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.

Types of Beam Designs

There are many different types of beam designs and materials to choose from when designing a structure. Engineers can choose from various shapes, sizes, construction materials, and construction techniques. Deciding on the proper beam design for a particular structure can be a complicated process. Structural engineers and builders have many different beam designs and materials to choose from when attempting to create a sound structural design.

Cantilever Beams

Structural beam design software is a builder’s best friend when planning a new structure. Structural beam design software helps eliminate potential structural failures and design flaws that may not be noticed until after construction has begun.

Beam design can be a complicated process. An experienced builder may know which type of beam is used to achieve a desired visual style of a structure, but is that beam able to support the load of the structure adequately? Does it leave open the possibility of expansion of the structure later on?  Is there a cheaper beam that would be adequate for the design of the structure?

The elements of beam design is a topic of great interest for structural engineers and contractors. Beam design is integral in the design and construction of a structure. Most structural beams are comprised of wood, steel or concrete. Each of these construction materials reacts differently under the stress of a load. Each also has its own unique advantages.

Elements and Examples of Beam Design: Concrete Beams

Loading Diagram

The loading diagram is perfect for all of those teachers that wanted to see a free body diagram.  The loading diagram is a visual representation of the loading on the beam being designed.  Below the loading diagram there is also a summary of the various loads on the beam.  This is available in any of the beam design modules, but excludes the footing and column design modules.

The loading diagram above shows all of the different loads available:

• point loads (in green)
• uniform loads (shown on the center span)

In a separate article entitled “Accurate Flitch Beam Design Made Easier with Software” there was an allusion to the difficulty associated with designing the connection between the solid sawn members and the steel members of a flitch beam.  In this article there will be a more in depth discussion on the methodology for attaching the different materials of a flitch beam so that all the materials act as one solid member.

Flitch beams must be connected together to appropriately transfer loads to the wood and steel portions of the beam in proportion to the relative stiffness of each material.  Most structural engineering software packages don’t provide this calculation; two sample methods are provided below for determining this connection.

Accurate Flitch Beam Design Made Easier with Software

Flitch beam design software is a useful tool for architects, engineers, designers, and builders. Flitch beams are a common type of composite construction. Composite construction materials are formed by combining two or more materials in a way that allows them to function as a single component structurally. Flitch beams are created by layering wood beams with steel plates or plywood in order to form a wider, lighter structural beam. Bolts hold the layered components together to form a single unit.

These advantages make flitch beams a desirable and attractive choice in light frame construction projects:

Stresses in Beams
In a separate article entitled “Structural Analysis of a Beam” there was a brief discussion of stresses and their function in structural analysis.  In this article there will be a more in dept discussion of normal, bending, and shear stress.

Normal Stress
A normal stress is a stress that occurs when a member is loaded by an axial force.  The value of the normal force for any prismatic section is simply the force divided by the cross sectional area.

A normal stress will occur when a member is placed in tension or compression.  Examples of members experiencing pure normal forces would include columns, collar ties, etc.

The process used for determining the adequacy of a wood, steel, or even a concrete beam is essentially the same. Once a beam has been selected the method is as follows:

• Determine the loads
• Calculate the stresses
• Check the allowable stresses against the actual stresses.

Determine the Loads
The first step in the structural analysis of a beam is determining the amount of load, or weight the beam is going to support.  There are two major categories of loads: