How to Install Strip Seal Expansion Joint? [PDF]

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A strip seal expansion joint is a mechanical device used to seal an expansion joint formed between two slabs of pavement or slab to absorb temperature-induced expansion and contraction safely.

The gap between the two adjacent slabs is filled with a rubber strip to guarantee water-tightness and prevent debris and corrosion ingress.

Components of Strip Seal Expansion Joint

1. Edge Beams

This is a special claw-legged profile member that shall be made of extruded rolled steel section combining good weldability with notch toughness.

2. Strip Seal

The strip seal is provided to ensure water-tightness. The part that has to be inserted into the groove (provided in the edge beam) should have a bulbous shape.

The strip seal made of chloroprene should possess high tear strength, insensitivity to oil, gasoline, and ozone; it should also have a high resistance to aging. The seal should be vulcanized in a single operation for minimum full length of joint.

The standard requirements of the strip seal properties are tabulated in table 1.

Table 1: Standard Requirements of Strip Seal

Properties of Strip Seal	Specified value
Hardness	63±5 shore A
Tensile strength	Min 11 Mpa
Elongation at fracture	Min 350 percent
Tear propagation strength
Longitudinal	Min 10/N/mm
Transverse	Min 10 N/mm
Shock elasticity	Min 25 percent
Abrasion	Min 220 mm3`
Residual compressive strain (22 h/70 deg C/30 percent strain)	Max 28 percent
Ageing in hot air (14 days / 70 deg C)
Change in hardness	Max ±5 shore A
Change in tensile strength	Max -20 percent
Change in elongation at fracture	Max -20 percent
Ageing in ozone (24 h/50 pphm/25 deg C/20 percent strain)	No cracks
Swelling behavior in Oil (116 h/25 percent C) ASTM oil No.
Volume change	Max 5 percent
Change in hardness	Max 10 shore A
ASTM Oil No.3
Volume change	Max 25 percent
Change in hardness	Max 20 shore A
Cold hardening point	Min -35 deg C

3. Anchor Loops

Anchor loops shall be made of weldable steel connecting the rigid anchorage with deck reinforcement.

Pre-Installation of Strip Seal

1. The rolled steel profiles for edge beams shall be long enough to cater for a 2–lane carriageway.
2. These shall be cut to the size of actual requirements by means of a miter box saw. 
3. The alignment of the cut-to-size steel profiles shall be made with the actual bridge cross-section on work tables.
4. After the steel profiles are set in place, they will be chucked to the tables using screw clamps and tacked by arc welding.
5. The anchor plates shall be cut to the required size by the gas-cutting technique. 
6. The anchor loops shall be bent to the required shape and welded to anchor plates.
7. The assembled joints shall then be clamped and transported to the worksite.

Handling and Transport

1. Transportation and storage of the strip seal will be supported on auxiliary brackets to hold the joint assembly together.
2. It shall be stored under a cover supported by suitable lumber padding to prevent damage.
3. The joint expansion material shall be handled with care.

Installation of Strip Seal Expansion Joint

1. The width of the gap in strip seal to cater for movement due to thermal effect, prestress, shrinkage and creep, superstructure deformations, and sub-structure deformations shall be calculated and informed to the manufacturer.
2. The gap dimension shall be preset, depending upon the temperature at which the joint is likely to be installed.
3. Considering the width of the gap for movement of the joint, the dimensions of the recess in the decking shall be left out.
4. The surfaces of the recess shall be cleaned for dirt and debris.
5. The deck slab's reinforcement shall be suitably adjusted to permit the unobstructed lowering of the joint into the recess.
6. Prior to placing the strip seal joint, the presetting shall be inspected.
7. The joint shall be lowered and placed in the prepared recess.
8. The joint shall be leveled, aligned, and the anchor loops on one side of the joint shall be welded to the exposed reinforcement bars of the structure.
9. The auxiliary brackets shall be released to allow the joint to take up the movement of the structure after the joint is held firmly on both sides. High-quality concrete shall then be filled into the recess and packed.
10. The concrete must have the property of low shrinkage and shall be of the same strength that of the structure, which shall not be less than M35 grade. 
11. Proper compaction and careful curing of concrete is particularly essential. Once the concrete is cured, the movable installation brackets shall be removed.
12. A rolled-up neoprene strip seal shall be cut and inserted between the edge beams by using a crowbar pushing the bulb of the seal into the steel grooves of the edge beams.
13. Once the concrete in the recess is initially set, a sturdy and robust ramp shall be laid over the joint to protect the exposed steel beams and neoprene seals from site traffic.

FAQs on Strip Seal Expansion Joint

Read More:
1. Control Joint vs. Expansion Joint Difference
2. Expansion Joint in Concrete – Types and Characteristics