Post-construction Monitoring Research Articles

Construction and Performance of Alternative Concrete Pavement Designs in Wisconsin

The design and performance of concrete pavement test sections constructed in Wisconsin in the summer of 1997 to validate the constructability and potential cost-effectiveness of alternative concrete pavement designs incorporating variable dowel strategies and slab thicknesses are described. To reduce the number of dowel bars across the transverse joints and remain consistent with dowel bar installation equipment currently used within the state, four alternative dowel patterns were examined. Test sections were constructed with alternative dowel materials including fiber-reinforced polymer (FRP) composite dowels, solid stainless steel dowels, and hollow core mortar-filled stainless steel dowels as well as a variable slab thickness. Postconstruction monitoring including deflection testing, joint distress surveys, and ride quality surveys have been done. Observed joint distress including minor spalling, chipping, and fraying is mainly due to joint saw cut operations. No transverse joint faulting or slab cracking has been observed. Deflection testing to date indicated general uniformity of foundation support in all test sections. Deflection testing has also been done across transverse joints to quantify deflection load transfer efficiency. Joint tests in the fall of 1997 and 1998 indicated reduced load transfer efficiencies in all test sections compared with control sections, most notably in the FRP composite dowel test sections and the placement alternative with three dowels in each wheelpath. Ride quality surveys indicated general uniformity among sections.

00/03134 Synergistic opportunities for refining/petro-chemical plant integration

In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L−1. The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L−1) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO42− concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed.

Analysis and Stabilization of Failing Earth Dam Founded on Claystone

A minor slide occurred in the downstream face of an earth dam. Initial observations and limited optical survey data suggested the failure was shallow, but continued measurements from inclinometers in the embankment and survey monuments, as well as visual observations of deformation patterns, revealed a more extensive and severe failure located in the underlying weathered claystone foundation. Deep inclinometers were installed, and inclinometer readings indicated that approximately 1 cm per day of movement was occurring along a very discrete zone in the foundation. Horizontal survey measurements confirmed this displacement, and an emergency soil buttress was constructed at the toe of the dam to reduce movement. The residual strength along the slip surface was estimated by back analysis of the sliding block, assuming a safety factor of 1.0 and incorporating end restraint to assess the lower-bound residual strength. The remediation scheme included installation of an internal drainage system and a soil buttress. Postconstruction monitoring shows that the dam is continuing to move at a decreasing rate and is apparently approaching static equilibrium.

Environmental impact assessment of a mixed tropical hardwood integrated pulp and paper mill— a case study

An overview of the environmental impact assessment (EIA) for a mixed tropical hardwood integrated pulp and paper mill in Sabah, Malaysia, is presented. The EIA before the mill construction included, among other things, a detailed baseline study and also environmental impact predictions based on certain mill design and pollution abatement measures. Subsequent to mill construction (during the operational stage), data were gathered to determine the quality of the ambient air as well as the effluent and the receiving bay water quality. These post-construction monitoring results were then compared with the earlier impact predictions, and showed, in general, a good correspondence.

Predicting Potential Sound Levels : A Case Study in an Urban Area

Allowable sound pressure levels for industrial, commercial and residential sources of noise are typically governed by state and/or local noise regulations. This paper presents a six-step methodology which was successfully applied by a supermarket in Massachusetts to secure state permission to build and operate a new 52,000 square foot store. This multiple step process included baseline noise monitoring, obtaining reference sound levels of the proposed rooftop refrigeration equipment, predicting future sound levels, and recommending soundlevel mitigation techniques. Post-construction monitoring at the store verified that actual worst-case sound levels agreed with predicted values.

Marine outfalls for small coastal communities in Atlantic Canada

Atlantic Canada is a relatively sparsely populated region with a few large urban centres and many small communities. Many of these communities rely on secondary treatment plants for treatment and disposal of domestic wastes. However, with a generally low tax base and a small pool of technically qualified personnel, maintenance on the plants is often of low quality so that their performance deteriorates after a few years of operation. In this paper the argument is advanced that ocean outfalls provide a more satisfactory means of treating and disposing of domestic wastes in such cases. Details are provided to confirm the low level to which some plants perform; and the design, installation, and postconstruction monitoring of a small ocean outfall are described to show the advantages of this alternative. Key words: ocean outfalls, marine treatment, waste disposal, pollution, environment.

Design and construction of a shallow tunnel with large span in an urban area

A project to construct a tunnel with a 36 m span at a soffitt depth of about 8 m in strongly jointed layers of sandstones and claystones is described in detail. Each stage of the project is covered from exploration and testing; design; stability analysis and construction through to post-construction monitoring.

Water Diversion at Low‐Level Waste Disposal Sites

Shallow depth to groundwater, surface drainage, and subsurface flow during storm events can cause major environmental problems in low‐level radioactive waste management operations in humid regions. These three problems were encountered at two waste disposal sites on the Oak Ridge Reservation. In September 1983, two similarly designed, engineered drainage projects were initiated at the disposal sites. The SWSA 4 (solid waste storage area four) project was designed to divert surface runoff and shallow subsurface flow originating upslope of the site away from the disposal area. The second project, a passive French drain constructed in SWSA 6, was directed strictly toward suppressing the site water table, thus preventing its intersection with the bottoms of disposal trenches. Postconstruction monitoring for performance evaluation showed that the water table in the SWSA‐6 area is suppressed to a depth >4.9m below the ground surface over 50% of the site, as compared to a depth of only 2.1m for certain parts of ...