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Happy Birthday, Frederick Law Olmsted!
This just in from John: Happy Birthday to Frederick Law Olmsted!
Concrete Pour Video – Post Tension Slab
A short video showing some of the processes involved in pouring a post-tension slab in a larger multi-story project...
Thermal mass is a phrase one hears often in our corner of the overall industry, due to the fact that when properly used, it can significantly increase the efficiency of a given building envelope: although this idea now has a sort of buzz or currency, it's actually one of the oldest energy control techniques, and was very common in concert with solar envelope design from ancient times...
Lobby Day for Affordable Housing
The California Housing Consortium brought in Senate Pro Tem Senator Steinberg, Senator Mark DeSaulnier, Assemblyman Cameron Smyth and the heads of HCD and CalFHA to talk about the critical bills that are in process to recapture the hard-fought affordable housing funds from the butchering of the state’s redevelopment agencies. About forty of us walked the capitol’s halls to visit legislators, their staff and the Governor’s staff completing almost 40 meetings to press the case for affordable housing....
Multi-Family Housing And Solar
The massive solar array that seemingly floats over the new affordable housing building at 7th and H in downtown Sacramento is composed of 680 solar PV (photovoltaic) panels that provide power to the common "house loads" of the building. Common loads include things like elevators, stairwell lighting and the central cooling towers on this redevelopment project. The array uses a net metering system that runs the electric meter backwards, or slower, when the sun is shining and power is being produced...
Living In An Mogavero-Designed Eco-Urban House
I was a happy, dedicated Davis resident, who thoroughly enjoyed the bicycle paths, greenbelts and kid-centric culture but my wife, daughter and I moved to West Sacramento for one simple reason: being able to purchase a super-sustainable, ultra-chic eco-urban home in the Good project...
Natural Ventilation: UCD Tercero Student Housing Phase Two
Solar chimneys in 2000 year old structures throughout the Middle East served as a historical precedent for a natural ventilation system to cool the UC Davis Tercero Student Housing project. Utilizing the cool evening Delta breeze is a common practice for nighttime cooling in the Sacramento Valley. The system is automated for public spaces and allows for occupant control within individual bedrooms. The Central Stair is a continuous four story volume open to each floor based on a new provision in the California Building Code. This provided a “thermal chimney” that promotes natural ventilation through the stratification of the air. The hot air rises to the operable louvers that exhaust the extra heat at the top of the stairs. Cool exterior air is introduced through motorized louvers located at multiple window seats throughout the hallway on every floor. The system is controlled through the building’s energy management system which monitors interior and exterior temperatures, triggering louvers and large fans to assist in what is essentially a building-wide natural ventilation economizer cycle. The geometry of the natural ventilation scheme coincided with the creation of community spaces and led to an elegant system using passive and active elements that allow the building to breathe. The use of daylighting in these spaces further reduces the energy footprint of the building and enhances the students’ occupant experience. – Craig
How To Specify Galvanized Steel So That It Looks Good
We use uncoated galvanized steel as a sustainable finish in many of our projects. It is sustainable because galvanizing produces a durable, no maintenance finish with a sixty-year plus lifespan. Recently we have noticed that its appearance can be less uniform than we have seen on previous projects. The galvanized coating on steel is both protective and decorative. ASTM A123 Zinc (Hot Dip Galvanized) Coatings on Iron and Steel is the industry standard for specifying typical galvanized steel coatings. This specification focuses on the protection from corrosion (cathodic protection) afforded by galvanized steel. Many factors affect the APPEARANCE of galvanized steel, but do not reduce protection from corrosion. The support structure for the rooftop photovoltaic array at our 7th and H project provides an example of adequate cathodic protection, yet a problematic appearance if the structure was located in a highly visible location. During the pre roofing conference held on January 24, 2012, the PV support structure was observed to have a very un-uniform galvanized finish appearance. Portions were dark dull gray while other portions of the same I beam were shiny. The PV array support structure is acceptable, but Mogavero is concerned that the appearance of the galvanized finish on the second floor terrace gazebos will not be as intended unless this appearance is not addressed by the galvanizer. The galvanizer should be made specifically aware that finish is an important part of the design and that steps need to be taken to ensure a more uniform finish with a natural reflectivity range of 70% or greater. The following comments are based upon research conducted at the American Galvanizers Association. Galvanized coating is created in several layers, the surface (or “zeta: layer) grows in columns perpendicularly outward from the base steel. It appears that the surface layer of the zinc coating (zeta layer) is overgrown (too thick) in the dull areas and thinner in the shiny areas. My research indicates that there are several potential causes and remedial steps to ensure a more uniform finish. Steel chemistry Steel with chemistry outside the recommended limits and ranges for galvanizing is known as “reactive steel.” This steel may have higher levels of phosphorous and silicon than is appropriate for an exposed galvanized surface. Steel Mil Certificates indicating phosphorous and silicon content may not be a reliable indicator as the certificates are generally an average of sample pieces and do not necessarily reflect the actual chemistry of each part. The galvanizer should specify steel phosphorous and silicone limits within optimum galvanizing tolerances. The galvanized coating is created through a metallurgical reaction between the steel and the zinc in the galvanizing kettle. For non-reactive steel, the metallurgical reaction is complete within six or seven minutes. After that time, no additional zinc is deposited on the steel. For reactive steel, the coating experiences linear growth with respect to the time it is exposed in the galvanizing tank: the longer reactive steel is left in the galvanizing tank, the thicker the coating. Adding nickel to the galvanizing bath Nickel can be added to the galvanizing bath to help control reactive steels by reducing intermetallic formation. This process is effective as long as the steel has 0.20% silicone content or less. Tin and aluminum can also be added to the galvanizing bath to produce a better overall appearance. Cooling time During hot-dipped galvanizing, the steel is heated to approximately 830 degrees F. Reactive steel continues reacting as long as there is free zinc available and the temperature is 500 degrees F or higher – even when outside the galvanizing bath. This happens when reactive steel on thick, heavy parts is cooled slowly. If the reactive steel consumes the entire eta layer, the zeta intermetallic layer will grow to the surface and will transform the part from shiny to dull as the part cools. When steel is dipped into a quench tank immediately after galvanizing, the temperature of the steel drops several hundred degrees quickly; thus stopping the metallurgic reaction. Quench options include water, chromate and phosphate. Withdrawal speed Withdrawal speed can affect the thickness of the galvanized coating. The faster steel is removed from the galvanizing kettle, the less zinc is able to drain off the steel before solidifying. This means faster withdrawal rates can create thicker coatings. Blasting Blasting is a process whereby abrasive particles are propelled at the steel surface using compressed air. Blasting interferes with the growth of the zeta layer, rather than growing in long columns when the surface is flat. Blasting creates many peaks and valleys so the growing crystals collide and interfere with each other to the point that they cannot continue to grow. The American Galvanizers Association comments that “Blasting is not a replacement for sourcing steel with the recommended chemistry; however, in those times when you must galvanize reactive steel, blasting can help decrease the coating thickness.” Specifications The specifications should make the intent clear to the Galvanizer. For example: FINISH Galvanizing: Hot-dip process ASTM A385-11 (exposed sunshades and trellises) ASTM A123 (concealed locations) typical and ASTM A153 for threaded fasteners performed after fabrication into largest practical section. Weight of coating not less than 2 oz. per sq. ft. of surface. Where damaged, repair surface with one coat of hot process galvanizing repair compound, “Galvalloy”, Galvweldalloy”; or equal. Exposed galvanized fabrication, not scheduled to be field painted shall present a uniform visual appearance. Do not use reactive steel as defined by the A6A. If reactive steel is used as a component, the galvanizer is responsible to take such measures as are required to assure a uniform appearance.Measures may include: Blasting steel prior to galvanizing Adding nickel tin or aluminum to the galvanizing bath Quenching galvanized components to shorten cooling time Limiting the time the steel is in the galvanizing bath. Exposed galvanizer fabrication exhibits excessive variation in finish appearance including color, reflectance or dross inclusions as determined by the Architect shall be rejected. Exposed galvanized hand nails exhibiting rough (not smooth) finish including dross inclusion or other deposits shall be rejected. Conclusion It is critical that the Architect inform the galvanizer to the importance of the visual surface appearance at the second floor terrace gazebos and develop an action plan to assure the final result is as intended. Action plan may include all or some of the following: Specify and obtain non-reactive structural steel. Adding nickel or other elements to the galvanizing bath. Limit time the steel is immersed in the galvanizing bath. Quench the steel for rapid cooling. Slow withdrawal speed to maximize zinc runoff, then quench to cool. Blasting the steel prior to galvanizing. One additional item: the American Galvanizer’s Association web site notes concern that adequate drain holes and vent holes be provided to allow galvanizing the interior of capped tube steel members. Gusset plates may need to be cropped (would require the approval of the Structural Engineer) to ensure unimpeded flow of the galvanizing solution. These features were not included in the gazebo shop drawings. The galvanizer should review the shop drawings and provide input prior to fabrication.
We all own the streets…
I just had a guest opinion editorial published in the Sacramento News and Review, on a topic which is close to home for many of us here at MNA – bicycle and pedestrian safety. A teenage pedestrian was struck and killed by a motorist near West Campus High School recently, and in the inevitable discussion after, I heard far too many expressions that boiled down to caveat emptor, with a subtext of “Teach kids to fear for their lives even when following the law as pedestrians; it’s solely their obligation.” This is leavened with “Damned pedestrians think they own the street: teach ’em they don’t.” But the pedestrians do in fact own the street. So do you. We all own the street, with a legal and moral right to safely use this public-commons resource. Motorists, motorcyclists, motor-scooter riders and bicyclists all have a unique responsibility, tied to their ability to travel very quickly. We are all required, by law, to only progress at a rate of travel which is safe for the conditions. We are required to drive slowly enough to make a safe stop if a kid runs into the street, if another motorist stops short, or if a police cruiser pops out of an alley. There is not a legal right for motorists to progress quickly for their own convenience with little or no regard for others’ safety. There is not a legal right for motorists to have priority on the roads over pedestrians, bicyclists or any other vehicle. If a pedestrian crosses the street legally and safely and a motorist hits them, the motorist is squarely at fault, both legally and morally. When the average motorist begins to understand, accept and act on the responsibility they have in driving—the safe use of the most deadly potential weapon most will ever own—without blaming the victims when the driver errs on the side of speed and convenience at the cost of someone else’s safety, only then will we see a marginal decrease in such incidents. When the typical police response to bicyclist and pedestrian deaths is no longer to blame the victims but rather to find the driver who is both responsible and legally culpable; when that driver is tried for manslaughter, reckless endangerment, reckless driving, gross negligence or other applicable charges; and when this gets publicized, that’s when we’ll see a really significant decrease in these kinds of incidents. I’m looking forward to that day. Here’s a link to the published article: Sacramento News and Review Article: Don’t forget who has right of way… – Gerard
Excellent Street Redevelopment in West Sacramento
David Mogavero says: "...We have the fortune of currently working on two great redevelopment infill projects in West Sacramento. As a result, we are working in the area where the City has just completed a major change of their public realm through reconfiguration of their streets just west of Tower Bridge..."