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Hydraulic jacking is a serious threat to concrete spillway chutes, demonstrated by the catastrophic spillway chute failure at California's Oroville Dam in 2017. To improve the understanding of uplift pressure and joint flow developed at open, offset joints and enable design and evaluation of anchors, drain systems, and joint remediations that could help prevent such failures, laboratory tests were performed in a supercritical flume furnished with a model joint where the gap width to offset height ratio was varied over a 725∶1 range. The tests included measurement of boundary layer velocity profiles approaching the joint. Uplift pressures were normalized to the velocity head near the boundary, which is related to the depth-wise velocity profile exponents determined in the experiments and can be estimated for field applications from the chute friction factor. The normalized uplift varies with the joint aspect ratio and the flow depth to offset height ratio. The new relations reduce the uncertainty of modeled uplift pressures by a factor of 2.87 over previous methods. Example applications demonstrate practical upper limits for potential uplift pressure. Subsequent articles will address discharge into offset joints, the dissipation of uplift via drainage, and the effect of different methods for remediating existing offsets to reduce uplift. Practical Applications: Concrete spillway chutes develop cracks and must necessarily be constructed with joints, both of which are prone to displacement over time that may create offsets into the flow. Flow striking such offsets is brought suddenly to rest, similar to a pedestrian tripping on a sidewalk crack. The local stoppage of flow at the offset creates dangerously high pressures that can be injected into the foundation, leading to erosion beneath the slab and potential uplift failure, often called 'hydraulic jacking'. This mechanism has caused several notable failures including the Oroville Dam spillway in 2017. Protection against such failures is usually provided by a combination of the weight (thickness) of the slab itself, anchors that hold the slab down, and subsurface drains that reduce the buildup of pressure. This paper provides experimentally based equations for predicting uplift pressure to enable effective design of new spillways and evaluation of existing spillways. The new equations are significantly more accurate than previous methods because they account for the roughness of the chute surface and the reduced flow velocity near the boundary. Subsequent papers will address flow rate through joints, pressure dissipation by drainage, and methods for treating existing offsets to reduce potential uplift. [ABSTRACT FROM AUTHOR]

For evaluating the resistance performance of cement-stabilized soils in cold regions, the variation of the strength of the cemented sand–gravel (CSG) mixture concerning the hydration process should be explored. This paper aims to study the effect of freeze–thaw (F–T) cycles on the strength and microstructure of a CSG mixture with 10% cement that is subjected to 12 cycles of freezing at a temperature of −23°C for 24 h and then melted at room temperature of 24°C for the next 24 h. The uniaxial compressive strength (UCS), California bearing ratio (CBR), and weight volume loss of the samples were measured after individual F–T cycles. Furthermore, the change in the microstructure of the CSG mixture in various F–T cycles was explored. The results showed a considerable reduction in the UCS up to Cycle 3, then a slight increase for Cycles 3–6, and finally a gradual decrease for further cycles. However, the CBR and weight loss slightly fluctuated up to Cycle 6, and then gradually decreased for subsequent cycles. The majority of compounds of hydrated cement were damaged in the first three cycles. In the following cycles, between Cycles 3 and 6, the portlandite compound was dissolved and recrystallized within the microvoids. Depending on the environmental conditions, carbonation may be generated from the hydrated cement fraction, which fills the microvoids and improves the strength and structure of the mixture. During further cycles after the sixth cycle, the mechanical action of the ice lenses coupled with the disintegration of the hydrate compounds imposed many new microvoids and cracks with considerable length and width, which intensified the strength reduction of the moisture and weakened the adhesion between grains. Since cement is widely used in pavement and dam engineering for stabilizing soils, the durability of cemented soils is of prime concern. This study may help improve the durability and resistance of cemented soils in cold climates. The F–T action not only influences the macrostructure of cement-stabilized soils by imposing a wide crack and ice lens but also induces a considerable change in the complexes existing in the hydrated cement paste of the mixture. Three patterns govern the change of the mixture microstructure in various F–T cycles that correspond to the observed trend in strength. The mentioned trend for the microstructure change and, consequently, the strength variation of the CSG mixture are associated with many factors such as pH, cement content, CO2 content, moisture content within the mixture, and relative humidity within the environment. Accordingly, the pattern of microstructural changes in the CSG mixture after the middle F–T cycles may vary depending on environmental conditions. [ABSTRACT FROM AUTHOR]

Red beds (RBs) are widely distributed in all continents of the world. With the rapid development of road and railway construction, the construction of roads and railways in RB areas is increasing. However, when RB is the filler, it will expose three aspects of serious deficiencies in compaction, mechanical bearing capacity, and water stability, which will cause fatal harm to the subgrade. Therefore, RB has to be abandoned and cannot be used as a subgrade filler. In this paper, different microwave irradiation temperatures (DMITs) from room temperature of 25°C to 700°C were used to reveal the enhancing mechanism of RB in three aspects based on the analysis results of microscopic composition and structure. The microscopic composition and structure show that RB can be divided into a low-temperature section (25°C–400°C) and a high-temperature section (500°C–700°C) under the microwave condition. The low-temperature section has some improvement in the engineering performance of RB, but the influence is limited. The engineering performance of RB is improved completely in the high-temperature section. Specifically, the coarse size of RB increases with the rise in microwave temperature, which is beneficial for improving fine size. The compaction property of RB is not largely affected by the water content and can still meet the most stringent subgrade filler requirements, even under saturated conditions or 0. The California bearing ratio (CBR) value can maintain more than 20% under the ultimate working condition, far higher than the code requirements. The increase of internal friction angle and cohesion can enhance the stability of the cut slope, which is conducive to construction in remote mountainous areas. The water resistance of RB is positively correlated with the microwave irradiation temperature, especially at 700°C; RB experiences secondary hardening after encountering water, the mechanical strength increases, and the softening coefficient reaches 107.44%. The research shows that after microwave high-temperature stabilization, the engineering characteristics of the RB are thoroughly strengthened, and it becomes a high-quality subgrade filler to eliminate the three diseases of RB subgrade completely. Compared with the traditional method of adding stabilizers, microwave in situ RB stabilization reduces the site construction's complexity, saves a lot of stabilizer use and transportation costs, and can effectively reduce carbon emissions. This study provides a positive perspective on the in situ application of the RB soft rock subgrade. It could be a starting point for understanding the microwave-based stabilization of soft rock soils subgrade filler in situ. [ABSTRACT FROM AUTHOR]

This paper describes a public domain semiautomated data screening and quality assurance processing tool useful for both discrete and continuous data. This application serves both a field research project assessing salinity and methylmercury drainage load control options and the requirements of a public domain watershed-based water quality forecasting model used to provide decision support for short-term salinity management in the San Joaquin River Basin of California. The US Army Corps of Engineers HEC-DSSVue data management and visualization platform was enhanced in the former application with Python scripts that performed the basic data quality assurance functions. Analogous tools were developed for use on the HOSTGATOR cloud server using the same Python scripts and algorithms to migrate quality-controlled data directly to a server for use by the Watershed Analysis Risk Management Framework (WARMF) water quality forecasting model. The Python scripts for both applications are easily adaptable by other potential users who do not currently have the resources to implement an enterprise-level hydrological data management and real-time quality assurance software system. [ABSTRACT FROM AUTHOR]

Some areas of the California coast have physical conditions—such as local bathymetry, topography, shoreline orientation, and other factors—that increase the risk for damage from tsunami inundation compared with other regions. Technical tsunami hazard analyses can inform decision-makers on regional planning and policy decisions. In this paper, we focus on recent efforts in California to delineate various tsunami hazard zones along the coastline under the Seismic Hazard Mapping Act, wherein structural mitigation measures will be recommended. To define the zone wherein structural mitigation measures are recommended, we present a state-wide tsunami reliability analysis that combines existing probabilistic hazard information and structure fragility curves derived from recent events. We examine design-life chances of significant structural damage for various structure types along all developed coastlines throughout California and use this analysis to show how hazard and risk have different correlations throughout the State. Finally, we outline an approach for creating mitigation zones, which provides state-wide tsunami risk consistency for all structures in the tsunami inundation zone. [ABSTRACT FROM AUTHOR]

Roads constructed over poor ground conditions that carry high traffic volumes and axle loads may, over time, experience persisting occurrences of pavement distress. Road construction, be it a new or a rehabilitation project, is both costly and time-consuming. An appealing option that improves pavement durability, reduces construction cost and time, accelerates strength development over a short curing period, and decreases pavement thickness is to chemically stabilize local road materials. In contrast to other aggregate materials, there has been a gap in evaluating and quantifying the feasibility of chemical stabilization of sandstone aggregate that possesses marginal quality as a road construction material. Therefore, the aim of this paper is to provide an experimental investigation of relative strength development of sandstone aggregate subbase of marginal quality stabilized with combinations of Portland composite cement (PCC), ordinary Portland cement (OPC), and styrene–butadiene latex copolymer (or polymer). The samples were prepared with different gravel-to-sand (G:S) ratios of 2.1, 1.2, and 0.4 and subsequently stabilized with a polymer-cement (P/C) blend. Samples were compacted and cured under dry and wet conditions before measuring their unconfined compressive strength (UCS), indirect tensile strength (ITS), and California bearing ratio (CBR). At the same curing condition and P/C contents, it was found that the UCS and CBR of P/C-stabilized samples increased with increasing G:S ratios. At the same polymer and cement contents, the P/C-stabilized samples with the highest G:S ratio of 2.1 also demonstrated a significantly higher rate of UCS strength development compared with the samples with lower G:S ratio and unstabilized samples. Soil stabilization with a combination of 0.75% polymer and 5% cement contents yielded the highest UCS that was approximately seven times the UCS of unstabilized samples and an ITS of 0.73 MPa. Stabilization with a combination of 0.75% polymer and 3% cement contents yielded the highest CBR value that significantly exceeded 30% after only 4 days of soaking and was seven times that of unstabilized samples. This paper has thus demonstrated the potential improvement to the strength development of sandstone aggregate subbase stabilized with P/C blend under the optimal curing condition and the importance of identifying and using the optimal proportion of polymer and cement to achieve the target strength development and improvement. [ABSTRACT FROM AUTHOR]

In California, after three decades of water market development, volume of water traded in the market remains lower than desired. Total volume of water traded annually accounts for just around 2%–5% of total water used. Vast difference in the marginal values of water in agriculture and urban or environmental uses suggest that significant economic gains can be achieved by easing the barriers to trading water across sectors. This paper draws attention to the role of state and local policies in restricting water transfers. Using novel, purpose-built, satellite-mapped data of a sample of water-trading irrigation districts in California, this paper shows how districts' water transfer decisions are made in response to conflicting pressures of drought-induced high-water demand against the need to support the agricultural economy and the environment in water-exporting areas. The time period under study is 1991–2019, which spans the entire history of water market activity in California from inception to maturity, and helps illustrate the role of changing local and state policies on irrigation districts' water market participation. Despite policy-induced restrictions, this paper shows that sample irrigation districts are highly responsive to demand in water-buying areas, have increased the volume and frequency of water transfers, particularly in the last decade. This paper highlights important research and policy questions about the distribution of economic and environmental effects of water transfers in source area communities that could affect the future potential of water markets in easing structural and drought-induced water scarcity in California. [ABSTRACT FROM AUTHOR]

This paper presents the analytical formulation and computational implementation of a conceptual probabilistic performance-based seismic design (PBSD) framework for ordinary standard bridge (OSB) structures. An updated probabilistic performance-based earthquake engineering (PBEE) assessment methodology is used for the parametric performance assessment of four distinct OSBs in California to investigate the effects of varying key structural design parameters over a primary design parameter space on risk-based structural performance measures. The dire need for a systematic PBSD framework for OSBs is illustrated given the significant variability in risk-based performance levels exhibited by these traditionally designed testbed OSBs. A PBSD methodology involving the design of the bridge piers is proposed wherein a risk-based feasible design domain in the primary design parameter space is identified which facilitates the risk-informed design/decision making process in the face of uncertainty. Sensitivities of risk-based feasible design domains compared with other (secondary) design variables and with the method employed for damage hazard assessment are investigated. [ABSTRACT FROM AUTHOR]

The existing machine learning (ML) models for vibration-based damage assessments often use highly compressed features or are restricted to preprocessed signals with fixed durations and sampling rates. Additionally, the learning capacities of ML models and computational resources are limited, which restricts using raw signals as direct input. This paper studied Mel filter banks (MFBs) for seismic signal processing, inspired by speech recognition technology. It is argued that the same filter designs in audio engineering may not be appropriate for seismic records, and therefore, a customized filter bank formulation was developed. Hybrid deep learning models for rapid assessments (HyDRA) were introduced as multibranch neural network architectures that enable end-to-end training for different types of processed vibration data structures. Moreover, the performance-based earthquake engineering (PBEE) equation was adjusted to integrate ML model uncertainties for probabilistic assessments. The proposed concepts were validated in a case study based on a data set of 32,400 nonlinear time-history analyses of a highway bridge in California. Insights and guidelines are provided for optimum filter design based on 5,184 experiments. Several HyDRA architectures were compared with benchmark models. The optimized MFB feature type outperformed features obtained from continuous wavelet transform and a stacked vector of conventional earthquake engineering indexes. A Bayesian variant of HyDRA was investigated to showcase its integration in the modified PBEE equation. Adopting custom filter banks with the HyDRA architecture enables effective feature extraction from raw vibration records by diversifying feature space and preserving information in the time and frequency domains. [ABSTRACT FROM AUTHOR]

Extended high fluctuations of internal water pressure have often been causally linked to pipeline failures in water distribution systems, especially when this exposure has continued over many years. However, as yet, there is little solid quantitative evidence to support this in real water systems. This paper examines the impact of internal pressure and other critical parameters on the integrity of water pipelines in five districts operated by a California water utility. Eight years of data from the utility's Annual Pressure Survey and 25 years of water pipeline failure data were collectively analyzed using spatiotemporal clustering tools and a Poisson regression model. The analytical procedures and results presented in this paper are designed to support both the water utility's short-term operations and its long-term programmatic drinking water pipeline planning and management practices. [ABSTRACT FROM AUTHOR]

Rapid and accurate evaluation of the damage state of structures after a seismic event is critical for postevent emergency response and recovery. The existing rapid damage evaluation methodology is typically based on fragility curves incorporated into earthquake alerting platforms. However, the extent of damage predicted solely based on the fragility curves can vary significantly depending on ground motion characteristics. This paper presents a methodology for damage assessment of structures while accounting for temporal and spectral nonstationarity of ground motions using continuous wavelet transform and image-analysis techniques. The methodology involves the establishment of a prediction model for wavelet transform of ground motions and damage state of a structure using convolutional neural networks. The methodology is demonstrated in this paper through two case studies: (1) a low-rise nonductile concrete building frame in California and (2) a four-span concrete box-girder bridge in California. The proposed methodology identified damage states with an accuracy greater than 75% in both cases. [ABSTRACT FROM AUTHOR]

This paper presents full-scale experiments and computational analyses on exposed column–base plate connections with ductile anchors. The aim is to examine the seismic performance of these connections for their prospective use as weak bases, wherein steel moment frames are designed to concentrate inelastic rotations in the base connections rather than in the connected columns. The connections feature upset thread anchor rods in which the threads are milled to a smooth shank, providing a designated stretch length over which inelastic deformations may be concentrated. The shank is frictionally isolated from the footing using polyethylene tape. The four full-scale experiments investigate the effects of axial force, rod diameter, and rod material grade. The test specimens withstand (without anchor rod failure) the application of two Applied Technology Council–the Joint Venture partners of the Structural Engineers Association of California, the Applied Technology Council, and the Consortium of Universities for Research in Earthquake Engineering (ATC-SAC) protocols applied consecutively (each to drift amplitudes of 5%), followed by additional cycles to 6.5% drift amplitude. Complementary line element–based and continuum finite-element simulations are conducted to examine to what extent the experimentally observed response may be generalized to untested configurations. Implications for design are summarized, along with the limitations of the study. [ABSTRACT FROM AUTHOR]

Rainwater harvesting provides a potential source of supplemental water supply to meet increasing urban demand. Distributed solutions based on many small capture devices are often viewed as inefficient in terms of both cost and volume of water captured. This paper describes a framework for assessing the value of distributed rainwater capture as a substitute for a share of municipal water supplied to residential and commercial buildings. The analysis was applied to the Ballona Creek watershed in Los Angeles County, California, evaluating several cistern sizes and participation rates to estimate the amount and value of water, energy, and carbon savings offset by captured water. Results show that rainwater capture may be an efficient approach to augmenting water supply under certain conditions. From the perspective of the water supplier, capturing water for outdoor use is cost-effective, but including indoor use is not due to installation and maintenance costs. From the perspective of the homeowner, installing a cistern for irrigation would result in net cost savings over time, and under certain conditions, higher benefits are realized from larger cisterns. [ABSTRACT FROM AUTHOR]

With the increasing occurrence of extreme wind events (e.g., hurricanes) and growing interest in performance-based wind engineering, a better understanding of the structural response and collapse under extreme wind loads is needed. Studying the inelastic nonlinear response of buildings through collapse under wind hazards can lead to safer structures and inform future economic designs. The objective of this paper is to investigate the performance of a 20-story steel moment-resisting frame, from the SAC project, under wind loads at different wind speeds. SAC is a joint venture between the Structural Engineers Association of California (SEAOC; the S in SAC), the Applied Technology Council (ATC; the A in SAC), and California Universities for Research in Earthquake Engineering (CUREe; the C in SAC). The building design was first assessed for compliance based on the latest code requirements. Next, a nonlinear dynamic analysis under three different hazard levels was used to conduct a performance-based assessment. The analysis showed that the building conservatively meets the different performance targets. The building was deliberately underdesigned, which resulted in an 18% reduction in used materials, to conduct a comparative nonlinear response analysis and performance-based assessment. The nonlinear analysis for both building designs was extended under increased wind loads through collapse. Overall, the different parts of the study confirm that current code methods can lead to overly conservative structural designs and suggest that incorporating a performance-based approach along with a well-controlled nonlinear response under extreme wind events can lead to safer and more economical designs and is worthy of further investigations. [ABSTRACT FROM AUTHOR]

A hydropower resource assessment (HRA) can be considered a reconnaissance survey in which the total hydropower potential in a region is quantified. Hydropower potential for purposes of this paper is defined as the potential power that can be extracted from a reservoir. A product of mean annual streamflow flowing in a stream reach and the hydraulic head in a potential reservoir to be constructed in the stream reach with turbine efficiency and unit weight of water determines the power potential. Traditionally, an HRA considered only hydrologic and hydraulic information to quantify the total hydropower potential in a region. With the advancements in computational technology, the HRA can be enriched with geospatial environmental information. This additional information can help to identify the potential stream reaches and their rank for future hydropower development in a region. This paper considers three different types of information, and hence, three criteria, including (1) hydrologic and hydraulic information; (2) environmental information; and (3) combined hydrologic and hydraulic and environmental information to search for potential stream reaches. A methodology was proposed to identify the high-power-density sites for potential development using these three criteria. The methodology was tested to a USGS subbasin in the state of California. The impacts of the criteria on potential site identification are clearly observed in the results. [ABSTRACT FROM AUTHOR]

This paper analyzed damping ratios inferred from 1,335 seismic responses recorded in 154 instrumented buildings in California. These values were inferred using a parametric system identification technique in the time domain, and subjected to a series of reliability screening tests to retain only high-quality data. The resulting damping ratios conformed a data set of 1,037 high-quality values inferred exclusively from the seismic response of buildings, a database several times larger than previous studies of damping inferred from seismic response. The data set was analyzed using a linear mixed-effects statistical model to account for the fact that many of the data points were clustered, because they came from damping ratios in the same building shaken by various earthquakes. It was shown that damping decreases with increasing building height, which is the factor that best explained the relatively large variance observed in the data. Contrary to some previous recommendations, it was found that once the variation with height is taken into account, the primary structural building material is not statistically significant in the damping ratio of buildings subjected to earthquakes. However, when including the combined material and lateral resistant system as a factor in the statistical model, an additional 6% of the variance was explained. Results showed that steel buildings with moment-resistant frames have, on average, a slightly higher damping ratio than those with steel braced frames. The amplitude dependency of damping showed that there was no significant correlation between damping ratio and the overall lateral deformation demand in the building as measured by the peak roof drift ratio for amplitudes typically observed during moderate earthquake motions once a minimum level of amplitude is exceeded. [ABSTRACT FROM AUTHOR]

Regional seismic risk assessment involves many infrastructure systems, and it is computationally intensive to conduct an individual simulation of each system. This paper suggests an approach using active learning to select informative samples that help build machine learning models with fewer samples for regional damage assessment. The potential of the approach is demonstrated with (1) failure mode prediction of bridge columns, and (2) regional damage assessment of the California two-span bridge inventory with seat abutments. The active learning approach involves the selection of column attributes or bridge models that are more informative to the creation of machine learning-based decision boundaries. The results reveal that an active learning target model based on 100 bridge samples can achieve a level of accuracy of 80%, which is equivalent to a machine learning model based on 480 bridge samples in the case of damage prediction following an earthquake. With the proposed approach, the computational complexity associated with regional risk assessment of bridge systems with specific attributes can be drastically reduced. The proposed approach also will help plan experimental studies that are more informative for damage assessment. [ABSTRACT FROM AUTHOR]

Expansive black cotton soil (BCS) exhibits volumetric instability when exposed to moisture fluctuation, rendering loss of geomechanical strength. The present paper evaluates the effectiveness of stabilizing BCS with two different types of fibers, polypropylene (PF) and glass fiber (GF), in conjunction with envirosafe alkali-activated binder (AAB) at different proportions of fly ash and slag in alkaline mixture. AAB is produced by blending an alkali-activator solution of sodium silicate and sodium hydroxide with aluminosilicate precursors (Class-F fly ash/slag) at 0.4 water to solid (w/s) ratio. PF and GF are varied from 0% to 0.4% with 5% AAB in BCS. Unconfined compression strength (UCS), indirect tensile strength (ITS), and California bearing ratio (CBR) tests are carried out as performance indicators of geomechanical strength of both fiber-reinforced AAB treated BCS. The research also focuses on proposing an optimum dosage of fly ash–slag ratio and fiber reinforcement in AAB-BCS. Monte Carlo Simulation is used to determine the reliability index for each case. The influences of varying dosages of fibers and fly ash–slag proportions in BCS show a significant improvement in shear strength and tensile properties. The reliability analysis also shows that the amount of fibers and fly ash–slag proportions are essential factors in UCS, ITS, and CBR strength for both PF and GF reinforcement. [ABSTRACT FROM AUTHOR]

Frequent, extended, and high fluctuations of internal water pressure are suspected to be causally linked to water main failures. However, there is little solid quantitative evidence to support this for real water systems. This paper examines the influence, extent, and impacts of hydraulic pressure magnitude(s) on the physical integrity of water mains in five selected districts in California. The principal objectives of this study were to: (1) characterize spatial and temporal patterns of relatively high water main failure rates, and (2) statistically test for direct correlative linkages between observed high local pressure regimes and pipe failures. To accomplish these goals, eight years of data from the utility's annual pressure survey (APS) was collected and analyzed. Areas with a consistently high failure rates showed notably stronger correlations between two variables, which reflects the role of pressure on increased failure rates and likely development of failure clusters. Weaker correlations, however, were observed when analyzing the entire district and nonfailure hotspots. These results can contribute to the development of more comprehensive long-term programmatic water main planning and management strategies. [ABSTRACT FROM AUTHOR]

The paper compares two liquefaction case histories in California: (1) the response of the Wildlife site in the Imperial Valley to the 2010 El-Mayor Cucapah earthquake (Mw = 7.2, amax = 0.15 g); and (2) the response of the Treasure Island Fire Station (F.S.) site in the San Francisco Bay area to the 1989 Loma Prieta earthquake (Mw = 6.9, amax = 0.16 g). Both histories involve silty sand critical layers with nonplastic fines contents, FC = 24-27%, similar normalized shear wave velocities, Vs1 = 145-155 m/s, low cone penetration test (CPT) cone penetration resistances, and groundwater tables at essentially the same depth. The corresponding data points plot almost on top of each other on the shear wave velocity field liquefaction charts, which predict liquefaction at both sites. While Treasure Island F.S. did liquefy during the shaking, Wildlife did not and was far from liquefaction as indicated by piezometers at the site. This paper constitutes an attempt to understand the reason for these very different pore pressure responses through a detailed analysis of similarities and differences between the two histories. It is concluded that preshaking by previous earthquakes is the most probable explanation of the higher liquefaction resistance exhibited by the Wildlife site and other sites in the Imperial Valley. While the Wildlife critical layer was subjected to about 60-70 earthquakes capable of generating significant excess pore pressures between its estimated 1907 deposition and the 2010 earthquake, the Treasure Island F.S. layer was subjected to only about two earthquakes capable of doing so between deposition in the 1930's and the 1989 earthquake. This difference is due to the very high seismic activity in the last 100-plus years in the Imperial Valley compared with a seismically quiet San Francisco Bay Area after the 1906 earthquake. The significance of the prior seismic history is corroborated by recent results from centrifuge and large-scale experiments. These results as well as the methodology developed in the paper may be helpful when analyzing the observed high liquefaction resistance of sandy sites located in other seismic regions. [ABSTRACT FROM AUTHOR]

Traditional meter gates for farm delivery flow measurement from an open channel conveyance have traditionally incorporated round canal gates (Armco type) for control. In recent years, some irrigation water agencies (i.e., irrigation districts) have replaced deteriorating round gates with lower-cost rectangular gates that cover round holes. Similar to the situation described in a companion paper, where round gates were examined, there have been no investigations into flow measurement uncertainty using the existing rating tables for these gates. In this study, two commonly used rectangular gate sizes, 0.46 m (18-in.) and 0.61 m (24-in.), were tested under scenarios of various gate openings, upstream heads, and head differences. Coefficient of discharge (Cd) values were computed based on actual gate open areas. These improved Cd values were used to generate new discharge rating tables for 0.46 m (18-in.) and 0.61 m (24-in.) rectangular meter gates. Limitations for these rectangular gates are discussed. If guidelines presented in this paper and in the companion paper are followed, the average instantaneous flow measurement uncertainty that could be expected is better than ±5%. However, uncertainty is higher (up to approximately ±9.5%) at the lower end of the recommended gate openings [0.10 m (4 in.)] for these rectangular gates. [ABSTRACT FROM AUTHOR]

During military contingency operations, aircraft are required to land, taxi, and takeoff on unpaved surfaces. In some cases, operational time limitations do not allow for the construction of paved surfaces to establish airfield operations. The original flexible pavement design procedure for paved surfaces, which is based on the California Bearing Ratio (CBR) and the -factor (Alpha-factor), was extended and applied to the design and evaluation of aggregate-surfaced pavements. With the reformulation of the CBR-Alpha for the design of flexible pavements, efforts were also directed at defining a new equation for the design of aggregate-surfaced airfields. This paper focuses on the development of a new CBR-Beta procedure for the design and evaluation of aggregate-surfaced airfields. Data from previous studies conducted on aggregate-surfaced full-scale test sections were used for this purpose. The new performance curve proposed in this paper for aggregate-surfaced airfields has the same format as the equation that was proposed and accepted for flexible pavements. [ABSTRACT FROM AUTHOR]

Using a longitudinal data set that inventories single-family home sale transactions within 3.2 km (2 mi) of the Central District redevelopment area of Oakland, CA, this paper finds that the targeted efforts to redevelop the Central District have partially mitigated the District's negative impact on surrounding neighborhoods. The paper examined the Central District from 1992 to 2006, a period during which the District changed in character from a business district to a mixed-use vibrant area. During the period 1992 through 2000, proximity to the Central District negatively impacted housing prices up to 1.6 km (1 mi) from the District boundary. However, the magnitude of the impact reduced in the 2001-2006 period and dissipated after 0.8 km (0.5 mi) from the District boundary, indicating that the redevelopment efforts had a positive spill-over effect on surrounding property values. [ABSTRACT FROM AUTHOR]

This paper is a companion to 'Displacement-Based Method of Analysis for Regular Reinforced-Concrete Wall Buildings: Application to a Full-Scale 7-Story Building Slice Tested at UC-San Diego' and presents key results obtained from a full-scale 7-story reinforced concrete building slice built and tested on the George E. Brown Jr. Network for Earthquake Engineering Simulation Large Outdoor High-Performance Shake Table at the University of California, San Diego. The building was tested in two phases. This paper discusses the main test results obtained during Phase I of the experimental program. In this phase, the building had a rectangular load-bearing wall acting as the main lateral force-resisting element. The building was subjected to four historical California input ground motions, including the strong-intensity near-fault Sylmar record, which induced significant nonlinear response. The test addressed the dynamic response of the building, including the interaction between the walls, the slabs, and the gravity system as well as four issues relevant to construction optimization: (1) reduction in the longitudinal reinforcement; (2) use of a single curtain of reinforcement to transfer shear; (3) constrain of plasticity in the first level of the wall using capacity design; and (4) use of resistance-welded reinforcement in the boundary elements of the first level of the walls. The building responded very satisfactorily to the ground motions reproduced by the shake table and met all performance objectives. The effects of kinematic system overstrength and higher modes of response in the experimental response were important; this verified to a large extent the displacement-based method of analysis presented in the companion paper. [ABSTRACT FROM AUTHOR]

In 1996, California Department of Transportation (Caltrans) initiated an extensive project to develop mechanistic-empirical (ME) pavement design and analysis tools, which will help state design engineers incorporate the impact of new products and technologies, increased traffic volumes and axle loading, and variable climatic conditions. As part of the development of new ME design procedures, Caltrans is developing a suite of dedicated software. CalME is a ME design program for flexible pavements that parallels the NCHRP 1-37A (MEPDG) and is calibrated for California conditions. CalBack is a sophisticated back-calculation program that contains specific features pertinent to California and is designed to work standalone, or in concert with CalME. CalBack is a unique and important addition to the existing knowledge base in that it possesses multiple data input/output methods, several new analytical modeling methods, and numerous user performance options. This paper describes the successful development and implementation of CalBack in three ways: (1) why and how Caltrans developed CalBack; (2) how CalBack functions; and (3) representative studies that show how well the software performs. Application of CalBack in several California projects, including the case studies presented in this paper, has shown that back-calculated moduli for different layers in the flexible and rigid pavement systems agreed reasonably well with laboratory measured values. Furthermore, the importance of avoiding temperature gradients when evaluating portland cement concrete pavements with the falling weight deflectometer is also well captured by CalBack. [ABSTRACT FROM AUTHOR]

This paper presents a case study on the seismic response of a recently constructed freeway overcrossing located in southern California, which is equipped with elastomeric bearings and fluid dampers at its end abutments. The analysis employs the substructure method and a reduced order stick model. The macroscopic constitutive laws of the springs and dashpots that approximate the mechanical behavior of approach embankments, pile foundations, center bent, abutments, elastomeric bearings, and fluid dampers are established in the companion paper. The paper presents an in-depth analysis of the seismic response of the bridge equipped with the response modification devices accounting for the effects of soil–structure interaction. The various response quantities presented are compared with the corresponding response quantities of a hypothetical bridge with integral abutments. Advantages and challenges in the two design configurations are identified and discussed. [ABSTRACT FROM AUTHOR]

This paper focuses on the benchmark control problems for seismically excited nonlinear buildings. The benchmark study focuses on three typical steel structures, 3-, 9-, and 20-story buildings designed for the SAC project for the Los Angeles region. This paper reports the application of the active control scheme on the 3- and 20-story benchmark buildings, where the control action is achieved by a fuzzy logic controller. The main advantage of the fuzzy controller is its inherent robustness and ability to handle any nonlinear behavior of the structure. The performance of the controller is validated through the computer simulation on MATLAB. The control scheme satisfies the control constraints and is presented according to the evaluation criteria provided with the benchmark problems for comparison with other schemes. Four different earthquakes (El Centro 1940, Hachinohe 1968, Northridge 1994, and Kobe 1995) will be used in the simulation. [ABSTRACT FROM AUTHOR]

California Civil Code §§895 through 945.5, also known as “SB 800,” has dramatically changed the legal landscape for residential construction projects in California. The law sets forth new, legislatively defined, actionable defects; a detailed prelitigation repair process; and available damages and defenses. This paper examines the impacts of the law on design professionals and concludes that the law appears to have supplanted the standard of care for design professionals in connection with residential construction—meaning that their services may now be measured against codified standards instead of against the performance of their peers. Alternatively, rather than supplanting the standard of care, the law may have the practical effect of shifting the burden of proof from homeowner claimants to the allegedly negligent design professionals, thereby requiring the defendant design professional to show that their services comply with the standard of care in order to escape liability. In either event, the playing field has changed dramatically for design professionals. This paper suggests ways in which design professionals might tailor their practices to best position themselves for claims which are sure to arise out of SB 800. [ABSTRACT FROM AUTHOR]

Connectivity is important to the structure and function of systems. In water infrastructure systems, connections between components determine flow patterns and operational flexibility. Network theory can provide tools to assess and view connectivity in water resource networks that augment current methods in water resource systems analysis. This paper presents an analysis of connectivity and resilience in the network of California's water resources infrastructure using network theory visualization and metrics. Applying these techniques to a link-node network used in a statewide hydroeconomic model of water management in California, the analysis shows how such metrics are useful to describe aspects of connectivity and identify important system components. Both the entire system and the San Francisco Bay Area subsystem are analyzed using measures of centrality, spacing, and linkage. The analysis also assesses the effects of network degradation by removing selected components, revealing complex relationships between connectivity, efficiency, and central dominance. The results demonstrate tools to understand network structure in California's water system. Finally, insights are presented from the analysis in the context of the broader literature on resilience in engineered and environmental systems. [ABSTRACT FROM AUTHOR]

This paper presents the findings from a computational investigation performed on the Borax corporate headquarters building, a four-story steel frame structure in which 75% of the steel moment-resisting connections suffered brittle fractures during the 1994 Northridge earthquake. A companion paper provides detailed documentation of the forensic investigation and repair design performed immediately following the earthquake on this structure, which was less than one year old when the earthquake struck. This paper describes a series of preliminary analyses conducted shortly after the forensic investigation and repair were completed. The main objectives were to investigate the behavior of the structure during the earthquake, and to determine whether different levels of established, advanced analysis techniques could estimate the distribution and extent of the damage. The results showed that a three-dimensional nonlinear dynamic analysis using a site-specific accelerogram provides strong correlation with the observed damage, while elastic static and dynamic analyses, two-dimensional nonlinear static and dynamic analyses, and three-dimensional nonlinear static analyses show less correlation. In addition, the results indicate that substantial redistribution of forces may have occurred, and that force distribution most likely had a noticeable effect on the pattern of failures observed in the structure. [ABSTRACT FROM AUTHOR]

The Borax corporate headquarters building, a low-rise steel moment frame, was less than one year old when it sustained significant structural damage during the 1994 Northridge earthquake. Seventy-five percent of its steel moment-resisting connections suffered severe brittle fractures. This paper presents a detailed documentation of the forensic investigation performed on this structure immediately following the earthquake. A companion paper presents the findings from a subsequent computational investigation performed on the structure. The two primary failure modes at the Borax building were column flange fracture and pull-out of the girder flange from the column. The failures are primarily attributed to a fundamental flaw in the standard code-prescribed welded-flange bolted-web connection and the extreme ground motion at the site. The paper also describes the repairs made to the structure. These repairs were completed before the SAC research that now guides repair and retrofit of these structures was available. [ABSTRACT FROM AUTHOR]

Dense networks of low-cost wireless sensors have the potential to facilitate prolific data collection in large and complex infrastructure at costs lower than those historically associated with tethered counterparts. While wireless telemetry has been previously proposed for structural monitoring, comparatively less research has focused on the creation of a complete and scalable data management system that manages the storage and interrogation of wireless sensor data. This paper reports on the development of a novel wireless structural monitoring system specifically tailored for large-scale civil infrastructure systems by architecturally combining dense wireless sensor networks with a suite of information technologies remotely accessible by the Internet. The architectural overview of the proposed Internet-enabled wireless structural monitoring system is presented including a description of its functional elements (for example, wireless sensors, database server, and application programming interfaces). The monitoring-system architecture proposed is validated on the New Carquinez (Alfred Zampa Memorial) Bridge in Vallejo, California. A permanent wireless monitoring system is installed consisting of 28 wireless sensor nodes collecting data from over 80 channels. The bridge sensor data are transferred by a wireless cellular connection to a remote database server where it is stored and available for interrogation by software clients granted access to the data. To illustrate the ability to autonomously process the bridge response data, the stochastic subspace identification method is used to extract accurate modal characteristics of the bridge that are used to update high-fidelity finite-element models of the bridge. The Internet-enabled wireless structural monitoring system proved to be scalable to a large number of nodes and has thus far proven stable and reliable over long-term use. [ABSTRACT FROM AUTHOR]

This paper presents an agroeconomic approach to assess the economic impact of improving nitrogen and irrigation management practices in California's Tulare Lake Basin and the Salinas Valley. The approach employs a self-calibrated mathematical programming model with a constant elasticity of substitution production function and two nests: one for irrigation and one for nitrogen. Agricultural crop yields are maintained as a worst-case for improving nitrogen use efficiency. Small reductions () in nitrate load to groundwater can be achieved at relatively low costs. Load reductions of 50% may require more costly nitrogen management practices and a broader education strategy with higher reductions in farm net revenues and irrigated area. Other policy instruments such as a tax and levees on applied nitrogen may help reduce groundwater load and raise revenues for alternate drinking water supplies in affected areas. The model also provides further evidence that it is possible to integrate agronomic and economic models that account for substitutability of applied nitrogen and water in agricultural production for policy analysis. [ABSTRACT FROM AUTHOR]

The long-range monitoring of civil infrastructure systems monitored with dense sensor arrays that are capable of generating voluminous amounts of data from continuous online monitoring requires the implementation of a proper data processing and archiving scheme to maximize the benefits of structural health monitoring operations. This paper focuses on the areas of data management, data quality control, and feature extraction of meaningful parameters to describe the response of large-scale infrastructure systems to ambient excitation in the context of structural health monitoring (SHM). Recordings from the monitoring system installed on the Vincent Thomas Bridge (VTB) in San Pedro, California form the database of the proposed data-management and archiving methodology. The data processing methodology for the VTB is based on the calculation of the sensor array acceleration covariance matrices for every hour of available data and the subsequent orthogonal decomposition of the covariance matrices. The dominant proper orthogonal modes of the bridge are determined, and their statistical variations over an extended observation period covering several months of continuous data are quantified and analyzed. The empirical probability density functions for the mean daily bridge accelerations are computed and used to compare the statistical variations in different periods of operation of the bridge (working days, weekends, holidays). It is shown that the computed statistical distributions of the bridge response can provide a quantitative baseline through which to facilitate the early detection of any anomalies indicative of a possible structural deterioration resulting from fatigue (service loads) or extreme loading events, i.e., earthquakes, artificial hazards, or other natural hazards. [ABSTRACT FROM AUTHOR]

Many pumps are used for irrigation in central California, but a great number of them are operating inefficiently. In this paper, the information recovered from over 15,000 electric irrigation pump tests in central California is analyzed. The objectives of this study are to define the common characteristics attributed to pumps with best and worst performance and to identify the possible target groups that might benefit from improvements, obtaining potential energy savings. The results showed that pumps with lower reported total dynamic head (TDH) and flow rate () usually have poorer overall pumping plant efficiency (OPPE) values, but high flow rates and input power are typically associated with better OPPE values. According to this analysis, energy savings of more than could be achieved for well pumps, with a per-pump average of . For non-well pumps, the total potential savings are and the average per pump is . [ABSTRACT FROM AUTHOR]

In this study, an attempt was made to evaluate and select an optimal Maintenance and Rehabilitation (M&R) strategy for a designed flexible pavement by integrating Life-Cycle Cost Analysis (LCCA) and California Mechanistic-Empirical (M-E) design procedures (CalME). A 20-year design life pavement stretching 11.27-km-long section of 4-lane Highway 53, in Lake County, California is considered for this project level study. Three M&R strategies available in the CalME program were evaluated including, Extended Pavement Preservation (EPP), Preservation-Preservation-Rehabilitation (PPR), and Rehabilitation only (R). These strategies are applied as certain levels of distresses (rutting and cracking) are reached. The California-customized RealCost LCCA program was also employed to compare the various M&R strategies using the Equivalent Uniform Annual Cost (EUAC). LCCA demonstrated that EPP was the best economical alternative to maintain the pavement in a good usable condition for as long as 80 years of service. The methodology employed in this paper also demonstrated that extended life pavement may be achieved from a 20-year design by selecting the optimal preservation techniques and optimizing their time of application. [ABSTRACT FROM AUTHOR]

California's Sacramento-San Joaquin Delta is the major hub of California's water supply system and is central to the ecosystem of many native threatened and endangered species. Conflicts over the Delta have evolved over more than a century. This paper traces changes in this conflict in game-theoretic terms, with its implications for the region's physical and ecological decline and governance. The Delta is not a zero-sum problem and win-win resolutions may exist if stakeholders cooperate. Game theory provides some insights on the potential for win-win solutions. The Delta problem has had a Prisoner's Dilemma structure, in which stakeholder self-interest makes cooperation unlikely within a reasonable time frame. However, the core of the Delta conflict is changing as the unsustainable future becomes more widely understood. Today's Delta problem has characteristics of a Chicken game, where cooperation is in everyone's interest, but it is unlikely because parties deviating from the status quo are likely to bear more of the costs of a long-term solution. The State of California may become the victim (or chicken) of the Delta game, bearing the greatest costs, if it continues to rely on leaving parties to develop voluntary cooperative solutions without a sufficient mechanism for enforcing cooperation. [ABSTRACT FROM AUTHOR]

Heavy vehicles can considerably affect traffic flow particularly during heavy-traffic conditions. Large numbers of heavy-vehicle lane-changing maneuvers can contribute to increase the number of traffic accidents and hence to reduce the freeway safety. The increase in the number of heavy vehicles on freeways has been the motivation to establish strategies to reduce the interaction between heavy vehicles and passenger cars. Previous studies have examined different lane-restriction strategies for heavy vehicles using microscopic traffic-simulation packages. Those packages mostly use a general lane-changing model to estimate the lane-changing behavior of heavy-vehicle and passenger-car drivers. The general lane-changing models ignore the fundamental differences in the lane-changing behavior of passenger cars and heavy vehicles. However, an exclusive lane-changing model for heavy vehicles can increase the accuracy of simulation models. The application of such a model can result in a more reliable evaluation of lane restriction strategies. In this paper, different lane restriction strategies are defined for heavy vehicles. For each strategy, the macroscopic and microscopic traffic measurements of two freeway sections in California are analyzed, using the VISSIM default lane-changing model and an exclusive heavy- vehicle lane-changing model. The results show that the VISSIM default model unrealistically overestimates the observed number of heavy-vehicle lane-changing maneuvers and potentially overestimates the number of traffic accidents. Using the exclusive lane-changing model for heavy vehicles enhances the accuracy of the VISSIM traffic simulation model in microscopically estimating the lane-changing maneuvers of heavy vehicles. [ABSTRACT FROM AUTHOR]

Realistic time history simulation of drilled pier/pile-soil systems under dynamic and static loading is essential for the development of effective performance-based earthquake designs of deep foundations. This paper presents the results of the numerical simulation of a series of static and dynamic tests on drilled piers performed at the University of California, Berkeley. A nonlinear soil model was implemented based on multiaxial cyclic bounding-surface plasticity within a general finite-element framework, OpenSees. The model requires a small number of parameters that can be easily obtained through conventional site investigations. The results of the simulations show that the model can reasonably simulate nonlinear response of the soil and that it does a good job of capturing the actual load deformation curves obtained from in situ dynamic and static pier load tests. Although the model is suitable for a fully nonlinear total stress analysis of soil-pile systems under multidirectional shaking, further studies are needed to enhance the model capacity by incorporating the cyclic stiffness and strength degradation caused by full stress reversals. [ABSTRACT FROM AUTHOR]

This paper demonstrates an innovative reliability analysis approach for prediction of asphalt rutting performance. In this approach, reliability was evaluated by considering the variability in laboratory test results, layer thicknesses, stiffnesses, and measured in situ performance. The effects of input design parameters variability on predicted performance were determined using the calculated distributions of calibration coefficients. To assess the contribution of each input parameter's precision to the precision of calculated calibration coefficients, various cases were created by including and excluding the variability in these parameters in the calibration process. These distributions were also used for rutting performance prediction and reliability evaluation of highway sections. In this way, rut depths for different reliability levels can be predicted without performing computationally intensive calculations within the design software. The results indicated that distributions of calibration coefficients calculated by using measured rut depths (performance variability) are very similar to calibration coefficient distributions calculated by using thickness and stiffness (construction) distributions. This result suggests that variability in performance can be effectively predicted by using the variability in thickness and stiffness for HVS test sections because thickness and stiffness were found to be the major factors that control the variability in measured rut depths. The effect of laboratory test results variability on calibration coefficient distributions was found to be negligible when compared to the effects of stiffness and thickness variability. Although the reliability approach proposed in this study was developed using the results of a specific laboratory test and rutting models used for design in California, the general procedure can be applied to any pavement design software for any type of distress. [ABSTRACT FROM AUTHOR]

This paper describes a framework to determine the total maximum daily flow diversions (TMDFDs) of freshwater from the San Francisco Bay Delta that can be undertaken without causing the extinction of salmon, striped bass, and delta smelt. The framework comprises three models: the watershed analysis risk management framework (WARMF) model of tributary rivers, the Link-Node estuary model of the Bay Delta, and the monthly cohort life-cycle model of fish. The first two models simulate the environmental conditions of river segments and estuary 'Nodes' in which fish live. The fish model deposits eggs in river segments on specified months. The eggs become larvae, juveniles, and young as they move downstream to the estuary 'Nodes' where they may die, be eaten, or be entrained into pumps that divert water for export to northern and southern California cities and Central Valley farms. Thus, flow diversion is mechanistically connected to fish decline. These models are integrated by the graphical user interface (GUI) of WARMF to serve as a decision support system (DSS). The DSS allows users to enter alternatives of daily flow diversions, including no diversion. The DSS calculates projected fish declines. A stakeholder process is then used to select an acceptable water diversion plan. [ABSTRACT FROM AUTHOR]

In today's world of specialization, civil engineers may benefit from a return to an earlier period when breadth of knowledge, skills, and attitudes were appreciated: the Renaissance era. A broad set of skills is especially important in meeting the challenges of restoring deteriorating infrastructure and working with restricted financing. This paper presents the case of the Golden Gate Bridge Seismic Retrofit Phase II Project to illustrate how important it is for civil engineers to possess solid technical expertise coupled with a cross-disciplinary knowledge of design and construction to achieve project success. These qualities allowed the engineers to integrate construction knowledge into the design process and design knowledge into the construction process, in spite of the project's traditional design-bid-build delivery method. Of equal importance to the success were the engineers' commitment, integrity, and persistence. The Phase II Project involved modifying the 70-year-old bridge's five south approach structures. By applying modern earthquake engineering standards, these structures are now capable of withstanding a seismic event comparable to the Great San Francisco Earthquake of 1906. The final outcome was a complex yet cost-efficient seismic upgrade of the iconic Golden Gate Bridge, a project that was constructed within budget and without claims. In 2007, the project received the American Society of Civil Engineers' Outstanding Civil Engineering Award. [ABSTRACT FROM AUTHOR]

The BART Transbay Tube (TBT) is an immersed cut-and-cover subway tunnel that runs from Oakland to San Francisco, California. The loose sand and gravel backfills placed around the tunnel are considered to be liquefiable, and the clays under the backfill are soft in some zones along the alignment. These conditions could potentially result in uplift of the tunnel during strong earthquake shaking. This paper describes centrifuge model tests performed to verify numerical methods used to assess the stability and to evaluate the potential uplift mechanisms of the TBT. The observed mechanisms of uplift were a ratcheting mechanism (sand migrating under the tunnel with each cycle of relative movement), a pore water migration mechanism (water flowing under the tunnel), and a bottom heave mechanism, involving soft soils below the base of the trench. A fourth potential mechanism, viscous flow of liquefied soil, was not observed. The volume of the tunnel relative to the volume of the trench and the densities and permeabilities of the nonhomogeneous backfill were important parameters affecting the uplift of the tunnel. From the experiments reported here and analyses reported by the designers, it was concluded that the magnitude of uplift is limited and, hence, that an expensive ground improvement project to densify the backfill was unwarranted. [ABSTRACT FROM AUTHOR]

California has adopted innovative legislation to tackle climate change. Energy-efficient buildings, lower-emissions industrial processes, and more fuel-efficient transportation vehicles operating on cleaner fuels are among the many strategies that are being implemented. However, to attain the needed reductions, California must find additional strategies to reduce greenhouse-gas emissions, especially from the transportation sector, which is a large fraction of the total emissions problem. This paper discusses the efforts that are underway to further increase transportation efficiency, shift transportation to less CO2-intensive modes, and slow or reverse growth in vehicle-kilometers of travel (VKT). The legislative mandate is leading to a new focus on methods for quantifying travel changes and emissions reductions, ranging from spreadsheet approaches to integrated transportation-land use models. It also is renewing interest in travel-demand management and land-use policies that could reduce overall travel. While a number of cities have embraced these strategies, their success in the face of the state's continuing growth will likely depend on both federal and state policies and funding incentives. [ABSTRACT FROM AUTHOR]

Departments of transportation in the United States are under increasing pressure to accelerate projects to meet user-defined constraints and reduce the inconvenience to the traveling public. Although there is information about acceleration projects in other industries, there has been little specifically aimed at highway projects. A domestic scan sponsored by the National Cooperative Highway Research Program was tasked with providing information in this area. The objective of this paper is to synthesize the resulting information into fundamentals that support successful planned accelerated highway project delivery. Case studies of how departments of transportation successfully accelerated the construction of four very different projects in California, Florida, and Texas serve as the basis for identifying these fundamentals. The fundamentals include upfront and detailed planning, designs that facilitate accelerated construction, a collaborative environment for project stakeholders, and incentives and disincentives to motivate construction contractors. [ABSTRACT FROM AUTHOR]

This study is the second of two companion papers to examine the seismic collapse safety of reinforced concrete frame buildings, and examines nonductile moment frames that are representative of those built before the mid-1970s in California. The probabilistic assessment relies on nonlinear dynamic simulation of structural response to calculate the collapse risk, accounting for uncertainties in ground-motion characteristics and structural modeling. The evaluation considers a set of archetypical nonductile RC frame structures of varying height that are designed according to the seismic provisions of the 1967 Uniform Building Code. The results indicate that nonductile RC frame structures have a mean annual frequency of collapse ranging from 5 to 14×10-3 at a typical high-seismic California site, which is approximately 40 times higher than corresponding results for modern code-conforming special RC moment frames. These metrics demonstrate the effectiveness of ductile detailing and capacity design requirements, which have been introduced over the past 30 years to improve the safety of RC buildings. Data on comparative safety between nonductile and ductile frames may also inform the development of policies for appraising and mitigating seismic collapse risk of existing RC frame buildings. [ABSTRACT FROM AUTHOR]

The San Francisco Bay Area, California has experienced significant population growth over the last 60 years. The design practices for residential foundations have evolved substantially over this period, as a result of improved geologic characterizations, better engineering understandings of foundation performance, building code changes, and project litigation. The majority of residential foundations are constructed on expansive soils and bedrock, with the primary movement as a result of swell due to wetting of materials in an arid environment. A survey of design practice of practicing geotechnical engineers in the bay area was conducted using a written questionnaire and telephone interviews to compile data regarding the most commonly used design procedures, design details, drainage recommendations, and construction monitoring practices. The results of this survey are compiled and presented in this paper. Three primary foundation systems were identified in the survey as being commonly used in the bay area-rigid footing grids, drilled piers, and mats/slabs. To illustrate problems that have occurred with each of these foundation systems, case histories are presented for recent bay area expansive soil projects for each of these three foundation types. [ABSTRACT FROM AUTHOR]

Traffic sensors have been deployed for decades to freeways to meet the requirements of various traffic/transportation applications, most noticeably traffic control and traveler information applications. A unique feature of traffic sensor deployment is that it is a continuous and evolving process. That is, with new applications that emerge, additional sensors are usually required to be deployed to meet new requirements. This process is also sequential in nature and the new deployment has to consider existing sensors. In this paper, we propose a modeling framework to capture this sequential decision-making process for traffic sensor deployment. The framework is based on our recent findings that (1) optimal sensor deployment for a single application can be determined by a staged process or, more formally, a dynamic programming (DP) method and (2) new sensor locations for new applications can be optimally solved by the DP method via considering existing sensors. We illustrate the framework using two applications: ramp metering control and travel time estimation. It is found that the proposed scheme can appropriately capture the decision-making process of traffic sensor deployment and can generate optimal sensor placement at any stage by considering sensors that have already been deployed. The model is tested using global positioning system enabled cell phone data and traffic simulation on a real-world freeway route in the San Francisco Bay Area. [ABSTRACT FROM AUTHOR]

Today's engineers must be more than just technically competent. To be successful in our increasingly global economy in which teamwork and interdisciplinary interaction are the norm, engineers must have excellent communication skills. In recognition of industry needs, the San José State University College of Engineering redesigned its technical communication course to ensure that students graduate with writing and speaking skills that will transfer readily to their career needs and the global arena. The course aims to motivate students through exploring topics that are meaningful to them and using communication formats that they will see in the workplace. Combining technical communication with study of the environment broadens the course to meet multiple Accreditation Board of Engineering and Technology outcomes. This paper describes the course goals, organization, management, selected assignments, and assessment. Assessment data indicate that at the end of the semester students, on average, have gained between 0.8 and 1.1 points on a 12-point evaluation rubric and have gained an appreciation of the unique characteristics of and need for technical writing. [ABSTRACT FROM AUTHOR]

The application of expert systems has emerged as a cost efficient tool in civil engineering over the past decades. Use of these tools for decision making in land use will be outlined in this paper. In this study, soil-structure interaction (SSI) is discussed by using expert systems, namely, neural network (NN) approaches. This method provides a new point of view for evaluations of SSI and land use. Data from 58 local sites in California, namely, earthquake, structure, and soil property data, are used. In the expert system approach, two NN architectures are used: the back propagation NN architecture and the general regression NN (GRNN) architecture. There are 21 parameters considered as input and 4 output parameters. The four output parameters chosen are soil-to-structure rigidity ratio, period lengthening, foundation damping, and whether SSI effects can be neglected or not. The results show that the GRNN approaches are more useful and powerful for evaluation of SSI and land use. [ABSTRACT FROM AUTHOR]