Bridge Expansion Joint for Bridges with Expansion Joints in Deck Slabs on Helical Piles

Helical piles (screw piles) are used for bridge rehabilitation and new construction where conventional pile driving is not feasible. The installation of helical piles near existing expansion joints requires careful planning to minimize the effects on the joints. Helical pile installation involves rotating the pile into the ground using a hydraulic motor. The rotation causes minimal vibration compared to conventional pile driving, making helical piles suitable for installation near existing expansion joints and sensitive structures. Load capacity of helical piles depends on the number and size of the helical plates, the pile length, and the soil conditions. The load capacity is determined by the torque required to install the pile, which is correlated with the soil bearing capacity. The pile is installed to the required torque to achieve the design load capacity. Installation near existing expansion joints is less disruptive than conventional pile driving because the vibration is minimal. However, the rotation of the pile can cause soil disturbance that can affect adjacent expansion joints. The installation must be monitored to ensure that the soil disturbance does not affect the joint performance. Post-installation inspection of existing expansion joints must verify that the helical pile 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. Helical pile testing after installation verifies that the piles have achieved the required capacity. The test involves applying a load to the pile and measuring the displacement. The test results are compared with the design requirements to verify that the piles are performing as intended.