Bridge Expansion Joints
Reinforced Elastomeric Slab Seal Expansion Joints – Bridge Expansion Joints
Reinforced Elastomeric Slab Seal Expansion Joints ( Movement up to 80MM): This type of joint consists of reinforced elastomeric pads connected to a supporting steel structure which itself is cast into the concrete structure of the bridge. The joint accommodates movements by width.Typical reinforced elastomeric joint is shown in the figure below.
Functions of Elastomeric Joints
The first and foremost requirement of an adequate joint design is that joint should be capable of accommodating all movements of the deck viz. Translation and rotation. In the process, it must not cause unacceptable stresses either in the joint itself or in the structure by the way of restraint. A further requirement is low noise level especially in an urban environment .Therefore expansion joints should be
- Should permit the expansion/contraction of the span/spans to which it is fixed with out causing any distress or vibration to the structure
- Cause no inconvenience/hazard to the road user and offer good riding comfort.
- Should be capable of with standing the traffic loads including dynamic effects
- Surface exposed to traffic should be skid free and resstant to polishing
- Ensure accessibility for inspections and easy maintenance with all parts vulnerable to wear being easily repalceable
Single Strip Seal Elastomeric Joints
Single Strip seal elastromeric joint(Movement up to 80mm). Single strip expansion joint consist of two edge beams with anchorages and with elastomeric sealing element held firmly in the housing of edge beams that guarantee the water tightness the joint. The maximum gap between the edge beams at the road surface when the joint fully opens due to maximum contractions of the deck shall be limited to 80mm for comfortable passage of traffic. The edge beams protects the adjacent bridge deck concrete from damage due to vehicular impact and also transfer the vehicular loads to the deck structures through robust anchorage system. Typical single strip seal joint is shown in the figure below.
More susceptible to vandalism Contact pressure of seal with steel noising which is the key for effective sealing mechanism decay considerably with age. Hence more safeguards are required during installation for ensuring desired level of compression in the seal. Susceptible to detachment of seals from