Archive for the ‘Civil Engineering’ Category
Providing Alternative Energy by Alternative Means
Underwater line transmission on the Trans Bay Cable project in the San Francisco Bay Area.
Alternative energy is all the rage these days with everything from salt water desalination to cellulose being suggested as potential sources of energy. But when it comes to ways to deliver that energy to consumers, power utilities have been mostly on land transmission lines carried over transmission towers.
These towers have been controversial not only for their aesthetic effect but more important, their health effects. The high voltage carried by the lines cause them to emit EMF waves which have been known to cause adverse health effects.
As a result, power companies are re-thinking their modes of transmission in this New York Times article.
One such company is Transmission Developers (based in Toronto, Canada), which is focusing on underwater transmission line projects that can eliminate the need for transmission towers on land.
Underwater installation even has the cautious support of environmental groups, which have vehemently protested against transmission via land. The biggest environmental impact so far seems to be potential industrial pollutants being disturbed into the water during installation.
The cost of underwater transmission is comparable to land transmission (approx. $10M/mile vs. $1-4M/mile, respectively). Some of the additional cost is used to convert the energy to DC current (which is easier to transport in underwater cables), and may be offset when the line help open up new markets traditionally served only by land transmission lines.
Locally here in the Bay Area, the Trans Bay Cable project laid 33 miles of underwater transmission line to connect the power grid.
In conclusion, it looks like power companies are getting serious about not only greening their energy sources but transmission as well.
Nearing the Light in the Tunnel at Devil’s Slide
Taking Hwy 1 underground between Pacifica and Montara.
The much-anticipated Devil’s Slide tunnel project may soon reach the light at the end of the tunnel (literally). Work crews have been rotating between shifts to maintain a 24-hour production schedule.
The project moved ahead after numerous land slides in recent years that have posed a serious safety issue to drivers and cause the roadway to be closed during repairs (not to mention cost for emergency repairs).
According to the Caltrans website, the two tunnels will connect Hwy 1 between Pacifica and Montata, running about 4200-ft. (about three-quarters of a mile) in length. Construction was sequenced the two bores to be 60 yards apart so there would be no damaged between the bores due to blasting to remove rock.
The Monterey Herald covered the story in a brief article, citing project completion in fall of this year.
The project incorporates not only the tunnels but a bridge (super structure) approach into the tunnels and roadway re-alignment of Hwy 1. Inside the tunnels, electrical, metering and ventilation systems will regulate vital systems such as air monitoring for drivers.
The New Austrian Tunneling Method is used for the tunnel boring operation, relying on the strength of surrounding rock and shotcrete walls behind it to maintain the integrity of the tunnel during and after construction.
If operations run smoothly, Caltrans will indeed again be living up to its slogan of “improving mobility across California”.
Making Smart Buildings Smarter
Looking to computers to give buildings their brain.
Smart buildings have grown from buzzword to reality as their mechanical systems have grown increasingly automated.
They are called smart for their ability to regular HVAC systems, lighting and even elevator loads as in the case of the newly opened Burj Dubai.
Although smart buildings have come a long way, they are becoming dated in the way their systems transfer data and allowing for upgrades.
An article in the Journal of Commerce points out that designer should look to the Internet on making smart buildings smarter. The concept began with smart grids developed by power utilities that can regulate demand and help stabilize the system during peak demand.
Researchers in the energy field suggest that similar systems should be used for buildings, which is how computers connect and form the Internet. Rather collecting all building systems in one central location be monitored as is the current common practice, sensors can be installed within building systems to communicate to each other to create an intranet of sensors.
Current building design, however, are geared towards centralized systems – hence the terms such as central heating, which are controlled by a thermostat. Adding networking sensors would be prohibitively expensive, and the Journal of Commerce article cites a number of $1000 to install a $1 sensor within centralized systems.
The vision that researchers imagine is where the smart grid providing power to a building will communicate within sensors. Not only will the sensors gather data real-time, they will also transfer data to the smart grid to adjust power loading.
Although this may still be some time away, this concept has upstart the idea of centralizing building system controls and open it up for re-consideration towards truly smart buildings.
