SAP2000 3-hinge arch buckling
SAP2000 3-hinge arch buckling
(OP)
Hello,
I am trying to analyze a 3-hinge arch to find the buckling load. I have attached the SAP file here, which has the modeling done correctly. I suspect I am not doing to P-delta analysis correctly.
My objective is to apply equal value point loads at the two knees and the top ridge, starting with P1=P2=P3 =36 kips and trying to determine at what equal value load the arch would buckle. The answer should be P1=P2=P3 = 43.1 kips. Other checks can be:
1. At P1 (left knee) = P2 (at ridge) = P3 (right knee)=36 kips, the downward deflection at the ridge should be 1.8189 in.
1. At P1 = P2 = P3 =40 kips, the downward deflection at the ridge should be 3.1909 in.
May I ask if someone could take a look and tell me what is not being done correctly? Thanks.
I am trying to analyze a 3-hinge arch to find the buckling load. I have attached the SAP file here, which has the modeling done correctly. I suspect I am not doing to P-delta analysis correctly.
My objective is to apply equal value point loads at the two knees and the top ridge, starting with P1=P2=P3 =36 kips and trying to determine at what equal value load the arch would buckle. The answer should be P1=P2=P3 = 43.1 kips. Other checks can be:
1. At P1 (left knee) = P2 (at ridge) = P3 (right knee)=36 kips, the downward deflection at the ridge should be 1.8189 in.
1. At P1 = P2 = P3 =40 kips, the downward deflection at the ridge should be 3.1909 in.
May I ask if someone could take a look and tell me what is not being done correctly? Thanks.





RE: SAP2000 3-hinge arch buckling
Left support : 0,0
Left knee : 50 ft, 30 ft
Ridge (hinge) : 100 ft, 40 ft
Right knee : 150 ft, 30 ft
Right support : 200 ft, 0
Cross-section of the arch member: 5.5" x 30.25"
E = 1800 ksi
RE: SAP2000 3-hinge arch buckling
Attached is the 3-hinged arch I want to analyze to determine at what value of P, the arch will buckle.
Cross-section of the arch member: 5.5" x 30.25", E = 1800 ksi
I have been using non-linear P-delta analysis and applying P in small increments. Is there an easier way to obtain Pcr?
Thanks.
RE: SAP2000 3-hinge arch buckling
RE: SAP2000 3-hinge arch buckling
RE: SAP2000 3-hinge arch buckling
There is also an option to run large deformation snap through buckling analysis, but you would need to change the P-Delta case option to P-Delta plus large displacements and switch 'Results saved' to Multiple steps