Bridge Expansion Joint for Bridges with Expansion Joints in Deck Slabs on Geosynthetic Reinforcement

Geosynthetic reinforcement is used to improve the bearing capacity and reduce the settlement of soft ground under bridge approach fills. The installation of geosynthetics near existing expansion joints requires careful planning to minimize the effects on the joints. Geosynthetic types used for ground reinforcement include geogrids, geotextiles, and geocells. Geogrids are rigid or semi-rigid polymer grids that provide tensile reinforcement to the fill. Geotextiles are flexible polymer fabrics that provide tensile reinforcement and filtration. Geocells are three-dimensional polymer cells filled with soil or aggregate. Geosynthetic installation involves placing the geosynthetic on the prepared subgrade and covering it with fill. The fill is compacted in layers to achieve the required density. The compaction can cause vibration that can affect adjacent expansion joints. Vibration from fill compaction can affect adjacent expansion joints. The vibration level depends on the compaction equipment and the distance from the compaction to the joint. Vibration monitoring is recommended during fill compaction near existing joints. Settlement of geosynthetic reinforced fills can affect adjacent expansion joints. The settlement depends on the compressibility of the subgrade soil and the thickness of the fill. Settlement monitoring is recommended during and after fill placement near existing joints. Post-installation inspection of existing expansion joints must verify that the geosynthetic installation has not caused any damage. The inspection should check the joint gap width, the concrete edge beam condition, and the anchor bolt torque. Any damage must be repaired before the bridge is returned to service.