1. Project Goals/Objectives:

The overall project goal is to utilize the full-scale data assess current methods for estimating the effect of lateral spreading on pile foundations and pipelines, and develop new procedures if necessary. Specifically for Year 7, our objectives are to extend results obtained from Tokachi experiment to other experimental results and to model lateral spreading of blast experiment using seismic loading in OpenSees.

2. Role of this project in supporting PEER’s mission (vision):

This project supports PEER’s mission in two ways:

3. Methodology Employed:

Two full-scale experiments using controlled blasting were conducted in November and December 2001 in the Port of Tokachi on Hokkaido Island, Japan, to study the performance of lifeline facilities subjected to lateral spreading. This research project was the joint collaboration between the University of California, San Diego, (UCSD) and several Japanese organizations led by the Port and Airport Research Institute (PARI). The primary objective of the test was to assess the performance of lifelines subjected to lateral spreading using controlled blasting. The PEER Lifelines Program funded UC San Diego’s participation in the test with support from Caltrans, Pacific Gas & Electric and the California Energy Commission. Two tasks were proposed for Year 7:

PEER Lifelines Program with $610,000 funded the initial year of this project in order to carry out both experiments in Japan. This was matched by over $2.5 million by the Japanese to make the total effort over $3 million. For Year 7, PEER Core Program continued funding the analysis portion of the project at the $55,000 level.

4. Brief Description of past year’s accomplishments (Year 6) & more detail on expected Year 7 accomplishments:

Blast-induced liquefaction at Tokachi Port, Japan

In all, UCSD installed 6 test specimens. The pile specimens in the experiment program consisted of a single pile, a 4-pile group, and a 9-pile group. In addition, two natural gas pipelines and one electrical conduit were installed. All of them were extensively instrumented with strain gauges to measure the distribution of moment in the specimens during lateral spreading. Other instrumentation, including pore pressure transducers, GPS units, and slope inclinometers, were also installed to measure the degree of liquefaction as well as the movements of soil and lifelines. This data will allow us to compute the loading conditions during lateral spreading, as well as to assess the capabilities of our numerical models being developed within PEER.

The objectives of this study is to conduct damage and performance assessments of those lifelines subjected to lateral spreading, as well as to evaluate loading conditions on the structures during lateral spreading. Currently, the final test report on the experimental portion of the work is being published. Proceedings of workshop for all researchers involved in the project were published in December 2003 on a DVD/CD format containing all data from all 17-research organizations. In Year 6, a consistent simplified p-y approach was successfully used to model all piles at the site, though we were unsuccessful in modeling the blast loading. In Year 7, we are developing the OpenSees model of the site using the newly available data, as well as comparing the results to other lateral spreading experiments in the centrifuge and 1-g shake table.

5. Other Similar Work Being Conducted Within and Outside PEER and How This Project Differs:

The PI has conducted and is currently conducting research sponsored by Caltrans on the full-scale behavior of deep foundations in liquefied sand. These experiments also utilize controlled blasting to induce liquefaction. Though primarily focused on Cast-In-Drilled-Hole (CIDH) piles, these experiments also considered pile groups. This proposed research differs from these projects in two primary ways. First, in the previous research, only the soil in the immediate vicinity of the pile was liquefied and inertial loading was simulated used hydraulic actuators. In the Japan test, the soil was liquefied for a great distance around the piles, and loading was be from lateral spreading soil. Secondly, the piles in the previous experiments had the free-head condition. In the proposed research, a pile cap was incorporated to test the fixed-head condition. The PI’s are not aware of any ongoing full-scale field experimentation on the performance of pipelines subjected to lateral spreading.

6. Plans for Year 8 if project is expected to be continued:

In Year 8, we plan to extend the results of the experiment (0.8 m of lateral spread) to several meters of lateral spreading using OpenSees. We will also use the recently available, more detailed Japanese data from the experiment to further refine and assess our numerical model.

7. Describe any actual instances where you are aware your results have been used in industry:

None yet. Project is ongoing.

8. Expected Milestones & Deliverables:

Milestones:

Deliverables: