Steven C. Sweeney

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: I. Seismic and Quasi-Static Testing

This and a companion paper compare the results from shaking-table testing, quasi-static testing, and analytical predictions, to provide a coherent description of the seismic response of low-rise reinforced masonry buildings with flexible roof diaphragms. Two half-scale, low-rise reinforced masonry buildings with flexible roof diaphragms are subjected to earthquake ground motions on the Tri-axial Earthquake and Shock Simulator at the United States Army Construction Engineering Research Laboratory, Engineer Research and Development Center. Following the shaking-table tests, diaphragms and top four courses of attached masonry walls are salvaged from the half-scale structures and tested quasi-statically in their own plane. In contrast to what is usually assumed in design, the half-scale specimens do not behave as systems with a single degree of freedom associated with the in-plane response of the shear walls, but rather a system with a dominant degree of freedom associated with the in-plane response of the roof diaphragm. A new index describing the potential for diaphragm damage is introduced, the diaphragm drift ratio. A companion paper, Part II: Analytical Modeling, presents analytical work intended to corroborate and extend results from experimental testing.

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: II. Analytical Modeling

This and a companion paper compare the results from shaking-table testing, quasi-static testing, and analytical predictions to provide a coherent description of the seismic response of low-rise reinforced masonry buildings with flexible roof diaphragms. This paper presents the development, implementation, and results of coordinated analytical modeling intended to corroborate and extend the results of experimental work discussed in a companion paper, Part I: Seismic and Quasi-Static Testing, and more important, examine the efficacy and accuracy of different analytical modeling approaches. Specifically, linear elastic finite-element models, simplified two-degree-of-freedom models, and nonlinear lumped-parameter models are created and all agree well with measured responses. Based on these, a simple design tool for the analysis of low-rise reinforced masonry buildings with flexible diaphragms is developed and verified.

Structural Health Indices for Steel Truss Bridges

Steel bridges represent a significant portion of the nation’s aging bridge inventory. The United States Army’s inventory has over two hundred steel bridges that are vital to the operation of nearly every Army Installation. The Army regularly inspects their bridges to ensure the continued functionality of the bridges. However, current inspection techniques and schedules may not be able to detect certain defects that could compromise bridge integrity. To supplement current inspection standards, the US Army Engineer Research and Development Center (ERDC), has contracted to install a structural health monitoring (SHM) system on the historic steel truss Government Bridge at the Rock Island Arsenal. ERDC envisions a system that measures strain, acceleration, tilt, and electrical resistance to determine the bridge’s structural health. Research into the usefulness of the Damage Locating Vector (DLV) method, and the damage indices that the method calculates, in detecting corrosion damage has been conducted. Numerical studies on a finite element model of the Government Bridge have indicated that the DLV method has potential as a damage detection algorithm on such a large structure. Laboratory experiments using corroded members in a model truss have additionally shown that the DLV can be used to monitor corrosion induced damage.

Seismic Evaluation of Low-Rise Reinforced Masonry Buildings with Flexible Diaphragms: III. Synthesis and Application

This paper outlines the last two phases of a joint research study performed by the University of Texas at Austin and the U.S. Army Corp of Engineers, Construction Engineering Research Laboratory, Engineer Research and Development Center (CERL). The study coordinates and synthesizes experimental testing, analytical modeling, practical implementation, and real-world application to enhance FEMA-310, the predominant seismic evaluation methodology for low-rise reinforced masonry buildings with flexible diaphragms. In earlier phases of study, conclusions from shaking-table testing, quasi-static testing, and analytical modeling were used to develop a simple tool for the seismic analysis of these types of buildings. In this paper, the tool is developed in the context of performance-based earthquake engineering into a supplementary evaluation methodology intended to fill a gap in FEMA-310. The tool is applied to four existing buildings and ultimately shown to be simple, useful, and necessary.

Multimetric Monitoring of a Historic Swing Bridge

The Rock Island Arsenal Government Bridge, built over the Mississippi River in 1896 between Rock Island, IL and Davenport, IA, is just one of over two hundred bridges owned by the United States Army. The swing span of the Rock Island Arsenal Government Bridge has the ability to rotate 360° in either direction and can lock each end of the span on either abutment. The bridge carries highway and rail traffic; the swing span allows for the passage of barge traffic on the river. The Army regularly inspects and maintains their bridges to ensure their functionality. To supplement the regular inspections of the swing span of the Government Bridge, the US Army Engineering Research and Development Center (ERDC) has installed a structural health monitoring system composed of both a fiber optic sensor network and a wireless smart sensor network. This multi-framework system measures strain, acceleration, and orientation and uses these metrics to perform structural health monitoring of the bridge. The monitoring is designed to automatically record the measured changes in strain caused by swing events and record the accelerations measured during train events and other scheduled times of day. The integrated monitoring system has been successful in recording the necessary multimetric sensor data and using it to monitor the swing span of the Government Bridge.

Miter gate gap detection using principal component analysis

The U.S. Army Corps of Engineers (USACE) operates and maintains 236 lock chambers at 191 lock sites on 41 waterways throughout the contiguous United States. Waterway navigational locks are important parts of the nation’s infrastructure. Locks enable the flow of billions of dollars of commerce and support efforts for flood control. Proper maintenance of the locks and early detection of damage is crucial; however, due to shrinking budgets, adequate funding to apply traditional scheduled maintenance and visual inspection is not available. Structural health monitoring (SHM) systems have been considered to assist in establishing more efficient maintenance, repair, and replacement priorities for navigational locks. This work was undertaken to develop and implement a real-time methodology that provides lock operators with a robust, accurate warning system of gap(s) at the gate-to-wall interface. This initial effort, which focused on horizontally framed miter gates and on damage that is assumed to take the form of a gap at the gate/wall interface (quoin), developed a methodology to identify the occurrence of damage in miter gate structures using data from strain and water level gages that is collected continuously from the SHM system deployed by USACE. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.

Full-Scale Testing of Thermoplastic Composite I-Beams for Bridges

United States. Department of the Army. Office of the Assistant Chief of Staff for Installation Management.

Investigation of hydrophobic concrete additive for seawall replacement at Pililaau Army Recreation Center, Hawaii : final report on Project F09-AR05A

Department of Defense Corrosion Prevention and Control Program (U.S.) United States. Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics.

Demonstration and validation of stainless steel materials for critical above-grade piping in highly corrosive locations : final report on Project F07-AR15

Abstract : The problem of accelerated corrosion damage to Department of Defense (DoD) assets in marine coastal settings is greatly compounded when the affected infrastructure is critical to military mission and operational safety. Exposed piping networks that supply water for fire protection of fueling facilities require a high maintenance investment to prevent catastrophic system failure during operation. This demonstration/validation project evaluated the use of low-carbon stainless steel materials for fire-suppression water pipes at the Chimu-Wan tank farms on Okinawa Island, Japan, one of the most corrosive locations in the world for steel infrastructure. Highly corroded carbon steel pipes at the site were replaced with two grades of stainless steel, and minor corrosion-mitigation modifications were made to pipe supports. After the rehabilitated system was commissioned, the pipes were inspected and tested according to established practice. Based on a March 2017 inspection report provided by installation personnel, the stainless steel materials appear to be performing as expected after almost a decade of exposure. They will require only periodic routine inspection and maintenance to mitigate small areas of surface corrosion that may appear over the intended 30 year service life. The return on investment calculated for this project is 1.21.

USACE SMART Gate: Structural Health Monitoring to Preserve America’s Critical Infrastructure

This paper focuses on structural health monitoring of the downstream miter gates on the main channel of Lock and Dam 27 just north of St. Louis, Missouri. Miter gates are the most prolific gate type employed by the United States Army Corps of Engineers (USACE), used at more than 75% of all lock and dam sites throughout the United States. Structural health monitoring of these gates is important, because it provides a method for detecting damage, including degradation of boundary conditions, fatigue cracking, dragging of debris, or discrete occurrences of damage, such as barge impact, which may otherwise go unnoticed until the damage propagates and costly repairs become necessary. By knowing in real time the extent and location of damage, a better informed decision can be made as to whether or not the gate is in immediate need of repair. The initial Structural Monitoring and Analysis in Real Time of Lock Gates (SMART Gate) study of Lock and Dam 27 is focused on achieving several specific condition monitoring targets. The target that will be addressed in this paper is the ability to detect contact degradation between the lateral edge of the lock gate and the wall of the lock chamber. Preliminary results from finite element models show that contact degradation is a localized phenomenon, which is empirically known to occur over time. Initial field results have revealed seasonal changes in strain readings as well as non-linear strain behavior during the beginning of a chamber fill event. This paper presents initial efforts to combine these findings synergistically to detect contact degradation between the quoin and wall boundary on the downstream miter lock gates at Lock and Dam 27. doi: 10.12783/SHM2015/287