What is diaphragm in Etabs?

What is diaphragm in Etabs?

To recap, a diaphragm is a horizontal element and the primary function in Etabs is to bind the vertical elements rigidly without allowing any out-of-plane deformation.

How do you find mass moment of inertia in Etabs?

By summing the mass of individual elements (floor elements, walls, beams and columns including the applied line loads and floor loads that constitute the seismic mass or the “mass source”) multiplied by the square of the distance of its centroid to the center of rigidity.

How do I create a mass source in staad pro?

The mass source must be understood as the actual mass that will be used in the modal analysis. The modal analysis is the first step to perform a dynamic analysis. The analysis dialog presents two options to define the masses source in the model: Node mass.

Why do we provide diaphragm in Etabs?

The main purpose of using diaphragm is to transfer the lateral load to the system. But you got to transfer these load effectively to the main frame system that is shear wall and columns. Hence you assign diaphragms.

How do you find the center of mass in Etabs?

During analysis, ETABS automatically calculates this coordinate for each floor diaphragm. The diaphragm assignment must be present in the model. Center of rigidity and center of mass are then displayed by selecting Display > Show Tables > Analysis > Results > Structural Results > Centers of Mass and Rigidity > OK.

What is mass reference load case in staad?

Click the load item Repeat Load -> Reference Load, Select the required defined Reference Load cases and click [>] to include them in the current primary load case. Clicking [>>] will include all defined Reference Load cases. You can add appropriate combination factors for each reference load.

Why do we match base shear in Etabs?

Therefore as mass increases base shear also increases. Based on experience in field base shear of a structure is almost equal to base shear produced in equivalent static method. So we go for matching.

How does Etabs calculate total building weight?

If you want to find the weight of the structure for seismic purposes, then you can do one of two things. Based on how your mass source is defined (as in what loads contribute to mass), you can show the mass and then multiply by “g” (acc. due to gravity) to get W.

How to define mass source in elementetabs?

Etabs has 3 options to define mass source. Element mass source : defines mass using mass per unit volume of materials defined. And also considers additional loads like LL and SDL. Additional Mass: it includes loads like cladding etc.

What is the difference between mass source and additional mass source?

Element mass source : defines mass using mass per unit volume of materials defined. And also considers additional loads like LL and SDL. Additional Mass: it includes loads like cladding etc. Specified Mass: when u select this option only selected load patters are considered for calculations of…

Is it necessary to include live load in the mass source?

Because it won’t include the live load and other loads like floor finish and wall load in the calculation of earthquake load. No, in case the inclusion of live load in Mass Source is not required as per your applicable design code, and other parameters including ‘Additional masses’ have been correctly applied. Otherwise, yes.

What does the mass source command do?

Just to correct you here (and my self too) that mass source command is used for calculating Center of Mass of the diaphgram. So this option is used even for wind load or any other load where we need these two centers. Pardon for my old post which was a mistake More sharing options… 3 years later… 1 month later… 2 months later…