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Pantheon is a building in Rome built at about 126 AD. It has world's largest un- reinforced concrete dome in the world. I am amazed to know that Romans were able to built a dome of such scale without any reinforcement , a feat that few will dare to attempt now. It has a diameter and height equal to 142 ft(43m). This building is in continuous use since 7 century.

http://www.aleckassociates.co.uk/structural-engineering/history-of-structural-engineering-the-pantheon/ sheds light on the structural engineering aspects of Pantheon.

Temperature and shrinkage are source of tensile stresses so reinforcement is need to arrest cracks.

Is it necessary to adjust insertion point accordingly for each element? i know it would economise the design but what is the easy way of adjusting insertion points?

Idea is to use the stiffness properties of crossection based on its expected behaviour in particular situation, as mentioned in commentary. Commentary gave the example of analysis under wind and earthquake situations. In case of wind structure is intended to remain elastic under service loads so use properties based on gross crossection or 1.4 times the reduced crossection properties which are based on section 10.10.4.1) In case of earthquake reduced crossection properties are required at service level to estimate drifts and related p-delta/second effects. So in case of wind load you can check drifts based on gross crossection properties against unfactored loads. But P-delta effect may dictate final configuration of member and for that reduced crossection properties are needed. Remember P-delta effect is increased in the values of moments and shear forces due to gravity loads acting on deformed member shape. P-delta analysis estimates the increase in these values. Another situation where one must use reduced properties is long term deflection of flexural members.

actually i was editing the ACI reference but my pc had no power suddenly :-) so sorry for that,thanx for reply Rana sab

first point: Both methods addresses same behaviour. Moment magnification is a term used when we are taking second order effects due sway of structural system while elastic second order method(Euler) addresses slenderness of individual members. ACI code directs us to reduce stiffness of members when computing forces due to second order effects so ETABS requires us to specify stiffness modifiers and then it can calculates theses effects . Second point: Code uses Stability Index or Pu/Pc as tool to estimate magnified moments and second order effects can still be there in braced frame as there might be some slender member (Euler's equation is used in that case). Third point: Yeah one must check for slender members. I think, limiting values for drift control are not there to control structural damage instead they are for non structural damage(citation needed): hence it does not mean that there are no second order effects. Cant comment on remaining material.

its around 18:30 hrs

kam kam aur kam!

apart from ETABS remember that i used some softwares where they have written in manual that the limited version contains random errors so dont use it for design so if some one cracks that it will too generate errors..just dont blindly download any tool and start looking for crack and the use...pls read manual first.. but for ETABS i didnt find anything like that

Not true! On a lighter note, normally your Boss would tell you that and bump up the steel by 30%.