High-rise building codes & standards for Nova Counties (Arlington, Alexandria: 2013, apartment)

[GustavoFring]

Can anyone provide me with a link or a concise summary of the basic construction requirements for high-rises in Arlington, Fairfax and Alexandria counties? DC would be great too, but I know this is just a Nova Forum. I'm basically interested in knowing what sort of requirements for framing (steel vs concrete reinforced) and other structural rigidity requirements. I've found each county's webpage that has the information buried deep in there, but given that I'm not a structural Engineer. I was hoping someone could give it to me in laymen terms.

Thanks!

[GustavoFring]

What I'm trying to avoid is this..

https://en.wikipedia.org/wiki/Skyline_Towers_collapse

It looks like this building does not contain a steel frame (I think). The cause of this was premature removal of concrete forms before the floors had completely set. While that wouldn't be a concern in a completed building, the Earthquake last year proved that this area is susceptible to at least moderate tremors, so I'd like to do my research and only buy into a building that would be more likely to withstand the (rare) moderate earthquake.

[g3org3]

The entire state follows the same code (although interpretation can vary). It's not a concise summary, but here it is: Virginia Department of Housing and Community Development - State Building Codes and Regulations (http://www.dhcd.virginia.gov/StateBuildingCodesandRegulations/Virginia_Uniform_Statewide_Building_Code.htm - broken link)
Personally, if earthquakes were a major concern, I'd avoid steel and concrete and look for wood.

[irvine]

There are plenty of reinforced concrete frame buildings in Los Angeles that have survived many earthquakes. The same for the late 19th and early 20th century unreinforced masonry buildings throughout the city. There is however a very real risk of structural failure of the unreinforced masonry buildings in particular.

In the DC area I wouldn't worry at all. Earthquakes here will never cause the damage it has and could cause in other US cities like LA, St. Louis, San Fransisco, etc. The building codes in this area are designed around the local conditions.

[NC211]

There is no way you're going to get a solid answer to this question on a web forum. Call an engineering firm, architect, or major general contractor. They'd tell you. Lazard, Clark, HITT, etc.

That being said, if you're building in CBD DC, better check your height and site lines to sensitive
government facilities, unless you want a nice little visit from the secret service. More than one balcony on a trophy office building with views of the Capitol building,
WH, etc have been closed down due to sniper security issues.

[GustavoFring]

Originally Posted by NC211

There is no way you're going to get a solid answer to this question on a web forum. Call an engineering firm, architect, or major general contractor. They'd tell you. Lazard, Clark, HITT, etc.

That being said, if you're building in CBD DC, better check your height and site lines to sensitive
government facilities, unless you want a nice little visit from the secret service. More than one balcony on a trophy office building with views of the Capitol building,
WH, etc have been closed down due to sniper security issues.

I'm not going to be building anything, I'm just someone who likes living in high rises and want to know a bit about the building before buying into one.

[NC211]

Ahhh, ok, my apologies!

Your biggest risk of harm in an apartment building isn't earthquake, but fire. That being said, fire is an element of design that is taken very seriously around here. I'd be comfortable in a newly built or renovated apartment building that was built or renovated durin the past decade.

[tysonsengineer]

Originally Posted by GustavoFring

I'm not going to be building anything, I'm just someone who likes living in high rises and want to know a bit about the building before buying into one.

As a civil engineer, I can assure you nothing like that picture happens in Virginia. We are in a a low seismic zone historically (over the past 50 million years). USGS Map

Regardless our design event on load is never as much of a factor as wind load, snow load, water load, dead loads, and live loads which drive the design. What does this mean? many of the same structural components that go into high seismic zones are provided for high rises in this region already, they are simply provided for different reasons. While we don't get large earthquakes we do get sizeable wind events which also require strengthening of shear wall designs (ie big ass steel reinforced columns for high rises).

Additionally, one should note that the soil formation has much more impact on a buildings stability during an event than the actual strength of the earthquake. If you look at the 5.5 event this past summer, if that event were to happen in San Fran bay, it would have dire damage due to the presence of marine fills and sands which become a slurry mush when the earth begins to shake. Instead, on the east coast, we have significant bedrock and clays which actually keep our building foundations stable during earthquakes. All of this again reduces the design constraints for earthquake events, which just means the design is more driven by other design events.

Lastly, when you see collapsed buildings like that, they either predate international building codes which have gotten reaaaaaally damn good in the past 30 years at preventing collapses, or they were built ignoring those codes. In the US it's basically impossible to build a structure without it meeting codes. During the construction of a high rise you have nearly 10 times more presence of inspector than the equivalent inspections required per square foot of single family detached. Every bolt, girder, and column is certified individually to assure the structural capabilities. Theres also masssssive amounts of redundancy in the design provided in order to assure even if one component is missed(which it wont be) it would be covered by 4 other redundant functions.

Empirically you can see how well the new codes work when you look at the Japan earthquake. In a huge historically significant earthquake, no high rise buildings collapsed, the damage came from low rise buildings and the tsunami of course.

The key will be how old is your building, was it built with monolithic concrete poured columns or steel reinforced, and is it located along a waterway?

If it was built after 1980 in the US you are safer in it than you are in any single family home.


Last note, the example you show was an issue during construction itself. The contractor removed a temporary element which had to remain until the complete skeleton of the building could support its own weight and the foundation was filled back in with earth which would have created the passive force to hold up the structure. Unfortunately the contractor made the huge mistake of removing that shoring prematurely which caused the collapse. This of course would not be an issue in a finished built building as you would not have anyone messing around with the foundation of the building. Additionally, if anyone was, new regulations require full structural analysis anywhere near other existing buildings to ensure they're foundations are not compromised by external construction.

[tysonsengineer]

PS if anyone ever needs a site civil around here

------> all this engineering knowledge could be purchased from me via contract :P seeing as I am still a practicing engineer. Admittedly I am not a structural engineer, so please dont come to me with a building structural project, stick to transportation, environmental, water resources, and land development and I'm your man.

[Fundman]

A concrete high rise apartment building is far safer than a low-rise building. The 3 and 4 story buildings are made of wood and fire is a real concern since it will spread for unit to unit very quickly.