When you first look at a building, you notice the roof, walls, and windows. However, if you’ve wondered how buildings large and small are able to withstand high winds, drastic temperature changes, and even seismic activity underground, the answer is expansion joints. What are they and what role do they play in today’s modern buildings? Here’s what you need to know about how expansion joints impact a building.
Division is the Key
The most important thing expansion joints do in most buildings is divide long slabs of concrete into multiple sections. Doing so alleviates the stress that would be placed on any one slab, allowing vibrations from seismic activity or strong winds to be spread out more evenly within the building’s structure.
Used in More Than Buildings
You may be surprised to learn that expansion joints are used in a variety of structures other than buildings. In fact, they are commonly found in all types of ships, on railroad tracks, floors and sidewalks, and piping networks. This can be a critical safety component for ships and railroad tracks in particular since even the slightest bit of damage inflicted during temperature changes or other factors could lead to a ship’s hull being breached or railroad tracks becoming uneven and leading to a derailment.
Factors for Using Expansion Joints
When contractors are deciding where and how to use expansion joints during a construction project, many factors come into play. Some of the most common include the average temperature and humidity level of the area, climate predictions regarding weather changes in the years following construction, the plan and elevation of the building, and any unique irregularities the building may have following construction. Since they play such an important role in the safety of a building or other structure, contractors carefully analyze the stress levels that will be placed on a building due to ground settling and other factors when deciding on the placement of expansion joints.
Expansion Joints and Fire Protection
Along with acting as stress relievers for a building, expansion joints also play an important role in a building’s fire protection levels. Within a typical building, the floors, walls, and ceilings are split in half with expansion joints. In recent years, joints have been developed that are water and fire-resistant. Because of this, it allows the expansion joints to make it harder for heat, smoke, and flames to spread from one room to another. Essentially acting as fire barriers, expansion joints are often credited with saving a building from being severely damaged when a fire occurs.
Structural Frame Stiffness
When joint movements are being calculated for a building, structural frame stiffness must be part of the equation. To ensure the expansion joints are placed correctly within the building, the gap for each joint should be as small as possible, since this will allow for a full range of predicted design movement.
Critical to the structural integrity of a building, expansion joints can compensate for a building’s irregularities as well as offer protection from fires and other issues.