Wednesday, June 25, 2008

off reading

Well, it's been a slow time for posting. The sun shines, work beckons, and I have a new book.

Err... make that I have a new e-book reader, with new books on it.

So, I'm off to escape into a good story for a while. But I'll be back!

Saturday, June 21, 2008

Counting a blessing

A friend is one who knows us, but loves us anyway. -- Fr. Jerome Cummings

Mrs. Spit and I are staying with a friend this weekend. We've come to visit and are enjoying the time together.

Having friends so good that I can drop in for a weekend, even though 1/2 that weekend I'm busy with something else and can't visit, is worth more than I can speak of.

I'm also so very happy that they are supportive with the loss of Gabriel, and actually care how we're both doing.

True friends - more valuable than gold.

Tuesday, June 17, 2008

The joy of victory, the agony of defeat.

Roughly this time last year, Mrs. Spit and I were basking in the joy of victory. After years of trying and failing to get pregnant, we had finally succeeded with a little help from our doctor. Heady times, anticipating joining the ranks of parents everywhere.

It was exciting stuff, that morning when the test showed success! We were both jubilant.

A year later, we are still enduring the agony of defeat. It's a long road this, with many twists and turns, ups and downs.

As I was donating blood plasma last night, the nurse assistant was asking me if we were trying again. She was thinking of those stats of so many parents who lost a baby and had another within a year of the loss. We're not in that boat yet. We just starting to seriously consider going down the road again.

The road marked "Pregnancy" is a little more obscured in our life than in many people's. It's not an easy road, either in the finding or in the journey. We will be inundated - ok, Mrs. Spit will be inundated, I'll be along for support - with medical involvement this time. The terms "high risk" "chance of recurrence" "hypertension" "perinatology" will be tossed about like leaves on a brisk fall wind the next time. Instead of overwhelming joy, we can see a sense of reluctance to get too excited, because we've lost one baby already.

This is why I vacillate. Some days I'm ready to try again - immediately. Others, I don't know if I'll ever be ready to try again. It's as much my own pain as the pain of seeing the tribulations that Mrs. Spit has endured. I don't want to see her ever have to go through that again. I promised to love her and protect her - but this is one thing that I can't protect her from.

I know my Gabriel is in Heaven. I know I'll join him someday. This comes to mind every time I hear this new song on the radio by Natasha Bedingfield. I find solace in my own pocket full of sunshine. I've included partial lyrics here:

Natasha Bedingfield - Pocket Full of Sunshine

I got a pocket, got a pocketful of sunshine.
I got a love, and I know that it's all mine.
There's a place that I go,
But nobody knows.
Where the rivers flow,
And I call it home.

And there's no more lies.
In the darkness, there's light.
And nobody cries.
There's only butterflies.

Take me away: A secret place.
A sweet escape: Take me away.

Take me away to better days.
Take me away: A higher place.

Monday, June 16, 2008

It's an Asterix moment

Have you ever read the Asterix comics? I used to love these comics as a kid. I read all of them that were at my local public library. Great stuff.

So why is it an Asterix moment you might ask? Well... as it was a book made for kids, it was done with clean language. But whenever a character did something that merited, shall we say, colourful language, the text turned into a series of great symbols. Even better than the normal character set can produce in this text. Like "Oh %@#$^&( !$#%* @#$%^ that hurt!!!"

So today, I was the recipient of some paperwork from one of my contractors. We'll call them Contractor Garlic. I've dealt with Garlic before in the bridge building experience. It wasn't a pleasant experience once everything was said and done. Lots of mud on lots of people, and I'm not talking the real stuff here. I was glad when we finished that project, to put it mildly. Mrs. Spit would tell you that it one of my most stressful years with work since we've been together.

So, today I got some stuff from Garlic. And what the %^#$ is this ^@#$^^ trying to pull?!?! They know the rules, the contract, and the specifications that form the basis for this job. Yet they are trying to sell a pile of bull^#$* and pass it as Belgian Chocolate.

It's a new project, but it's going to be a LONG flaming four months of dealing with these potlickers (to use a phrase from a colleague of mine). At least we'll be on them like white on rice from day 1, instead of being the nice guys we tried to be the last time we dealt with them.

So, like Asterix. I'm going to be hearing a lot of language this summer that needs a censor before it passes the ears of the little ones of the world. So, like Asterix, I'll smile and nod... and beat the metaphorical snot out of them when they pull these tricks this time! *Sigh* I hate projects like this.

I like Garlic, but not when it goes bad.

Sunday, June 15, 2008

Father's Day...

The day is almost over.

It's been an odd day. I've thought about Gabriel a lot today. As I've done different things today, everywhere there were reminders that today is Father's Day. Radio, TV, shopping, going to lunch with Mrs. Spit - pretty much throughout the day I was reminded that today is the day that we as a culture celebrate fathers.

Today sucked.

I wasn't stuck in the fetal position in the corner trying to make the world just disappear. I didn't run around downtown demanding recognition for all of the men who have lost their children far too soon. I just existed. I did avoid going to church today, because I didn't think I would be able to do so well with all of the kids with their parents.

Mrs. Spit has been awesome today. She was similarly introspective today. She wanted me to have a three-month old baby boy today as well. Alas, Gabriel sits on a shelf near me in my kitchen as I type this - or at least his ashes do.

My son has gone to be with the Son in Heaven. I'll never have more than a fleeting memory of him until I see him again one day. And the worst part is, the world doesn't know that I'm a father just like so many men. I'll never be able to raise my son to be an upstanding man and productive member of society.

Today sucked, and I'm glad it's over.

An impressive author

In these days of the internet opening lines of communication, have you ever noticed that it can be harder to get in contact with someone? Take authors for example. I've seen sites where they say "Mr. X reads all of his emails, but doesn't have the time to respond to every one. Please write anyways, because they like feeling loved and cherished by their fans." And I often think "Sure, and I read all the junk mail that comes to my house as well." Unwanted mail is still unwanted mail.

So, earlier yesterday I was visiting the website of Brandon Sanderson. Brandon is a fairly new author in the Fantasy genre. He's written the book Elantris, along with a trilogy called Mistborn - with book three coming out later this year.

Frankly, I had never heard of him before last fall. There are tons of authors in this genre, and not every one appeals to me. So how did I hear of Brandon? Well, it was in a news release from Tor Books:

Tor announces that the final novel in bestselling Robert Jordan’s legendary Wheel of Time® fantasy series will be completed by author Brandon Sanderson.

New York, NY: Friday, December 7, 2007

Tor Books announced today that novelist Brandon Sanderson has been chosen to finish the final novel in Robert Jordan’s bestselling Wheel of Time fantasy series. Robert Jordan, one of the greatest storytellers of the 20th and early 21st centuries, died September 16th after a courageous battle with the rare blood disease amyloidosis.

Like many other fans of the late, great Robert Jordan, I went "Huh?" Never heard of the guy. But apparently Harriet (RJ's widow) had suggested and approved of him - so done is done. And like so many fans of RJ, I went looking and found out more about Brandon, and read Elantris. It was really good! I'm presently working on Mistborn. Both have made me feel much better about what would come as book 12 in the Wheel of Time. The fact that I knew that he would be working from COPIOUS background information, including an outline for what was to happen in book 12, didn't hurt things.

So, yesterday I was on Brandon's website looking around. Not only does he offer another book for fans to download and read - the book isn't even published yet! He's seemingly beta testing one of his books. This is pretty brave. And he also has the obligatory section about emailing the author - except this one is different than many:

Brandon does try to reply to all of his reader mail. However, all time spent answering email is time he can't be writing, so sometimes he lets himself get backlogged. It may take several months to get a reply!

So I sent him an email, mentioning how I've enjoyed his work very much thus far, and that like many in the Wheel of Time fanbase, I'm EAGERLY awaiting the release of the final book the the rather massive series (11 books, all in the 700-900 pages size). I also had a question, because when I went looking at Amazon, I see that his books aren't available in ebook format. I figured, hey, the guy is offering his book for free in ebook format, why not make some money off of it? Everyone knows about the atypical "starving author" stereotype.

Well, shocker of shocker, I received a response today. Yes, less than a day later, Brandon responded, and at length.

I won't share the whole email, but will offer this from it:

I've been getting a lot of good wishes from Wheel of Time fans, and frankly I'm humbled at how positive and supportive everyone is being. We lost a great man, and I know I can't replace him. But I CAN make sure we all get to read that last book as he intended.

As someone who was truly saddened by the untimely death of Robert Jordan, I am very happy that the person who is trying to finish his work is so equally indebted to him for his contribution to the genre. I am also impressed by how friendly and approachable he is being as he carries this yoke of expectation upon his shoulders.

If you have any enthusiasm for the fantasy genre, I highly recommend Brandon's works thus far. Not only are they great reads, but he's a really nice guy!

Friday, June 13, 2008

more to come...

My delightful wife, Mrs. Spit, was complaining that I haven't done a meme yet - she said that she tagged me on Monday.

To this I made the Scooby Doo confused noise... huh?

I was utterly confused. Looking back at her blog, which I read daily thanks in part to Google's reader app, I saw this:

People I want to know more about:

  1. Mr. Spit

This didn't translate across the ether very well. Another blog I read had this question listed as:
List those who you would like to answer the above questions.

I know there's a difference between men and women and how we communicate. I feel that my Mrs. misses the point here. One of these was obvious... and, sorry dear, it wasn't yours!

So I'll be on this and report back later... sheesh, who knew married life on the interweb could be so hard?

Wednesday, June 11, 2008

The day after the night before...

The blogging will continue when the sleep quotient improves...

Thanks for watching this space! More to come on the bridge building, even though the project is getting handed off next week to a different guy. There's only so much 1 guy can juggle, and this along with the other bridge I'm building this summer would probably have killed me!

And I WON'T miss driving down the cruddy road every day. Man, it was as slick as a field covered in goose droppings today!

So I'm home. Mrs. Spit is happy to have me here, the dogs are thrilled - except that their food is frozen solid. Sorry dogs! Really, you'll live with an empty stomach. Oh yeah, try telling that to the 180 pound mastiff!!!

Monday, June 9, 2008

A tree of tears

Sunday was a pretty dismal weather day. It was cool. It was overcast. The weather forecast was for a deluge.

Mrs. Spit and I were worried. We had up to 30 people coming to our house to be there with us as we planted our Weeping Birch in memory of our infant son. As we left church in the morning and the rain was spitting, I recalled the song by the late Stevie Ray Vaughn - The Sky is Crying. The sky was crying when this master of the electric guitar died in a helicopter crash, and it was crying as we were getting ready to remember the short life that touched our lives and the lives of many of our friends. It's not a coincidence that my lovely gardener wife picked a tree that would be perpetually weeping for our son.

As I think back to that fateful day, exactly 6 months ago yesterday, when the doctors told us that Gabriel would have to be born now, or the love of my life could die as well. I cried. I bawled. Tears ran down my face like a mountain stream. The hopes and dreams of fatherhood had slipped from my fingers, and I couldn't do anything.

Yesterday, we planted our tree. With a group of 20 friends around us, we placed it in the ground, in some good dirt. We shoveled the dirt into the hole, and gave the tree a good drink of water.

We followed with good food shared among everyone. People brought good dishes to go with the slab of roast beast that was on the rotisserie all afternoon.

People left us alone together, tired, but dry. Yes, we spent the whole time in the backyard. The weather held off until just after I got the cover back on the grill. I'd like to think that Gabe standing there, please with the gesture of remembrance that we made. We'll see him seated in Heaven one day. We'll never forget him, even though we were only blessed with his life for a scant thirty minutes.

I can only hope that if we have a next child, that the sky will smile rather than cry for them.

Sunday, June 8, 2008

Tree Day

It's Sunday today. A day of rest.

This morning we will go to church. It will be really quiet. Not because nobody goes to our church, but because today is the church picnic. We're not going. We're not anti-social - just the opposite. Mrs. Spit and I will be having a bunch of friends over to the house later today.

Today is the day that we plant a tree in the backyard in remembrance of our son, Gabriel. The tree is a Young's Weeping Birch. It will have its own little corner in the yard - right next to the garden. I dug the new garden plot yesterday. Peeling off the grass and turning the soil so that we can plant the tree today. Hard work, but memorials shouldn't be easy.

Today I'm sore of body to match the soreness of spirit that I'm feeling.

Saturday, June 7, 2008

I'm discombobulated

Where to go from here.

To try again with a positive attitude, or to accept a negative outlook and give up without trying to have another child.

Having my son Gabriel die due to Mrs. Spit's pre-eclampsia means that we have a pretty decent chance at going through that hell again.

Let's put it this way, in baseball, we'd be pretty damn good batsmen if we were hitting .300. Well, that's roughly our chance of ending up with another bout of pre-e the next time we try for a baby.

Gabriel is dead, and I'm not sure if I even want to try again - except for those times that I'm sure that I want to try again.

I'm feeling tired, exhausted really. And in the midst of it all, I'm feeling discombobulated. I don't know my own mind, and it f'n sucks.

Friday, June 6, 2008

Building a bridge... 7

Time to clear the air about these battered piles and why they are used in addition to the vertical piles. As I mentioned last time, if the piles were not installed properly, the bridge would sink. So, the piles hold up the bridge. But did you know that the piles are also holding up dirt? Before I get dirty, another of Mrs. Spit's favorite enginerd jokes:

Two engineering students were walking across campus when one said, "Where did you get such a great bike?"

The second engineer replied, "Well, I was walking along yesterday minding my own business when a beautiful woman rode up on this bike. She threw the bike to the ground, took off all her clothes and said, "Take what you want."

The second engineer nodded approvingly, "Good choice; the clothes probably wouldn't have fit."

From the top of the piles to the top of the road is a distance of approximately (I say approximately as I don't have the drawings in front of me) 4 metres / 12 feet. On one side of the piles will be the actual bridge girders, bridge deck etc. On the otherside we have the roadway. This is a large volume of compacted earth against a vertical wall. The wall keeps the dirt in place and functions much like a retaining wall.

My boss did his master's thesis on retaining walls, specifically mechanically stabilized earth walls. Thesis. So I'm not going there. What I will say is that the amount of lateral force exerted on a retaining wall increases as a linear function of the height of the wall. In non-math speak, a wall twice as tall as its neighbour will have to resist roughly twice as much earth pressure as the shorted wall. Remember the golden rule? Something has to resist this lateral force.

By driving the front row of piles as battered piles, they will function to carry load in two directions. Most of their strength is in the vertical direction. They will have a portion of their vertical strength reduced and directed at resisting lateral forces. In this way they will help hold up the bridge as well as the road fill next to the abutment.

A key to the photos along with this post. Top: Piles partially embedded with vibro hammer. Middle: view of the new abutment from the old bridge. Bottom: Waiting for the diesel hammer with all of the batter piles vibro'd into the ground.

Thursday, June 5, 2008

Building a bridge... 6

It rained today. Lots. Lightning as well. Usually this is fun to watch. Not quite as much when you're pile driving and the crane is 100' tall. Thankfully, it stayed the heck away from the bridge site! That wasn't funny... onto something that is:

An engineer was crossing a road one day, when a frog called out to him and said, "If you kiss me, I’ll turn into a beautiful princess." He bent over, picked up the frog and put it in his pocket. The frog spoke up again and said, "If you kiss me and turn me back into a beautiful princess, I will stay with you for one week." The engineer took the frog out of his pocket, smiled at it and returned it to the pocket. The frog then cried out, "If you kiss me and turn me back into a princess, I’ll stay with you for one week and do ANYTHING you want." Again, the engineer took the frog out, smiled at it and put it back into his pocket. Finally, the frog asked,

"What is the matter? I’ve told you I’m a beautiful princess, and that I’ll stay with you for one week and do anything you want. Why won’t you kiss me?" The engineer said, "Look, I’m an engineer. I don’t have time for a girlfriend, but a talking frog, now that’s cool."


On to battered piles. Now that we had the back row of piles driven into the ground, it's time to do the front row. This bridge was designed with two rows, with the front row being battered. In engineerese, a battered pile is one that is installed at an angle away from the vertical. For this particular bridge, the front row of piles are installed with a batter of 1 horizontal to 6 vertical. In other words, for every six feet / meters you move up the pile, the pile leans away from the vertical one foot / meter. Or, the pile is installed at an angle or roughly 15 degrees away from the vertical. The photo shows the first pile being set in place. We have not yet started driving. If you compare this photo to the last one in the previous bridge post, you will note that there is another piece to the puzzle that is the driving frame. To aid in keeping the pile in position, the contractor installed another crosspiece welded to the top of the back row of piles. Along with the other steel, this keeps the piles going where we want them to go, instead of wandering all over the river bank.

What's the purpose of a battered pile you might ask? Surely it's not just to look different. Considering that, when the bridge is done, you will never see these pile unless there is a serious problem of scour (another topic for another day) - so why batter them? Pretend that you are a force (think back to high school physics class where your eyes glazed over at the talk of force vectors) and you are being applied to the bridge. Run with me for a minute here... I'll try and not get technical and talk about statics and the strength of materials - at least, not today. The mass of the finished bridge will be bearing on these piles. Albert's good friend, gravity, will be pulling the bridge down onto the earth. Without these piles, the compacted dirt would not be strong enough to hold up the bridge - the bank would fail and the bridge would be in the water, instead of over it. So we drive piles into the ground so that, through a combination of end-bearing and skin friction, they will support the bridge.

Oh dear, more technical terms that I need to explain. End-bearing. Picture a drinking straw. Now picture taking that straw and pushing it into a milkshake. All the way to the bottom. We need a really thick shake for this analogy, so thing of one of the golden arches chemical compositions for this analogy. Once you've gotten the shake all the way to the bottom and you are now pushing against the bottom of the cup - that is analogous to an end bearing pile. The force that you are applying to the straw (you can stop now) is bearing on the end of the straw against the bottom of the cup. All of the force is taken on the end of the straw / pile. Now, picture pushing another straw into the cup, only you are going to stop pushing before you get to the bottom. When you take your hand off of the straw, the straw doesn't sink out of sight, but rather it sits rather stationary. This is because the weight of the straw is being held by the friction of the shake against the surface of the straw. This is skin friction. On a pile, the earth around the pile holds the pile in place by friction. Here in Alberta, most piling is supported by skin friction because the bedrock is far, far, far too deep to design the piles to be end bearing.

Now that that is, hopefully, cleared up - here's where it is significant. So in this bridge our piles are supported by a combination of both mechanisms. Why? We are driving them into some hard clay shale material. Thus there will be a portion of the pile capacity from both bearing mechanisms. The dead weight of the bridge will be held by the piles. Dead weight is the weight of all of the concrete and steel that constitutes the bridge structure. Live load is the force applied by vehicular traffic, the wind, seismic forces, and Marvin the Moose to the bridge. Dead weight generally follows the direction of gravity - straight down. The vertical piles are assumed to function primarily in a vertical direction and don't resist a lot of lateral force.

Remember the golden rule - for every action there is an equal and opposite reaction? Ok, so it's the golden rule of structural science, sorry. For every force, there is a resisting force to counter it. When the resistance is not equal to the force - something has to move. If the piles were not able to resist the force applied to them, the bridge would sink.

And now Mrs. Spit tells me that I've been typing too long, so this will continue next time! Any maybe, if you're nice, I'll finish explaining a battered pile to you! D'oh! So much for trying to not go into too much depth... if you'll pardon the pun. ;-)

Wednesday, June 4, 2008

Building a bridge... 5

Once all of the piles are stood up in the driving frame, it's time to start putting them into the ground. Sometimes the contractor will start straight away with the diesel hammer. This contractor is using the vibro-hammer, as mentioned earlier. In this photo you can see the first 5 piles on the left have been vibrated partially into the ground. It appears that the hard layer that is stopping this system is dropping off to the right, as you can see by the level that the pile tops are at. The vibro-hammer is seen attached to the top of the 6th pile. The contractor tells me that the process is usually faster than we had here. Each pile took roughly an hour to vibrate into the group. Yes, it makes for a really dull day for the inspector when there is no pile driving to count - but I still had to be around in case they started with the diesel hammer. It's an hour drive from town, or 3 hours from home for me.

Here's what the first set of piles looked like once the vibro-hammering was done:

Soon after the picture above, they setup with the diesel hammer to start driving the piles to their final elevation. This is a much faster process. Each pile took about 15 minutes from setup to completion. The picture below shows the contractor setting the leads and hammer onto the next pile to be driven. You can see the old through-truss in the background. In two years, that bridge will be no more, but it makes for a convenient detour for the time being!

After another couple of hours (plus or minus) we can see the contractor removing the diesel hammer from the piles. Each of these piles are now embedded in the ground just over 8.5 m / 28'. They will constitute the back row of piles for this abutment. The second view shows the same piles from a slightly different viewpoint. This is where I'll leave off until it's time to put in the battered piles. And no, this has nothing to do with baking! (I know someone is thinking about that... come on, you can admit it! ;-D )

Tuesday, June 3, 2008

In lieu of my son

While I'm enjoying the series I'm doing on building a bridge, I'm feeling rather melancholy about the whole thing at the same time.

You see, as I detail the process of building a bridge, I'm surprising myself at how much I can talk about it. I know, some people find it boring, but then - I'm not very well versed in the world of knitting and I still read Mrs. Spit's blog! (love you dear!)

The thing is... I can't help but think of the enjoyment that I would have taken in teaching my son about the world, and about the little corner of it that constitutes my job.

I continue to mourn the future that I will never have here on Earth with Gabe. Everything about his time cooking in the oven, I could only dream of what I would do my my child once they came. When Gabriel was born and died, so too did my dreams of a future with him die in that delivery room.

I miss you Gabe. I'm so glad that you Mom lived, because this life would suck so much worse if I had lost you both.

Building a bridge... 4

We are still talking about installing the piles that form the foundation for this bridge. I know, it seems like it's taking forever, doesn't it? Trust me - I know! It truly is taking forever! But, like any good craftsman/woman knows, a good setup makes the final job a better product. I have to hand it to my piling contractor - they take their time to get a good setup nailed before applying hammer to pile.

Speaking of hammers, let's take a look at one:What you can see here is a diesel hammer and the pile driving leads. When in operation, the hammer rides up and down on the upper steel members of the leads. The purpose of the leads is to hold the hammer in position as it works. In addition, they are used to control and align the pile while it is being driven.

A diesel hammer is a pretty simple piece of kit. The functional parts are the helmet, the cylinder, the piston, the mechanism for spraying diesel into the chamber, and the exhaust. The helmet is the piece that actually rests on the top of the steel pile. It looks like an over-sized bottle cap. The pile fits inside the helmet. In this way, the pile is kept in place and is unable to fall over if there is no other support in place for the pile. However, this contractor has some serious support, as you will see in a moment or three. The cylinder assembly rests on top of the helmet. The cylinder is a heavy duty steel jacket that contains the combustion chamber. Picture taking an diesel engine, removing a single cylinder with the piston, and then super-sizing it. The piston doubles as the actual hammer. On this unit it weighs around 1800 kg. The whole assembly is around 20' / 6 m long, and with the leads it weighs roughly 9,000 kg.

How does it work? Glad you asked. Once the leads with the hammer are in place over the pile, the cylinder is manually raised up and mostly out of the cylinder (about 50% stays inside the unit. The method for this varies, either the crane lifts it or a hydraulic assembly internal to the hammer is used to raise it. Once at the extent of normal travel, the hammer is tripped and it falls to the bottom of the cylinder. As it reaches the bottom, a spray of diesel is injected into the chamber. The air is superheated by the compression, which then ignites the diesel, which fires sending the piston up and out. The process then repeats until it is stopped. The only difference between this and the diesel engine in my Jetta is that the cylinder head and the piston in my car don't make contact. When the piston hits the bottom of the cylinder in the hammer, the force of that impact is transmitted directly to the pile. This is where the "hammer" part of the name comes into effect. More on the actual hammering in a future post.

Now, we were talking about the setup for pile driving. In this shot, taken at max zoom from my little camera from across the river, you can see the contractor setting up temporary piles. These piles will be used as supports for the cross members of the pile driving frame. The piles are being installed with a vibro-hammer. Instead of a hammer actually hitting the piles, this grasps the top of the piles in a clamp. A hydraulically actuated eccentric weight in the hammer then rotates at a good rate. This has the effect of making rapid small impacts on the pile, vibrating it and the ground below, vibrating it into the ground. If you've ever seen the effect on granular material (silt/sand/gravel) when a vibration is applied to it - this is the same thing, up-sized.

So, I was mentioning the driving frame. Earlier you saw it getting prepared for install. Here you can see it in place, with a couple of piles stood up in it. They are resting on the ground. About 34' of pile is hanging in the wind above the frame. Even with that, they are held securely in place prior to the commencement of driving operations. Our friend the welder is working on the angle iron brackets that hold the piles from moving laterally during driving. The advantage of this sort of system is that there is very little movement of the piles, and their position can be managed quite effectively. How accurate do they need to be? Well, our friends in the Alberta government allow a tolerance of +/- 50 mm. Yes, they allow the piles to be out of position in the horizontal plane by a total just shy of 2 whole inches. This would be part of the reasoning for getting a surveyor to locate the pile locations. You don't want them in the wrong place!

Monday, June 2, 2008

Building a bridge... 3

When last we left you, we had the abutment area excavated and the pile locations laid out. Now it's time for pile driving. But first, this message:

Hello. My name is Mr. Spit, and my wife approves of this joke:

An architect, an artist and an engineer were discussing whether it was better to spend time with the wife or a mistress. The architect said he enjoyed time with his wife, building a solid foundation for an enduring relationship. The artist said he enjoyed time with his mistress, because of the passion and mystery he found there. The engineer said, "I like both."


Engineer: "Yeah. If you have a wife and a mistress, they will each assume you are spending time with the other woman, and you can go to the lab and get some work done."

Back to the narrative...

The piles in question for this bridge are HP310x63. I know, outside the world of heavy construction, this looks like so much code. Unlike people's commonly held misconception, we don't use "I" beams anymore. Though the steel might look like an "I", it's really more of an "H" shape nowadays. So, the piles are HP type (it's a steel thing, these are under the category HP in the Canadian Institute of Steel Construction) lengths of steel. These are 12.192 m / 40' long. The 250 refers to the nominal depth of 250 mm / 10", and the 63 tells us that this steel weighs in at 63 kilograms per metre. So the designation says that we are using standard lengths of steel that weigh in at roughly 3/4 of a metric tonne. In reality, this is a fairly small piece of steel for a bridge. As a result, as this bridge has some hard material below the regular dirt, we need to reinforce the ends of the piles. If you look at the photo, there are plates welded onto the ends of the piles for just this purpose. This strengthens the pile so that when we drive them into hard shale they will not be damaged. Damaging the primary foundation for a bridge? Not a cool thing... so we reinforce...

Now, during pile driving, it is the job of the engineer to monitor the progress of the steel into the ground. The government is rather sticky about maintaining records of pile driving. They want to come back in 50 years and know how deep the foundation runs, and as well, how much strength they can expect from the foundation when they change the legal loads that can drive across the bridge. How is this done? That stalwart of mathematical prowess... counting. Yeah, I'm serious! We count how many times the pile gets hit with the hammer. We monitor how many of these blows occur for every 0.25 m of the length of the pile. How do we do this? We talk nicely to the Contractor, and they measure out and mark the piles with this interval. During driving, I stand nearby and do the counting, recording it for each pile. It's remarkably easy - when things are going well. It's only when something weird happens that this becomes difficult. Thankfully, this isn't that often.

The last important aspect of pile driving is to keep the piles properly aligned in their proper locations and relative positions. This is done using a driving frame. In this photo, you can see a welder setting up the primary frame for this bridge. It is basically a couple of heavyweight H-beams connected with angle iron along the length and H-beams chunks at the ends. The angle iron is placed such that when the piles are placed between them, they will be held at the spacing required by the design. In this case, the spacing between piles is 1600 mm.

Next time I'll go into the actual setting up of the frame and getting started on pile driving.

Sunday, June 1, 2008

Building a bridge... 2

The last post gave some background on the big bridge. Of course, we've now moved onto construction. As mentioned, we can't start on the pier construction until summer. However, this has no effect on our ability to build the abutments.

What's an abutment? Glad you asked. It's where the bridge abuts on the ground. Every bridge has two abutments. These are the ends of the bridge where the load from the bridge is transferred to the ground. Bridge foundations generally have abutments and, if they are more than one span, piers. At these locations the bridge deck load is transfered to the foundation substructure, and thence to the earth. I say this in a general way, because there are different systems for carrying the bridge deck. The deck is the system that carries traffic across the bridge. The substructure is everything below the bearings. And the bearings are what supports the bridge girders on top of the substructure. Lastly, the substructure rests on a foundation. So, bottom to top we have the foundation, the substructure, the superstructure (includes the bearings and load carrying elements), and the traffic. Pretty simple - right?

Sure, and we all love math and physics and go by the term - enginerd. At least, everyone that I work with in my office does!

Moving along before my sense of humour fails to tickle your funny bone. Here's an applicable joke to sate you before the dirt moving starts:

As priest, a doctor, and an engineer were waiting one morning for a particularly slow group of golfers.

Engineer: What's with these guys? We must have been waiting for 15 minutes!

Doctor: I don't know, but I've never seen such ineptitude!

Priest: Hey, here comes the greenskeeper. Let's have a word with him.

Priest: Hi George. Say, George, what's with that group ahead of us? They're rather slow aren't they?

George: Oh yes. That's a group of blind fire fighters. They lost their sight while saving our club house last year. So we let them play here anytime free of charge!


Priest: That's so sad. I think I will say a special prayer for them tonight.

Doctor: Good idea. And I'm going to contact my ophthalmologist buddy and see if there's anything he can do for them.

Engineer: Why can't these guys play at night?

Now that you've got a better idea of the engineer's mindset, let's carry on.

Mr. Contractor showed up onsite and proceeded to tear apart the lovely job of roadbuilding that was performed several years ago. For, while the slopes comply with the design in every way - they don't have space for the abutments. For while the road was built to grade, the slopes don't have any allowance for the roughly 3 m / 10 ' depth of abutment structure, girders, and deck that have to be build.

The eagle eyed among you will notice that the gravel bar has disappeared. It rained a couple days before this photo and presto - the water has gone up. Isn't nature grand? The hillside has been excavated for two purposes. 1) to expose the ground to a level just below the final depth of concrete that will be placed for the abutments, as this corresponds to the level just below the top of the steel piles that will carry one quarter of the weight of the bridge. 2) a ramp was built to enable the pile driving contractor to access the abutment area to drive the piles.

Here's a closer look:The surveyor has laid out the locations of the 14 steel H-piles that will be driven into the ground to support the abutment. In a month or so, this will be a seething mass of reinforcing steel prior to the concrete pour.

That's all for today. If you're interested in where in the world this is, punch the following into Google Earth: 53.16361N,115.9114W and you'll be taken to an aerial view straight away.