bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Modified ASTM E 1105 to Evaluate the Resistance of Masonry Barrier, Mass and Skin Walls to Rain
Authors: Krogstad NV , Weber RA
Published: March 2009

Test procedures are proposed to evaluate masonry barrier, mass and skin wall systems using ASTM E 1105, Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Curtain Walls, and Doors by Uniform or Cyclic static Air Pressure Difference. Variables involved in these tests, such as water flow rates, size and positioning of spray grids and duration of testing are also reviewed. Studies comparing the penetration rates at different flow rates and at different air pressures are reviewed. Systematic procedures are presented for masking off portions of walls in order to determine significant sources of leakage. Further procedures are outlined to isolate sources of leakage after areas of leakage are found. Several case studies are reviewed on different types of wall systems. Each of the case studies includes a discussion of the problems found and how ASTM E 1105 tests were used to determine the leakage sources.
A Theoretical Model of Water Penetration into Concrete Masonry Units
Authors: Barkofsky PR , Driscoll ME
Published: March 2009

The effect of water damage on masonry walls is well known, and a variety of test methods have been developed to measure the susceptibility of masonry to the forces that drive water within wall systems. Several test methods and their correlation to these forces are discussed in a separate paper.

This paper offers a qualitative model of water penetration that relates the inherent properties of masonry and the external conditions to which it is exposed to its ability to resist water leakage.

Darcy's equation of flow through porous media describes the resistance to flow offered by the tortuous networks of channels in a permeable material and quantifies the force necessary to overcome this resistance. Considering the environmental conditions that a wall is exposed to, we can modify Darcy's equation and use it to characterize masonry's propensity for water transmission driven by the forces of rain velocity, capillary pressure, differential air pressure, and gravity based on masonry material properties. In addition, with data typical of environmental exposure characteristics, the singular and additive effects of these forces can be computed and compared.
History of Slurry Wall Construction
Authors: Ressi di Cervia AL
Published: March 2009

The slurry wall industry started in Italy in the 40's and spread throughout the world in three decades. It has divided into three distinct markets: Structural Walls, Deep Cut-Offs and Slurry Trenches. Each market has followed a different development pattern. Progress has been made in design, equipment and technology to fulfull the needs of each of those segments of the industry.
Innovative Aspects of Leachate Containment with Composite Slurry Walls: A Case History
Authors: Manassero M , Viola C
Published: March 2009

The main technological and construction features of a composite cement-bentonite slurry wall carried out for containment of subsoil pollution due to a chemical plant located in the northern part of Italy, are presented.

The subsoil profile shows a high permeability sand and gravel layer, 3 to 15 m thick, underlined by a natural low permeability stratum of overconsolidated and cemented clay, more than 150 m thick.

The solution adopted for remedial works was aimed to gain advantage from subsoil conditions which were nearly ideal for cut-off barrier effectiveness.

Design approach, preliminary and final checks are also described in the paper.
Underreamed Drilled Shafts Installed Using Slurry Methods
Authors: Schoenwolf DA , Dobbels DJ
Published: March 2009

This paper presents a case history on the use of end-bearing, underreamed drilled shaft foundations installed using slurry methods to support a 21-story building in Boston, Massachusetts. Factors leading to the selection of drilled shaft foundations for the project, design criteria, results of a pre-construction testing program as well as production foundation installation and quality control procedures are presented. Data on performance of the foundation system through the completion of construction and comments regarding the general applicability of underreamed drilled shafts installed using slurry methods are also presented.
Deep Foundation Elements Installed by Slurry Wall Techniques
Authors: Johnson EG , Johnson KE , Erikson CM
Published: March 2009

Deep foundation units, installed using slurry wall techniques, are generally referred to as Barrettes or Load Bearing Elements (LBEs). This paper reviews examples and applications of this foundation type, and describes two case studies in which these units were utilized in Boston.

Current design issues and construction installation details are presented. The design discussion focuses on the selection of foundation type and load transfer into the bearing stratum. Issues related to construction include excavation equipment and stabilization, bottom cleanup, installation of reinforcement, tremie concrete placement, and quality control during installation. for both case studies, the LBEs were installed for projects constructed by the “up/down” method, which is described in the paper. Although there are some unique advantages when used with this construction method, the selection of LBEs should be considered for conventional construction as well.
Construction of Diaphragm Wall at Wells Dam East Embankment
Authors: Roberts DL , Ho D-M
Published: March 2009

A concrete diaphragm wall was constructed at the Wells Dam east embankment to cutoff seepage. Sinkholes were observed on the embankment crest in early 1990, more than 20 years after the construction of the embankment dam. After extensive investigations a diaphragm wall was adopted to positively cutoff seepage and to stop internal erosion.

The wall was excavated in vertical panels with clam shell bucket through the embankment core and riverbed deposits overlying bedrock to a maximum depth of 70 m (230 ft). A total of 11,600 sq m (125,000 sq ft) of diaphragm wall was constructed. The success of the wall was evaluated based on core drilling, water tests, piezometer data and geophysical survey after the construction.

This paper presents a brief description of the project and sinkhole investigations, with the main emphasis placed on the construction of the concrete diaphragm wall, including procedure, quality control and verification, and difficulties.
Plastic Concrete Slurry Wall for Wister Dam
Authors: Erwin ED , Glenn JM
Published: March 2009

After near failure in 1949 by piping through the embankment, Wister Dam operated with no serious leakage problems to actively threaten the safety of the embankment. However, investigations revealed horizontal and vertical cracking that, combined with the dispersive clay embankment material and lack of sand filter, made the potential for a piping failure too great to ignore. Significant underseepage occurred at modest pool differences through preferred seepage paths that appeared to be cracks resulting from differential settlement. Emergency repairs performed in 1949 and 1950 apparently hydrofractured the embankment. To minimize the potential for a piping failure of the dam a sand filter was constructed in the downstream embankment and a plastic concrete slurry wall cutoff was constructed along an upstream berm. A method for determination of maximum safe panel length for the slurry wall was devised and a plastic concrete mix design was developed to increase the ability of the wall to yield or deform.
Design and Construction of a Plastic Concrete Cutoff Wall for the Island Copper Mine
Authors: Davidson RR , Denise G , Findlay B , Robertson RB
Published: March 2009

A plastic concrete slurry wall was constructed at the Island Copper Mine on Vancouver Island to prevent excessive seepage from the ocean into a large copper mine open pit during a south wall push-back which would lead to pit slope stability problems and flooding. An unusually low strength plastic concrete was chosen as a backfill to sustain relatively large deformations without cracking and to resist erosion if a crack should develop. Very difficult construction problems were successfully surmounted including excavation through a loose, pervious mine rock waste dump and embedding the toe of the wall into a very hard glacial till. Pit slope excavation has been completed through the cutoff soils without problem.
Design, Construction and Performance of a Deep Circular Diaphragm Hall
Authors: Bruce DA , Chan PHC , Tamaro GJ
Published: March 2009

The new Richmond Avenue Pump Station in Staten Island NY was successfully constructed to a depth 27m below existing grade within a 16.5m circular, 50m deep slurry wall cofferdam. Construction was carried down through water bearing sands with minimal dewatering of the interior of the cofferdam and with no distress to the surrounding residential structures. This paper describes the design, construction and performance of the slurry wall and the general excavation.
Permanent Slurry Walls at Baltimore Metro's Shot Tower Station
Authors: Patel A , Castelli R
Published: March 2009

The general approach and State-of-the Art methods used for the design of the permanent slurry walls for an underground transit station are presented. The design included alternative studies, geotechnical investigations, seepage analysis, structural design, constructability aspects and architectural interface in selecting slurry walls as the station's permanent walls. The station's wall design also required the installation of jet grout walls in lieu of slurry wall panels where existing underground 115 kV electric lines crossed the station. The paper addresses evaluation and analytical methods used in resolving significant issues that confronted the designers in adoption of slurry walls as the station's permanent walls, and presents preliminary findings of the construction instrumentation monitoring program.
Infrastructure: The Battlefield of Corrosion
Authors: Fasullo EJ
Published: March 2009

Our nation's decaying infrastructure and its associated cost have put the engineering community on the alert. All responsible parties must cooperate to save and extend the life expectancy of these vital structures. Innovative ideas for the accurate prediction and determination of the condition of the various structures is needed badly. New testing techniques that use state-of-the-art, computerized equipment need to be developed.

Time is running out. We can no longer postpone the maintenance of our infrastructure. Thus, new financial ways and means have to be developed to pay the cost. The public and private sectors have to join forces to get the job done quickly and at an affordable cost.Our educational institutions also have to take a very active role to educate future generations and engrave in their minds the importance of preserving and maintaining existing structures. New approaches to educating engineers may be needed. Innovation in engineering design solutions must be encouraged by dealing with the issues of professional liability and establishing an engineering fee structure that rewards new ideas.
A New Approach to Power-Model Regression of Corrosion Penetration Data
Authors: McCuen RH , Albrecht P , Cheng J
Published: March 2009

Corrosion penetration data have traditionally been fit with the power model using a log transformation of both the exposure time and the penetration. The transformation has several disadvantages, including (1) the resulting model gives biased estimates of the penetration, (2) the sum of the squares of the errors in penetration are not minimized even though the sum of the squares of the logarithmic errors are minimized, and (3) the logarithmic transformation results in greater emphasis being placed on the penetration for the shorter exposure times.

An alternative method of fitting power models is discussed. The numerical calibration method is shown to produce better fitting and more rational power models than is provided with a logarithmic transformation. Unbiased power models can also be fitted. The fitting procedure is more complex than that for the log transform method.

The two fitting methods were compared using 32 sets of corrosion penetration data. The average standard error ratio for the numerical procedure was 58 percent of that for the logarithmic analyses, which suggests that the numerical procedure consistently produced better penetration estimates for the largest measured exposure time. Thus, more accurate 75-year projections of penetration should be expected with the numerical model. Analyses of the records suggest that record lengths of at least 10 years are necessary to produce accurate model coefficients.
A Review of Computational Simulation Techniques
Authors: DeGiorgi VG , Kaznoff AI
Published: March 2009

Accurate computational simulations require combining established numerical procedures, including modeling techniques, with accurate material characterizations. Accurate computational simulations also require an understanding of the physical phenomenon represented in a particular problem. The current work defines the steps required for the creation of an accurate computational simulation. A review of existing corrosion related computational simulations is incorporated into the discussion. An example case history of the creation of a computational simulation of a prototypical surface ship impressed current cathodic protection system is presented.
Corrosion Control of Weathering Steel Bridges
Authors: Albrecht P
Published: March 2009

Bare exposed weathering steel is an economical alternative to ordinary painted steel if the weathering steel develops a protective oxide coating, meaning that the bridge need not be painted during its service life. To ensure satisfactory corrosion performance, engineers should follow the guidelines for the use of weathering steel in bridges described in this paper.
Performance of Rehabilitated/Protected Concrete Bridge Decks
Authors: Babaei K , Hawkins NM
Published: March 2009

This paper is based on a research study aimed at determining the relative effectiveness of three bridge deck protective systems (i.e., latex-modified concrete (LMC) overlay, low-slump dense concrete (LSDC) overlay, and cathodic protection (CP) in preventing or halting reinforcing steel corrosion and corrosion-induced deterioration in salt-contaminated concrete. The paper documents the results of testing five LMC, five LSDC, and two CP bridge decks. The test bridges had experienced severe corrosion-induced deterioration and/or severe salt contamination before protection. At the time of testing the average age of both the LMC and LSDC overlays was about seven years, and the average age of the CP installations (slotted system) was five years. Also, among the concrete overlaid decks, seven had been subjects of previous similar investigations. Thus, the study determined changes in the effectiveness of concrete overlay protective systems with time.

The mode of internal concrete fracture caused by reinforcing steel corrosion and its magnitude were determined. Performance information was expressed in terms of corrosion-induced deterioration as well as rate of corrosion-induced deterioration. A criterion was established for the condition beyond which deterioration impairs deck serviceability. Accordingly, the effective service lives of the rehabilitated/protected decks were estimated. Also, the performance information was analyzed for factors affecting the condition of a rehabilitated/protected deck. Overlay surface cracking and overlay thickness were found to affect the corrosion-induced deterioration in the concrete overlaid decks. Correlations were made between those factors and the deterioration. In CP decks various types of concrete deterioration were found, their magnitudes were measured, and their causes were identified. Those types of deterioration, generally, were not related to corrosion of reinforcing steel. The cost-effectiveness of concrete overlay and cathodic protection strategies were determined on the basis of bridge deck life-time costs and compared.
The Nupipe® Reconstruction Technology
Authors: Hinte JB
Published: March 2009

Increasing awareness of deteriorating infrastructure systems has led to the development of a new pipeline reconstruction method which forms a tight-fitting, new PVC pipe within an existing pipe. This unique process can be used for reconstructing pipes ranging from 4-inch through 12-inch diameter for both municipal and industrial applications. The new PVC pipe provides structural support and isolates the existing conduit from further corrosion from the effluent.
Estimating the Life Cycle of Reinforced Concrete Decks and Marine Piles Using Laboratory Diffusion and Corrosion Data
Authors: Berke NS , Hicks MC
Published: March 2009

Chloride induced corrosion is a major cause of the deterioration of steel reinforced concrete structures in marine environments, and in Northern environments where deicing salts are used. The time-to-corrosion initiation and subsequent corrosion induced damage is related to the time that it takes chloride ions to reach a critical level at the steel. In this paper it is demonstrated that chloride ingress into concrete follows Fick's Diffusion equation for properly cured concretes. It is shown how the diffusion coefficients and chloride surface concentrations can be used to predict the chloride profile as a function of time. The effects of concrete mixture proportioning and concrete admixtures on the diffusivity of chloride and chloride corrosion threshold level are shown. The results of several experiments and models developed show that reducing the water-to-cement ratio and increasing concrete cover over the steel greatly reduce the chloride ingress as recommemded by the American Concrete Institute codes. Furthermore, even more dramatic decreases in chloride penetration can be obtained by the use of microsilica in the concrete mixture. It is also shown that calcium nitrite when admixed into the concrete significantly increases the chloride levels at which severe corrosion will occur. The above results are used to estimate the time to corrosion and failure for different types of reinforced concrete structures. These models can be used by a design engineer to estimate the life of reinforced concrete exposed to chloride ingress.
Investigation of Rebar Corrosion in Partially Submerged Concrete
Authors: Funahashi M , Fong K-F , Burke ND
Published: March 2009

A large number of ocean and harbor concrete structures have been in service for more than a century. However, the cost associated with repair of these structures damaged by corrosion of steel in concrete is a major maintenance expense for the owners. Due to wave and tidal action of sea water, these structures are divided into atmospheric, tidal, and submerged zones. The most devastating corrosion damage occurs at the splash area which is somewhere between the lower part of the atmospheric zone and upper part of the tidal zone. However, it is generally believed that steel corrosion in the submerged concrete is stifled because the oxygen concentration in the concrete is too low to sustain the corrosion activity. To investigate the corrosion mechanism in partially submerged concrete structures, the corrosion potentials, total corrosion current, and macro-cell corrosion current of the steel in concrete specimens were monitored. The results obtained from the three zones (submerged, tidal, and atmospheric zones) were compared and discussed.
An Automatic Pipe Corrosion Inspection System
Authors: Shimizu M , Mukai N , Hamada M , Shimamura J
Published: March 2009

Corrosion in various buildings and factory piping has been a serious concern for many industries. Corrosion-related leaks or pipeline bursts may cause expensive damage to property and result in shutting down the operation. Therefore, nondestructive corrosion inspection of inside piping has become more important. Utilizing ultrasonic waves, internal corrosion and metal loss can be measured. However, existing inspection techniques were not satisfactory to determine the accurate condition. In this scenario, an automatic pipe corrosion inspection system was developed, utilizing state-of-the-art electronics technology. The system consists of an inspection device and a data processing unit. The inspection device travels on the external pipe surface, while the data processing unit displays the condition of both the internal surface and a cross section areas of the pipe. The data collected by the robot is also numerically analyzed to calculate the pipe thickness distribution, the minimum thickness, metal loss percent and corrosion rate and to estimate the remaining service life of the pipe based on proper theory. This inspection can also be applied on the threaded pipe section to determine the allowable metal loss. To verify the performance and accuracy of the data collected using the robot, partifical corroded pipes are tested. This paper will discuss the abilities and limitations of the automatic pipe corrosion inspection system and the results of the verifications tests.
Predicting Service Life of Concrete Bridge Decks Subject to Reinforcement Corrosion
Authors: Cady PD , Weyers RE
Published: March 2009

The deterioration of the nation's highway infrastructure is proceeding at an alarming rate. A major element of the problem involves chloride-induced corrosion of reinforcing steel in concrete bridge components. In order to rationally implement bridge management strategies, it is generally recognized that life-cycle cost analyses of viable alternatives are required. This necessitates the development of reliable means for predicting the service lives of alternative procedures. The major components of a rational model for predicting service life in this scenario center on the time for the chloride ion concentration to reach the corrosion threshold level at reinforcement locations and the corrosion reaction time necessary to produce loss of serviceability. Obviously, the definition of the terminal serviceability in terms of deterioration level also constitutes an important element of the model. This paper examines a semi-empirical deterioration model for predicting service life based on fundamental concepts, augmented with historical data.
Measuring the Underground Corrosion of Steel Piling at Turcot Yard, Montreal, Canada — A 14 Year Study
Authors: Escalante E
Published: March 2009

This paper describes a 14 year study of the corrosion of steel H-piles in soil at Turcot Yard, Montreal, Canada. The program was directed at evaluating the corrosion of these piles in disturbed and undisturbed soils. Three sets of steel H-piles were placed in the ground, one set without protection, a second set coated in the disturbed soil region, and a third set with concrete caps. Each set consisted of six vertical piles driven to bedrock and one pile placed horizontally in an excavation which was then backfilled. A steel pier, supporting a portion of the Transcanadian Highway, was included in the study. Electrochemical polarization measurements were made annually during the period of exposure, and periodically, selected piles were extracted for examination and physical measurements. The results show that corrosion of the steel piles in undisturbed soil is less than 0.33 mils per year (8.1 μm/y), but in all cases, corrosion is low. The electrochemical polarization measurements indicate that corrosion of the steel piles supporting the pier has decreased by more than an order of magnitude over the 14 year period.
Bond Loss Between Epoxy and Alkyd Coated Reinforcement Rebars and Concrete
Authors: Maldonado LA , Castro P , Marrufo JH , González W , Zapata A
Published: March 2009

Organic coatings are increasingly being used to control corrosion of reinforcing bars but relatively little importance has been given to their effect on the mechanical properties of reinforced concrete elements. This study evaluates the bond loss of coated rebars with respect to uncoated rebars using pull-out tests on 0.15 m× 0.30 m. cylinders and in 0.66 m (length) × 0.15 m (width) × 0.20 m. (height) beams. Three thicknesses of epoxy coatings were tested in both, cylinders and beams. Six thicknesses of alkyd coatings were tested only in cylinders. There were also tests on cylinders and beams with uncoated rebars. Average losses of bond strength for #3 and #4 bar sizes with respect to the uncoated ones were, respectively, 13% and 15% for beams, 25% and 27% for cylinders using epoxy coatings and, 29% and 35% for cylinders using alkyd paints.
Repair and Cathodic Protection of Corrosion Damaged Reinforced Concrete Wharves in the Middle East
Authors: John G , Leppard B , Wyatt B
Published: March 2009

The deep water port of Mina Zayed, Abu Dhabi, was constructed between 1970 and 1978 and consists of pre-cast reinforced concrete beams and slabs with in situ concrete topping, supported by tubular steel piles. The first signs of deterioration were recorded in 1977, evidenced by cracking of the lower corners of the pre-cast beams. A number of detailed inspections were carried out during 1979, 1983, 1985 and 1987, allowing a study of the progressive deterioration to be recorded.

This paper summarises the construction of the port, the deterioration that occurred and the repair/rehabilitation procedure used. An impressed current cathodic protection system incorporating metal oxide coated titanium mesh in a sprayed concrete overlay was used to prevent further deterioration. The system incorporated 83 individual units providing protection to over 11,000 m2 (121,000 ft2) of concrete.

A particular problem associated with interference in the polarisation/de-polarisation of the reinforcing steel due to large repaired areas was noted during the repair work and is summarised in this paper.
Use of Microcosms versus Conventional Biodegradation Testing for Estimating Chemical Persistence
Authors: Carson DB , Saeger VW , Gledhill WE
Published: March 2009

Extrapolation of laboratory biodegradation data to the field is critical in assessing the environmental fate of a chemical. Laboratory systems used to evaluate biodegradation may vary from simple river or lake die-away tests to complex microcosms. The relative merits of rate data derived from systems of widely varying complexity have long been a subject of discussion. Data obtained from studies utilizing simple screening tests and microcosms containing sediment and natural water are presented and compared. Among the chemicals tested are biphenyl, linear alkylbenzene sulfonates, and phthalate and phosphate esters. Results suggest that pertinent biodegradation rate data can be obtained from relatively uncomplex test systems. Potential concerns about the environmental fate of test chemicals raised in simpler biodegradation tests could be addressed by specific environmental monitoring for existing chemicals rather than testing in more complex systems.
Biodegradation and Reduction in Aquatic Toxicity of the Persistent Riot Control Material 1,4-Dibenz-Oxazepine
Authors: Haley MV , Vickers EL , Cheng T-C , DeFrank J , Justus TA , Landis WG
Published: March 2009

1,4-Dibenz oxazepine (CR), a strong sensory irritant, has previously been reported as recalcitrant to degradation. Alcaligenes denitrificans denitrificans, CR-1, ATCC #53957, isolated from microcosms spiked with CR, shows potential as a tool for the degradation of CR waste. A. denitrificans were found to have an extremely high tolerance to CR (200 mg/L). The isolates grew well on the synthetic media spiked with 200 mg/L CR, but showed minimal growth on the microcosm media without CR. No detrimental effects of CR-1 on Daphnia magna were observed. After ten days, the organisms were able to reduce the CR concentration from 200 to 25 mg/L. After 22 days, the concentration of CR was below detectable limits. Ten days after A. denitrificans was inoculated into a stock solution of CR, the toxicity to D. magna was reduced more than 50% but not eliminated. Treatment of the CR solution with A. denitrificans resulted in the elimination of toxicity to Selenastrum capricornutum. In trying to elucidate the degradation pathway, it was discovered that CR-1 also degrades o-nitrophenol, 3-methylcatechol, and catechol.
Testing Sediment Toxicity with Hyalella azteca (Amphipoda) and Chironomus riparius (Diptera)
Authors: Ingersoll CG , Nelson MK
Published: March 2009

Methods for testing the toxicity of whole sediments are described for the amphipod Hyalella azteca and the midge Chironomus riparius. Amphipod tests (static and flow-through) start with juvenile animals (≤ third instar) and continue up to 29 d until reproductive maturation. Flow-through tests with the midge start with first instar larvae (<24 h old) and continue up to 29 d through adult emergence. Data obtained from these laboratory exposures can be used to assess the effects of contaminants in sediments on survival, growth, or emergence of amphipods and midges. The methods were used to assess the potential toxicity of field-collected contaminated sediment from two sites in Waukegan Harbor, Illinois, an inlet of Lake Michigan contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic compounds (PACs), and metals; and a single site at Homer Lake, a small recreational lake in the agricultural region of central Illinois. Survival of both species was reduced after short-term (10-to 13-d) and long-term (29-d) exposure to contaminated sediment. In addition, sublethal effects were indicated by reduced growth of amphipods and a delay in emergence of adult midges.
The Use of Sediment Heavy Metal Bioavailability as a Method of Environmental Hazard Assessment
Authors: Marcus JM , Scott GI
Published: March 2009

Different areas along the rapidly developing South Carolina coastline were examined for heavy metal (Cr, Cu, Pb, Ni) inputs to nearby aquatic ecosystems using sediment levels as the relative indicator of contamination. The American oyster, Crassostrea virginica (Gmelin), was monitored concurrently for metal concentrations to assess what portion of the total sediment metal burden was biologically available for uptake and accumulation. This was accomplished by computation of a sediment bioavailability factor (SBAF) that allowed the integration of sediment and tissue data into a quantitative index useful for relative comparisons between areas.

The SBAFs calculated for the land-use practices of recreational marinas, an industrial waste water treatment facility, and an abandoned industrial site were compared and contrasted with each other and with other sites that ranged from pristine to contaminated. A graded effect on availability of metals from sediments to oysters was observed. Those practices with continuous inputs exhibited higher bioavailability factors than did those that were intermittent.
Comparative Sensitivity of Sediment Toxicity Bioassays at Three Superfund Sites in Puget Sound
Authors: Pastorok RA , Becker DS
Published: March 2009

The primary objective of this study is to evaluate the relative sensitivity of seven sediment toxicity bioassays comprising a total of 13 endpoints. The bioassays were conducted simultaneously on dilution series of contaminated sediments collected from three Superfund sites in Puget Sound. Sediment chemistry measurements confirmed that effective gradients of contamination were established within each of the sediment series tested. The Photobacterium phosphoreum (Microtox with saline and organic extract of sediment) and the Dendraster excentricus embryo abnormality tests were generally the most sensitive bioassays in terms of ability to detect statistically significant (P ≤ 0.05) effects relative to responses to reference sediments. The rank order of statistical sensitivity of the other tests was as follows: Rhepoxynius abronius mortality = Eohaustorius estuarius mortality > Neanthes arenaceodentata biomass > Neanthes arenaceodentata mortality = Dendraster excentricus chromosomal abnormality > Rhepoxynius abronius nonreburial > Eohaustorius estuarius nonreburial = Panope generosa mortality. The bioassays differed in their statistical sensitivity (i.e., as measured by the number of significant toxic effects) and biological sensitivity (i.e., as measured by EC50) to particular sediments contaminated with different kinds of chemicals (e.g., polycyclic aromatic hydrocarbons versus metals). For example, the Photobacterium phosphoreum saline extract test was not always as biologically sensitive (i.e., low EC50) as other bioassays (e.g., the Rhepoxynius abronius and Eohaustorius estuarius bioassays appeared to be more sensitive to aromatic hydrocarbons).
Effects of Sediment and the Route of Exposure on the Toxicity and Accumulation of Neutral Lipophilic and Moderately Water-Soluble Metabolizable Compounds in the Midge, Chironomus riparius
Authors: Lydy MJ , Bruner KA , Fry DM , Fisher SW
Published: March 2009

The toxicity and accumulation of eleven moderately water-soluble metabolizable (MSM) or neutral lipophilic (NL) compounds were examined in the midge Chironomus riparius in tests without sediment (water only) and in treatments with sediment to which the test chemical was added directly to the water (spiked water) or directly to the sediment (spiked sediment). In general, the toxicity of NL compounds was significantly reduced when sediment was present regardless of whether the compound was added to the water or the sediment. The observed reduction in toxicity when sediment was present was attributable to sorption of the chemical to sediment, dissolved organic carbon (DOC), and particulates and was anticipated from literature Kow and measured Koc values. The toxicity and accumulation of MSM compounds in sediment and nonsediment systems were much more variable than for the NL compounds. For 1-naphthol, no significant difference in the distribution of parent chemical was seen in the water or sediment when used, although the toxicity of 1-naphthol was lowest when the compound was added directly to water in the presence of sediment. For the remaining MSM compounds, toxicity was significantly reduced only when the chemical was added directly to sediment. In general, partition coefficients were less useful in predicting the environmental behavior of MSM compounds. The most notable effect of sediment upon the MSM group was that the persistence of the parent compound was greatly increased in the sediments when the chemical was added to sediment.
Toxicity of Nitrogen-Containing Aromatic Compounds (NCACs): Quinoline and 4-Azafluorene Behavior in an Escherichia coli Test System—Evidence of Membrane Effects
Authors: Catallo WJ , Cleland DR , Bender E
Published: March 2009

This research addressed the effects of two prominent nitrogen-containing aromatic compounds (NCACs), quinoline and 4-azafluorene, on respiratory electron transport (ET) in Escherichia coli. ET was estimated spectrophotometrically using reduction rates of iodonitrotetrazolium chloride (INT), which is reduced in vivo to a red colored formazan (INTF). It was noted that both NCACs gave anomalous dose-response behavior in INT assays: in a defined “threshold” dose range, INT reduction rates near or above the controls were observed. Comapred with controls and low doses, the threshold doses for the NCACs showed different INT reduction kinetics, decreased cellular oxygen consumption, and decreased viable cell densities. These observations and experiments with E. coli spheroplast preparations, gram positive cells, and deep rough mutants supported the hypothesis that the NCACs caused removal of outer membrane constituents and probably interference with cell membrane function. Data from the INT bioassays, comparative oxygen demand studies, assays of INT response in bacteria with different outer membrane characteristics, and transmission electron microscopy are presented in support of this hypothesis.
Flow Cytometric Techniques to Assess Toxicity to Algae
Authors: Gala WR , Giesy JP
Published: March 2009

Flow cytometry provides a fast and quantitative method to determine the effects of a toxicant on individual algal cells. The effects of the surfactant, sodium dodecyl sulfate (SDS), and the herbicide, atrazine, on the viability of Selenastrum capricornutum cells as measured by monitoring green fluorescence of algal cells stained with fluorescein diacetate (FDA) by flow cytometric techniques were compared to the results of standard 96-h algal toxicity tests. Cell viability (green fluorescence) was a sensitive measure of the effects of SDS on S. capricornutum. The EC50 values for the reduction of the viability of cells after 48-h of exposure was 104.8 mg/L SDS (95% C.I., 63.7 to 172.3 mg/L), which was similar to the 96-h EC50 for specific growth rate (81.4 mg/L SDS; 95% C.I., 62.0 to 106.8 mg/L). Cell viability was not as sensitive to the effects of atrazine as was growth rate because of the algistatic properties of this herbicide. The 96-h EC50 of atrazine for algal growth rate was 128.2 μg/L (95% C.I., 118.9 to 132.2 μg/L), relative to the 48-h EC50 of 1500 μg/L atrazine for cell viability, as measured by the flow cytometric techniques. Unlike growth rate endpoints, flow cytometric measurement of cell viability was able to distinguish between algicidal and algistatic toxicants.
Comparative Developmental Toxicity of Acetylenic Alcohols on Embryos and Larvae of Xenopus laevis
Authors: Dawson DA , Schultz TW , Baker LL , Wilke TS
Published: March 2009

Xenopus laevis embryos and larvae were tested to assess the relative toxicity and teratogenicity of a series of 14 acetylenic alcohols. Tertiary propargylic alcohols and alkene-ols were expected to act as simple narcotics and not be teratogenic. However, primary and secondary propargylic and homopropargylic alcohols might be metabolically activated, by alcohol dehydrogenase, to become teratogenic. Mid-to-late blastula stage embryos were exposed to graded concentrations of each alcohol for 96 h. Embryo malformation (EmEC50) and lethality (EmLC50) endpoints were determined for each alcohol, and the Mortality/Malformation Index (MMI) was calculated as a measure of relative teratogenic potential. Additionally, untreated, healthy-appearing 5-day-old tadpoles were exposed to each alcohol for 96 h, and the tadpole lethality endpoint (Td5LC50) was determined. The ratio of the embryo LC50 to tadpole LC50 (E/T) was calculated as a measure of alcohol reactivity. The primary propargylic alcohols had teratogenic potential, producing head, eye, gut, and skeletal malformations and MMI values > 3.0. All other alcohols caused only edema and improper gut coiling. The E/T ratios indicated that primary and secondary propargylic and homopropargylic alcohols were reactive, whereas tertiary propargylic alcohols and alkene-ols were not. In addition, quantitative structure-activity relationships (QSARs) were explored, and comparisons of tadpole and fathead minnow lethality data indicated that toxicity in one system can be used to predict toxicity in the other.
Toxicity and Toxicokinetics of Pentachlorophenol and Carbaryl to Pontoporeia hoyi and Mysis relicta
Authors: Landrum PF , Dupuis WS
Published: March 2009

Two Great Lakes invertebrates, the amphipod Pontoporeia hoyi and the mysid shrimp Mysis relicta, were exposed to pentachlorophenol (PCP) and carbaryl to determine actue mortality. At pH 8, the LC50 for P. hoyi after 96 h was 0.6 ± 0.3 μg mL-1 for PCP, while that for carbaryl was 0.23 ± 0.04 μg mL-1. The LC50 for M. relicta at pH 8 and 96 h was 54.1 ± 10.3 μg mL-1 for PCP and for carbaryl 0.23 μg mL-1 (0.103–0.356, n = 2). The differences in the LC50 values between P. hoyi and M. relicta for PCP result in part from differences in the uptake clearances of the two animals, 3.1 ± 0.9 mL g-1 for P. hoyi compared to 0.4 ± 0.1 mL g-1 h-1 for M. relicta. A similar difference occurred in the respective carbaryl uptake clearances for the two organisms, 3.74 ± 0.63 mL g-1 h-1 for P. hoyi and 0.134 mL g-1 h-1 (0.135 to 0.133, n = 2) for M. relicta. The cumulative toxicant concentrations in the organisms that result in 50% mortality, LD50, were estimated from a toxicokinetics model that was parameterized with the measured uptake and elimination constants and the LC50 values. The M.relicta LD50 for PCP was approximately ten times larger than that for P. hoyi and confirmed the relative sensitivities of the organisms as described by their respective LC50 values. For carbaryl, the LD50 for P. hoyi was greater than that for M. relicta. Thus M. relicta is apparently more sensitive to accumulated carbaryl than P. hoyi despite the similar LC50 values for the two organisms.
Peroxisome Proliferation as an Epigenetic Mechanism of Carcinogenesis: Relevance to Aquatic Toxicology
Authors: Yang J-H , Kostecki PT , Calabrese EJ
Published: March 2009

This paper addresses the issue of epigenetic carcinogenesis in fish models with particular emphasis on peroxisome proliferation. The paper reviews the biology, physiology, and biochemistry of the peroxisome in rodents and its purported role in mammalian carcinogenesis. The paper then compares what is known about peroxisomes in fish to the mammalian situation, including the capacity of known rodent peroxisome proliferators to cause this phenomenon in fish models.
Coastal Oil Drilling Produced Waters: Chemical Characterization and Assessment of Genotoxicity Using Chromosomal Aberrations in Cyprinodon variegatus
Authors: Daniels CB , Henry CB , Means JC
Published: March 2009

Oil drilling operations generate very large volumes of produced waters which contain a complex mixture of sub-surface water and solid and liquid geological materials, including crude oil, drilling fluids, and treatment chemicals. In coastal regions, these produced waters are discharged into fresh or brackish marshes or wetlands which also serve as the spawning sites for a wide variety of economically important species of fish and shellfish. Recently, concern has focused on potential impacts of produced waters upon these productive and sensitive ecosystems. In the present study, we report the results of investigations which characterize the chemical contaminants present in produced waters and surficial sediments collected at two sites in coastal Louisiana. Trace organic analyses of the produced waters revealed a complex and variable mixture of normal-, alkyl-, and heterocyclic polynuclear aromatic hydrocarbons. Examination of surficial and sub-surface sediments demonstrate that extensive areal distribution of the produced water hydrocarbons has occurred through time. Embryonic stage genotoxicity bioassays of the produced waters indicate that the polycyclic aromatic hydrocarbons being discharged in these coastal waters cause increased mutational frequencies in Cyprinodon variegatus. Since the observation of chromosomal aberrations is usually rare in the cells of the organism and since cell replication and differentiation are maximal in the early developmental stages of these and other species of aquatic organisms, the results suggest that the potential exists for adverse effects of these discharges on estuarine productivity. Further study of the impacts of produced waters in this and other species is indicated.
The Interrelation of Exterior Wall and Structural Systems in Buildings
Authors: Horowitz JM
Published: March 2009

The object of this paper is to discern recurrent interactions between the exterior wall and structural systems in buildings. A general discussion in which the reader is introduced to the basic structural imperatives of high rise construction is presented first. Dynamic building movement due to gravity loads, wind loads, and thermal expansion/contraction are examined next so that an understanding can be gained regarding the performance requirements for exterior wall systems. Each of the basic design approaches to exterior wall construction (conventional masonry, panel systems, aluminum-framed systems) are discussed with emphasis placed upon their interrelation to the building structure. Various case studies are analyzed which demonstrate how these issues are handled on specific projects. Conclusions are drawn and correlations observed which can help the architect and structural engineer become sensitive to one another's goals.
Full-Scale Performance Testing of Curtain Walls
Authors: Sakhnovsky AA
Published: March 2009

A curtain wall testing procedure is outlined, including aspects of the construction of mock-ups, static and dynamic testing, and on-site field tests. Background comparisons, advantages, and limitations of current static and dynamic test methods are covered. Applicable standards are listed and discussed.
Field Testing of Pressure-Equalized Rain Screen Walls
Authors: Brown WC , Rousseau MZ , Dalgliesh WA
Published: March 2009

One approach to controlling rain penetration into walls is to design them using the pressure-equalized rain screen principle. This design minimizes the wind pressure difference across the exterior cladding (rain screen), thus reducing the predominant force that drives rain into the wall. A pressure-equalized rain screen wall is essentially a cavity wall with sufficient venting in the cladding to enable the cavity pressure to equalize to the exterior pressure. Additional design requirements include an effective air barrier system on the inside of the cavity and horizontal and vertical baffles to form compartments within the cavity. Two buildings with vented cladding were monitored for pressure equalization. Successful pressure equalization was confirmed with a well-vented precast concrete wall system. On the other hand, the cavity pressure of a poorly vented masonry wall system did not equalize with the exterior pressure, with the result that much of the wind pressure was taken by the cladding. While the initial cost of a pressure-equalized rain screen design may be higher, it can be recovered through lower maintenance costs and a modest reduction in the design wind load for the cladding.
Silicone Adhesives/Sealants in Curtain Wall Design
Authors: O'Brien WR , Horschig DM
Published: March 2009

Silicone adhesives/sealants offer building owners and architects greater design flexibility than mechanically captured curtain wall systems. This paper will discuss the benefits and capabilities of silicone sealants, particularly in structural applications. Structural properties and performance characteristics of silicone sealants will be explained.
Structural Sealant Glazing in the 1980s
Authors: Parise CJ , Spindler RG
Published: March 2009

Discussed are history of structural sealant glazing, basic systems, features and advantages, major concerns and potential problems, system selection, building code requirements, system components, structural considerations, field glazing versus shop glazing, remedial and reglazing considerations, testing and quality assurance, postconstruction inspection and maintenance, roles of participants, resources and needs, durability and life expectancy, and future projections.
Bases for Selecting Natural Stones from a Quarrier's Point of View
Authors: Hiltunen JK
Published: March 2009

Investigations in Europe show that granite is a very economical facade material considering the overall cost of investment, installation, and maintenance over a 50-year period.

When selecting granite for building projects, it is important to investigate the availability of various materials, as well as panel size limitations. When judging availability, one has to study the capacities of quarries, country of origin, age of the quarry, etc. In addition, existing inventories as well as quality control and valid quarrying permits are very important factors.

The cost of granite facades can be reduced by allowing variation in panel sizes, by using panel sizes which are in correct ratio to the flexural strength of the material, by allowing more variation in color, and by giving sufficient time for delivery.
Architectural Precast Concrete: A Material for the 21st Century
Authors: Freedman S
Published: March 2009

This paper discusses the applications and advantages of architectural precast concrete as: (1) cladding; (2) load-bearing elements; and (3) forms for cast-in-place concrete. The wide variety of colors, forms, and textures available to meet esthetic and practical design requirements are also discussed.