In the post processing mode when analyzing a simple frame structure I am finding that I can not recreate or understand some of the corner stresses that are showing. My first attempt was to obtain stresses using a rectangular timber beam shape from the section data base. With this setup the table and graphical corner stresses values do not align. Upon further investigation, I've found that using a user defined shape for a solid rectangle of concrete, a trapezoid shape of concrete, and a t-section of concrete (all with the same dimensions) the beam corner stress values vary wildly. When doing these three checks the beam force, moment, and shear values are all in general agreement.
What software are you using? Can you share the file or some screen captures?
Don't know how to upload screen shots to this forum, but I've attached a simple program below. I'm using STAAD.Pro V8i (SELECTseries 5). When looking at this program in postprocessing/Beam/Stresses tab I get maximum Corner 1 and Corner 2 stresses of -14895.832psi (concrete rectangle), -104.174psi (concrete tapered), -104.172psi (concrete tee), and -14876.266psi (timber beam). All sections are 12"x6". I understand differences between concrete and timber values, but not how the two corner stresses could be so high without it be a program error.
STAAD SPACESTART JOB INFORMATIONENGINEER DATE 07-Oct-19END JOB INFORMATIONINPUT WIDTH 79UNIT FEET KIPJOINT COORDINATES1 0 0 0; 2 10 0 0; 3 20 0 0; 4 30 0 0; 5 -10 0 0;MEMBER INCIDENCES1 1 2; 2 2 3; 3 3 4; 4 5 1;DEFINE MATERIAL STARTISOTROPIC CONCRETEE 453600POISSON 0.17DENSITY 0.150336ALPHA 5e-006DAMP 0.05TYPE CONCRETESTRENGTH FCU 576ISOTROPIC STEELE 4.176e+006POISSON 0.3DENSITY 0.489024ALPHA 6e-006DAMP 0.03TYPE STEELSTRENGTH FY 5184 FU 8352 RY 1.5 RT 1.2ISOTROPIC STAINLESSSTEELE 4.032e+006POISSON 0.3DENSITY 0.489024ALPHA 1e-005DAMP 0.03ISOTROPIC SOPN_DSS_6X12_WETE 230400POISSON 0.15DENSITY 0.025ALPHA 5.5e-006END DEFINE MATERIALMEMBER PROPERTY AMERICAN1 PRIS YD 1 ZD 0.52 PRIS YD 1 ZD 0.5 ZB 0.49993 PRIS YD 1 ZD 0.5 YB 0.5 ZB 0.4999MEMBER PROPERTY AITC4 TABLE ST SOPN_DSS_6X12_WETCONSTANTSMATERIAL CONCRETE MEMB 1 TO 3MATERIAL SOPN_DSS_6X12_WET MEMB 4SUPPORTS1 TO 5 PINNEDMEMBER RELEASE1 END MX MY MZ2 START MX MY MZ2 END MX MY MZ3 START MX MY MZ1 START MX MY MZ4 END MX MY MZLOAD 1 LOADTYPE None TITLE LOAD CASE 1MEMBER LOAD1 TO 4 UNI GY 0.1PERFORM ANALYSISFINISH
Yes, there seems to be an issue in reporting the corner stress for the timber section. This issue has been reported as a defect #1060527. Thank you fro bringing it into our attention.