Showing papers in "Civil Engineering in 1995"

Turning Down the Power

Abstract: Traditionally, utilities have responded to demands for more power by simply increasing the energy supply. But this results in higher costs for both the supplier (in the form permitting, planning and construction of new powerplants) and the user (in the form of higher energy bills). A more cost-efficient way to manage energy resources may be through a strategy known as demand-side management. One technique of demand-side management is the energy audit. During an energy audit, the user is shown how it can streamline its operations to cut energy costs. A prime candidate for the energy audit is the wastewater treatment plant--the major customer for many of the nation's smaller utilities. This article describes the steps that go into energy audits at wastewater treatment plants. Steps include creating the audit team (either with outside consultants, inhouse staff from both the utility and the treatment plant, or a combination), evaluating usage schedules, conducting field investigations, evaluating all equipment, identifying energy-conservation measures and implementing subsequent retrofits.

Guarding Against Scour

Abstract: Scour causes 60 percent of all highway bridge failures in the United States. Tragic stories of bridges collapsing and causing fatalities prompted the Federal Highway Administration to establish the National Bridge Inspection Program, which requires that bridges be inspected for scour every 2 years. This article describes recent bridge failures, reports on the national response, and reviews the latest scour-monitoring technology. Two instruments--magnetic sliding collar and sonic fathometer--have emerged as promising devices to measure maximum scour depth at bridge piers and abutments. The cost of the devices is expected to be reasonable for state departments of transportation.

Mother Nature’s Pump and Treat

Abstract: Known under the general term of phytoremediation, using vegetation as a remedial agent has existed in its basic form for many years, mostly in applications involving waste-water treatment. Recently, however, scientists began experimenting with phytoremediation as an in-situ clean-up option for contaminated soils, sediments and ground water. After approximately five years of lab and field research, phytoremediation is now a full-fledged, albeit very young, technology with a promising future in the hazardous waste clean-up industry. Having learned from the overly hyped advent of bioremediation, most experts go out of their way to caution against thinking of phytoremediation as a panacea for hazardous waste. Rather, it is seen as an exciting new technique with a specific niche: as a polishing step after the hot spots are dealt with, or as a long-term solution for a more isolated, less contaminated site. You wouldn't want to site a day care center for this, says Scott Cunningham of Dupont, Newark, Del., But for areas that are more remote, this is entirely appropriate. Phytoremediation could represent real savings for the government and other entities with pressing clean-up projects. Although the costs vary from site to site, depending on the contaminant, most experts estimate that phytoremediation is only 20% as costly as conventional excavation, incineration and pump and treat systems. But phytoremediation's greatest advantage could be in how it is being received by the public. It stands to reason that a family living near a munitions dump will be far more inclined to support a mass plantation of trees or a new wetlands area than an excavation and incineration operation. It's incredibly politically correct at the moment to use natural processes to remediate our environmental excesses, says Cunningham. And phytoremediation makes technical sense on top of it.

Designing for the “First Flush”

Abstract: This article explains some of the details involved in separating the first flush of a storm event from the remainder of the storm. It also explains how to provide primary treatment of pollutants by detention. Detention allows settling of suspended solids and evaporation of volatiles. Design parameters are quantified and one example is designing for those parameters (the sand filter bed constructed for the Irving Transit Center in Dallas, Texas) is presented. The article also outlines how to determine the size of detention facilities for pollution abatement in storm runoff while also attenuating peak flows and provides a detailed analysis of a sample project.

Oklahoma City Aftermath

Abstract: The explosion that ripped through the Alfred P. Murrah Federal Building in Oklahoma City shortly after nine a.m. on April 19 killed 168 people, injured more than 500 and damaged more than 300 buildings. Also among the casualties of the blast was a lingering American faith that terrorism was something that happened somewhere else--in other countries, or at high-profile structures like the World Trade Center in New York. How should the U.S. government respond to this changed world when it comes to constructing new buildings or securing existing ones. Factors to be balanced in the eventual decision include costs, aesthetics and the principle of maintaining maximum public access in a democracy. A key issue is whether or not to require that government buildings be designed to protect against progressive collapse.

Not Your Father's Concrete

Abstract: A simple mixture of water, aggregate and cement, conventional concrete is environmentally-friendly by nature. But with landfills bloating and hazardous wastes becoming increasingly difficult to dispose of, the concrete industry is revanping cement manufacturing as well as introducing a new generation of concrete additives and admixtures made from recycled materials in an effort to meet the demands of a green marketplace. The recipe for a good concrete mix is a little like one for homemade chili: it was passed down to you. You start with the same base you've always used then toss in other ingredients to create the desired effect: cayenne pepper for a slow burn, jalapenos for a burst of flavor, maybe leftover beans, rice or vegetables, some corn meal for texture, and finally a dash of beer or tobasco to taste. For years, the concrete industry used the same basic recipe: water, aggregate and cement, with a few additives and admixtures thrown in for various effects. Now the industry is trying out some new ingredients processed from old materials, finally exploiting concrete's environmentally beneficial properties. Whether it's recycling hazardous wastes or containing them in concrete reinforced with recycled styrofoam, the industry is betting that concrete can be a major tool in conserving natural resources and in the disposal of wastes that threaten to bury us far faster than we can pave over them. The only substance people consume more of than concrete is water; every year one ton of concrete is produced for each person on earth. Although concrete actually takes a lot less energy to produce than other materials like steel and plastic, the production of cement--the powdery sine qua non that binds concrete's constituent elements and which accounts for 11%-15% of a typical concrete mix--is acutally one of the most energy-intensive manufacturing processes around. With such an intense world-wide thirst for concrete and so much cement needed to keep up with the demand, there is a movement afoot in the concrete industry to do more than merely increase cement production to make more concrete. Innovative companies, researchers, and industry coalitions have realized that the life cycle of a concrete slab can be one of perpetual regeneration, starting with cement's infernal birthplace--the kiln, which in many cement plants now doubles as a hazardous waste or tire incinerator.

Lessons from kobe

Abstract: On Jan. 17, Kobe, Japan became the first post-World War II, heavily populated, industrialized area to bear the full brunt of a high-magnitude earthquake. Engineers hope the resulting destruction will stir other cities from a dangerous complacency. People will study Kobe, Japan for years, looking for lessons in the ruins. They will examine crumpled concrete, buckled steel, collapsed spans of bridges, sunken port jetties and snapped gas pipes. They will study the variously damaged buildings--some standing, some out of plumb and some reduced to a pile of rubble. The most important lesson, however, has already hit home with a force comparable to the one that struck Kobe at 5:46 a.m. on Jan. 17. What happened to Japan's sixth largest city could happen to any number of cities in the U.S. Los Angeles, San Francisco, Seattle, St. Louis, Boston and New York are, like Kobe, densely populated and, in most cases, largely unprepared for a direct hit from a high-magnitude quake. Cities with a large inventory of structures that don't conform to modern standards must step up retrofitting efforts. Officials need to encourage better lifeline protection so that, when damage does occur and fires break out, rescue workers have the means and the ability to help.

Capping with Fiber Clay

Abstract: Landfill-cap construction is expensive and often results in economic hardship, especially for small towns. Costs for conventional clay or geomembrane caps for municipal solid-waste landfills in the Northeast can approach $100,000 per acre. Three landfills, in Hubbardston, Mass., Corinth, N.Y., and Marlborough, N.H., sought to improve the process and become the first in their respective states to use fiber clay--collected from the waste of paper mills--as barrier-layer material. Now, other municipalities are considering fiber-clay landfill caps and a new project is under way in Montague, Mass. A money-saver for both the mill, which saves disposal costs, and the town, the innovative process serves as a true example of a win-win situation.

New Construction Materials Proliferate in Japan

Abstract: Research and development of new construction materials is extensive in Japan, and many new materials are being used in Japan now. The author analyzes the research environment in Japan, describing the collaboration of the big five Japanese construction firms with government and academia. Today the big five firms dominate the research activities and operate the best laboratories in that nation. Part of their motivation is to find materials that will give each firm a competitive edge in the market, domestically and internationally. Often these new products are the result of joint ventures with manufacturers of components of these products. In addition, quality is more important than price in Japanese construction and many of the new products are very costly to use. However, many are unique and are used where their advantages outweigh the costs. Several examples are given in the categories of advanced concretes and fiber-reinforced composites. Recent applications and material properties are described. Self-placing concrete is one such new material. Fiber-reinforced concretes and fiber-reinforced plastics are used in many new materials, many of them smart, in that their properties allow the materials to adapt to changes and to stresses in the material. Others are fire-resistant, light-weight and have better durability characteristics. A few of these new materials are being evaluated in the U.S.

Seismic isolation in bridges

Abstract: In the U.S., the use of seismic isolation in new bridge construction and retrofit projects has been growing as awareness of seismic risk has spread across the country since the 1971 San Fernando earthquake through the 1989 Loma Prieta and 1994 Northridge earthquakes--not to mention the false, but nonetheless consciousness-raising, prediction of a major earthquake on the New Madrid Fault in 1990. To date, isolator bearings have been used to outfit about 75 structures, of which slightly more than half are retrofit projects. Recent projects in New York State, St. Louis, Indiana and New Hampshire that involve the use of several systems demonstrate the use of seismic isolation in retrofitting bridges to better withstand earthquake forces.

The Northridge Fractures: Are We Learning the Right Lessons?

Abstract: After the Northridge earthquake in January 1994, engineers found problems with special moment-resisting frames. There were multiple facture modes, and typical damage involved primary crack initiation at the juncture between the surface of the lower beam flange groove weld root pass and the surface of the column flange. At least 100 buildings with such damage had been discovered when this article was written, and more will possibly be detected as investigations continue. Many engineers and public officials have included poor welds as part of the problem, and the author believes this is an incorrect conclusion. He discusses steel properties, triaxality, strain and stress in connection with the moment resisting frames. He also suggests that current testing methods need to be changed. Welding is always the scapegoat when failures occur, he states, and offers six arguments to refute myths about welding. He says that making welds more complicated and costly will not prevent damage during another earthquake. Changing seismic codes in regard to welding should be done with great care. No code provision can prevent a connection from cracking. Finally, the presence of a code does not imply compliance; that is the responsiblity of the client and the contractor.

Bridge to the past

Abstract: Engineer/archaeologist James O'Kon rediscovered a lost Mayan bridge in Mexico's tropical rain forest. Although little evidence remains of the seventh century bridge, archaeological accounts, field surveys, aerial photos, and modern computer technology provide the proof that it existed. This article notes that for 700 years the pre-Columbian bridge at Yaxchilan was the longest in the world, crossing the Usumacinta River between what is now Mexico and Guatemala. The archaeological history and the field surveys led the author to an engineering hypothesis: a rope-cable suspension bridge was constructed across the river supported by towers and anchored by masonry supports at the abutments. The hypothesized structure is well within the realm of Mayan technology and offers a logical solution to the question of how Yaxchilan operated on a year-round basis.

The Boom in In Situ Bioremediation

Abstract: In situ bioremediation was first applied in 1972 when a subsurface release of high-octane gasoline threatened the water supply of a small town in Pennsylvania. Soluble inorganic nutrients and aeration accelerated the biodegradation of hydrocarbons. Since then, research and applications have increased. The method is increasingly being used now, principally to decontaminate or to protect ground water. In recent years, there have been improvements in oxygen delivery, new hydrogeological strategies, and the industry has improved its ability to forecast performance. Remediation processes involve the reduction of molecular oxygen to water while an organic compound is oxidized to create energy, cell mass and carbon dioxide. Oxygen transport has been the limiting factor. Recently scientists have explored the use of hydrogen peroxide to deliver greater quantities of oxygen. Air sparging, or injecting oxygen, is also described. Solid-phase oxygen release systems are a newer method in which a relatively insoluble oxygen in a matrix gradually releases oxygen when exposed to water. Bioavailability, or the rate of constituent dissolution, is also discussed. This is a problem with dense aqueous phase liquids, and the best strategy may be to prevent migration of dissolved constituents beyond the source zone. Intrinsic biodegradation or the natural unassisted biodegradation of contaminants is also being studied. The use of zero valent iron to reduce contaminants, especially chlorinated solvents, and nitrate reducing bacteria are also discussed. In the future, we are likely to see in situ bioremediation of chlorinated solvents by anaerobic methods, although this will be limited because of cost and complexity.

Forging the Link

Abstract: The Northridge earthquake that jolted Los Angeles, California, was baptism by fire for a new transit system. Just barely a year old when the earthquake struck in January 1994, the Metrolink system became a vital transportation link in Los Angeles' postquake recovery. This article describes how emergency engineering and a coalition of Southern California organizations constructed 24 km (15 mi) of track, moved tons of cut and fill, erected six commuter rail stations, and built six bridges to accommodate commuters. From clearing derailed locomotives to fast-tracking land acquisition and development, the 74-day, $16 million project helped mitigate the loss of highway transportation.

Cleanup Solution--Conflict Resolution

Abstract: Distrust and misinformation often prevent timely resolution of ground-water contamination problems. In Toms River, N.J., engineers used a computer-generated model of the cleanup site in conjunction with management software to reconcile the physical imperatives of remediation with the concerns of citizens groups and government officials. Constructed in 1950 and operational since 1952, the Toms River, N.J. chemical-manufacturing plant produced dyestuffs and epoxy resins, generated both liquid and solid wastes during the manufacturing processes, and disposed of these wastes on-site. Inadvertent spills of chemicals on the plant site contaminated the soil and leached into the ground water. Eventually several plumes of contaminated ground water migrated from their respective sources toward the Toms River. The success of the strategy we proposed hinged on the skillful application of ground-water simulation models in combination with least-cost management models. Fortunately, a carefully calibrated simulation model of ground-water flow had been constructed for the site by ENVIRON, Princeton, N.J., using the MODFLOW and MODPATH programs developed by the U.S. Geological Survey. This model figured prominently in the preparation of containment design based on ground-water withdrawal only. Thus this key design tool was available to the technical team at the outset of the investigation. Effective plume containment demanded a least-cost management model that ensured ground water along the periphery of the plume would move toward the contaminant source. The generation of inward ground-water flow along the entire plume perimeter, including its base, would contain the plume areally and vertically. Consequently, the newly established technical team had to design a well withdrawal-and-recharge system that would result in the total reinfiltration of all treated water while guaranteeing the flow modification needed for plume containment.

A Second Life for Dredged Material

Abstract: To ensure safe, navigable waters, rivers and waterways must be dredged. Dredging in the U.S. requires long-term alternatives for placement of more than 300 million cu yds of dredged material per year, according to the National Research Council. Dredged material has been used successfully throughout the U.S. for the development of wetlands and aquaculture; beach nourishment; shoreline stabilization and erosion control projects; the enhancement of agriculture, forest and horticulture; open cast mine reclamations’ solid waste management, construction and industrial projects (such as port development) and material transfer for fills, according to the U.S. Army Corps of Engineers. Most Corps wetland restoration and creation projects are aimed at stabilizing shoreline and sediment, controlling erosion and developing fish and wildlife habitats. Researchers at the Corps’ Waterways Experiment Station, Vicksburg, Miss., have developed and tested a number of engineering field methods, including the use of geotubes and bioengineering that work with dredged material to almost guarantee a thriving habitat. These techniques have been used successfully at many sites throughout the Chesapeake Bay area and as part of a demonstration marsh developed along the Houston Ship Channel.

What Price Congestion Management

Abstract: Congestion pricing--the idea that, when more people want to use a road, they should pay (or pay more) for the privilege--was dismissed in the 1950s and rejected in the 1970s in the U.S. The 1990s were going to be different, advocates predicted: a combination of new political and environmental realities and technological advances in toll collection would make the concept both practical and palatable at last. That may yet prove to be correct but right now it’s by no means certain. The ISTEA Congestion Pricing Pilot Program results are so far disappointing. Progress may depend on private efforts such as the SR 91 Express Lanes in California and privatization projects in Washington State.

A primer on micropiles

Abstract: A major study of micropile technology has recently been funded by the Federal Highway Authority and completed by the authors. The subject is defined as a drilled and grouted, cast-in-place, reinforced pile of nominal diameter less than 300 mm. Micropiles have exceptional qualities not least of which are their relatively high axial load holding performance and their ability to be installed in very difficult locations and geologies. The bulk of the FHWA study relates to design, construction and performance. However, this article provides an overview of the technology with respect to characteristics, definitions, historical development and applications, in order to establish common background for other publications on the subject.

Selecting Tower Cranes

Abstract: Looming over the skyline like steel dinosaurs, tower cranes can look deceptively similar But these beasts of burden are not a homogenous species, and selecting and positioning the right crane is critical to project planning for high-rise construction Tower cranes offer several advantages over conventional cranes, and though the advice of the crane vendor can be helpful, the entire project management team should have a thorough understanding of tower cranes special needs and characteristics to be able to use them correctly Tower cranes are available in a wide variety of types, sizes and capacities As in any other type of crane, lifting capacity is one of the more important considerations However, length of reach (radius), maximum hook height above ground and the crane's positioning also factor into the selection Tower cranes have a distinct advantage over conventional lattice-boom crawler or truck cranes because the boom, or jib, looms high above the work site The tower crane's jib can place its load anywhere within its radius of operation without interfering with the structure over which it swings In addition, the operator can be either on the crane or control the crane remotely using instrumentation located on the building structure, while enjoying an excellent view of the load and its surroundings at all times

Removing Metals From Soil

Abstract: Metals-contaminated soils have been among the most intractable hazardous-waste remediation problems. Conventional mitigation methods of capping, stabilization and landfilling all have serious limitations, and there has been no way to actually remove metals from soils--until now. In its first full-scale application in the U.S., an innovative treatment combining soil washing and soil leaching succeeded in removing lead from soils at the Twin Cities Army Ammunition Plant in Minnesota, as well as in reducing other metals to below health-risk levels. Completed last summer, the $9.5 million project could point the way to a permanent solution--at a cost comparable to traditional approaches--to the cleanup of metals-contaminated soils at foundries, platers, smelters, battery reclaimers, ordnance plants and other industrial sites across the U.S.

Touchdown for O-Cell Test

Abstract: The Los Angeles Memorial Coliseum was badly damaged by the Northridge earthquake. There was seven months to complete 3 years of work to be ready in time for football season. The project fell behind schedule immediately. It took three weeks to install the first two 95-foot-long piles. Severe caving soil conditions and cramped interior space caused the delay. A conventional load test was considered. However, loading pile from the top was not an option because of the limited space in the concourse. Law/Crandall’s engineers suggested performing a relatively new load test using a system called the Osterberg Load Cell. The O-Cell could be used to test the pile’s capacity. As the engineers discovered it could also improve the foundations by preloading the pile to consolidate and stiffen the soils at its base. This meant the piles could be shortened and remain as effective as the original design. The innovative use of this new technology was successful. The L.A. Coliseum opened on its target date.

The bell tolls for tollbooths

Abstract: The toll-road industry is turning to electronic-toll-collection (ETC) facilities to relieve congestion at toll plazas. New lane construction at toll plazas is expensive and impossible at older facilities where development along the tollways constrict the facilities. This article proposes two methods for nonstop toll collection: low-speed, nonstop collection in dedicated ETC lanes and express lanes. Dedicated lanes restrict travel to a speed that does not deviate greatly from conventional traffic or minimizes lane changing so that nonstop and stop-and-go traffic are separate. Express lanes are a separate high-speed roadway that isolates the ETC traffic from users paying by conventional means. Lane configurations and safety considerations are discussed.

Dredging Up the Past

Abstract: Disposal of contaminated dredged materials has become a national problem. The nation’s ports and harbors have postponed dredging because of the cost and difficulty in finding sites for these materials. In doing so, they jeopardize their economic health, since container ships need deeper channels to enter ports. Several engineers have devised methods to deal with these sediments. Some deal with containment, and innovation in new computer modeling that track flow paths and types of contamination to optimize the design of confined disposal facilities. Another method takes contaminated sediments and contains them in geosynthetic tubes that can be buried, or used for shoreline enhancement applications to create wetlands or fish farms. A method called LADS converts contaminated sediments to clean lightweight aggregate. Several kinds of equipment deal with dewatering the sediments, so less volume needs to be remediated or disposed of. A bio-remediation technique treats contamination in-situ and other methods are based on chemical extraction. Some consultants are using computer modelling to determine which soil types are likely to be contaminated with which pollutants. The idea is to pinpoint areas that need dredging and remediation, or disposal, and so minimize costs. Several case histories are described.

Air-Supported Roof Redux

Abstract: Long-span, low profile, air-supported roofs have been dramatic additions to a dozen public arenas built in the 1970s and early 1980s. The advantages of these roofs were overshadowed by problematic snow removal, the potential for ponding and deflation, and relatively high operating expenses. Design improvements and better operational management have surmounted many of these problems. Further developments toward a new generation of designs should make long-span air-supported roofs a viable structural option once again. The first application of the long-span, low-profile, air-supported roof in Osaka in 1970 was also the “purest” in following the logic and mathematics of designer and air-supported roof inventor David Geiger’s original patents. The roofs that followed responded in different ways to the needs of the stadium building type. Since that time, new fabrics and conventional roof systems have been developed that approach the air roof in life-cycle costs. As currently implemented in the Vancouver, Tokyo, and Indianapolis stadiums, air supported roofs would be a suitable structural solution in areas of light or no snowfall.

Making the Trains Run On Time

Abstract: The Skokie, Ill. rail shops were constructed in 1928 and all cars in the Chicago Rapid Transit system are repaired and maintained at this yard. But as the cars have become more sophisticated over the years, technology at the yard has not kept up. The shops have become functionally obsolete. But now, as part of a $60 million project, the complex is being upgraded to accommodate the today's contemporary cars, improve preventive maintenance; reduce the manual labor associated with highly repetitive operations; and enhance safety conditions for CTA personnel. The updated rail yard will consist of two new buildings, 290,000 sq ft of maintenance and office space, and improved test tracks. Repairs on the cars will also be done more efficiently due to new equipment being purchased. Construction should be completed in 1997, and operations must continue uninterrupted at the facility at all times during the project.

Project Management: One Step Beyond

Abstract: Good project managers are made, not born. But those with a special dedication to a project look beyond the most basic measures of success toward building constructive relationships within the project team, as well as with the client. Finishing a project on time and within budget are the simplest measures of a project’s success, but equally important are other goals that represent the team’s attitude and dedication to a project. In this definition, good project management encompasses not only considering time and budget, but providing quality professional service that is responsive to client needs, assisting the project staff in their professional and technical development, and developing a relationship of trust with the client as well. Fundamentally, project management centers on filing and tracking paperwork. But in a much bigger and important way, project management is about helping a project team enjoy their work, inspiring the project team, and creating in them a sense of mission. These measures of a project’ success should be monitored through each aspect of the project: startup, execution, close out, and quality control.

Northridge Postscript: Lesson on Steel Connections

Abstract: Immediately after the Northridge earthquake in January 1994, the general concensus was that steel-framed buildings performed extremely well. Later, inspectors were surprised to find weld cracks in more than 100 welded steel moment-resisting frame buildings. More damage may be found after several hundred similar buildings are examined. These buildings are all standing, but the potential for catastrophic failure during future earthquakes has prompted the profession to reevaluate the connections and has led Los Angeles to draft an ordinance for the inspection of welded steel moment resisting frame buildings. Simpson Gumpertz and Heger, Arlington, Mass. undertook one such inspection and has designed repairs for a seven-story office building with a welded steel moment frame. Our conclusions from this investigation hold important lessons for the engineering community as it addresses the condition of other steel-framed buildings. Among the key findings: 1.) concealed connection failures that are not detected and repaired could compromise a building's resistance to future earthquakes; 2.) Failure of moment connections may not necessarily be discovered by an inspection of only a handful of connections. A large sample of connections should be inspected to help ensure that connection failures have been detected. 3.) The design of American Institite of Steel Construction-recommended seated beam connections used typically in unbraced steel frames is not suitable for buildings subjected to earthquake loading with cyclic loads and significant joint rotations. 4.) Conventional welded moment connections lack the necessary ductility for the expected magnitude of plastic deformation of moment-resisting steel frames in a design earthquake and, as a result, are not suitable for buildings subjected to earthquake loads. 5.) Ultrasonic testing of groove welds that connect beam flanges to columns does not reliably detect cracks in the welds, especially where the backup bar is in place, and in the zone near the beam and column webs. 6.) The jumbo steel sections typically used in fabrication of of the columns of unbraced steel moment frames have a notch toughness that is not acceptable for buildings subjected to the shock loads that may be imparted by a strong earthquake.7.) The flux-core arc welding process used to field fabricate moment connections of a steel frame building may produce weld metals with relatively low notch toughness.

Documenting Design-Build

Abstract: For engineers more familiar with the traditional design–bid–build process, design–build might present some unforeseen risks and responsibilities. To define and allocate these, the Engineers Joint Contract Documents Committee offers a family of standard contract documents that provide a clear and structured guide to the process. Proponents of design–build value it as a method of delivering completed projects faster and cheaper than the traditional design–bid–build method. In teaming the architect/engineer with the contractor, communication between the two improves, and more ideas are brought into the process. But design–build often creates roles and responsibilities for owners, engineers and contractors not found in the traditional design–bid–build project–delivery system. Until now, engineers have had to create contract documents for design–build projects on a case–by–case basis. Earlier this year, the Engineers Joint Contract Documents Committee (EJCDC) completed a family of standard design–build contract documents that define the responsibilities and allocate the risks involved. The documents address issues such as the design–builder selection process, preparation of the request for proposal, scope definition, standards of care, warranties and guarantees, geotechnical investigations, quality and communications.

Is virtual reality for real

Abstract: Virtual reality, an advanced visualization technology, will change certain aspects of civil engineering. The method allows people to simulate conditions, render designs and test these before proceeding to the next stage of a project. Research is being done on software programs that link real-time construction schedules with 3-CAD designs and animate projects to create images. Stanford University and the Dillingham Construction Co. are working together on a project involving construction of a new hospital around an existing one. Researchers developed a model that helps hospital staff and suppliers see how they have to coordinate operations with the construction schedule. Using the system, engineers can see conflicts early in the planning process and avoid them and also visualize the iterative effect of a particular change on other aspects of the construction. Greiner Inc., is developing virtual reality capabilities in-house. According to the firm's senior animator, the equipment can cost as much as $500,000, and most clients aren't willing to pay for virtual reality yet. Greiner uses the system to visualize complicated buildings and other projects. They can tie a building construction procedure to a time line, for example. The method is also used for traffic flow simulations and toll booth operations. Virtual reality modeling language was standardized in early 1995 and this will enhance the development of this technology. Hypertext Markup Language is another vital tool relating to virtual reality, in that it allows users to create hyperlinks to other documents, graphics and Web sites, which in turn enables users to achieve. The San Diego Supercomputer Center is active in this effort and have a new repository on the World Wide Web for exchanging information, software and utilities related to the virtual reality markup language.

Bioremediation Comes of Age

Abstract: Only five years ago engineers and scientists met with EPA officials to weigh the merits of bioremediation as a hazwaste cleanup tool. Now bioremediation has become an accepted effective cleanup method. Its a simple process, induced by natural cellular activity called phagocytosis that occurs in soil between indigenous microflora or organic carbon-bearing molecules, such as petroleum-based hydrocarbons. When introduced to hydrocarbon-saturated soil, the microorganism creates a biofilm around the hydrocarbon molecule and breaks it down into simpler compounds of carbon and oxygen. When the hydrocarbon or nutrient source is depleted, microbe activity ceases and the microbes die. A large portion of the hazardous-waste contamination in the U.S. stems from such petroleum-hydrocarbon products that have been discharged or spilled into the soil at petroleum production well pads, airports, military bases and large manufacturing plants. At these sites hydrocarbon contaminants--crude oil; paraffin; diesel and jet fuel; gasoline; chlorinated solvents and benzene, toluene, ethylbenzene and xylene (BTEX)--are present. Bioremediation removes these contaminants from soil organically, while maintaining the microbial populations that keep soil healthy and viable.