An end member assembly (EMI) includes an end member body (400) and a support column (500). The end member body (400) includes an outer side wall and an inner side wall that together at least partially define an end member reservoir. The inner side wall at least partially defines a passage through the end member body. The support column (500) extends into the passage and is accessible from along opposing ends of the passage. A sealing element can be disposed in fluid communication between the end member body and the support column. An elongated gas damping passage can extend through the end member assembly in fluid communication with the end member reservoir. A gas spring assembly can include a flexible spring member (200) that at least partially defines a spring chamber with an end member (900) and the end member assembly (EMI) on opposing ends thereof. A restraining assembly (1000) can be secured within the spring chamber.