The pixel tracking detectors in the ATLAS and CMS experiments are scheduled to be replaced with upgraded versions during the next long shutdown period at the LHC. The upgraded detectors are designed to take advantage of the high-luminosity operation of the LHC which is due to begin in 2029. This means that the active sensor area must increase, and these additional sensors need mechanical support, cooling, and electrical and data transmission services. The mechanics must suitable for the increased radiation dose that will arise from the increase in luminosity. These requirements demand the use of novel mechanical solutions and materials.