Concrete structures and other building systems often incorporate joints that accommodate movements due to thermal and/or seismic conditions. These joint systems may be positioned to extend through both interior and exterior surfaces (e.g., walls, floors, and roofs) of a building or other structure.
In the case of an exterior joint in an exterior wall, roof, floor, and so forth, exposed to external environmental conditions, the expansion joint system should also resist the effects of the external environment conditions. In vertical joints, such conditions will likely be in the form of rain, snow, or ice that is driven by wind. In horizontal joints, the conditions will likely be in the form of rain, standing water, snow, ice, and in some circumstances all of these at the same time. Additionally, some horizontal systems may be subjected to pedestrian and/or vehicular traffic.
With particular regard to bridge expansion joints, a major cause of structural deterioration of piers, columns and beams on bridges is leaking and/or deterioration of joints. Water laced with de-icing salts and atmospheric contaminants directed through expansion joints can shed directly onto critical structural elements of the bridges. Potential corrosion and subsequent spalling may occur thereby necessitating expensive reconstruction of beams, piers, columns, wing walls, and so forth.
Moreover, expansion joint products do not fully consider the irregular nature of some expansion joints. It is common for an expansion joint to have several transition areas along the length thereof. These may be walls, parapets, columns, or other obstructions. As such, the expansion joint product follows the joint as it traverses these obstructions. In many products, this is a point of weakness, as the homogeneous nature of the product is interrupted. Methods of handling these transitions include stitching, gluing, and welding. In many situations, it is difficult or impossible to prefabricate these expansion joint transitions, as the exact details of the expansion joint and any transitions and/or dimensions may not be known at the time of manufacturing.
Additionally, in many products, the afore-referenced transitions present weak spots from both a water proofing aspect and a fire resistant aspect. Both expansion joints and fire resistive expansion joints typically address either water tightness aspects or the fire resistive nature, but not both. This has typically resulted in the installation of two systems for each expansion joint where both a fire rating and water resistance is required. In many cases, however, there simply is not sufficient room in the physical space occupied by the expansion joint to accommodate both a fire rated system and a waterproofing system.
Accordingly, there exists a need for improved expansion joint systems, which can not only accommodate thermal and/or seismic movements, but also assist in alleviating and/or preventing deterioration of structural features due to environmental factors. There is a further need for such expansion joint systems that can also address fire and water resistance in one system.