Posts Tagged lateral loads
Beam Design and Structural Design in Commercial and High-Rise Buildings
Beam design and structural design in high-rise buildings is constantly evolving. Structural designs are created to withstand earthquakes and high winds, conform to building codes, and construct impressive visual designs. Beam designs can significantly affect the stability of a high-rise building as well as the aesthetic appeal of a structure.
The structural design of a high-rise building is greatly dependent upon lateral loads. For this reason, bean design in high-rise buildings deserves careful consideration. Specially designed internal support system help keep the structure stable, especially in high wind and during earthquake tremors.
Factors Affecting Beam Design and Structural Design in Commercial and High-Rise Buildings: Drift and Acceleration
Another factor that plays into the beam design and structural design of commercial and high-rise buildings is drift. Drift is defined as the ratio of the building deflection over its height. Structural engineers must also take into consideration building acceleration when designing beams for commercial and high-rise buildings. Building acceleration is a measure of the speed with which drift occurs. This plays a critical role in the stability of a high-rise structure.
Beam Design in Commercial and High-Rise Buildings: Shear Wall Systems
One popular way to stabilize a high-rise building is by using shear wall construction. A shear wall is designed to withstand the combined forces of shear, moment, and axial loads caused by wind loads and gravity loads in a high-rise building. A shear wall system joins solid structures that remain constant from floor to floor to add strength and stability in a tall building. However, shear wall construction inhibits the design of the foyer or lobby of a building. To achieve an open, inviting space, structural engineers often must use a combination of other support systems to allow for the desired design of the building.
Transfer beams are often used in conjunction with a shear wall system in commercial and high-rise buildings. Transfer beams are designed to transfer the load from the shear walls to the lower frame of the structure. This combination of transfer beams and shear wall supports has proven reliable, even in high winds and during an earthquake.
Beam design and structural design in commercial and high-rise buildings can utilize many different design techniques to achieve the desired height and visual attractiveness specified by the architect and owner. Beam design and structural design in commercial and high-rise buildings is an ever-evolving process.
The column module in StruCalc is set up to design most posts in residential or light commercial projects. The program first asks the user to specify the type of column to be designed. There are five different types of materials available in the column module:
- solid sawn
- structural composite
- tube steel
Each of these materials then has selections from the current National Design Specification in use for species, grade, width and depth.
After the material has been selected the overall height of the post must be entered followed by the unbraced length in each direction. The unbraced length of the column would be the distance between any sort of bracing that might be provided within the structure (drywall, sheathing, kickers, etc.). The column end condition, K (e) is automatically set at 1.0 for pin-pin supported columns and 2.1 for cantilevered columns.
Once the overall conditions of the column have been established the loads must be entered. The module first asks for any vertical load applied to the column followed by the load eccentricity. The load eccentricity is a measure of how far away from the center of the column the load is applied. Looking at the post in plan view there would be both an x and y measurement to how far the load is away from the center of the column, and hence, the module asks for both to be entered.
Once the vertical loads have been applied, the module then asks for any lateral loads to be entered. Lateral loads can be entered in the form of:
- a uniform load across the entire column
- point loads placed at various locations on the column
- partially distributed loads on the column
It will also ask which face of the column the lateral loads are being applied. As well as if the lateral loads are wind and/or seismic loads (for wood, glulam, or structural composite columns).
One other important feature within the column module is the ability to do a stud wall design. This part of the module will verify the adequacy of stud size and spacing based on the length of the studs and the vertical and lateral loads applied to the studs. This part of the module will unfortunately not specify shearwall nailing. Here is a view of how StruCalc applies loads and measurements in stud column design:
Here is a view of how StruCalc applies the loads and measurements in its normal column design module:
Finally here is a view of the load entering interface for column design please click the thumbnail for a detailed view:
Within the column module of StruCalc there is the ability to calculate a cantilevered column.
The column module typically assumes a pin-pin connection for the end supports, but the end condition can be changed to a cantilever inside the module. Once a cantilever has been designated by selecting the Cantilever Column checkbox the Column End Condition or K(e) value will change from 1 to 2.1 and the top of the column will then be unrestrained.
This is particularly useful for posts that are supporting lateral loads of some kind such as:
- pole barn supports
- car port supports
- wind post design
- fence post
You can view the representation of this type of a column in StruCalc by clicking the thumbnail below
Follow this link for more information on StruCalc columns