For steel structure it can be up to 400 ft, however in this case the expansion joint will have to be designed to take much larger relative movement which might not be feasible, hence its spacing is limited by the allowable movement which is practically feasible for the expansion joint.
Tips for placing concrete expansion joints
Place joints around 30 times the slab thickness apart. So, for a slab which is 100mm thick, the joints should be placed around 3,000mm (3 metres) apart. Make sure joints are cut deep enough: they need to be at least a quarter of the thickness of the slab.
Expansion joints are required when the temperature change is greater than 25°F. Scepter Rigid PVC Conduit has a coefficient of linear expansion of 3.6 x 10-4 in./ft./°F. Generally, a 100 ft. run of PVC conduit will undergo a change in length of 3.6 inches for every 100°F temperature change.
Generally speaking, expansion joints should be no farther apart than 2 to 3 times (in feet) the total width of the concrete (in inches). So for a 4‑inch thick concrete slab, expansion joints should be no more than 8 to 12 feet apart.
ASTM F-1120 is often used to specify expansion joints because for many years it was the only ASTM standard addressing metal expansion joints. The specification ASTM F-1120 was developed in the “Ships and Marine Technology” technical committee of ASTM.
As per IS- 456:2000, in the case of buildings, structures exceeding 45 m in length are designed with one or more expansion joints. As per IS 3414 which is a specific code for joints, it is mentioned as 30 m. It is clear from the above table that the maximum spacing for the expansion joint is 140 m.
British Standard BS 5385 recommends that a Joint should be able to absorb 20% of the width of the Joint in movement accommodation; these Joints far surpass the minimum requirement. The movement Joints fit this criteria for expansion and compression on a lateral basis.
As a general rule, expansion joints are provided if the length of the concrete structure exceeds 45 meters. This is because longer structures are more prone to expansion and contraction due to changes in temperature and moisture.
Spacing between attachment weld and Main joint weld min 40mm. Longitudinal welds of adjacent pipe joints shall be 100 mm. Butt welds 20 mm or 3t whichever is greater. Welding is a process used to join materials, often metals, by heating and melting the parts to be joined and adding a filler material to create a bond.
Movement joints in internal walls are not normally necessary for single dwellings unless the walls are straight and unbroken and over 6m long, in which case the block manufacturer's recommendations should be adopted. This may include the use of bed joint reinforcement in the courses above and below window openings.
In the 2023 NEC®, Section 352.44(B) was added which requires expansion fittings to be installed above grade when direct buried PVC conduit emerges from the ground and compensation is needed for earth settling or movement, including frost heave.
Expansion joints in walls at 30 m maximum intervals. (If the walls are panel walls between columns at not more than 9 m centres no joints are necessary.) Control joints over centre of openings may be given at half the spacing of expansion joints.
A general rule of thumb is that for every 100°F temperature change in a 100 ft. run of PVC conduit, the conduit will undergo 3.6" of expansion or contraction. In installations where the expected temperature variation exceeds 25°F expansion joints must be used.
The minimum allowable width of an exterior movement accommodation joint is 3/8″ for joints 8′ on center and 1/2″ for joints 12′ on center. Minimum widths must be increased by 1/16″ for every 15 degree Fahrenheit temperature change over 100 degrees from summer high to winter low.
The formula for thermal expansion is ΔL = αLΔT, where ΔL is the change in length L, ΔT is the change in temperature, and is the linear expansion coefficient, which varies slightly with temperature.
guide, the joint spacing (in feet) for plain concrete pavements should not exceed twice the slab thickness (in inches). For example, the maximum joint spacing for an 8-in [203-mm] slab is 16 ft [4.9 m]. For treated bases and stiff subgrades, this general guide may produce too long a joint spacing.
There is no specification related width of the expansion joint. However, as a general specification, it can be taken to 20 to 25 cm. As per IS- 456:2000, in the case of buildings, structures exceeding 45 m in length are designed with one or more expansion joints.
An expansion joint is cut through the entire concrete slab. On the other hand, control joints only go about a quarter of the way through it.
Limit Rods are control units designed with a gap to allow the rubber expansion joint's movement range (axial, angular, lateral, and torsional) during normal operation. In the event of main anchor failure, the limits rods will engage and function as a secondary restraint.
Abstract. ISO 15348 specifies the terminology and the general rules for the design, manufacture, control and type testing of metal expansion joints incorporating corrugated bellows.
The misalignment creates unneeded stress on the body of the joint by perpetuating a flex and handicapping the movement capabilities of the expansion joint.
A flexible piping element that consists of two corrugated bellows, a connecting center section, and accompanying end connections. Primary motion lateral. The main purpose of the universal expansion joint is to accommodate lateral movements that a single expansion joint cannot handle.