Normally, the objective of expansion joints of bridges is to maintain continuation among two parts of the structures which remain in relative movements owing to thermal deformation, creep, shrinkage and displacement/deflection of the structures subject to traffic load. Expansion joints should have the capacity to accommodate all movements of the deck slab.
On the basis of movement, the following expansion joints are found :-
Small movement joints which have the capacity to accommodate total motion up to 45 mm.
Medium movement joints which have the capacity to accommodate total motion ranging from 45 mm to 130 mm./li>
Large movement joints which have the capacity to accommodate total motion surpassing 130 mm.
On the basis of construction, the small movement joints are categorized as follows:-
Sliding plate joints
Compression seal joints
Asphaltic plug joints
Poured sealant joints
Benefits of sliding plate joints :-
These types of joints are suitable for short and medium span bridges.
These types of joints are simple in structure and very cost-effective.
Benefits of compression seal joints :-
These seals are adaptable, considerably reasonable in cost and easy to replace.
Benefits of asphaltic plug joints :-
They arrange smooth roadway surface for traffic.
They have good resistance capacity against water and snow.
No debris is accumulated at the top of joint.
Benefits of poured sealant joints :-
These joints can be utilized easily and self leveling.
These can be arranged short span of time and they are ideal for rehabilitation/repair project.
Expose good elastic properties over a wide array of temperature fluctuation.
Types of medium movement joints on the basis of construction :-
Strip Seal Joints
Finger Plate Joints
Benefits of Strip seal joints :-
Perfectly set up strip seals contain considerably good performance.
Damage seals are substituted with lowest traffic interruptions.
Benefits of Finger plate joints :-
It accommodates all moments of the structure both horizontal & vertical.
It is suitable for medium and long span bridges.
Silent and skid & vibration free in operation.
It offers easy examination, maintenance, repair or replacement.
Type of large movement joint on the basis of construction :-
Bolt-Down Panel Joints
Modular Elastomeric Seal Joints
Benefits of Bolt-Down joints :-
These are fabricated in different widths relative to the entire permissible movement range.
Benefits of Modular Elastomeric Joints :-
These types of joints offer water-resistant and vehicular load transfer over an extensive expansion joint openings.