2.10
Types of Building Separation Joints
Building separation joints divide large or complex building structures into smaller, discrete units that can move independently. These joints are cate…
Consider a large shopping mall with a geometrically complex building structure. This complex is subdivided into small, geometrically compact, independent units using building separation joints.
These joints are classified as volume change joints, settlement joints, and seismic separation joints.
Volume change joints are placed at horizontal or vertical discontinuities in the building to relieve the effects of expansion and contraction of the building units.
Generally, these joints are located at intervals of 150 to 200 feet.
The tower and the adjoining low-rise wing of the building are separated using settlement joints designed to avoid distress due to different rates of settlements anticipated for the different types of foundation provided.
Seismic separation joints are provided between building segments to allow individual units to move independently during an earthquake, preventing damage to one another.
Lastly, the individual units existing on either side of the plane of the building separation joint can have their distinct foundations, columns, and slabs, making them independent structures that can move as a unit in response to the forces acting on them.
View the full transcript and gain access to JoVE Core videos
Q1: What are the three main types of building separation joints?
Building separation joints are classified into three types: volume change joints, settlement joints, and seismic separation joints. Volume change joints relieve expansion and contraction effects at discontinuities, typically spaced 150 to 200 feet apart. Settlement joints prevent distress from differential foundation settlement rates. Seismic separation joints allow independent movement during earthquakes.
Q2: How do volume change joints address building movement?
Volume change joints are positioned at horizontal or vertical discontinuities to relieve the effects of expansion and contraction in building units. They accommodate dimensional changes caused by temperature and moisture variations in masonry materials. These joints are strategically spaced at intervals of 150 to 200 feet to manage stress from expansion and contraction in masonry walls.
Q3: Why are settlement joints necessary in buildings with different foundation types?
Settlement joints prevent structural distress caused by differential settlement rates between building sections with varying foundation types or soil conditions. A tower and adjoining low-rise wing, for example, may settle at different rates. These joints separate the structures so each can move independently without transferring damaging forces to adjacent units.
Q4: What is the primary function of seismic separation joints?
Seismic separation joints divide buildings into smaller, independent segments that can move freely during earthquakes without damaging one another. Each segment has its own distinct foundations, columns, and slabs, allowing individual units to respond independently to seismic forces. This design minimizes structural damage in earthquake-prone areas.
Q5: How do building separation joints create independent structural units?
Building separation joints subdivide large or complex structures into discrete units by providing complete separation of structural elements. Each unit on either side of the joint can have its own distinct foundations, columns, and slabs, enabling them to function as independent structures. This arrangement allows each unit to move as a separate entity in response to various forces.
Q6: What spacing intervals are recommended for volume change joints in elongated structures?
Volume change joints in elongated structures are generally spaced at intervals of 150 to 200 feet apart. The exact spacing depends on material properties and the extent of dimensional changes expected due to temperature and moisture variations. Proper spacing ensures effective relief of expansion and contraction stresses throughout the building.
Q7: How do building separation joints differ from movement joints in their application?
Building separation joints create completely independent structural units with separate foundations and elements, allowing distinct movement in response to settlement, seismic activity, or thermal changes. Movement joints in buildings address localized expansion and contraction within a single structural system. Separation joints divide the entire building into autonomous segments, whereas movement joints accommodate internal stresses within connected structures.