CASE Study in LBYCVT3 Computer-Aided Structural Analysis Effects of Support Conditions in the Behavior of Two Dimensional Frames Analyze the frame below using ETABS. Create four different models with different support conditions. The support conditions are as follows: 1. Pinned Supports 2. Fixed Supports 3. Soil-Structure Interaction using Soft Soil Condition 4. Soil-Structure Interaction using Dense Soil Condition TEST BEAM 1 TEST BEAM 2 TEST COLUMN 2 TEST COLUMN 1 TEST JOINT TEST SUPPORT

*All reinforced concrete members shall be modeled as cracked based on NSCP Sec 410 requirements. Columns = 0 .7Ig (ETABS input I2 and I3 = 0.7) Beams = 0.35Ig (ETABS input I2 and I3 = 0.35) Design Criteria: I. IDENTIFICATION From the analysis, determine the following: 1. Vertical Reaction at Test Support under pinned condition for load combo 4: 268.57 kN

______________________________ 2. Vertical Reaction at Test Support under fixed condition for load combo 4: ______________________________ 268.82 kN

3. Vertical Reaction at Test Support under soft soil condition for load combo 4: 355.10 kN

______________________________ 4. Vertical Reaction at Test Support under dense soil condition for load combo 4: ______________________________ 275.84 kN

5. Horizontal Reaction at Test Support under pinned condition for load combo 5: 27.63 kN

______________________________ 6. Horizontal Reaction at Test Support under fixed condition for load combo 5: 25.29 kN

______________________________ 7. Horizontal Reaction at Test Support under soft soil condition for load combo 5: 24.49 kN

______________________________ 8. Horizontal Reaction at Test Support under dense soil condition for load combo 5: 27.16 kN

______________________________ 9. Horizontal deflection at Test Joint under earthquake load case:Pinned: 0.0555 mFixed: 0.0337 mSoft: 0.0843 mDense: 0.0564 m

10. Maximum bending moment in Test Beam 1 under pinned condition for Load Combo 2: -73.534 kN-m

______________________________ 11. Maximum bending moment in Test Beam 1 under fixed condition for Load Combo 2: -73.533 kN-m

______________________________ 12. Maximum bending moment in Test Beam 2 under pinned condition for Load Combo 2: -69.954 kN-m

______________________________ 13. Maximum bending moment in Test Beam 2 under fixed condition for Load Combo 2: -69.365 kN-m

______________________________ 14. Maximum bending moment in Test Beam 1 under soft soil condition for Load Combo 2: -86.657 kN-m

______________________________ 15. Maximum bending moment in Test Beam 1 under dense soil condition for Load Combo 2: ______________________________ -68.704 kN-m

16. Maximum bending moment in Test Beam 2 under soft soil condition for Load Combo 2: -141.672 kN-m

______________________________ 17. Maximum bending moment in Test Beam 2 under dense soil condition for Load Combo 2: ______________________________ -62.547 kN-m

18. Maximum bending moment in Test Column 1 under fixed condition for Load Combo 2: -35.76 kN-m

______________________________ 19. Maximum bending moment in Test Column 2 under pinned condition for Load Combo 2: 16.69 kN-m

______________________________ 20. Maximum bending moment in Test Column 2 under fixed condition for Load Combo 2: 18.07 kN-m

______________________________ 21. Maximum bending moment in Test Column 1 under soft soil condition for Load Combo 2: ______________________________ 66.87 kN-m

22. Maximum bending moment in Test Column 1 under dense soil condition for Load Combo 2: ______________________________ 38.60 kN-m

23. Maximum bending moment in Test Column 2 under soft soil condition for Load Combo 2: ______________________________ 33.06 kN-m

24. Maximum bending moment in Test Column 2 under dense soil condition for Load Combo 2: ______________________________ 18.68 kN-m

25. Maximum shear in Test Beam 1 under dense soil condition for Load Combo 3: 31.29 kN

______________________________ 26. Maximum shear in Test Beam 1 under soft soil condition for Load Combo 3: 24.31 kN

______________________________ 27. Maximum shear in Test Beam 2 under dense soil condition for Load Combo 3: ______________________________ 72.40 kN

28. Maximum shear in Test Beam 2 under soft soil condition for Load Combo 3: 60.16 kN

______________________________ 29. Maximum shear in Test Beam 2 under pinned condition for Load Combo 3: 73.53 kN

______________________________ 30. Maximum shear in Test Beam 2 under fixed condition for Load Combo 3: 49.51 kN

______________________________ II. Graph and compare the variation of bending moments for pinned and fixed supports for Test Beam 2 under load combination 2. Explain the results.

As shown in Figure 1, the variation of bending moments for pinned and fixed supports were plotted.

Figure 1. Moment Diagram Comparison of pinned and fixed support under COMBO2

Figure 1 shows that the bending moment produced on test beam 2 using a pin support is almost the same with the one with the fixed support. The moment diagram for the pinned support coincides with the moment diagram of the fixed support thus the support conditions doesnt have a considerable effect on the bending moment of test beam 2.

III. Graph and compare the variation of PM chart for pinned and fixed supports for Test Column 2 under load combination 2. Explain the results.

Figure 2. Axial-Moment Comparison of pinned and fixed support under COMBO2

Figure 2 shows a comparison of the axial and moment for the pinned and fixed support. Through the graph, it can be observe that the fixed support results to a higher axial-moment than that of the pinned support. Results were shown in Table 1 to clearly compare the results.

Table 1. Table of Axial Forces and Bending MomentPinned

StoryColumnLoadLocPV2V3TM2M3

STORY1C2COMBO20-349.09-6.420000

STORY1C2COMBO21.3-344.59-6.420008.346

STORY1C2COMBO22.6-340.08-6.4200016.693

Fixed

StoryColumnLoadLocPV2V3TM2M3

STORY1C9COMBO20-349.5-11.4000-11.561

STORY1C9COMBO21.3-345-11.40003.255

STORY1C9COMBO22.6-340.49-11.400018.071

IV. Graph and compare the variation of PM chart for soft soil and dense soil condition for Test Column 2 under load combination 2. Explain the results.

Figure 3. Axial-Moment Comparison of soft and dense soil under COMBO2

As observed in Figure 3, the axial-moment of the dense soil performed higher than that of the softer soil. The axial force for the dense soil is higher than the softer soil. Meanwhile, when it comes to the moment, the soft soil offers a higher bending moment than the dense soil. The difference is due to the compromised dimensions of the foundation. A proper design for the dimensions should be done in order for the two supports to have of the same performance. Shown in Table 2 is the comparison of the axial force and bending moment.

Table 2. Table of comparison of axial and momentSoft

StoryColumnLoadLocPV2V3TM2M3

STORY1C13COMB20-462.77-12.710000

STORY1C13COMB21.3-458.26-12.7100016.528

STORY1C13COMB22.6-453.76-12.7100033.056

Dense

StoryColumnLoadLocPV2V3TM2M3

STORY1C17COMB20-358.73-7.180000

STORY1C17COMB21.3-354.23-7.180009.338

STORY1C17COMB22.6-349.72-7.1800018.675

V. Graph and compare the variation of bending moments for soft soil and dense soil condition for Test Beam 2 under load combination 2. Explain the results.

Figure 4. Bending Moments for soft and dense soil under COMBO2Figure 4 shows that at a location of 0-2.5m, the bending moments of a dense soil was higher than that of the soft soil. However, when the location exceeded 2.5 m, the soft soil has higher bending moments. In order to resist the greater effect of overturning, the area of the foundations can be adjusted.