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SAP 2000 Nonlinear Analysis

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                    I am designing a five-storey glass wall structure. Each storey is attached by some tension rods. I have assigned each of the tension rod as "nonlinear element" as "hook" (tension only) and give it the proper stiffness, weight etc. On the other hand, I have set the proper "Time History Case". I was told that if I would like to look at the axial force of each of the tension rod, I need to look under the section of "NLLINK ELEMENT HISTORY FORCES" instead of the ordinary "Load Combination" because it only proforms the linear analysis. As I found that the axial force for most of the tension rods are zeros and only a few of them with positive number.
 
            The following are the problems I have encountered:
               
            1>    Is it right that I should only look under  "NLLINK ELEMENT HISTORY FORCES" instead of the ordinary "Load Combination" for all the nonlinear elements forces? Because I can still find negative axial force (compression) if I look under the ordinary "Load Combination" while I find zero or positive axial force (tension) if I look under the "NLLINK ELEMENT HISTORY FORCES".
                 
            2>    If yes, does it mean that for those tension rod with zero axial force are in fact under compression, but only becasue they are set as "hook", so their axial forces become zero? I would like to find the maximum value of axial force of all the tension rods.
 
            3>    Besides the tension rods, there are some other sections in the structure like circular hallow sections etc. I believe I should look under the ordinary "Load Combination" for their element forces instead of the time history case. Is that right?
 
            4>    One of the loading is temperature difference of +35 C na d-35 C. I have inputted it as one of the loading of "TYPE = TEMPERATURE" and "BY ELEMENT TEMPERATURE = 35" Is that right of should I inputted "70" instead? Also, I have setted the reference temperature for all the elements is 0 C.  
 
            Thank you so much.
 
Enny