Span Tables for LVL Beams: A Prescriptive Approach

When it comes to designing beams, there are various approaches that contractors can take. One common method is using laminated veneer lumber (LVL) beams, which offer increased strength and stability compared to traditional timber framing methods. However, with the rise of LVL beams, some may wonder what designers did before these products were available.

In this article, we'll explore how to use span tables for LVL beams to calculate the required carrier beam for a main floor, using a prescriptive approach.

Design Requirements

Before we dive into the details, it's essential to understand the design requirements of our project. Our floor joists will be 2X12s on 16-foot centers, with a minimum live load of 40 psf and a stiffness requirement of L/480. We also have a carrier beam in the middle, which will support the LVL beams.

Staggering Joints vs. Continuous Beams

In traditional timber framing, it's common to stagger joints to minimize the hinge effect over columns. However, our contractor has taken a different approach by building up the beam with 3-4 2X12s, with all the joints over the column. While this method may seem unconventional, it can be effective in certain situations.

Calculating the Carrier Beam

To calculate the required carrier beam, we'll need to use span tables for LVL beams. These tables provide the necessary information to determine the required beam size based on various factors, including span length, load, and stiffness requirements.

Assuming our design loads are correct, we can use the span tables to determine the required beam size. For example, if we have a 20-foot span with a live load of 40 psf and a stiffness requirement of L/480, our calculation might yield a beam size of 3-4 inches deep.

Prescriptive Approach

The prescriptive approach involves using standard building codes and regulations to design our carrier beam. In this case, we can use the International Building Code (IBC) or the American Society of Civil Engineers' (ASCE) code for calculating the required beam size.

By following these guidelines, we can ensure that our carrier beam is designed to meet the necessary strength and stiffness requirements.

In conclusion, using span tables for LVL beams offers a prescriptive approach to designing carrier beams. By understanding design requirements, staggering joints, and continuous beams, we can create a more robust and stable structure. Whether you're an engineer or a contractor, this approach provides a reliable method for calculating the required beam size.

Span tables for lvl beams