Bridge Expansion Joint for Bridges with Expansion Joints in Deck Slabs on Ground Anchors

Ground anchors are used to stabilize retaining walls and slopes near bridge abutments. The installation of ground anchors near existing expansion joints requires careful planning to minimize the effects on the joints. Ground anchor installation involves drilling holes into the ground, inserting the anchor tendon, and grouting the hole. The drilling can cause vibration that can affect adjacent expansion joints. The prestressing of the anchor can cause ground movement that can affect adjacent expansion joints. Vibration from ground anchor drilling can be minimized by using rotary drilling instead of percussion drilling. Rotary drilling creates less vibration than percussion drilling, reducing the risk of damage to adjacent expansion joints. Vibration monitoring is recommended during ground anchor installation near existing joints. Prestressing of ground anchors can cause ground movement that can affect adjacent expansion joints. The prestressing force is transferred to the ground through the anchor bond zone, causing compression of the ground in the bond zone. This compression can cause the ground to heave near the anchor head, which can affect adjacent expansion joints. Post-installation inspection of existing expansion joints must verify that the ground anchor 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. Ground anchor testing after installation verifies that the anchors have achieved the required capacity. The test involves applying a load to the anchor and measuring the displacement. The test results are compared with the design requirements to verify that the anchors are performing as intended.