A method of manufacturing a bearing support structure of a gas turbine engine, includes: obtaining a bearing support and a casing assembly, the casing assembly having first and second casings extending around a central axis and connected together via struts, the bearing support securable to the first casing at attachment points; selecting a distance between the attachment points of the bearing support and the struts as a function of a required stiffness of the bearing support structure; and adjusting a position of the bearing support relative to the casing assembly until the attachment points are distanced from the struts by the selected distance and joining the bearing support to the casing assembly at the attachment points.