SLAB

[newman]

with building modeller, I can create a RC structure with slab (with 20 cm thickness). But, when I create its spf format, I think, my structure has not any thickness. what is the problem?
I also want to know that how can create slab with thickness only by the Seismostruct tabs? There is no option I think. I only can create a rigid diaphragm without any thickness for the slab. Am I right?

[seismosoft]

There is no problem, what you see is the rigid diaphragm of the slab. The slab loads (dead load, additional dead load and live load) are calculated and applied at the supporting beams. Please refer to the building modeller section of the manual.
Seismosoft Support

[newman]

Thank you.
Please help me. the mass source in my work, should be calculated based on (Dead load + 0.2 Live load). I don't know what happen when I use the distributed dead and live load in my slabs.
if I use the coefficient loads in the slab setting (0.2 for live and 1 for dead), these coefficients used only for loading OR used for mass and the loading calculations both? I mean, how the mass source calculated when I used the option of "the loads automatically inverted to weights" in the setting program?
In fact, I want to have a model which determine the mass source based on "Dead load + 0.2 Live load" and determine the final loads based on "Dead+Live".

[seismosoft]

You can determine the dead and live load coefficients from the Building Modeller settings.
The gravity vs. mass settings can be etermined in the Program Settings>Gravity and Mass window.
In any case, if you want a model with the mass equal to "Dead load + 0.2 Live load" but the gravity loads equal to "Dead+Live", you need to work it out yourself. The Building Modeller create models with the same combination for mass and gravity loads.
Seismosoft Support

[newman]

I have a 3d-model wich is created by building modeller. I had a slab (5mx5mx0.15m) with four supporting beams, based on concrete material with specific wieght: 24 KN/m3, and also 2.84 KN/m2 dead load and also 1.96 KN/m2 live load. For supporting beams, a distributed load equal to 8.453 KN/m was defined. Now, in its seismostruct model, my loads does not exist in the "applied loads" tab, but, an additional mass was assined to my suporting beams equal to 1.73671 ton/m. But I think it's not true, why? please help me to know that how seismostruct calculate and reach to this 1.73671 value??

((24KN/m3x(5mx5mx0.15m))/4)/5m=(4.5 KN/m) /9.81=0.4587 Ton/m
((((1.96+2.84)KN/m2)*5mx5m)/4)/5m)=( 6 KN/m)/9.81= 0.6116 Ton/m
(8.453 KN/m)/9.81=0.8617 Ton/m

0.4587+0.6116+0.8617=1.932 Ton/m , but, seismostruct reported 1.73671

[z.gronti]

Dear newman,

Which is the value of the live loads coefficient? The way you calculate the combination of the dead and live loads indicates that you have set it equal to 1, is it correct?

[newman]

Yes. 1 for both.

[newman]

I have a 3D four-story model by seismo building madeller. I had a slab (5mx5mx0.15m) with four supporting beams, based on concrete material with specific wieght: 24 KN/m3, and also 2.84 KN/m2 dead load and also 1.96 KN/m2 live load. For supporting beams, a distributed load equal to 8.453 KN/m was defined. Now, in its seismostruct model, additional mass which was calculated by SeismoStruct and added to my beams, have different values in beams for third and four floor. my structure is ssymmetric in each floor. but, additional masses which were reported by sesimoStruct for the beams of each floor, have different mass!. I create the model one more time again, but the problem was remained. please check it:
https://uploadfiles.io/79p14

[z.gronti]

Dear Newman,

I took a look at your model and it seems to me that the masses are calculated correctly.

For example, in the 1st floor- slab's S3 dimensions are 4.6m x 4.6m and Beam's B6 length is 4.55m. Hence, if you make the proper calculations you will see that the additional beam's mass is calculated correctly. The slab's, S3, loads are divided by 4 to be distributed to the 4 supported beams due to the fact that your model is symmetric.