|
View previous topic :: View next topic |
Author |
Message |
spsvasan at eth.net Guest
|
Posted: Wed Oct 29, 2003 6:02 am Post subject: [e-Conf] Draft IS:800 |
|
|
Hello everybody,
(A) Comparison of Clauses 4.3.5.1 and 7.3.3.1 in Draft IS:800
The clauses 4.3.5.1 and 7.3.3.1 are very similar. But clause 7.3.3.1 is more elaborate and covers two more cases, viz, roof truss bearing and column web connection. Is there any reason for omitting these two cases in clause 4.3.5.1?
(B) Notional Horizontal Loads in Draft IS:800
The notional horizontal loads (Clauses 4.3.6, 4.1.2), and 5.5.1.2) are mentioned only regarding sway stability of the frames. Am I correct in assuming that notional horizontal loads need not be considered in strength check? If they are to be considered only for sway stability check, the load factor should be 1.0?
(C) Minor typo errors in Draft IS:800
(1) Table 7.2: Welded box sections: second expression below "Thick welds and" should be "h/tw" instead of "d/tw"
(2) Clause 7.5.2.2: The term "7.5.2.1" should probably read as "7.5.1"
(D) Comparison of Clauses 4.3.5.2(b) and 7.3.3.2
Clauses 4.3.5.2 (b) and 7.3.3.2 are similar, but, in addition, clause 7.3.3.2 permits simpler (?) equal division of joint moment to upper and lower columns. I think the provision regarding equal distribution of joint moment to upper and lower columns is not necessary. In any case, (MI/length) has to be calculated to check whether this equal distribution is permissible. Once we have I/l values it is easy to apportion the joint moment in proportion to their stiffnesses, which is more accurate..
(E) Clause 7.4.2.3 in Draft IS:800
The clause 7.4.2.3 gives the minimum size of base plate below stanchions. This clause is present in the 1984 code also. I do not understand the necessity of this provision. Is anything wrong in adopting smaller base plates, if the load transfer between stanchion and pedestal is otherwise proper?
(F) Table 7.6 in Draft IS:800
Table 7.6 pertains to the design of single angle struts.
(1) The constants k1, k2, and k3 depend upon the "gusset/connecting member fixity". The table gives values of the constants for fixed and hinged conditions. The note below the table indicates that intermediate values are to be adopted based on the "Stiffness of in-plane rotational restraint provided to the gusset/connecting member" Is there any reference showing how to calculate the stiffness of gusset/connecting member? Let us consider a truss. In calculating the in-plane rotational stiffness of the gusset plate, where do we apply the load or loads? How do we account for the flexibility of the top or bottom chord to which the single angle strut is connected? What value of [(gusset stiffness) / ( strut stiffness)] will entitle us to assume fixed end condition?
(2) There seems to be a typo in this table. The second value below k3 appears to be incorrect.
(G) Clause 7.6.1.5 and 7.7.1.4 in Draft IS:800
The two clauses 7.6.1.5 and 7.7.1.4 deal with the increase in effective slenderness ratio for laced and battened columns due to shear deformation effects.
I wish to know whether the shear deformation effect affects only global slenderness ratio of the column or does it also affect the local slenderness ratio of the column?
Regards S.P.Srinivasan
Posted via Email |
|
Back to top |
|
|
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You can attach files in this forum You can download files in this forum
|
|
|
|