Lateral expansion joints

The Lateral Expansion Joints also called as Tied Universal or Tied Lateral Expansion Joints and are used to absorb lateral deflection and angular rotation. When close control of movement is not necessary or shear loading is not present a tied universal expansion joint or Lateral Expansion Joint can be used in place of Hinge or Gimbal Expansion Joint.

lateral expansion joints
Lateral Expansion Joints with Three Tie Rod
lateral expansion joints
Lateral Expansion Joints with Four Tie Rod

The tied Universal Expansion Joint is designed to absorb large amounts of lateral deflection while absorbing the pressure thrust. The joint is made up of two single bellows elements connected by a piece of pipe called as center spool. The tie rods are then attached on the outer ends and span both the bellows and the center spool. This type of construction allows the bellows to absorb the thermal growth of the piping between the tie rod attachments while eliminating the pressure thrust on the system. The pressure thrust on the system is absorbed completely by the tie rods.

The length of the center spool piece between the two bellows elements in universal expansion joints is the major factor in deciding the amount of lateral deflection that can be absorbed by the Tied lateral expansion joints. As a thumb rule the longer the center spool the more lateral deflection or movement can be absorbed. The weight of the center spool if significant can be supported by providing lugs on the center spool.

lateral expansion joints
Lateral Expansion Joints with Flange Ends
lateral expansion joints
Lateral Expansion Joints with Pipe Ends

The most common application of the tied universal expansion joint is the Z shape system. In the Z shape system the the thermal growth of the horizontal sections is absorbed as lateral deflection by the product as shown in adjacent figure.

In this type of application the joint should be designed to fill the entire offset leg so that it’s expansion is absorbed within the tie rods as axial movement. One important advantage of this type of lateral expansion joint is that the piping system does not have to be in one plane. The two horizontal sections in angular expansion joints may lie at an angle in the horizontal plane as shown in adjacent figure.

Various Types of Lateral Expansion Joints

Fixed Flanges / Tie Rods (Type 3101)

Weld Ends / Tie Rods (Type 3102)
Weld Ends / Tie Rods (Type 3102)

 Lateral expansion joints Lateral expansion joints Lateral expansion joints
 lateral expansion joints


  • Absorbs large amounts of lateral movements in any direction.
  • Eliminates pressure thrust loads.
  • Absorbs the thermal growth of the piping between the tie rod attachements.
  • Available in a single or universal design.
  • Can support the dead weight of the centerspool.
  • Minimum guiding required.
  • Eliminates main anchors.


  • More space required for Tied Universal Expansion Joints as compared to Axial Expansion Joints.
  • For large deflections the length of the Lateral Expansion Joint may exceed the space available in the Piping System.