I got several problems in my project:
1.I have several elbows less than 5 degree in pipelines and got error "Bend angle specified for the bend element is within 5 degree of bend far end point, either use the bend far end point or move the specified node more than 5 degree away from the end point"
The problem is , the piping layout will be changed if I move the node. And a gap will be generated between the pipes if I connenct the skewed pipes together without a BEND.
Is it possible to build the elbow in CAESAR II less than 5 degree?
2. I have 384 element in the pipelines. ALLOWABLE STRESS button is actived for every element. Can you recommend a convenient way to active the button? I have to press button one element by another. it can't be propagated.
3.I have 2 uniformal Loads, snow load (lb/in)and seismic load (g-value). I can't input the two uniformal loads at the same time because they have different unit. What can I do for uniformal loads with different unit?

Any advices will be appreciated greatly!

1. Go to :
CONFIG/GEOMETRY DIRECTIVE/MINIMUM ALLOWABLE BEND ANGLE
and select 0.1

3. You have different vector for uniform loads between 1 and 3

2) You should NOT check the "Allowable Stress" checkbox on every element. Allowable stresses are propagated by the program. The same holds true for uniform loads and wind/wave data - these are all propagated even though the checkbox isn't checked. Consider these on/off switches, so once you set the data, that is what gets used until you change it again.

3) Uniform loads (all three vectors) are assumed to have the same units. So, either all uniform load vectors are "force/lenght", or all uniform load vectors are "g loads". You can't mix the two in the same job. If this is what you need, you'll have to duplicate the job and change the uniform load specifications.

For your item 2) Allowable Stress is a "carry forward" item. You only need specify this when it changes. If the piping code or the allowable stress does not change, don't check this box.
Item 3), yes, the unifrom load input does not support both load/length and g in the same model.

Are you trying to include the mass of the snow in the g calculations? CAESAR II will not consider any uniform load (load/length) as mass.

Thanks for all you guys quick response. This forum is extremly helpful.
Question No.1 Done. Thanks for mariantrifan's advice
Question No.2 Done. I will not check the box one by one.

Question No.3 What I did at present is to transfer the snow load into g-value, the same as the seismic load:
Snow Load (For Mcmurray, Alberta CA): 1.4 kpa (0.203)psi
Pipe Length: 60 ft
Pipe Dia.: 68"
Cross Area of Pipe:60*12*68= 48,960 square inch
Snow Weight: 0.203*48,960= 9938.88 lb
Piping System Weight: 100,000 lb
The snow weight 9938.88 lb added on the piping system 100,000 lb is equal to uniform load with g-value 9938.88/100,000 = 0.1 g in -Y direction. Then I input snow load 0.1 g together with seismic load.

Richard and Dave, is it correct for me to calculate snow load in g-value? Please advise.

That 0.1g will get you close.
One exception would be rigid elements - having more weight per area, the g load will put more snow on these elements. I cannot say it would be significant.
Did you want some of that snow mass reacting with the seismic component? If so, you should bump up you seismic g by another 10%. I guess it would depend if it's dry snow or frozen snow. We don't worry about such things in Houston.