Frieder Seible - US grants

In this project, an experimental laboratory will be upgraded during the construction period to enhance and improve the capability of the facility to conduct research projects on full- or large-scale five-story buildings of masonry, steel or reinforced concrete. The long strong floor will provide a capability to perform research on multi-span continuous bridges, not now available in the United States. The laboratory will be the only one of its type in the United States capable of full- or large-scale experiments on buildings and small- or large-scale projects on bridges. It will provide the United States with a unique experimental laboratory. Experiments on buildings and bridges will be performed using sophisticated loading devices and instrumentation.

Masonry construction comprises a large portion of building construction in the U.S. and the world. Reinforced masonry construction use is increasing in moderate to higher seismic zones because of its apparent features of economy, fire safety, architectural flexibility, and ease of construction. The present state of masonry structural analysis and design and materials and construction technologies do not enable an accurate prediction of building behavior under lateral loads such as seismic loads. This research project will examine the behavior of floor-to-wall and wall-to-wall intersections of structure components. The research will utilize existing data in this analytical research effort. This will provide conclusions relative to monotonic and hysteretic behavior of planar intersection response and formulation of a viable analytical and numerical model of intersection behavior.

The area of research to be undertaken is in the general field of bridge engineering. The first topics to be studied are: the estimation of prestress losses in existing bridge members and the fatigue of tendon anchorages and coupling joints. The results of the research will be useful to upgrade and rehabilitate existing bridges.

This research project will conduct integrated experimental and analytical studies on simple components, main subassemblages, and finally a complete multistory masonry building (Masonry Research Building). These studies will be conducted using small, medium, and full scale specimens. The objective of the studies is the development of a reliable methodology for investigating the in-plane behavior of multistory reinforced hollow unit masonry wall elements when a building is subjected to earthquake ground motions. Emphasis will be given to the development of the experimental methodology which will be used as a basis for studying the earthquake behavior of the full scale Masonry Research Building. Results from the two and three story in-plane wall tests will be used to verify the analytical models developed by others.

This research will provide equipment for outfitting the new University of California-San Diego (UCSD) Structural Systems Laboratory. This facility will provide unique capabilities in that it is designed for full-scale experimental testing of buildings up to five stories by using a massive 50 foot high reaction strong wall. The equipment will include hydraulic actuators, control systems, data collection systems, and support systems. This laboratory will have four main functions. First, it will serve as the focal point for the Structural Engineering Program at UCSD. Second, it will serve as a regional laboratory and complement other structural and earthquake engineering laboratories. Third, it will support international research programs such as the US-Japan Coordinated Earthquake Program in Masonry Research. Fourth, it will encourage interaction between academic researchers, practicing engineers, and the construction industry.

Damage to the freeway bridges in the Whittier Narrows earthquake of October 1, 1987 was one of the most significant aspects of damage to engineered structures designed for seismic lateral loads. Of particular importance was the performance of the I-605/I-5 separator, which was extensively damaged during the earthquake and came perilously close to collapse at a time when freeway traffic was at its heaviest and loss of life would have been extensive. The research project is directed to a study of the performance of freeway bridges in the Whittier Narrows earthquake. The research involves five stages: observed damage assessment, component strength and deformation analysis, dynamic analysis of selected bridge structures, recommendations on assessment and evaluation and prioritization for retrofitting. The intention of the research is to obtain maximum benefit from the lessons emphasized by bridge damage in the earthquake in the form of improved understanding of the vulnerability of existing bridge structures to seismic damage, calibration and assessment of analytical techniques for analysis of seismic response of bridge structures, and in the development and assessment of retrofit techniques to reduce the seismic risk of freeway bridges.

Within the framework of the joint U.S.-Japan masonry research program, the specific objective of the U.S. program is to develop an experimentally verified design and analysis methodology that will ensure satisfactory performance of reinforced masonry buildings under a wide range of seismic loadings. In particular, under severe earthquake loadings such buildings must exhibit ductile behavior. A key aspect of the philosophy adopted by the U.S. program is to support the design and analysis development by an increasingly complex set of experiments culminating with the study of a five-story full-scale masonry building. This experiment is essential to achieve the objectives of the program in that it will provide the final validation of the analytical and computational models developed, and thus will form the basis for the design recommendations to be made at the culmination of the overall project. This research project is a full-scale building test conducted at the Charles Lee Powell Structural Systems Laboratory at the San Diego campus of the University of California. The experiment is performed using a reaction wall concept, in which the building is subjected to generated displacement histories at the floor levels via hydraulic actuators in a manner that simulates the displacements during an actual seismic event.

Rehabilitation and strengthening of bridge structures have become a major focal point of the Nation's aging bridge inventory. To mitigate the staggering rehabilitation problem the Bush Administration is on record "...to be committed to develop a strong transportation research and technology program." The workshop will address a vital component of the national transportation research program the nation's bridge inventory and will associated ongoing research efforts. The workshop has three principal objectives, namely (1) to identify the state-of-the-art in bridge design and retrofit research, (2) to develop means of transferring research results to implementable technology and (3) to establish bridge research directions and priorities in support of the nation's bridge infrastructure for the 21st century. The workshop is the third in a series of NSF supported Bridge Research in Progress Workshop and is envisioned to be held in San Diego, California in Fall of 1992.

This project will organize, convene and report on an NSF regionally- based workshop on architectural research needs in earthquake hazard mitigation. The workshop will review the current state-of-the-art in relation to earthquake hazard mitigation in architectural and nonstructural systems, and relation to broader land-use planning issues and physical urban design issues. Future research needs will be identified and prioritized for these same systems under the goals of the Architectural and Mechanical Systems Program (AMS) program element. The workshop will focus on West-Coast issues.

9307840 Priestley This project carries out studies for the development of an innovative prestressed reinforced concrete system utilizing precast beams connected to columns by unbonded prestressing tendons continuous over the length of the multi bay frame. The tendons provide continuity and moment resistance to the beams and the tendons remain elastic when flexural cracking develops during seismic response. The major tasks are (l) testings of large scale assemblages, (2) modeling of hysterestic characteristics, (3) time history analyses of multistory frames, and (4) design details development. Considerable advantages in terms of increased frame ductility, simplified joint design, etc. might be achieved through implementation of this innovative PRESSS system concept. ***

The first U.S. 5-story full-scale research building which was tested at UCSD under simulated seismic loads to 1-1/2 to two times the seismic design and deformation levels, provides in its damaged state a unique opportunity to develop and experimentally validate new repair technologies. The proposed repair measures consist of epoxy injection, advanced composite wall and floor overlays as well as ceramic foam applications in the hollow core plank floors, with particular emphasis on materials and technologies originally developed and applied in the defense industry to show their potential for application in the civil sector. It is proposed to use loading sequences in the retest which correspond closely to the original seismic load test, in order to get a direct experimental seismic behavior comparison for the verification of the effectiveness of the proposed repair measures. The test results will provide important information about the repairability of damaged reinforced masonry structures and about the expected behavior of repaired structures under future seismic loads.

This project covers the construction and testing of a large scale five-story precast superassemblage under simulated seismic loading. The purpose of the project is to provide a realistic vehicle for verifying structural concepts, design methodology and analytical procedures developed in NSF research initiative `precast and prestresses seismic structural systems` (PRESSS) Phases 1 and 11, and to evaluate the seismic performance of precast designs in terms of reduced damage and residual deformation compared with conventionally reinforced buildings. The project forms the key element of PRESSS Phase III, in accordance with the original PRESSS master plan. The structure will consist of five stories, with a two-bay by two-bay plan. In one direction the lateral bracing will be provided by precast walls, and in the other direction, by precast frames, enabling different structural systems to be tested in orthogonal directions. Different precast flooring systems will be adopted at different levels to investigate diaphragm action and frame-floor connection details. Design will be in accordance with direct-displacement seismic design procedures developed as part of the earlier PRESSS phases. Testing will primarily be under a multi-degree-of-freedom pseudo-dynamic testing procedure developed earlier for a five-story masonry building. Sequential time-histories chosen to exercise the building to a series of limit states including (1) first-cracking, (2) first yield, (3) serviceability limit, (4) damage control, and (5) incipient collapse, will be applied to the structure. Results from the experiment will be used to finalize design recommendations from the PRESSS project. The five-story superassemblage test has extremely strong industry support, with more than 60% of the necessary cost being provided by the precast industry.

9714605 Seible Advanced composite materials such as carbon, aramid, or glass fibers in polymer matrices, such as epoxies, vinylesters and polyesters, have shown outstanding mechanical and chemical characteristics to be of great interest to civil engineering design and construction. Recent developments in manufacturing technologies and the need for new and more durable materials for rehabilitation of existing civil structural systems and renewal requirements of the aging building and bridge inventory have shown that the light weight of these polymer matrix composites can be cost-effectively employed, particularly in the seismic retrofitting of buildings and bridges. A concept which emerges from this combination of conventional civil construction materials, and for the civil engineering sector new polymer matrix composites (PMCs), is that of concrete filled composite tubes (CCTs), where the concrete takes on the compression force transfer and the carbon shell the functions of (1) formwork for the concrete, (2) confinement of the concrete, and (3) tension force transfer in both longitudinal bending and shear. The thin advanced composite tubes and stabilized against local instabilities by the infill concrete which can be pressure grouted and contain normal or lightweight aggregates. The research aims to systematically develop the basis for a new framing system made of filament wound hybrid glass/carbon tubes and filled on-site fully or partially with concrete. The research focus will be in three areas namely, (1) the analytical modeling and characterization of the fully and partially grouted advanced composite tube system and the proposed connections, (2) development of optimized hybrid schemes and fabrication techniques, and (3) the experimental full-scale validation of CCT beams and connections. The analytical models will be calibrated and verified by the test results and used for subsequent parametric studies to form the basis for general design model developments for concrete filled advanced composite tube framing systems. ***

Abstract
CMS 0117935
Seible

This award provides funding to the University of California, San Diego to conduct a national earthquake engineering research equipment workshop for the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). NEES is a project funded under the National Science Foundation (NSF) Major Research Equipment program and has been authorized by Congress for $81.9 million during FY 2000-FY 2004. In February 2001, NSF announced the NEES Earthquake Engineering Research Equipment Portfolio, Phase 1, consisting of eleven awards to ten institutions for $45 million. These eleven awards include new and upgraded shake tables, upgraded centrifuges, an upgraded wave basin for tsunami research, large-scale laboratory experimentation systems, and geotechnical and structural earthquake engineering field equipment. These equipment sites will be part of the NEES collaboratory and serve as national, shared-use earthquake engineering experimental research equipment installations, with teleobservation and teleoperation capabilities, networked together through the high performance Internet. In addition to providing access for telepresence at the NEES equipment sites, the network will use cutting-edge tools to link high performance computational and data storage facilities, including a curated repository for experimental and analytical earthquake engineering and related data. The network will also provide distributed physical and numerical simulation capabilities and resources for visualization of experimental and computed data. Through NEES, the earthquake engineering community will use these advanced experimental capabilities to test and validate more complex and comprehensive analytical and computer numerical models that will improve the seismic design and performance of our Nation's civil and mechanical systems. NSF intends to issue a Phase 2 program solicitation during 2001 to complete the NEES Equipment Portfolio. The purpose of this workshop is to bring the earthquake engineering community together to (a) summarize the NEES Equipment Portfolio, Phase 1, (b) assess other existing earthquake engineering facilities/equipment available in the United States, (c) identify possible missing components of the NEES Equipment Portfolio, Phase 1, and (d) recommend strategies to complete the NEES Equipment Portfolio during Phase 2. The earthquake engineering community can participate in this workshop via input on the web prior to the workshop and/or through attendance at the workshop. A report summarizing the recommendations from this workshop will be posted on the web for broad dissemination.

PI: Francesco Lanza di Scalea
Co-PI: Frieder Seible
University of California, San Diego
Proposal number: 0221707
Proposal title: Health Monitoring of Multi-Strand Steel Tendons and Cable Stays for Civil Structures

Project Abstract

Monitoring the structural health of existing constructed facilities is becoming an increasingly relevant aspect of engineering. Structural health monitoring includes ensuring proper structural performance and providing early detection of critical damage.

This project is aimed at developing a health monitoring method for multi-wire steel strand tendons and cable stays that are widely used in civil structures such as cable-supported bridges and prestressed concrete members. The ultimate purposes of the method are 1) real-time measurement of the applied loads and 2) detection of critical damage including corrosion and broken wires. The project will investigate the use of ultrasonic stress waves as potential candidates to perform these tasks.

Intermediate objectives of the research include: 1) the characterization of the dispersive behavior (velocity/frequency relationship) of stress waves propagating in multi-wire strands; 2) the perfection of a method for load measurement based on monitoring the stress wave propagation velocities; 3) the assessment of the sensitivity of stress waves to structural damage in the strands; 4) the development of a method for correcting the effects of temperature on the measurement of load.

Successful completion of the proposed activities will contribute to ensuring the safety of the Nation's critical civil infrastructure components, such as bridges. Broader impacts of the project will include educational aspects. A graduate student will be directly involved in all of the research activities. An undergraduate assistant will also collaborate to the project. The topics of structural health monitoring and non-destructive evaluation have been recently included in the curriculum development of UCSD's Structural Engineering department. Two courses on these topics are being developed, one at the undergraduate level and the other at the graduate level. Relevant findings resulting from the research activities will be incorporated into the classroom lectures for these courses. Demonstrations on ultrasonic measurements in strands will be given as part of the courses' programmed laboratory sessions.

Abstract
CMS-0217293
Seible

The George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) is a project funded under the National Science Foundation Major Research Equipment and Facilities Construction account. This cooperative agreement, awarded under NEES, establishes a NEES large high performance (LHP) outdoor shake table site at the University of California, San Diego (UCSD) and is an outcome of the peer review of proposals submitted to program solicitation NSF 01-164, "NEES: Earthquake Engineering Research Equipment, Phase 2." This outdoor shake table will be a 7.6 m x 12.2 m long single (horizontal) degree-of-freedom system. The table will have a peak horizontal velocity of 1.8 m/s, maximum stroke of +/-0.75 m, maximum gravity (vertical) payload of 200 MN, maximum overturning moment of 50 MN-m, force capacity of actuators of 6.8 MN, and a frequency bandwidth from 0-20 Hz. The major equipment for the LHP shake table facility consists of servocontrolled dynamically-rated actuators with large-servo valves, a large power supply, a vertical load/overturning moment bearing system, a digital three-variable real-time controller, concrete foundation and reaction mass, and weatherproofing system. The facility will be the only outdoor shake table in the U.S. and will enable large/full-scale testing of structural systems and soil-foundation-structure interaction that cannot be readily extrapolated from testing at smaller scale, or under quasi-static or pseudo-dynamic test conditions, as well as testing large-scale systems to observe their response under near source ground motion. The LHP outdoor shake table will be located 15 km from campus at the UCSD Camp Elliott field site. This two-acre site was selected so that the shake table could be used in conjunction with an adjacent soil pit and laminar shear soil box being provided by the California Department of Transportation. This site will allow room for multiple test specimens to be constructed and instrumented before placement on the shake table. A 177 kN rough terrain crane will be provided at Camp Elliott for loading, unloading, and everyday construction purposes. For heavier lifting capabilities, an 880 kN crane will be available on an as needed rental basis, with the individual experiment requiring the larger crane to cover this cost. This equipment will be operational by September 30, 2004, and will be managed as a national shared-use NEES equipment site, with teleobservation and teleoperation capabilities, to provide new earthquake engineering research testing capabilities through 2014. Shared-use access and training will be coordinated through the NEES Consortium. UCSD is providing $1,363,000 in cost sharing for this facility. UCSD will integrate this shake table equipment into its research program involving undergraduate and graduate students, Department of Structural Engineering curriculum, and K-12 and general public outreach. The University will also provide training opportunities for outside faculty, students, and practitioners through web-based tutorials and on-site training.

Ramesh Rao
University of California San Diego

"The New Role of Science and Engineering in Risk Reduction"


In February 2002, NSF funded a successful workshop in New York City, inspired by the events of September 11, to develop a research agenda related to unexpected events. Now, one year later and with the Department of Homeland Security established, the topic of homeland security is much better defined as it relates to the Federal Government and NSF. NSF is now engaged in developing a large cross-agency initiative in Cyber-Infrastructure. The workshop being funded by this grant is intended to bring the two areas of cyber-infrastructure and homeland security into juxtaposition, with the goal of developing a computer/information science research agenda within the context of homeland security, as related to cyber-infrastructure.