMERICAN11 12 21 22 51 52 59 60 PRIS YD 0.4 ZD 0.4SURFACE PROPERTY1 TO 32 THICKNESS 0.25CONSTANTSMATERIAL CONCRETE ALLSURFACE CONSTANTSMATERIAL CONCRETE ALLMEMBER CRACKED1 TO 32 34 TO 38 40 TO 67 -68 REDUCTION RAX 0.350000 RIX 0.350000 RIY 0.350000 RIZ 0.3500001 TO 32 34 TO 38 40 TO 68 76 -77 REDUCTION RAX 0.700000 RIX 0.700000 RIY 0.700000 RIZ 0.700000SUPPORTS1 TO 6 8 TO 11 13 17 19 TO 27 83 FIXEDSLAVE RIGID MASTER 48 JOINT 28 TO 33 35 TO 42 44 TO 47 49 TO 54 84 TO 86SLAVE RIGID MASTER 75 JOINT 55 TO 74 76 TO 81DEFINE IBC 2012SS 1.1 S1 0.375 I 1.5 RX 7 RZ 7 SCLASS 4 CT 0.0466 PX 0.2943 PZ 0.2943 TL 12 - FA 1.06 FV 1.65 K 0.9SELFWEIGHT 1 MEMBER WEIGHT36 38 UNI 3.2935 37 UNI 3.6725 26 47 48 UNI 2.2129 30 43 44 UNI 4.76536 38 UNI 4.8917 18 53 54 UNI 2.527 28 45 46 UNI 2.5829 30 43 44 UNI 3.017 8 31 32 41 42 61 62 UNI 3.429 10 15 16 27 28 45 46 55 56 UNI 3.243 4 24 68 UNI 3.35 6 9 10 UNI 3.111 2 19 20 UNI 2.5949 50 65 TO 67 UNI 4.6955 56 63 64 UNI 3.2424 32 42 50 UNI 6.4234 40 UNI 4.7976 77 UNI 3.5723 31 41 49 UNI 4.77LOAD 1 LOADTYPE Seismic TITLE EQ +XIBC LOAD X 1 DEC 0 ACC 0PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 2 LOADTYPE Seismic TITLE EQ -XIBC LOAD X -1 DEC 0 ACC 0PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 3 LOADTYPE Seismic TITLE EQ +ZIBC LOAD Z 1 DEC 0 ACC 0PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 4 LOADTYPE Seismic TITLE EQ -ZIBC LOAD Z -1 DEC 0 ACC 0PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 5 LOADTYPE Dead TITLE DEAD LOADSELFWEIGHT Y -1 MEMBER LOAD36 38 UNI GY -6.5835 37 UNI GY -7.3325 26 47 48 UNI GY -4.4229 30 43 44 UNI GY -9.5336 38 UNI GY -9.7717 18 53 54 UNI GY -4.9927 28 45 46 UNI GY -5.1529 30 43 44 UNI GY -6.017 8 31 32 41 42 61 62 UNI GY -6.839 10 15 16 27 28 45 46 55 56 UNI GY -6.483 4 24 68 UNI GY -6.65 6 9 10 UNI GY -6.211 2 19 20 UNI GY -5.1749 50 65 TO 67 UNI GY -9.3855 56 63 64 UNI GY -6.4824 32 42 50 UNI GY -12.8434 40 UNI GY -9.5876 77 UNI GY -7.1423 31 41 49 UNI GY -9.54SSELFWT Y -1 LIST ALLPDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 6 LOADTYPE Live REDUCIBLE TITLE LIVE LOADMEMBER LOAD36 38 UNI GY -5.8535 37 UNI GY -6.3825 26 47 48 UNI GY -4.3129 30 43 44 UNI GY -7.9536 38 UNI GY -8.1217 18 53 54 UNI GY -5.3927 28 45 46 UNI GY -4.8329 30 43 44 UNI GY -5.447 8 31 32 41 42 61 62 UNI GY -4.869 10 15 16 27 28 45 46 55 56 UNI GY -4.613 4 24 68 UNI GY -4.75 6 9 10 UNI GY -4.611 2 19 20 UNI GY -4.4249 50 65 TO 67 UNI GY -3.6855 56 63 64 UNI GY -6.6824 32 42 50 UNI GY -10.334 40 UNI GY -7.9976 77 UNI GY -6.2523 31 41 49 UNI GY -7.95PDELTA ANALYSIS SMALLDELTA PRINT LOAD DATACHANGELOAD 7 LOADTYPE None TITLE DL + LLREPEAT LOAD5 1.0 6 1.0 LOAD 17 LOADTYPE None TITLE 1.4DLREPEAT LOAD5 1.4 LOAD 18 LOADTYPE None TITLE 1.2DL + 1.6LLREPEAT LOAD5 1.2 6 1.6 LOAD 19 LOADTYPE None TITLE 1.2DL + 0.5LLREPEAT LOAD5 1.2 6 0.5 LOAD 20 LOADTYPE None TITLE 1.2DL + 1EQ+X + 0.5LLREPEAT LOAD5 1.2 6 0.5 1 1.0 LOAD 21 LOADTYPE None TITLE 1.2DL + 1EQ-X + 0.5LLREPEAT LOAD2 1.0 5 1.2 6 0.5 LOAD 22 LOADTYPE None TITLE 1.2DL + 1EQ+Z + 0.5LLREPEAT LOAD3 1.0 5 1.2 6 0.5 LOAD 23 LOADTYPE None TITLE 1.2DL + 1EQ-Z + 0.5LLREPEAT LOAD4 1.0 5 1.2 6 0.5 LOAD 24 LOADTYPE None TITLE 0.9DL + 1EQ+XREPEAT LOAD1 1.0 5 0.9 LOAD 25 LOADTYPE None TITLE 0.9DL + 1EQ-XREPEAT LOAD2 1.0 5 0.9 LOAD 26 LOADTYPE None TITLE 0.9DL + 1EQ+ZREPEAT LOAD3 1.0 5 0.9 LOAD 27 LOADTYPE None TITLE 0.9DL + 1EQ-ZREPEAT LOAD4 1.0 5 0.9 PDELTA 30 ANALYSIS SMALLDELTACHANGEPRINT STORY DRIFT 0.010000PDELTA ANALYSIS SMALLDELTA PRINT ALLSTART CONCRETE DESIGNCODE ACIMAXMAIN 25 MEMB 1 TO 32 34 TO 38 40 TO 68MINMAIN 16 MEMB 1 TO 32 34 TO 38 40 TO 68MINSEC 10 MEMB 1 TO 32 34 TO 38 40 TO 68RHOMN 0.01 MEMB 11 12 21 22 51 52 59 60TRACK 2 MEMB 1 TO 32 34 TO 38 40 TO 68DESIGN BEAM 1 TO 10 13 TO 20 23 TO 32 34 TO 38 40 TO 50 53 TO 58 61 TO 68DESIGN COLUMN 11 12 21 22 51 52 59 60CONCRETE TAKEEND CONCRETE DESIGNSTART SHEARWALL DESIGNCODE ACIFC 28000 LIST 1 TO 30FYMAIN 420000 LIST 1 TO 30TRACK 1TWO 1 LIST 1 TO 30DESIGN SHEARWALL LIST 1 TO 30END SHEARWALL DESIGNFINISH
You can go to Surface Forces at Y (Local) tab inside the Surface Results table and look at the FXY ( shear force ), FY ( vertical force) and Mz ( in-plane moment). Please refer to section 1.6.3 of the Technical Reference Manual titled Surface Element where the local axis system for surface and the various forces, along with sign convention, are explained through a few diagrams. To display the local axes for the surface elements, you can right click the mouse, go to Labels and check the box titled Surface Orientation.
On a different note, here are some observations regarding your model. Surface 17 is defined with nodes 63 75 48 and 36 as part of the surface incidence. However you have beams meeting the surface at nodes 66 72 45 and 39. Now by default the surface would be internally subdivided into 10 divisions by STAAD.Pro and unless these internally generated nodes match with the location of these nodes (66 72 45 and 39), no connectivity between the beams and the surfaces would be established. To ensure that connectivity is established between the surface and the beams 26,48 etc. when you define the surface element, you should consider the nodes 66 72 45 39 as part of the surface incidence.
Just to demonstrate, I replaced the SURFACE 17 by a SURFACE 33. You can check out the incidence data for that surface and also note that the number of divisions along each edge is also specified to minimize the model size as otherwise each edge would be divided into 10 divisions which would lead to a larger model size. You can control the edge divisions along the edges by going to Geometry > Surface page on the left. From inside the Surface dialog box on the right, expand the node corresponding to a surface and adjust the EDGE PROPERTY. You may want to check for other such occurrences.
Also please note that when a surface is internally converted by STAAD.Pro into a plate mesh, the beams along the edges are not split to match the mesh. For example the beam 37 in your model would not be automatically split when the surface 33 is meshed. What that means is, the connectivity between the beam 37 and the surface 33 would be at the nodes 66 and 72 only. So the loads applied on the beam 37 would be transmitted to the surface at these node locations. If you would like the connectivity to be established along the length of the beam, you should split the beam 37 manually into 5 divisions to match with the edge division for the surface 33. In that case the load transfer will happen at all the nodes along the length of the member. I have split the beam to demonstrate this.
Finally you have defined supports at the corners of the surfaces. However when the software generates an internal plate mesh, the intermediate nodes will not have these supports. This is fine if you have the wall supported on isolated footings at corners but if you have a continuous support below the wall, you may want to use the GENERATE option for the supports to define a continuous support underneath the surface. Please refer to the section 5.27.1 of the Technical Reference for discussion on this GENERATE option. There is actually no GUI option to specify this and so you need to add this command in using the editor.
For example you can have a series of fixed supports created along the internally generated nodes along the base of the wall between the nodes 9 and 21 using the command as shown next
SUPPORTS
…
9 TO 21 GENERATE FIXED
Also I would suggest that you go through the entire section 1.6.3 in general, as it contains valuable information on modeling/analysis & design of surfaces.
A modified file with the changes applied to just surface 33 and beam 37 is uploaded for your reference. You can apply the same principles to make the necessary changes at other locations in your model.
4341.Structure1.std
Answer Verified By: Gilbert Fontenard
Thanks Mr. Sye contribution. I used "4341.Structure1.std" file. I run this file as well as posted by Gilbert when posted question. The results are as below for wall where continuous support generated.
Also in box type shear wall, Stair, Elevator, the continuous support is generated for two opposite wall only. For all four walls continuous support not generated. It does not allow to 1. Repeat same node twice in a program.
2. or more than two node in a line (such as T type shear wall.
Hope to hear feedback from learned STAAD user.
Thanks
Kanu Vaidya
kvaidya@aesser.com
Hi Sye, I have revisited the model to apply some of the changes you have suggested but I have encountered the following problems: 1: It can't define a more than one continuous footing for one node. In the model I have two wall that would joined, such as at the corner of a staircase or a an elevator, therefore a continuous footing would be required to run in two directions starting from one point. An example of this would be node 1. 2: For surface No 33, would the loads from the beam above be fully transferred to the entire wall, seeing that section of the wall below the beam extends beyond the beams length.
3: If my intentions are to use a mat foundation, how best can this be modeled for this type of structure.
I hope to hear from you soon concerning these queries and I am also willing to provide further clarification if the questions are unclear. Best Regards