Thermal Mass

By Claude Goguen, P.E., LEED AP

Thermal mass is used in the building industry to define the inherent property of a material to absorb heat energy; it has nothing to do with insulating materials. A wall material with high thermal mass can moderate daily temperature variations.

A lot of heat energy is required to change the temperature of high-density materials like precast concrete, and this is why concrete has high thermal mass. Wooden walls, by comparison, are much easier to heat with their lower thermal mass. High thermal mass precast concrete walls act like thermal sponges, absorbing heat during the day, and then slowly releasing the heat as temperatures fall at night.

Precast improves energy performance
Precast concrete’s thermal mass flattens out daily temperature differentials and therefore reduces heating and cooling loads on the building’s HVAC system. The resulting energy savings increase with high swings in ambient temperature. When outdoor temperatures are at their peak, the inside of the building remains cool, because the heat has not yet penetrated the precast concrete mass, producing a time lag as seen in Figure 1. Precast slowly releases heat into the interior spaces during late afternoon and evening when buildings are usually empty. This delay in heat transfer is known as “damping.” Read More »

USGBC

The U.S. Green Building Council is positioned to help bring more sustainable building design and construction into existence.

By Kyle Kerstiens, Assoc. AIA, LEED AP

Every industry is saturated with the idea of becoming more environmentally friendly in one form or another, and the precast concrete industry is no exception. Architects are designing more sustainable projects using USGBC & LEED standards. So what’s the selling point for sustainable buildings? According to the USGBC, in comparison to the average commercial building, green buildings:

• Consume 26% less energy
• Have 13% lower maintenance costs
• Have 27% higher occupant satisfaction
• Have 33% less greenhouse gas emissions
  

What is the USGBC and LEED?
The U.S. Green Building Council is a nonprofit organization whose primary goal is to make more environmentally friendly buildings available to everyone. Based in Washington, D.C., the USGBC has a mission of market transformation toward sustainable design and construction. Its main focus for achieving this goal is the LEED green building certification program. Beyond the certification, USGBC has educational programs, a strong advocacy program, a network of state and local chapters, and an annual conference and expo called Greenbuild.

LEED is a third-party certification program and the nationally accepted benchmark for the design, construction and operation of high-performance green buildings and neighborhoods. Developed by the USGBC in 2000 through a consensus-based process, it serves as a tool for buildings of all types and sizes. Certification offers third-party validation of a project’s green features and verifies that the building is operating exactly the way it was designed to. Read More »

Under the HSC Canopy

Florida precaster finds success with high-strength concrete and encourages other manufacturers to market it.

By: Sue McCraven

It’s summer 2011. Our sluggish economy lurks overhead like a dark cloud. High unemployment lingers. Construction opportunities are scarce in many regions of the country. Any good news is welcome. For producers who want to learn more about the business potential of high-strength concrete, here is a Florida precaster who has jumped into HSC with both feet.

A little history
Thirty-five years ago in his native Great Britain, Alex McCulloch saw some amazing stone balustrades that were reproduced with precast “dry-pack” concrete. Historical restoration such as the precast balustrades is painstaking work for British producers who repair magnificent structures dating back to the 17^th century. In Wales, Scotland, Ireland and Great Britain, only natural stone is acceptable for building such elite structures as the irreplaceable Westminster Abbey in London, site of the recent royal wedding. When restoration work becomes necessary, only the expensive dry-pack concrete can provide exacting color and a high-quality finish. Read More »

The Devil is in the Details: Why Connections are Critical

Structural engineers understand that most failures are the result of poor connections. From the Kansas City Hyatt Regency walkway collapse that took more than 100 lives to a broken child’s swing resulting in a bruised knee, the strength of the link between adjoining elements is critical to safety. Bolts, tiebacks, welds, straps, anchors, chains, wedges, links, pins, hooks, hinges, nails or, sometimes, glue: It’s usually the integrity of connections that make or break any man-made system.

We all know construction is an inherently dangerous business. Precast concrete fabrication, for example, entails moving, transporting, hoisting and erecting massive concrete components. In the construction industry, safe and strong connections will always require careful attention to detail. This Safety Toolbox will test your knowledge of chain sling safety.    Read More »

Making Strides

Cement manufacturers join the green movement and strive to make their products more environmentally friendly.

By Bridget McCrea

Sustainability hasn’t come easy for the cement industry, but that doesn’t mean attempts aren’t being made to create “greener” options for this critical, base material. A powdery substance made by calcining lime and clay, mixed with water to form mortar or mixed with sand, gravel and water to make concrete, cement’s environmentally friendly properties aren’t always easy to identify.

But that doesn’t mean the industry is sitting on its hands while the rest of the world attempts to minimize its carbon footprint (the total set of greenhouse gas emissions caused by an organization, event, product or person). David Shepherd, director of sustainable development at the Portland Cement Association in Skokie, Ill., admits that whittling down cement’s carbon footprint hasn’t been easy. Read More »

LEED Marketing

Ready or not, Leadership in Energy and Environmental Design is rapidly becoming the hallmark of sustainability by which project bids may live or die.

By William Atkinson

LEED is an internationally recognized green building certification system providing third-party verification that a building or community was designed and built using strategies aimed at improving performance in several metrics. These areas include energy savings, water efficiency, CO₂ emissions reduction, improved indoor environmental quality, stewardship of resources and sensitivity to their impacts.

Developed by the U.S. Green Building Council, LEED provides building owners and operators with a concise framework for identifying and implementing practical and measurable green building design, construction, operations and maintenance solutions. Read More »

Building Blocks-Dellinger Precast

By: Ron Hyink

Dellinger Precast Inc. was made with the bricks of hard work and the mortar of lasting friendships upon the cornerstone of quality products and dedicated employees.
Forty years ago, Gary Dellinger came home from Vietnam and, with little more than pocket change, went to work on his parents’ farm in rural North Carolina. One Friday while baling hay, the 23-year-old saw his future drive by right in front of him. It was a truck with a precast concrete septic tank and rig passing by on the country road next to the farm near Denver, N.C.

Immediately he thought, “No one around here makes those – they have to be hauled in!” Everybody out here has to wait a week or two weeks to get a precast tank, he said to himself. So he jumped in his car, followed the truck and watched as the driver set the tank, then followed him to his home base in Hickory, N.C., some 30 miles away.

Gary thought, “I can do this. It’s just manual work – when you’re raised on a farm, you can do this.” He would soon learn that concrete manufacturing calls for more than just muscle and a market for septic tanks when he established Dellinger Precast Inc. Read More »

Green Piece-Reducing Cement’s Footprint

By Kyle Kerstiens, Assoc. AIA, LEED AP

Concrete is second only to water as the most used substance in the world. Because of this need for concrete, cement, which serves as the glue, is also produced in large volumes. This massive demand, along with the heat required to produce it, is why 5% of global CO₂ emissions is attributed to the cement industry. Even though concrete is seen as an important and necessary product – and with consumption seemingly ever on the rise – the cement industry has been working for many years to reduce that carbon impact in order to be competitive in the construction industry and to become better stewards of the environment.

In order to effectively transform the carbon impact, 10 of the world’s largest cement manufacturers formed the Cement Sustainability Initiative (CSI) in 1999. That number has since ballooned to more than 23 cement manufacturers that collectively account for about one-third of the world’s cement manufacturers and more than one-third of the world’s cement production. Their goal is to set up a framework of objectives on the road to sustainability. Read More »

Urban Oasis Emerging Over Texas Freeway

By Sue McCraven

It’s not easy to create ground, especially over a freeway,” explains Duane Milligan, TxDOT construction engineer for a 5.2-acre urban park that is part of a green initiative for downtown Dallas. Drivers rushing along the eight-lane Woodall Rodgers Freeway can see the increasing number of precast concrete beams spanning the airspace above them. A park is being born where there was no land.

“A phenomenal engineering design”
Called a “very meticulous project” and a “hybrid between a bridge and a building” by project engineers, the two Texas precasters for the Woodall Rodgers Deck Park also found the beam specifications for spanning the freeway to be out of the ordinary. Texas Precast Concrete Inc. in Waco and Speed Fab-Crete of Fort Worth produced the precast concrete components for the project. “This is not just your ordinary TxDOT bridge,” says Harvey Smith of Texas Precast, “nor a standard DOT precast, prestressed box beam.” Read More »

ELE International celebrating 50 years

“If it is worth building, it is worth testing,” says ELE International who this year celebrates 50 years as a major worldwide manufacturer and supplier of construction materials testing equipment.

During its 50-year period, ELE International has been involved with many innovations and changes. ELE’s John Sutton outlines the progress of the company itself and the materials testing industry in general.

The construction materials testing market

The first commercial soil mechanics laboratory in the United Kingdom was established following investigations to a slope failure at the Chingford Reservoir. At that time the only other soil mechanics laboratory in the United Kingdom was at the Building Research Station, which is now the Building Research Establishment. Read More »