Geotechnical

Seismic Evaluation of Hazard-Resistant Lifelines: Fusible PVC Pipe and Fittings

Anonymous — Thu, 18 Jul 2024 17:03:45 +0000

Seismic Evaluation of Hazard-Resistant Lifelines: Fusible PVC Pipe and Fittings Anonymous (not verified) Thu, 07/18/2024 - 11:03

Project Title: Seismic Evaluation of Hazard-Resistant Lifelines: Fusible PVC Pipe and Fittings

Industry Partners: Aegion Corportation - Underground Solutions Inc.

CIEST Personnel: Cory Ihnotic, Jessica Ramos, D.K Anderson, David Balcells

Primary Investigator: Prof. Brad Wham

Year: 2021

Project Summary: The intent of this study is to impose external loading conditions to test specimens that are representative of the significant deformations possible during earthquake-induced ground motions such as landsliding, fault rupture, and liquefaction-induced lateral spreading, characterizing the pipeline system capacity. This testing program seeks to define the seismic response of fusible PVC (fPVC) pipeline systems with both fused connections and external couplings, illustrating procedures and best practices for conducting full-scale tests and interpreting laboratory results. Thirteen large-scale tests were performed on 6-in. diameter DR18 (PC235) fusible PVC pipe (C900) with three different connection types. Test specimens were subjected to tension, compression, cyclic, and four point bending tests, determining the ultimate load capacity for each system in both axial and transverse directions.

Link to report: /center/ciest/sites/default/files/attached-files/240724_ciest-ugs_fusible_report_to_be_published.pdf

The intent of this study is to impose external loading conditions to test specimens that are representative of the significant deformations possible during earthquake-induced ground motions such as landsliding, fault rupture, and liquefaction-induced lateral spreading, characterizing the pipeline system capacity.

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Wire Mesh Tension Testing

Anonymous — Thu, 13 Jun 2019 20:04:59 +0000

Wire Mesh Tension Testing Anonymous (not verified) Thu, 06/13/2019 - 14:04

Year: 2019

Participants: David Kyle Anderson

Primary Investigator: Brad Wham

Summary: In summer 2019, former masters student David Kyle Anderson conducted 28 tension tests on 5 different types of wire mesh used for soil stabilization at CIEST. Wire mesh specific to the application of soil stabilization has been developed over time with variances in mesh geometry, individual wire strength, and number of twists found in the node of wire connections, buta guiding standard of testing material characteristics specific to this classification of mesh has not been developed. Given this lack of a uniform mode of comparison, this project’s goal was to compare the material characteristics of common wire mesh used in the application of soil stabilization under identical loading conditions, providing engineers a basis for selection of an appropriate mesh for a given project.

Read the full report here.

In summer 2019, former masters student David Kyle Anderson conducted 28 tension tests on 5 different types of wire mesh used for soil stabilization at CIEST.

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Seismic Response with Compacted Granular Columns

Anonymous — Sun, 13 May 2018 20:51:15 +0000

Seismic Response with Compacted Granular Columns Anonymous (not verified) Sun, 05/13/2018 - 14:51

Full Project Title: Seismic Response of Embankments on Liquefiable Soils Improved with Compacted Granular Columns

Year: 2018

Participants: Juan Carlos Tiznado Aitken, Shideh Dashti, Hiral Gandhi, Lauren Strand, Madison Philips

Summary: The main goal of this project is to investigate how the use of compacted granular columns (CGC) may help improve the seismic performance of embankments on potentially liquefiable soils. First, the separated effects of densification, reinforcement, and enhanced drainage mechanisms provided by CGC's will be evaluated through several reduced-scale centrifuge model tests perfomed at CIEST. Then, non-linear finite element models will be calibrated against the experimental data in order to perform a parametric study considering different soil conditions and design scenarios. Finally, the insights from the previous phases will be used to evaluate the validity and limitations of current engineering design procedures for CGC’s. This project is intended to enhance our understanding of the seismic behavior of geo-structures affected by liquefaction and lateral spreading as well as to collaborate in bringing engineering practice towards a performance-based design philosophy.

The main goal of this project is to investigate how the use of compacted granular columns (CGC) may help improve the seismic performance of embankments on potentially liquefiable soils.

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Sandia Senior Design Test

Anonymous — Mon, 19 Mar 2018 14:33:23 +0000

Sandia Senior Design Test Anonymous (not verified) Mon, 03/19/2018 - 08:33

Year: 2018

Participants: Daniel Green, David Manlove, Jordan Thoning, Nicholas Gentz, Steven Karl, Zachary Trahey, Dr. Shalom Ruben, Dr. Brad Wham, Hiral Gandhi

Primary Investigator: UC Boulder Mechanical Engineering Senior Design in conjunction with Design Center babyֱ��app and Sandia National Labs

Summary: The Sandia Senior Design Team were tasked to design a switch that activates at 9g, as part of a cubesat subsystem. As part of the test phase of their device, the team used the 15-g centrifuge at CIEST to replicate a cubesat launch profile and observed their switch activate through video stream.

The Sandia Senior Design Team were tasked to design a switch that activates at 9g as part of a cubesat subsystem for their senior design project.

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Centrifuge Study of the Seismic Response of Buried Reservoir Structures

Anonymous — Wed, 18 Oct 2017 20:50:00 +0000

Centrifuge Study of the Seismic Response of Buried Reservoir Structures Anonymous (not verified) Wed, 10/18/2017 - 14:50

Summary: The Los Angeles Department of Water and Power (LADWP) is currently replacing many of its open reservoirs with buried, reinforced-concrete structures to improve water quality. These underground structures in Southern California need to be designed to safely withstand seismic loading. The current state of practice for evaluating lateral seismic earth pressures on underground structures is based on simplified procedures or numerical tools that have not been calibrated or validated adequately against physical model studies. This study is to perform centrifuge testing and numerical modelling in order to investigate soil-structure interaction and to understand the mechanism of how the lateral pressure developed on the wall of an underground structure. The centrifuge tests are conducted at our centrifuge center.

The Los Angeles Department of Water and Power (LADWP) is currently replacing many of its open reservoirs with buried, reinforced-concrete structures to improve water quality.

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New Paradigm in Evaluating and Mitigating Urban Liquefaction

Anonymous — Wed, 18 Oct 2017 20:49:17 +0000

New Paradigm in Evaluating and Mitigating Urban Liquefaction Anonymous (not verified) Wed, 10/18/2017 - 14:49

Summary: This Faculty Early Career Development (CAREER) grant will create a new approach for evaluating the behavior of clusters of buildings on liquefiable ground during earthquakes and pave the way toward designing mitigation measures that improve building performance at a system level. Earthquake-induced soil liquefaction can cause substantial damage to urban areas where multiple buildings and infrastructure systems are clustered. Previous studies have shown that buildings located in close proximity to one another can interact in earthquakes affecting ground motions, settlement patterns, and building damage potential. The parameters that control the seismic performance of building clusters are poorly understood. As a result, mitigation measures that are currently designed perform poorly, particularly when the performance of a building is evaluated in the context of its surroundings. This award supports a systematic study of the impact of adjacent buildings on the effectiveness of liquefaction remediation techniques. In doing so, this award contributes to the resilience of cities globally.

This Faculty Early Career Development (CAREER) grant will create a new approach for evaluating the behavior of clusters of buildings on liquefiable ground during earthquakes and pave the way toward designing mitigation measures that improve building performance at a system level.

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NEESR Seismic Response of Shallow Underground Structures

Anonymous — Wed, 18 Oct 2017 20:48:29 +0000

NEESR Seismic Response of Shallow Underground Structures Anonymous (not verified) Wed, 10/18/2017 - 14:48

Full Project Title: NEESR: Seismic Response of Shallow Underground Structures in Dense Urban Environments

Summary: Shallow underground structures used for public transportation are a key component of sustainable cities. In dense urban environments, underground structures are often built near tall buildings. Although such buildings have the potential to alter ground motions in their vicinity and transmit significant forces to adjacent underground structures, the impact of these forces remains uncertain. This project will study the seismic response of temporary and permanent cut-and-cover box structures near mid- to high-rise buildings using a combination of centrifuge testing and numerical simulations. The data from centrifuge tests will serve two purposes: first, to understand seismic soil-structure-underground structure-interaction (SSUSI), and second, to calibrate and improve numerical models. Nonlinear numerical simulations of centrifuge tests will help assess and improve the capabilities of existing numerical tools in capturing SSUSI and key loading mechanisms. Parametric studies using calibrated models will be conducted to make design recommendations. Data from this project will be archived and made available to the public through the NEES Project Warehouse/data repository.

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This project will study the seismic response of temporary and permanent cut-and-cover box structures near mid- to high-rise buildings using a combination of centrifuge testing and numerical simulations.

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WTI Deep Patch Repair Modelling

Anonymous — Wed, 18 Oct 2017 20:47:06 +0000

WTI Deep Patch Repair Modelling Anonymous (not verified) Wed, 10/18/2017 - 14:47

Summary: The Western Transportation Institue has conducted a series of modelling tests of deep patch repairing method used in Highway in our 400 g-ton centrifuge. The purpose of this project is to evaluate and improve current FHWA Office of Federal Lands Highway (FLH) and US Forest Service (USFS) deep patch design and construction methods.

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The Western Transportation Institue has conducted a series of modelling tests of deep patch repairing method used in Highway in our 400 g-ton centrifuge.

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Earthquake Reconnaissance in Japan

Anonymous — Fri, 24 Jun 2016 19:44:22 +0000

Earthquake Reconnaissance in Japan Anonymous (not verified) Fri, 06/24/2016 - 13:44

Shideh Dashti, assistant professor of geotechnical engineering and geomechanics at CU-Boulder, co-led a scientific reconnaissance team mobilized by the Geotechnical Extreme Events Reconnaissance (GEER) Association to travel to Kumamoto-shi, Japan, after the two earthquakes that occurred on April 14 and 16.

Full story here: Earthquake reconnaissance: Students learn in Japan

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Physical Modeling of Buried Explosion in Soils

Anonymous — Sun, 18 Oct 2015 06:00:00 +0000

Physical Modeling of Buried Explosion in Soils Anonymous (not verified) Sun, 10/18/2015 - 00:00

Full Project Title: Physical Modeling of Buried Explosion in Soils by Geotechnical Centrifuge

Summary: Funded by the Multidisciplinary University Research Initiatives (MURI) program by Office of Naval Research (ONR). Buried explosion is a complex phenomenon, involving high strain-rate soil dynamics, fluid dynamics, fractures, shocks and multi-scale physics. A comprehensive experimental program using geotechnical centrifuge modeling was conducted in conjunction with computational modeling using finite element, boundary element and discrete element and meshless methods to achieve a new level of scientific understanding of the complex multi-phase phenomena. To address the experimental gaps in the current literature, an extensive series of centrifuge tests were conducted to examine the high-rate dynamic soil behavior under explosive loads with parametric variations of the charge size and shape, burial depth, soil type, water content, and g-level with both in-flight and post-detonation measurements. A novel integration of a high-speed imaging system into the centrifuge domain was developed to capture the blast response and allowed detailed characterization of the transient, multiphasic soil blast mechanics including early soil disaggregation and ejecta, gas–particle interactions, shock propagation and soil dome evolution. The blast-induced changes in the in-soil stress, acceleration, as well as the above-ground pressure and acoustic intensity were measured by an extensive suite of miniaturized sensors. Precise crater dimensions and geometry were captured by laser profilometry. The advanced centrifuge scaled modeling studio can be used for detailed parametric experimental investigations as well as physical benchmarks for validation and calibration of computational simulations for soil blast, cratering and many other applications.

Buried explosion is a complex phenomenon, involving high strain-rate soil dynamics, fluid dynamics, fractures, shocks and multi-scale physics. A comprehensive experimental program using geotechnical centrifuge modeling was conducted in conjunction with computational modeling using finite element, boundary element and discrete element and meshless methods to achieve a new level of scientific understanding of the complex multi-phase phenomena.

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