In 2017, the 777X Static Load Test Facility was in construction at the Boeing campus at the Snohomish County Airport in Everett, Washington. PSI was tapped to analyze the capability of the existing asphalt concrete (AC) pavement to support the movement and assembly of a 735,000 lb truss system over the existing pavement.
We used three methods to analyze the effect of loading the existing AC pavement under the weight of the truss system:
- Finite Element Method (FEM) analysis of a layered viscoelastic pavement using the FLEX-PAVE software, developed by North Carolina State University.
- Traditional layered-elastic analysis of the load using the US Army Corps of Engineers Pavement Transportation Computer Assisted Structural Engineering (PCASE) software to model the transport modules as vehicles.
- Advanced layer-elastic analysis using the WinJULEA software to understand stresses and strains at critical points within the pavement structure under the truss loading.
Following our analysis, the truss system was assembled onsite and moved into an overhead position as part of the 777X Static Load Test Facility.