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Concrete Repairs on Parking Garage Structures

Sample of a Parking Garage

Introduction

Parking garages are very distinct structures form all the other structures out in the world. These structures have large beams and columns and thick slabs that are designed to withstand the daily weight of thousands of heavy vehicles. Furthermore, the vast majority of parking structures are open which means that they are in direct contact with the open air.  The weather and chlorides that are present in the air can lead to long-term effects on the concrete. Due to the aforementioned, owners of concrete parking structures should take special care in monitoring the state of their structure.  Naturally, timely corrective measures  significantly add to the longevity of structures.

Cracks on your concrete parking structure

Cracks on concrete appear due to many different reasons. These reasons range from pouring a bad batch of concrete, to improper curing during the construction process. In other words, its those cracks that are caused by the constant movement, expansion and contraction of the structure and the vehicle traffic.

If you are in a parking garage and you stand still while cars are passing by, you will likely feel yourself vibrating. Of course, this is normal and you shouldn’t be alarmed. The heat and cold cycles of day and night cause the structure to expand and contract.  All these items come together to cause fissures in the concrete on a long-term basis.  It is normal for a concrete parking structure to contain cracks.   Small cracks typically do not constitute a serious structural problem although a review by a structural engineer is always recommended.

In any event, any type of crack should be filled at a minimum.  Your structural engineer will be the person who determines which cracks are serious and which are not. Additionally, the engineer will be the professional that will not only quantify the amount of cracking, but will also provide you with the best method of repair.  Needless to say, engineers have the training and the experience to provide you with guidance on dealing with cracks.  Furthermore, it is beyond the scope of this blog to instruct the regular lay person on the ins and outs of  analyzing a structure.

Concrete spalls on your parking garage

As mentioned above, cracks can pose an immediate serious threat to the structural integrity of the parking structure.   However, cracks can also cause long-term damage to the parking structure in the form of spalling.  This spalling occurs when chlorides seep into the concrete and cause the reinforcing steel inside the concrete to rust, expand, and then rupture the concrete.  Click here for our blog on the definition of a spall. This is of particular note in a parking structure that is not only open to the elements, but also contains cracks where these chlorides can easily access the reinforcing steel and make it rust.

Damage to beams

Parking structures tend to have wide open spaces.  Engineers design parkings to have as few columns as possible so as to avoid any collisions with automobiles.  This means that the engineers must design long beams that span from column to column.  As you might have guessed, the longer the beam, the more stress it takes from the vehicles driving over it.  At times, these beams show outward signs of stress by sagging and cracking.  Concrete beams are critical structural elements in a parking garage.  If you see widespread cracking on a beam, do not hesitate to contact a local structural engineer to inspect it.  Depending on the size, location, and direction of the crack, it could be a tell-tale sign that there is a serious structural failure lurking.

Other types of repairs

If I were to provide a comprehensive list of all the issues that can arise in a concrete parking structure, this blog would be many more pages long.   Cracking and spalling are by far the most common and prevalent issues in a concrete parking garage.  To further illustrate, there are several other types of repairs that are typical and these are as follow:

Water Intrusion

Although parking garages are open structures, we still like to walk to our car without getting wet while we are still inside the structure.  If cracks are large, they will let water seep down into the concrete slab and the water will eventually find its way downward by the force of gravity.  Water that goes through concrete picks up chemicals that can consequently damage the nice paint job on your car.  Furthermore, parking structures also have construction joints and caulk joints that can fail.  If these joints are not properly maintained, they can also fail and cause water to seep to the interior of the structure.

Rusting plates

steel embed
This is a steel embed

Some parking structures are what we call “pre-cast” where many concrete pieces are brought in and welded together in the field.  Each one of these concrete pieces has an “embed” which is a small steel plate where the different pieces make contact and where the welders make the connections to build the structure.  These embeds can rust and sometimes fail.  Needless to say, these failures can lead to catastrophic problems and even collapses.  Although collapses are rare, the owners of these structures should be vigilant and have a professional make periodic inspections on the embeds.

Conclusion

In conclusion, parking structures are very unique types of structures.  They are constantly exposed to the ravages of the weather.  Also, they are subjected to extraordinary stresses from the vehicles that day-in and day-out travel through it. Eventually, failures in the form of cracking and spalling will appear and it is up to the owner of the parking structure to ensure that a maintenance regimen is applied in order to identify these anomalies and cure them.  As mentioned above, a structural engineer is your best line of defense in providing guidance.

This guidance is on the form of an inspection to identify any cracking and spalling that has occurred.    In fact, this professional can also help you in providing you with plans, specifications, and a protocol to perform these repairs.  Engineers that specialize in concrete repair, such as G. Batista & Associates, can guide you through the entire process. This includes obtaining a suitable contractor to perform the repairs.

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Guide on How to Hire An Engineer to do your 40 year Recertification

How to Hire An Engineer to do your 40 year Recertification

The Beginning

You have received your notice in the mail and are asking yourself “what is a 40 Year Recertification?”.  Before you proceed to read this blog, make sure you know what a 40 Year Recertification is first.  Once you know the answer, you can then proceed with the next step.  Obviously, you must find a qualified professional to do this work. This blog will provide you with some guidance.

Finding a Professional

First of all, only qualified people can do 40 Year inspections.  Florida law says that it either a licensed engineer or architect can do the inspection. Obviously, there are many engineers out there than can do the inspection

G. Batista and Associates Books
Hard Hats and Books

and it is up to you to do some homework to find one.  A good place to begin your search is the internet. Although you can use the yellow pages or referrals, Google is the best place to begin the search.  Once on the Google page, you can type in “40 year recertification engineer Broward“. You can change the key words to include the place you live.  You should get several places that market this type of service.

Checking up on the Engineer

Now you are ready to put your investigator hat on.  The first place to check is the (DBPR) Department of Business and Professional Regulations  website.  You can click here to access the site where you can input the name of the inspector and/or the name of the licensed owner of the business.  This will let you know a little bit about the person and if there have been any complaints files against them or even if their license if active.  With this information, now you are ready to make the phone call and ask some smart questions.

Questions to ask the Engineer

Now you need to ask some questions and hopefully get some good answers.  You may want to have a paper and pen ready to jot down the answers so that after you speak to each, you can compare the answers.  Some of the questions may be as follows:

  • Do you carry Errors and Omissions insurance?  Needless to say, the more established and serious firms carry insurance to protect you and protect themselves. This is a good thing to have.
  • Do you have a written proposal that you can send me once I give you the information on my building?  Written proposals are very important.
  • How much do you charge for the inspection?  Do you include a second or third visit after you perform the initial inspection?  Read our blog on how much an inspection costs.
  • What are the payment terms? Can I pay you once the inspection is finished?
  • What is the time frame to do the inspection?

Signing the Contract

Finally, you have found your engineer and are ready to sign the contract.  At times it is important to have your attorney check the contract, especially

Signing the Contractif this is a large and expensive inspection.  The language in the contract should be plain and simple.  As such, you should be able to carefully read it and ask the engineer any questions you may have.  This inspection may be technical, but the contract language does not have to be.  You have every right to ask questions and get good honest answers.

Many contracts require payments up front.  It is normal to pay a portion up front, but try not to pay the whole amount until the inspection is performed.  Finally, you should monitor the progress  of the inspection. Engineers are licensed professionals and are held to a high ethical standard and as such you should not have problems.

Go to our main home page for G. Batista & Associates.

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What is Concrete Spalling?

Choosing the Engineer

Florida is a great place to live.  First, you have the beautiful beaches. Second, you have great weather throughout the year.   Third, you have great architecture that includes art-deco to modern styles.  However, these positive traits come with their fair share of problems.  The high concentration of “salt air” can seep into the  concrete over time.

This is a sample of concrete spallingEventually, the salt air damages the steel inside the concrete and causes it to rust.  Ultimately, this rust causes the concrete to spall.   There are some complex chemical reactions that take place  for a spall to occur, but we will try to keep it simple for those non-engineering types.  As an introduction, the picture shown here is an actual spall.  The classical spalled concrete will show the reinforcing steel (or “rebar“) once the concrete comes loose.

Passivation Layer

Lets start at the very beginning.  When the original builder installs the rebar inside the concrete, it is typically in a pristine condition.  That rebar has a protective layer that is called the “passivation layer”.  Coastal areas have high concentration of salts (chlorides) that penetrate the concrete through microscopic hole in the concrete.  Next, these salts come into contact with the steel and damages the protective “passivation layer” on the rebar.  When this protective layer is gone, the rusting process will begin and will continue over time.  At this point there is very little one can do to stop the rusting.

Concrete Spall defined

Now that there is an expanding piece of steel inside the concrete, it will only be a matter of time until the concrete breaks.  This rupture causes both small and large pieces of concrete to become dislodged.  Those detached pieces of concrete is the spall itself.  Needless to say, concrete spalls are potentially dangerous and even life-threatening.   On high-rise buildings they can damage properties below or even make contact with a person.  Spalling concrete should be repaired as soon as possible since it will spread and get worse.  Eventually, the rusting rebar will render the structure unsafe.

There have been many instances where structural collapses have occurred and people have been severely hurt as a result. Spalling concrete is a sign that your structure is under attack and this sign should not be ignored. Many people kick the can down the road and leave the repairs for a future date.  The old adage of “a stitch in time saves nine” is most certainly true.  A concrete repair that costs $1,000 today, will cost $10,000 a few years from now.

I like to think of spalling as a type of cancer.  In the same way that a cancer can grow until you die, the same is true of a spall.  The exception is that there is no “chemo-therapy” that will cure the spall.  The truth is that the only way to take care of the spall is to remove it using special techniques.  These methods that are employed by contractors to fix spalling concrete is varied and a little complex.  The ICRI (or International Concrete Repair Institute) has very specific guidelines on how concrete spalls are to be repaired.

Structural Engineering 101

Pantheon Dome
This is the pantheon dome

Concrete has been used for thousands of years in various forms. The Romans built magnificent concrete structures that survive to this day, such as the Pantheon, with its impressive concrete dome. The Pantheon (see picture), however does not have any reinforcing steel in it because of its design. The dome’s concrete was always compressed under its own weight. Concrete by itself, without any steel rebar inside of it, can withstand a tremendous amount of this compressive force. On the other hand, concrete cannot withstand a large amount of tensile force, which is the force that wants to pull it apart. Because domes are hardly built these days, the structures that we build today are subjected to both tensile and compressive forces.  Around the turn of the century engineers noticed that if you include reinforcing steel inside the concrete,  it could  withstand  a  tremendous  amount of  tensile  forces in  addition  to compressive forces. This meant that one could now design and build all sorts of structures without being hindered by concrete’s structural limitations. This is how the era of building modern concrete structures began.  As such, without including steel inside your concrete to support the structure, you would not have a soundly-built building.  The reinforcing steel (rebar) inside the concrete literally keeps your entire structure from crumbling to the ground.

Conclusion

To conclude, concrete spalls are a fact of life in Florida where there is a lot of “Salt air” in the atmosphere.  In reality, there is very little one can do to avoid any spalling to happen in a structure.  However, if one follows a typical building maintenance routine, the chances that spalling can be found and identified increases.  Buildings that are painted frequently and are maintained suffer the least from this malady.