What is the purpose of a floor diaphragm?
Definition and function: A horizontal system (roof, floor or other membrane or horizontal bracing) acting to transmit lateral forces to vertical-resisting elements. The floors and roof of a building, in addition to resisting gravity loads, are also generally designed to act as diaphragms.
How is diaphragm defined in Etabs?
- The current version of ETABS has both rigid and semirigid diaphragms.
- A rigid diaphragm is where the in-plane stiffness is so large that no two nodes can move relatively to each other.
- For the semi-rigid diaphragm, ETABS will numerically model the in-plane stiffness to represent the actual diaphragm.
What is diaphragm in building?
In structural engineering, a diaphragm is a structural element that transmits lateral loads to the vertical resisting elements of a structure (such as shear walls or frames). Diaphragms are typically horizontal, but can be sloped such as in a gable roof on a wood structure or concrete ramp in a parking garage.
What does the diaphragm muscle separate?
The diaphragm is a thin dome-shaped muscle which separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines, stomach, liver, etc.). It is involved in respiration, drawing downward in the chest on inhalation, and pushing upward in exhalation.
What is rigid and semi-rigid diaphragm?
Rigid diaphragms have infinite in-plane stiffness properties, and therefore they neither exhibit membrane deformation nor report the associated forces, whereas semi-rigid diaphragms simulate actual in-plane stiffness properties and behavior.
What is mass source in Etabs?
As the name indicates it’s the mass of the structure ie self weight as well as additional mass due to surface loads line loads ,usually DL +LL. It’s required to calculate base shear of the structure. In Etabs u need to define it whenever u perform a seismic analysis. Etabs has 3 options to define mass source.
What is diaphragm load?
Diaphragm loads are Building Direction 1, Building Direction 2, and Mz torsion loads applied at any point within a rigid or semi-rigid diaphragm. Typically these might be used for the application of externally determined level loads (for example from Wind Tunnel testing of large/ unusual structures).
What is a diaphragm plate?
A relatively thin, usually rectangular plate, used to stiffen a metal-framed structure; provides additional strength and rigidity.
How does ETABS model a semi-rigid diaphragm?
For the semi-rigid diaphragm, ETABS will numerically model the in-plane stiffness to represent the actual diaphragm. So if you have a metal deck modeled, it will use the stiffness of that metal deck.
What are the advantages of rigid diaphragms?
Formulation – The infinite in-plane stiffness components of a rigid diaphragm allows the stiffness matrix to condense, decreasing computational time.
What is the purpose of diaphragm in structural engineering?
First we need to understand the purpose of diaphragm. The main function is to transfer lateral loads to the vertical resisting components of a structure (such as shear walls or frames). Diaphragm are by default applied to the slab elements even you select whole geometry.
How is elongation/strain achieved in ETABS?
There is no elongation/strain developed. So to achieve this, ETABS ties all nodes within the diaphragm extents to the center of rigidity of the system with infinite in-plane stiffness. See image below. The user has the option of detaching individual nodes from the diaphragm if they choose.