Construction Materials & Methods

Pervious Pavement

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(As previously published in Modern Contractor Solutions.) Pervious pavement is a green, sustainable strategy that can assist in lowering stormwater runoff, naturally decreasing automobile pollutants, recharging the water table supply and moderating the heat island effect. Similar to other complex construction systems, in order for the sustainable pavement to perform as it was designed, it needs to be installed with precision and maintained with diligence. To drain water effectively on any given site, different geographical areas require special adjustments to the technology as well.

Green Elevator Strategies

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Eco-friendly inventions now enable elevators to operate with much less energy, use less building square footage by eliminating traditional elevator utility rooms, and incorporate eco-sensitive finish materials. Likewise, green strategies for eco-modernizations are also available to renovate traditional elevators. Yet beyond new green technologies and renovations, an elevator itself is an important green tool.

Smoke Migration in Elevator Shafts

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With the advent of high rise buildings, fire safety has been of particular concern for architects over the last 100 years. Architects must understand the basics of fire and smoke and the risks associated with creating tall buildings. The spread of toxic smoke that results from fires has been shown to often cause more damage than the fire itself, and it is responsible for more injuries and fatalities.

Concrete Innovations

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Since the Roman Empire, concrete has been used as a construction material because of its versatility. Concrete can take on several forms and serve many functions. Unité d’Habitation, by Le Corbusier, is an example of using concrete to easily transition from floor to wall and from rooftop to pool. Concrete can also be formed into geometric and organic shapes, as demonstrated by Richard Meier in the Jubilee Church.

Marmoleum Flooring

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Selecting the proper floor finish can be a difficult task for any project, especially educational facilities.  Almost every school you enter today has a cafeteria or multipurpose room that functions as an eating area.  The eating area is usually equipped with cafeteria tables that have attached seating.  These tables are large, can weigh several hundred pounds, and can contribute to damaging the selected flooring material.  If sheet vinyl flooring was selected, the vinyl would become dented and/or compressed at each table leg location.  Sheet vinyl does not have the have compressive strength to withstand such high point loads.  In just a short period of time, the entire floor would become visibly scared and unattractive.  Vinyl composite tiles would have the compressive strength to withstand the weight of the tables.  However, over an extended period of time, the tiles expand and contract, allowing dirt and grease to accumulate in the joints.  Virtually impossible to remove, the dirt and grease quickly become noticeable.   Ceramic tile is another viable option, but can become a slip hazard when wet.  Also, the grout will stain with repeated exposure to liquid, dirt and food.

Today's Grocery Store

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Grocery stores have undergone significant changes over the past decade.  Fifteen years ago, if a recipe called for a rare ethnic ingredient, you would have to search all across town for it; now the average mega mart has most of the ethnic ingredients you could ever want.  For years, grocery stores veered away from the old time service meat and deli counters and focused on self serve.  The size of the grocery store has expanded at a rapid rate; the average mega mart is around 50,000 square feet.  The stores started to feel less inviting and more sterile, much like a warehouse.  Grocery chains seemed to have lost touch with the customer.  Now jump to the present: the grocery store of 2009 is no less than a one-stop shop with all the bells and whistles.  Our grocery stores of today supply us with fresh food, dry goods, prepared foods, toiletries, housewares, clothes and even banks.  They have come a long way, and so have the designs.

 

Mechanical Talk: Comfort

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The human body has its own heating, ventilating, and air conditioning plant.  The epidermis, or skin, is its control system.  Water, being available in abundance in the human body, is a natural means of storing heat or rejecting it.  Remember science class in high school?  Who remembers what percentage of the body is water?  Wasn’t it some ridiculously high percentage?  When we heard the teacher tell us, we all made kind of an unconscious mental note that that just couldn’t be.  Nevertheless, when the human body needs warmth, the pores of the skin close up or constrict, hence the body retains moisture and stays warmer.  When the body needs to be cooled, the pores open up, allowing moisture to escape in the form of perspiration.  As the perspiration evaporates, heat is removed from the body and we feel cooler.  Evaporation requires one of two elements: either the surrounding air must be dry (we call it low humidity) or it must be moving.  If either exists, evaporation can occur.  In the old days, all cooling was by ventilation and it occurred by means of evaporation.  That’s why a convertible in the heat of summer can still be comfortable, even though the temperature is 95 degrees. We do not feel hot because, at 75 miles per hour, there are plenty of breezes to cause the evaporation we need to feel cool... unless, of course, we are parked on the expressway during rush hour.

Driven Piles vs. Jetted Piles - A Comparison

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“Pile jetting” is a technique that is frequently used in conjunction with, or separate from, pile driving equipment for pile placement.  Pile jetting utilizes a carefully directed and pressurized flow of water to assist in pile placement.  The application of a concentrated jet of water at the pile tip disturbs a ring of sub-grade soils directly beneath it.  The jetting technique liquefies the soils at the pile tip during pile placement, reducing the friction and interlocking between adjacent sub-grade soil particles around the water jet.  This greatly decreases the bearing capacity of the soils below the pile tip, causing the pile to descend toward its final tip elevation with much less soil resistance, largely under its own weight.  In less frequent applications, compressed air jets are used instead of pressurized water jets with the same end result.

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