Why expansion joints are used

Universal Expansion Joint Assemblies consist of two bellows connected by a center spool piece with flange or pipe ends. The main advantage of universal expansion joint over single expansion joint is that the universal arrangement provides greater absorption of axial, lateral, and angular movements than a Single Expansion Bellows Assembly. Externally Pressurized Pressure Balanced Assemblies are used when a large amount of axial movement is required to absorb and pressure thrust must be absorbed by the expansion joint.

However, for the current case, the opposing forces are generated from pressure acting on the outside of the bellows. In Restrained type piping expansion joints, the expansion joint hardware is capable of restraining the pressure thrust of the system by their design.

Intermediate anchors are installed to withstand the spring force generated due to the deflection of the expansion joint. The main anchors are not required. They are again of various types as mentioned below:. The tie rods are attached to the pipe or flange with lugs. These tie rods carry the pressure thrust generated in the system, eliminating the need for main anchors. Tied Universal Expansion joint Assemblies are mostly similar in construction to a Universal Assembly.

The only difference is that tie rods absorb pressure thrust and limit movements to lateral offset and angulation only. Hinged Expansion Bellows Assemblies limit movement to angulation in one plane. Hinged Assemblies Fig. Gimbal Expansion Bellows Assemblies are designed to absorb system pressure thrust while allowing angulation in any plane.

Gimbal Assemblies Fig. Pressure Balanced Elbow Assemblies are used in applications where space limitations are a concern. A system of tie rods or linkages is used in such a fashion that the pressure thrust acting on the line bellows is equalized by the balancing bellows.

The only forces transmitted to equipment are low spring forces created by the axial, lateral, or angular movements. Conversely, when the temperature drops, the materials cool causing the joint gap to open.

This requires the joint system to expand to follow the joint movement. Expansion joint transitions are essential for ensuring a sealed, safe, and energy efficient building envelope. Continuity of seal at changes in plane and direction, and between expansion joint systems, is achieved when factory-fabricated transition assemblies are specified and installed. Whenever possible, transitions should be factory-welded to the ends of longest possible lengths of straight-run material.

This minimizes the number of field-welded connections — saving time and reducing risk. Silica sand is an excellent extender for epoxy-based compounds and sealants. To prevent sidewalks from cracking in random spots and breaking apart, builders make lines in sidewalks.

Contraction joints are placed in fresh concrete before the concrete dries and has a chance to create its own joints, which we call cracks. Every concrete slab, inside basements, garages, etc. Expansion Joints provide space between concrete slabs as a buffer for expansion on hot days and contraction when it is cold.

Push the bull float in one direction only across the concrete, keeping its front edge slightly above the surface by raising or lowering the handle. Two or three times is enough. Length-to-width ratio of stucco panel cannot exceed 2.

Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough from drying shrinkage to account for temperature expansion. The simplest way to keep the roadbed from bending is to use a king post. In the illustration below, the downward force of the center of the bridge pulls down on the vertical post. This places the diagonal braces under compression. Expansion joints are provided in slabs, pavements, buildings, bridges, sidewalks, railway tracks, piping systems, ships, and other structures.

This article emphases on need of expansion joint in concrete, characteristics of expansion joints, types of expansion joint and installation of expansion joints. Bridge Expansion Joint 2. Masonry Expansion Joint 3. Railway Expansion Joints 4. Pre-Concrete Installation 2. After Concrete Installation. Characteristics of Expansion Joints Expansion joints permits thermal contraction and expansion without inducing stresses into the elements. An expansion joint is designed to absorb safely the expansion and contraction of several construction materials, absorb vibrations, and permit soil movements due to earthquakes or ground settlement.

The expansion joints are normally located between sections of bridges, paving slabs, railway tracks, and piping systems. The expansion joints are incorporated to endure the stresses.