News and Events - "DS Article"

Welcome to our newsroom! Here you will find the latest information about our company, projects and people. Browse articles published by our engineers and scientists in national publications and conference proceedings, view our press releases and read through news coverage of Terracon.

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Critical Roadwork: Design for Crucial Florida Road Project

I-75 corridor in FloridaAt one point, the north/south corridor of Interstate 75 (I-75) in Florida’s Broward and Miami-Dade counties was a road with relatively light traffic allowing motorists to cruise along at highway speeds most of the time. This changed after Hurricane Andrew blew through in 1992. Andrew leveled thousands of homes and businesses, causing a mass migration to the newer, available homes along the I-75 corridor. With this shift, new traffic patterns developed along I-75 and other major roadways, creating significant areas of congestion in some cases.

The Florida Department of Transportation (FDOT) responded to the challenges with plans to alleviate traffic congestion and improve connectivity. The plans included additional lanes and enhancements to existing roadways and reversible, dedicated open-road toll lanes. Early in 2014, construction began on the $485 million road project, which was scheduled in four segments.

Having provided geotechnical and materials testing services for a number of South Florida projects, Terracon served as an instrumental part of the Segment E improvements. As with most area projects, the geotechnical design was complicated by existing marshy terrain and unknown subsurface conditions. Terracon’s subsurface exploration team worked quickly to collect all the necessary data from the field, enabling our geotechnical engineers to collaborate with the project’s lead designer, WSP USA, to understand the conditions.

In order to test and confirm pile depths and capacities, Terracon’s pile-driving analyzer and operating engineers were deployed together during construction to work with the team. This data gathering phase was complicated by the need to keep traffic moving. Key challenges for the maintenance of traffic included reducing traffic shifts, limiting lane closures, and reducing weaving and merging.

As the project progressed into construction, Terracon went on to perform all the contractor quality control (CQC) testing of the materials on behalf of Dragados USA, the design-build contractor. CQC services included laboratory testing of soils and concrete, and other key components including bridge inspection, to ensure contractor compliance with FDOT plans and specifications.

In addition to working closely with WSP USA and DUSA, the Terracon team needed to coordinate with the construction engineering consultant firm (CEI), Target Engineering, and FDOT. Tasks included communication about data, scheduling, testing, and reporting results. A unique challenge for data reporting on this project was moving data entry from the Laboratory Information Management System to the Materials Acceptance Certification system at the midpoint of the project.

Terracon provided reliable data using properly trained, certified, and experienced staff to confirm the integrity of the materials used met the project specifications. The Terracon team included technicians who had completed FDOT’s Construction Training Qualification Program (CTQP).

They observed and tested more than 600,000 cubic yards of excavation and embankment material; 700,000 square yards of base material; more than 35,000 tons of asphalt materials; and more than 50,000 cubic yards of concrete.

With the project nearing completion and soon to be fully open to traffic, South Florida residents and commuters will greatly benefit from these unique, reversible toll lanes. The project provided an opportunity for Terracon to further demonstrate our transportation support capabilities and capacity utilizing multiple team members from three of our nearby offices. As a go-to consultant for critical transportation projects like I-75, Segment E, Terracon is committed to the transportation industry and proud to help our design and construction clients solve challenging issues through creative solutions.

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The Age of the Drone: How Unmanned Aircraft Systems Expand Building Investigation Boundaries

Unmanned Aircraft SystemWhen a window is too high to reach, a building is difficult to access by scaffolding, or a facility is too large to survey—call in the drones! The introduction of small Unmanned Aircraft Systems (sUAS), or drones, has added exciting new options for providing building investigation services with greater accuracy and increased efficiency.

Traditionally, assisting owners, architects, and contractors tackle building enclosure issues, performance deficiencies, and maintenance investigations of their properties has meant setting up staging equipment or acquiring the largest boom lift available and hoping for safe access. This access can be time consuming, expensive, and inadequate for the task at hand. Drones can provide a safer and quicker option for examining the components of a curtain wall, accessing a recessed ledge on an architecturally-challenging building, performing construction monitoring, or inspecting large roofs and structures in substantially less time.

Revolutionary Service Options

Access improvements and increased safety are attractive and easily recognized benefits of sUAS for due diligence services. The lesser known, more exciting, features are what drones are doing to revolutionize services and options for building investigations. Services such as photogrammetric mapping and thermographic imaging are quickly expanding in both application and effectiveness. Photogrammetric mapping is the use of photography for surveying and measuring distances between objects. Industry applications include mapping of architectural features for historic preservation, measuring existing structures’ elevations to be converted into CAD drawings and repair documents, and measuring spoil piles in geological and environmental earth moving projects. Photogrammetry allows a sUAS pilot to preprogram flight patterns over a desired location, and record the photos sequentially. The sequence of photos can later be “stitched” together to generate real-time overhead location maps, footprints of existing facilities, up-to-date elevation drawings for as-built documentation, and design and retrofit documentation.

Unmanned Aircraft System in flightThermography, a process utilized by building enclosure consultants for decades, is simplified through the use of sUAS. The value of a thermographic image allows technicians to identify temperature changes caused by possible moisture within a system, voids, or installation deficiencies not visible to the eye. Thermography equipment is most effective during a small window of time in the early evening dusk; when the sun has yet to set, but is low in the sky. Temperature differences between the roof assembly and the conditioned interior space are greatest during this time frame and allow for optimal imaging from thermographic cameras. Naturally expedient thermographic surveying of the roof area is critical for large facilities, but walking a large roof can be time consuming. Now, a thermographic camera can be mounted to a drone allowing the operator to cover more of the roof area. The GPS coordinates for all photos and drone footage are recorded when the image is captured, which allows for quick and accurate location and documentation.

Piloting the Industry

These new commercial capabilities require new licensing, permitting, safety considerations, and government oversight. The Federal Aviation Administration (FAA), state, and local authorities have several operation regulations of drones, with most states differing from federal requirements, and from one another. Private organizations, hobbyists, and businesses collaborate with the FAA to provide feedback for this dynamic industry, in an attempt to make sUAS effective and safe for the public. A remote pilot in command must be well aware of airspace when communication with air traffic control towers is required, where restricted and prohibited flight areas are designated, and of national airspace rules.

This technology is rapidly accelerating the execution of building enclosure investigations. Terracon’s facilities professionals are using drones to help clients with large scale projects and routine maintenance inspections, making building inspections easier and safer than ever before.

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Complex Demolitions: Do you have the right team to succeed?

Riviera Hotel and Casino demolition

Razing the Riviera

It’s not every day a Las Vegas icon needs to be demolished, but when it does, special expertise is required.

Terracon was selected in the summer of 2015 by the Las Vegas Convention and Visitors Authority to be a team member for a project to demolish all buildings on the 28-acre site of the iconic Riviera Hotel and Casino, located between the existing Convention Center and The Strip. Space was needed to attract larger conventions, and the Riviera site provided both the land for growth and direct access to the popular tourist area.

Working Together

The project team met multiple times over several months to discuss the project and work out responsibilities, schedules, and budgets. Other entities invited for input included the city, county, fire department, utilities (water, electric, and gas), regulatory authorities, and client stakeholders. The group was advised about possible environmental issues, including a Phase I site investigation.

Our team’s initial responsibilities included site exploration and reconnaissance to determine the impact, location, and quantity of asbestos, lead paint, hazardous materials, past leaking underground storage tanks, and associated contaminated soil at the site. After exploration and sampling, Terracon presented the results and provided budget estimates for complete removal of identified environmental concerns from the site. The collected data was then used to perform additional in-depth investigations and write remediation specifications for the removal and disposal of all asbestos and other hazardous materials, along with removal of the underground tanks and associated contaminated soil.

Safety is King in Demolition

After the bidding process and selection of a demolition and remediation contractor, the remediation and demolition began concurrently in April 2016. This meant safety considerations and procedures became even more important on this very busy and complex demolition site. The work was complicated by the intense summer heat (up to 115 degrees), which created a risk of dehydration to those working onsite. During the remediation phase, our team provided oversight and hazardous material removal verification. This work occurred while demolition was ongoing in areas with no environmental concerns and after other buildings were remediated.

Most of the buildings were mechanically demolished as the demolition contractor worked from east to west across the site. In the early summer, one building was imploded while remediation work continued on the older buildings on the west side. By mid-August, the remediation work was completed in the remaining buildings. In the early morning on August 16, the final three buildings were imploded and only rubble was left of the historic property. The remediation phase and the overall project was completed on time, meeting a very ambitious schedule within budget parameters and in a safe manner.

See the demolition work:


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Paving the Way: Preserve and Maintain Your Investment with Pavement Management Programs

Pavement managementYou wouldn’t consider driving your car 20,000 miles without changing the oil, rotating the tires, or having it inspected. Similarly, it is not a good idea to ignore needed maintenance of your pavements. Postponing timely pavement maintenance may buy more time, but that time will be expensive. Escalated costs for more extensive repairs are the likely result. Exposure to sunlight, rain, freeze/thaw cycles, traffic, and time, all have damaging effects on pavement. Pavement deterioration begins immediately after construction and without maintenance, environmental, and structural stresses can accelerate the process.

Life-Cycle Understanding Aids in Management

Pavement quality deterioration follows a typical life cycle. The initial 40 percent reduction in pavement quality occurs over the first three quarters of the pavement’s lifespan. At this point the pavement has reached a critical level of wear. Beyond that point, the pavement quality rapidly declines. The next 40 percent of quality reduction occurs over the next 12 percent of the pavement life. What may cost $1.00 per square foot to maintain pavements prior to the critical point rapidly increases to about $5.00 per square foot for repair if the pavement is left to further deteriorate.

Keeping pavements at certain levels of quality involves timely inspections, application of fundamental engineering decisions, and expenditure of funds. But if critical decisions about how and when to engage preventive maintenance strategies are appropriately made, the life-cycle costs of pavements can be lowered by 400 percent, even when the time value of the money to perform preventive maintenance is considered. Traditional approaches have left these maintenance decisions up to facilities personnel, who may engage a local contractor to select treatments based on reactionary, limited or biased information.

Planning Helps to Establish Engineering Budgets

Pavement management brings applied science and engineering into the process of identifying requirements needed to maintain pavements. An engineered pavement management program should consist of three major components:

  • A regular, scheduled pavement inspection program
  • A database to inventory collected data and consistently rate pavement quality
  • Engineering and economic analyses to evaluate strategies to increase return on investment and provide the engineer’s cost estimate associated with each strategy

This management approach is used to plan annual pavement repair/preservation programs and is an integral part of developing annual maintenance budgets for pavements. The management of pavements generally takes place at two levels, network and project.

This management approach is used to plan annual repair and preservation programs and is an integral part of developing maintenance budgets. The management of pavements generally takes place at two levels—network and project.

Network Level Management
In network level management, a relatively small percentage of the pavement is inspected to obtain a snapshot of the current condition. The data is also used to project the future condition of the pavement. Projections provide the information needed to identify and schedule potential project-level areas requiring maintenance and rehabilitation in current and future years.

The forecasted maintenance requirements can also be compared with the actual costs which can be allocated for pavement maintenance and rehabilitation. Using this comparison, coupled with projected pavement condition, priorities can be established for the entire network.

Project Level Management
At the project level, a detailed condition survey is undertaken to develop actual quantities for maintenance and repair. The results of project level pavement inspection are combined with budget and/or management constraints or both to produce the final maintenance and rehabilitation project list for any particular program year. Final plans and specifications are developed and used in the bidding process.

Terracon’s engineers can help clients with any of these pavement management services for city and county roadways, as well as parking lots and drive lanes associated with commercial developments, educational facilities, hospitals, and airports. In addition to evaluation and engineering services, we can provide construction support to include construction administration management, assist with the bidding process, and construction materials testing and observation. Our teams provide start to finish solutions for your pavement needs.

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Demolition and Clean Up Heat Up: Commissioned demolition of an incinerator

Many communities have obsolete infrastructure that represents an underutilized asset, often posing an environmental or safety hazard to the community. Terracon recently assisted one such community with a former municipal solid waste incinerator removal to allow repurposing of the building. Challenges on this project included the presence of hazardous ash impacting porous and non-porous surfaces, significantly limiting the recycling and reuse options for the non-porous (steel) components of the incinerator. To eliminate the exposure hazards and maximize the recycling potential to help control overall project costs, Terracon developed a cleaning and monitoring plan that allowed a large volume of the steel and other non-porous components to be recycled safely and effectively.

Terracon was contacted by a demolition contractor with whom we had completed previous demolition and cleaning projects at former incinerator sites. Our team developed a cleaning and management plan that was approved by the Minnesota Pollution Control Agency that allowed recycling of large volumes of metal materials. Terracon completed supplemental assessment for asbestos and cleaning validation to document the effectiveness of the cleaning process.

Unique Cleanup and Disposal

Cleaning was completed using high pressure washing, with wash water collected within the incinerator building. Terracon provided visual clearance of cleaned materials prior to off-site shipment for recycling. After cleaning was completed, the wash water and accumulated sediment required management and disposal.

Similar projects had utilized settling and/or bag filtration to remove heavy metal laden particulate from the wash water to below discharge limits of the local publicly owned treatment works (POTW).  Initial settling and bag filtration tests on the water showed that zinc and cadmium concentrations were well above the applicable discharge limits of the POTW. Terracon’s industrial wastewater group was contacted to assess the situation and determine if treatment was feasible, bringing our experience with pre-treatment of heavy metal laden wastewater in industrial settings to bear on this field application.

A round of jar tests was conducted to determine if the metals were dissolved, chelated, or present as a fine particulate. The metals were determined to be dissolved but not chelated. A pH of 10.5 was selected for the initial treatment, which is between the minimum solubility pH point for zinc and cadmium, and would provide for precipitation of metals from the wash water. The pH was then adjusted prior to discharge in accordance with POTW requirements.

Safety Considerations Met

Significant safety considerations were discussed and mitigated due to the handling of strong acids and bases in the temporary system under bad weather conditions. Terracon conducted the on-site treatment in temperatures below zero degrees F. Initially, the pH of the water was adjusted to 10.5 with caustic using an air wand for mixing. The solution was allowed to settle and was pumped into a temporary batch treatment system. Two plastic, 1,000 gallon tanks were used to neutralize the water prior to discharge.

The water met metals and pH limits of the POTW and the treated batches were discharged to the sanitary sewer system. This treatment process was significantly less costly than other management options considered. The project was completed on schedule and on budget. Following the project, the demolition contractor’s supervisor made a point to call the Terracon department manager and thank him for the professional, efficient, and friendly service that had been provided on-site under difficult conditions.

Terracon is a provider of environmental, facilities, geotechnical, and materials testing services. This project is an example of the collaboration of multiple practice areas within the environmental service line to help our clients meet their regulatory, business, and community needs.

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Cell Tower Welding Inspection Requires Expertise

looking down from cell towerIt’s not every day you get to climb a cell tower, and if you are afraid of heights this is not the job for you! Terracon was recently retained by Wirenet Company to perform a visual weld inspection on strengthening improvements made to a 330’ high cell tower. The tower inspections were required to verify wind load capacity, following the addition of a new antenna arrays which were recently installed.

To perform the inspections, Chris Dumford, an AWS QC-1 certified welding Inspector based in Cincinnati, was required to climb the tower to visually inspect the welds at each bolted flange. A total of nine flanges on each of the tower’s three legs needed inspection. Before the climb, Chris prepared by gearing up in the appropriate personal protective equipment (PPE) that included rubber-coated gloves, climbing harness with cable grab attached, high visibility vest, hard hat, and safety glasses. Since activities like a tower climb are never performed alone, Wil Beckwith, P.E., materials engineering manager, accompanied Chris during the tower inspection.

Only one leg of the tripod tower had pegs for climbing, so Chris was required to climb over to the other tower legs and rappel down each of the other two legs to complete the inspection. Part of Chris’ PPE was repelling gear that included a special harness and a safety rope that allowed him to rappel down each of the other two legs to perform the inspection. It took nearly 13 minutes to reach the top of tower by climbing up the pegs, and the inspection required him to climb the tower three different times. Chris inspected each of the welds for typical defects including cracks, undercut, overlap, porosity, and proper weld size. He deemed the welds acceptable per the provisions of AWS D1.1.

The Inspection of the cell tower included viewing welded stiffener plates, above and below connection flanges, for each support leg pipe section. These stiffeners were designed to add additional resistance to tower deflection at the bolted pipe flange connections. Each welded stiffener required multi-pass fillet welds with weld sizes that varied from 3/16” to 7/16” depending on location. The welding operations had taken several weeks to complete.

Climbing a cell tower is no easy feat. Terracon is fortunate to have the resources, and the no-fear-of-heights experts like Chris – who has climbed over 40 cell towers during his career.  In fact, Chris has done some recreational climbing and rappelling, which comes in handy on the job. Terracon’s many years of experience allow us to perform inspections on towers up to 400’ high as well as light poles, high-line electrical towers, windmill towers and other unusual tower structures for clients who need quality inspections for structural stability.

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Air Barrier Testing: Revealing Cost Reduction Solutions for School Systems

Air Blower TestingEver notice a breeze in older buildings even when it is not windy? Many buildings leak air, which means their owners are losing money. The Charlotte Mecklenburg School System (CMSS), the 19th largest in the U.S. with a $1.3 billion operating budget, recently decided to take action to identify school system buildings that might be exhibiting air leakage.

In early 2014, CMSS approved an architectural/engineering guideline change proposal to incorporate air barrier testing for all new buildings, additions, and major renovations. Using this guideline, CMSS’s plan was to decrease the air leakage from 0.25 cubic feet per minute (cfm) per square foot of exterior enclosure for buildings built in 2014 to 0.15 cfm per square foot of building enclosure for buildings built in and after 2018.

To help the school system determine sources of air leakage in one school built in 2015, Terracon performed air barrier testing in general accordance with the U.S. Army Corps of Engineers (USACE) Engineering Research and Development Center (ERDC), Air Leakage Test Protocol for Measuring Air Leakage in Buildings, using a proprietary (Retro-Tec) Blower Door Testing system.

Identifying Challenges

For effective use of test equipment, the building had to be divided into five areas to be tested separately. Splitting up the building into separate areas proved challenging due to the amount of ducts and air transfers which crossed firewalls and had to be sealed. All doors and mechanical ducts were sealed to prevent extraneous air leakage, which can disproportionately alter the results of the test. The flow through the building enclosure was recorded at 10 different pressure points. These points were placed on a graph which created a straight line that was then used to calculate the flow through the building enclosure at 75 Pascals, a unit of pressure in metric units.

Smoke pens, devices that emit a constant stream of smoke that can be used to show air movement, were used on the interior of the building to focus in on the source of leaks during the pressurization phase of the test. A stream of smoke was moved across different surfaces with potential for air loss, such as front windows, doors, electrical outlets, roof and wall intersections, and other areas. Terracon also used infrared cameras to help detect air leaks. By repeating this process, Terracon was able to identify significant sources of air leakage. For this facility, the exterior doors and the intersections of the exterior walls at the roof deck were the major offenders. In addition, large gaps were exposed at the door locks and at the thresholds.

Identifying Cost Savings

The allowable leakage rate of 0.25 cfm per square foot for an exterior enclosure area meets the target standard. The amount of leakage area this equates to is a single opening of approximately 36.7 square feet.

Other areas were identified, however, which could be easily repaired, providing the client additional savings in energy consumption. For an idea of how much these repairs could save, The National Institute of Standards and Technology issued a report stating that an office building with a total floor area of 24,200 square feet (approximately 30 percent of the floor area of the school building tested by Terracon) in the same climate zone saved more than $3,000 annually when air infiltration into the building was eliminated by 83 percent from its baseline. Equating this to the floor area of the entire school building, the expected annual savings is approximately $10,000.

By identifying the most efficient way to conduct air barrier testing for this type of school building, Terracon, in partnership with CMSS, was able to show results and recommend cost saving as well as energy conservation solutions, setting a baseline for future energy performance reviews within the system’s buildings.

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Incentive for Innovation: Assessment Strategies for Tax Incentives Drive Brownfield Site Redevelopment

Site Excavation and Soil StockpileSafely restoring a contaminated property and helping find purpose in its reuse is one of the most rewarding opportunities an environmental consultant can have. It requires a collaborative team with the creative vision to see beyond the condition of an existing site and instead see the possibilities for redevelopment.

With visions of a new hotel anchoring a project site located within a designated brownfields area in downtown Tallahassee, Fla., the owners of MountainShore Properties, Inc., initially knew they were in need of a partner to perform a Phase I Environmental Site Assessment (ESA). With knowledge and experience far beyond assessment, Terracon was able to support a successful brownfield site redevelopment using innovative assessment strategies and available incentives.

Identifying Complexities and Navigating Assessment Obstacles

Terracon was selected by MountainShore Properties, Inc. to perform the Phase I ESA based on an existing client relationship founded on a number of previously successful projects. Utilized as a storage and dry goods transfer/loading facility dating back to the early 1900s, the historic site was traversed by three rail spurs. Adding to the development project’s complexity, the Phase I ESA revealed recognized environmental conditions (RECS) associated with impacts to soil related to historic industrial activities that presented an obstacle for site redevelopment.

Following review of the Phase I ESA, Terracon was contacted to facilitate a site assessment. The team knew that if the assessment resulted in a recommendation for site remediation, development of the hotel could only occur if a Site Rehabilitation Completion Order (SRCO) without restrictions from the Florida Department of Environmental Protection (FDEP) could be achieved. The desired SRCO certifies the site as being remediated to regulatory limits with no need for future environmental cleanup.

Our team developed a large-scale comprehensive conceptual site model to adequately assess the site for chemicals of concern (COCs) while gathering data to support an arsenic as natural background assertion. The assessment incorporated the use of offsite and select onsite background sample locations to calculate specific background arsenic concentrations, integrated clay mineral X-ray diffraction testing, grain size sieve analysis, and statistical modeling of laboratory data to definitively prove arsenic was naturally occurring and not originating from human activity. The assessment also documented several metals and low level petroleum constituents in the top 2-feet of site soils. No groundwater impacts were identified. A combined document, Site Assessment Report and Remedial Action Plan, was submitted to the FDEP and subsequently approved. Arsenic was considered naturally occurring below two feet and consequently the top two feet of the site was excavated for proper disposal.

Utilizing Incentives

Terracon further assisted the client by identifying and obtaining tax credits under the Florida Brownfields Voluntary Cleanup Tax Credits (VCTC) Program. Through the VCTC program our client recovered fifty percent of cleanup costs in state corporate income tax credits. These tax credits have an estimated value of 85 cents on the dollar. In addition, because the site is in a brownfields area, it is eligible for tax incentives of $2,500 per future hotel employee.

Our team developed a close working relationship with FDEP which proved paramount to the success of this project. A SRCO was achieved for the property within a year of site assessment initiation. With the brownfield order closed, the owners are currently in the process of redeveloping the site and building a hotel. Terracon is also conducting the construction materials testing and threshold inspections for the hotel construction, and conducted the geotechnical evaluation and recommendations
for the hotel project.


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Modified Bitumen Roofing: A High Performance Option

No one cares about the roof… until water is dripping on your new computer.  A leaking roof is one of the leading causes of mold growth, inventory damage and destruction of building components such as walls, ceilings, finishes and furnishings not to mention computers.  While roof systems often account for less than 50 percent of the total building enclosure, defective roofing easily accounts for the lion’s share of building construction litigation.

Historically, built-up roofing (BUR) was the mainstay in low-slope roofing.  Many practitioners and owners were devoted to it for a variety of reasons, not the least of which were the durability and the redundancy of multiple layers.  Nevertheless, BUR has lost considerable market share due to costs, safety, environmental concerns, lack of skilled applicators and being just plain messy.

A modern day alternative is modified bitumen roofing, also known as “modifieds,” or “mod bits.”  Modified bitumen roofing has evolved as a high performance option to built-up roofing.  The waterproofing component in both systems is asphalt. While the quality of a BUR system is highly dependent on the skill of the guy mopping the hot asphalt (a dangerous job), with modified bitumen roofing the asphalt is applied to the reinforcing mat in the factory resulting in a more consistent product.

The reason it is called “modified” is because the asphalt is modified with elastomeric polymers that add elasticity and durability to the sheet. Installation of these systems is very similar to BUR but with far fewer safety concerns and far less mess. Modifieds can be applied with hot asphalt but are often applied with adhesives or with the “torch down” method thus eliminating much of the mess and improving safety. Roofing contractors who have historically installed BUR are familiar with modified bitumen roof systems and have easily transitioned to those systems.

Many of Terracon’s clients prefer modifieds.  Mecklenburg County Government in Charlotte, NC has utilized modified bitumen roof systems on the majority of their facilities including office areas, television stations, gymnasiums, courthouses, detention centers and natatoria over the past 10 years.  Each case is unique, requiring the modified systems to be designed to accommodate the varying conditions such as high interior vapor drive for pools and gyms. Modified systems meet code requirements for most low slope applications including fire and wind uplift classifications.

Ease of Use

These facilities are almost always occupied during construction and the work proceeds without significant interruption to day-to-day operations. Mecklenburg County facilities have various roof-top equipment requiring routine maintenance. Modified systems can withstand routine maintenance foot traffic without impairing long-term performance. Walkway materials, supplied by the mod bit manufacturers can be easily applied for areas of heavier traffic. The systems are durable and require low maintenance, which is a significant advantage for the County. The fumes from the cold adhesive are manageable and typically not a problem for the County or the building occupants and are certainly far less than the fumes from the old BUR asphalt kettles.

Various roof systems are available and most have their place in the construction industry provided they are carefully selected and detailed for the conditions encountered.  Modified bitumen is a viable option where durability, redundancy and low maintenance are critical and should be given careful consideration.

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Making a Splash! There's more to aquatic facilities than just water

Swimming pool constructionWhen you think of swimming pool design, the first image that might come to mind could be a large pool of crystal clear water. Before putting the first shovel in the ground or upgrading an older center, many factors need to be addressed for these unique aquatic facilities. The programming, planning, and rehabilitation of aquatic facilities for both recreational and competitive use include collaborating with clients, the design team, and even end users to create a plan that enhances and optimizes their vision and goals.

“For the majority of aquatic facilities, project planning for environmental, facility, geotechnical, and material factors is critical,” says Matt Reynolds, P.E., aquatics department manager for Terracon. “By assisting our clients in evaluating sites and identifying goals and objectives, we create a strategy to design new aquatic facilities or renovate existing aquatic facilities, optimizing end-user benefits.”

The importance of balanced environment

Many existing indoor natatorium facilities have poor air quality and moisture migration that are the result of years of deferred maintenance, ill-advised HVAC adjustments, and failing envelope systems (allowing water intrusion). To better plan for project needs, it is often necessary to conduct environmental studies to determine indoor air quality and assess whether the systems (building enclosure and HVAC) are contributors to the moisture imbalance and result in less than desired performance. These factors must be considered to truly rehabilitate a failing facility. The resultant remediation plan should address all of the systems beyond just the water-related pumps and treatment systems.

As an example, a collaborative effort of our building enclosure and HVAC specialists was required for a higher education project in San Antonio, which included a natatorium and gym with a common wall constructed circa 1990. Initially assessment findings identified a myriad of building issues indicating obvious water intrusion; gaps in mortar joints, debonding of Concrete Masonry Units (CMU), missing weep openings, deteriorated sealant expansion joints, unsealed openings at through-wall penetrations, however, the effort required additional review to address staining and mold growth on exterior walls, efflorescence of exterior split face CMU, corrosion of metallic surfaces in the pool building and fouling of mechanical equipment. A truly multi-disciplined team of professionals with expertise in building enclosure, mechanical and aquatic evaluation, testing, design and commissioning provided the university with recommendations followed by a comprehensive remedial design program to renovate the facility to meet the future needs of the growing higher education campus, restoring it as a showpiece.

Minimizing risk – Movement

Aquatic projects have the potential to pose interesting challenges. A unique one is known as a “floating shell.” This occurs when hydrostatic pressure below the pool floor is so significant that when a pool is empty, it pushes the shell upward, creating large cracks, leaks, and destroying pool piping. Once again, several different disciplines are needed to accurately address the related issues—geotechnical study which provides structural engineers with the best information to minimize foundation design issues while meeting applicable building codes and standards. Additionally, design standards to the pool engineering should be developed by a plumbing engineer to ensure that the system provides hydrostatic relief valves in each main drain sump and a sight sump to allow pool operators to view the in-ground water level with respect to the bottom of the pool prior to any pool draining procedures, thereby avoiding movement of the pool shell.

What it’s made of matters

Swimming pool shell engineering is critical component of the overall aquatic design, not only for slab-on-grade pools, but exposed or elevated shells. As an example, on an indoor natatorium project in Pittsburgh, Pa., Terracon was retained to determine the cause of leaking of a pool shell over occupied space below, that was installed only months prior to the evaluation. A pool shell water tightness test detailed leaks from many locations around the 8-lane by 25-yard competition pool into occupied space below the deck. There were obvious indications of design, installation, and materials quality issues. Concrete remediation recommendations and compatible waterproofing membranes were designed and remedial actions taken such that the tile setting manufacturer warranty was not voided. As a result, a water tight pool shell was restored and 25-year tile warranty was provided for the desired result on this new facility.

Making a splash with an aquatic facility is the easy part. Maintaining the facility performance for the intended use and long-term return on investment requires awareness of a myriad of issues to be addressed during the design and construction of any new facility. In addition, due to the complex nature of these facilities and their operational and often hostile environments related to building components, rehabilitation requires a team of multi-disciplined professionals working together to assess and restore the facility for its intended use. This will continue to challenge the industry as owners look to provide even more complicated and sophisticated aquatic facilities in a variety of building settings.