SFPUC - Pipe Protection System Testing
This project includes tests performed for the San Francisco Public Utilities Commission (SFPUC) for the seismic upgrade of Bay Division Pipelines (BDPLs) at specific fault crossings. The tests were performed with the Large-Scale Lifelines Testing Facility at Cornell University, which is part of the George E. Brown, Jr, Network for Earthquake Engineering Research (NEES) supported by the National Science Foundation (NSF). The seismic upgrade of BDPLs 3 and 4 involves the replacement of the existing BDPL 3 at its fault crossing. The design entails enclosing the new BDPL, in a segmental, reinforced concrete vault with special joints that can accommodate lateral offset and compressive deformation during fault rupture, thereby allowing for rotation and compression of the pipeline inside the vault at ball and slip joints, respectively. The length of the protective vault is approximately 300 ft, and the width, height, and lengths of the reinforced concrete segments are approximately 20 ft.
Five tests at 1/10th scale were performed to support the design of BDPL by focusing on the behavior of the protective, segmental concrete vault. The prototype length of concrete vault tested was 260 and 280 ft, depending on whether a joint or segment center was centered on the fault. The prototype width, height, and length of the reinforced concrete segments were 20 ft. Partially saturated sand was used as the soil medium in which the protective vault was embedded.
A critical aspect of the design is the relative movement of the concrete segments to accommodate lateral offset and compressive deformation of the fault. Understanding the movement of the segments relative to each other and the enclosed pipeline is a key part of the design process. The tests using the NEES equipment site at Cornell were performed to: 1) validate the design approach, 2) provide information about the relative movement of the segments, 3) understand better the interaction between the vault and secant pile wall, 4) gather data about the effects of the mechanical characteristics of the joints on the performance of the vault, 5) evaluate and calibrate three-dimensional numerical simulations of the soil-structure interaction in response to fault rupture, and 6) learn about the effects of expanded polystyrene (EPS) used as fill material between the vault and secant pile wall in the zone of fault rupture.
The full final report is available.
Test summaries and results.