Building a Bridge - Construction Part Two - Earthwork

On most projects, some type of earthwork is being performed during much of the project. Approaches may need embankment to reach the grade required for the abutments, or the subgrade may need the vegetation stripped, drainage concerns addressed, or something as exotic as a wick drain. It requires a foreman, or superintendent with a good knowledge of manipulating soil, and building a strong roadbed.

 If a wick drain is required, an excavator vibrates tubes into the ground to a target depth to allow water to be forced up when embankment is placed. A suitable drain strata is necessary to allow the water to escape, geotextile fabric may be placed before the embankment is placed and the embankment is placed in lifts over the area with wick drains. Eventually the heavy fill displaces the water. This allows the fill to not be compromised by excess water. On really swampy ground, the hydraulic fill may be placed above the final grade, the ground may sit for years, and the settling embankment eventually becomes stable. On one large project I watched, much of the saturated soil under the new embankment heaved outside the roadbed, and was eventually removed. The settlement was in feet. Although the embankment was placed decades ago, the roadbed is still sound, and thousands of vehicles travel the roadway daily. Even a direct hit from a hurricane didn't disturb the road.

The placing of embankment is more complex than just dumping dirt, and grading. Embankment is first tested for suitability. The testing involves determining the plasticity, optimum moisture, and thickness required to support the paving. Also, existing embankment is tested to determine if it can remain under the proposed fill. On some projects, grade profiles, with testing,  might indicate the embankment is all on site, and all that needs to be done is to place it in the correct position. This may require earthmovers, or excavators with dump trucks. Regardless of how the embankment is manipulated, fill requires placing the material in lifts, which usually is 12 inches or less. Eight inches is the usual rule of thumb, and exceeding the depth may cause a failure in compaction, scarifying the material, and re-compaction. On one project I was working, the material lifts weren't tested, the contractor continued their operation, and three feet later, when the inspector ran densities into the lower lifts, the material failed. The solution was pushing all the covering fill to the side, reworking all the material, and egg on the face of the contractor. At the time, I had the feeling the contractor was trying to pull a fast one, and was caught. I never knew, but the correction was obviously expensive.

All vegetation is required to be moved before any embankment is placed. The stripped material (usually 4 to 6 inches)may be hauled away, or stockpiled, for the final finish at the end of the project. The exposed subgrade is scarified to insure a good bond between the materials. Not performing this part of the requirement will lead to a layer of material that will never compact, delamination, or both. Delaminated embankment will slip and cause cracks, voids, or both. That, and if it's discovered, the new material will be removed at the expense of the contractor.

On some projects, the embankment is mixed with lime to consolidate and dry the material. For projects in urban areas, the lime is placed as a slurry. In open areas, the lime may be placed dry as a powder, or in a pellet form. Regardless of how it's placed, the usual percentage of lime is around 6% by volume, and requires large mixers (Like a large self-propelled garden tiller) water trucks, earthmoving equipment, and compactors. Mixing is to a depth two inches below the projected subgrade elevation. The material is checked for the lime content before the operation is complete. Failing to introduce the right amount of lime will lead to repeating the operation until successful. On a project, failing to place the correct amount is frowned upon. Continued failures lead to new supervisors. 

Placing lime with a slurry is probably the best method, since yield isn't affected by loss by wind, and removes the nuisance factor of lime dust. It can be delivered by transports in a slurry, or dry to be mixed in smaller trucks on site. A slurry pump is usually hooked to a fire hydrant, or a water pump for mixing on site. I doubt there are a few dozen of people in any state that have the experience to mix slurry on a project , and my near past experience shows transports of slurry being dumped on site. I've never figured the cost difference, but feel the difference isn't worth the problems.

Transports are great, until an exuberant dozer operator yanks the axle from under the truck hauling the lime. The operation comes to a halt, someone will probably get lime burns trying to the fix the truck, and finger pointing starts for the charges. A good operation has a basically firm bed to start with, so the transports only need a little help to pull through the subgrade  to prevent tire slippage. Spreading the slurry at the right speed removes the need to make another pass in the same location. Dragging lime transports is a delicate operation, and damaging one can be expensive.

Mixing is required to consolidate the material. Over days, the mixers eventually turn the mixed soil to a fine grain, the dozer, or motor graders, shape it to grade, and the compactors make continuous passes to compact the embankment. After compaction is reached, water trucks keep the embankment wet for three days. 

Embankment rarely has the optimum moisture content. If it's too wet, it will track, pump and fail the compaction test. If it's too dry, it will not reach compaction. To remove moisture, only blade mixing with a road grader may be all that's needed. Blade mixing is grading up a windrow on the edge, blading the windrow back and forth, and hoping the material becomes dry enough to be compacted to specifications. After two days of frustration one project, I was forced to rent a mixer to break a heavy clay small enough to dry. My boss didn't like it, but realized it was the necessary solution.

 Too dry of material is windrowed, sprinkled with water from a water truck, and either blade mixed, or mixed with a mixer. When the moisture is correct, compacters pack the material, and the motor graders fine tune the grade. Good crews make the process look easy. Bad crew make a mess, when they get some sections too wet, and others too dry. The goal is to get the material equally hydrated, and a good water truck driver can distribute the right amount of water in one pass. 

Compacters for embankment usually have pads, or sheepfoot studs. When optimum moisture is reached, the pads eventually "walk" out of the material, while motor graders sweep enough material across the roadbed to keep the indentions filled. When complete, the pads don't sink, and only leave a surface mark on the material. At this point, it's imperative to get the grade to the correct elevations. Failing to do so, might lead to the necessity of scarifying the material again, re-grading, and compaction. Good clays get as hard as concrete when compacted at the correct moisture. Trying to just cut enough material to make grade can lead to the blade only skidding on the surface, a loud squalling, and a frustrated operator.

Embankment may be needed to form a subgrade for construction activities, or to fill to an elevation ready for pile driving. I worked on one project where the embankment supervisor crossed up up with the bridge supervisor. The embankment supervisor wanted to continue his operation into the work area of the bridge supervisor, which the bridge supervisor had "homesteaded". His laydown area was to his liking, and access was good from a nearby road. The embankment would ruin the arrangement, and the bridge supervisor would need to stop production for a day to rearrange the area. The embankment supervisor go his wish. The bridge supervisor was far from happy, which he showed with expletives, threats, and some stomping around. In the end, I felt the embankment supervisor was over his head. Allowing a few hundred feet of space from the edge of a bridge at grade offers the opportunity to adjust the final grade of the road to compensate for minor errors in the bridge elevations. How do I know? I saw it happen before, and manipulating dirt is much cheaper than trying to adjust grade with an asphalt bond breaker, or concrete. The same embankment foreman showed his ignorance many times during the project, and was eventually let go, when the project was finished. If I hadn't been the subcontractor, and was the supervisor for the prime contractor, I wouldn't have hired him. I had experience with him before, and had no confidence with his work.

With the embankment operation in progress, pile driving is more than necessary to complete. That requires another post. 

Dementia, and a Personal Observation

My mother had dementia. Although the term is misused, and sometimes used as a derogatory description, it's a natural part of aging. Some have symptoms that require close observation, and help, while others are only marginally affected. Still, everyone is affected as they age. 

I had no idea my mother was starting to struggle with dementia, until I spent a long time with her. I moved in, after separating with my soon to be ex-wife. My mother wasn't eating enough, and after watching her, I realized much of her apparent cognizance was due to her rigid schedule. Operating on auto-pilot is the best description. Her day was set, her travels were set, and variances from either were stressful. 

Over time, I realized our conversations were rich in past events. She remembered things of her youth with clarity, but after answering the same questions over a few short minutes, I realized I had to throw away my impatience. She was unaware of her loss of short term memory, and if I had said anything, it would have only caused anxiety. She didn't need anymore stress. Life was getting short, and she needed to have the most dignity allowed. 

My mother became dehydrated. A trip to the doctor for her dizziness led to immediate hospitalization. My brother notified me at work, so I went to the hospital to check on her. She was sleeping comfortably, so I left her, and returned to see her the next morning. She was up, cheerful, and her doctor was in the room with her. they joked with each other, he left, she looked at me, and asked where I was. Either she had her names confused, or she was unaware of who I was. I immediately found her doctor, explained what happened, and he set up an appointment with a neurologist. A minor stoke was suspected. Months later, while talking to her cardiologist, he told me he didn't think she had a minor stroke, and the dehydration only increased he dementia.

Long story short, the neurologist was a waste of time. He couldn't perform the necessary tests, since my mother had a pacemaker. His fumbling around, and wanting to stretch out the visits only made me think he had a good insurance patient, and some cash flow. That, and my mother couldn't stand him. Her hearing loss, his soft voice, and basically ignoring her while talking to me, was infuriating. To make things worse, on our next to the last visit, we waited for two hours, only to have the nurse inform us the doctor was handling an emergency, and we would have to reschedule. The last visit revealed he really didn't have clue, but he wanted us to return in six months to assess whether she had any improvement. A first year resident could have seen her improvements, so we decided enough was enough. 

Over about a year, my mother stopped going to her Wednesday bridge group. I didn't ask why, but knew it became too much of a metal challenge. I would do most of her grocery shopping, and cook for her. After a minor car wreck, I realized it might be time to stop her from driving. Before that was necessary, she broke her hip. I was appalled, since I was standing next to her, when she went to pull her chair up at the table. In the emergency room, after I explaining to a nurse how my mother fell, she said "She didn't fall and break her hip; her hip broke, and she fell." It was reassuring, but I still felt guilt. After all the times I worried about such a thing happening, I was right there when it happened. 

A doctor explained to my mother, and I, there were only two options. One was doing nothing, but my mother would spend the rest of her life basically bedridden. The other was a hip replacement, which had a good prognosis, since it would allow her mobility after therapy. The decision was the replacement. 

An anesthesiologist approached me before the surgery to explain anesthesia can cause a worsening of dementia, and the increased dementia wouldn't become better. At that time, with few options, I crossed my fingers and prayed for the best. 

The surgery went well, but the dementia was worse, and my mother needed more care than I could offer. I had a job, and all the relatives that helped were in the same situation. After therapy at the hospital, she was released, and I moved her to a retirement home. 

My mother had volunteered at the retirement home for years. Everyone knew her, the director was more than reassuring, and my concerns left after a few days of her being there. She had her meals, the staff were friends, and she seemed happy. That was a relief. Her dementia was increasing, and knowing she wouldn't be neglected, and between my cousin, and I, she had a family member closely monitoring her care. Her therapy was taken care of daily, and I had the hope she would one day be able to regain her mobility, and could go home.

After about two weeks, a consultant with the group performing therapy approached me to talk. She suggested hospice, since she too had seen how my mother had no idea why those people were coming in every day to cause her pain. An explanation of how she had broken her hip led to her surprise and and a question: "I broke my hip?" This was on a Friday, and the consultant told me she would start the arrangements for hospice care at her room. 

On Saturday evening, my mother didn't seem to be hungry. She had only had a bottle of Ensure in the morning, and wouldn't eat her lunch. She wouldn't open her eyes during our limited conversation, and an effort to give her a spoon of her meal ended when she fell asleep. I used a napkin to remove the food from her mouth, and stayed with her most of the night. My cousin stayed with her the next day so I could work that night. I had a crew to run on a night project, and my days, and nights, were soon to be a little crazy. 

Monday morning arrived, and I arrived to check on my mother. She still wouldn't eat, and only briefly awoke to speak with me. I stayed as long as I could, but had to get some sleep for work that night. It wasn't enough, and the long night at work left me exhausted. I had talked to my cousin, and the report my mother was still mostly sleeping, and not eating, led to more concern. 

I arrived home after seven Tuesday morning, took a shower, set my clock for 11:00 am, and tried to catch a few hours of sleep before I went to see my mother. At 10:00 am, I was awakened by a phone call. It was a caretaker at the home. My mother had passed. It was over. and I was relieved she had some dignity during her last few days.

I've written a long post, and somewhat wandered away from the original inspiration for writing. I was thinking about the President, his obvious dementia, and delving into my experience to solidify my opinion. While I'm not a professional in the medical field, my experience with my mother left me with a perspective on those with dementia. The subtle signs can easily be missed, but the fumbling of words, forgetting of names, confusion, and dependence on others is far more than subtle. How the medical profession doesn't become vocal about the condition of the man that is not mentally capable to run a country is beyond me. That, and even an in-patient procedure requiring anesthesia may leave him in a condition where the Vice President will be in charge. 

So, here we are. How history reports this era is yet to be seen, but even before the election, Biden was showing signs of dementia. That, and he was hidden from those that needed to know his positions. Regardless of how this is all perceived, I can't begin to believe there was an honest election, or that Biden had anything more than a small minority of people to support him.

I can only do what I can, hope for the best, and pray those so willing to sacrifice a country for tyrannical power are severely punished for their actions. Hopefully, enough feel the same, and the efforts to destroy the United States will end.  

Building a Bridge - Construction Part 1 - Getting Started

After a contractor is notified they won a bid, a few things happen over the month, or longer, period before the ground is broken. First is the getting all the submittals for materials, subcontractors, EEO paperwork, insurance certificates, and any special designs, such as a falsework plans. I have no idea how many in a large company are delegated to this task, but know smaller companies may have only a few. During my career, it could be a daunting task, since I worked for a small company, and had other things to do, but it was part of my job description. Bidding was too, but it wasn't full time. There were way too many pieces of paper to be accumulated, and too much of it was bureaucratic make work. My supervisors/owners and office staff helped, and we scrambled to complete everything before the pre-construction meetings. Large bridges were beyond our bonding capacity. We did build some small bridges, but work on larger bridges was as a subcontractor for various. 

One task that was very important after winning a bid was creating a spreadsheet with all the bid items. Included were the anticipated labor costs, material costs, subcontractor costs, overhead items, profit, TIBS (taxes, insurance, BS/miscellaneous) and time. There were dozens of bid items included, and the information was needed to load the project into the accounting program. I know there are canned software applications out there for construction project management, but we never really had the need for the expenditure. We all came from the old school where we originally worked with columnar tablets, and the accounting was done the same. Years of building spreadsheets developed a method to take care of all we needed, and the canned accounting software was the only one that could handle the bid items when we first bought it. Over time, the software was upgraded, and we stuck with it. Manipulating spreadsheets became second nature. 

With TxDot work, and I imagine most other states, and municipalities, the placing of barricades is the first task. This may only be a handful of temporary advanced warning signs, but may include temporary striping, barriers, and message boards. Without these things, and SW3P items (storm water prevention) the project is not allowed to start. Storm water runoff items can a few feet of silt fence, or a elaborate configuration of silt fence, soil erosion logs, and rock filter dams. 

After the barricading is completed, field survey crews station the project, place temporary controls, and are usually available during the project for surveying tasks. Their efforts require a good understanding of the plans, and the instruments they use. While some of the surveying is completed by GPS, accurate measurements require a total station. 

Total stations aren't affected by the weather, shade, or the failure to allow the GPS instrument the time required to be as accurate as possible. Some, called robot guns, can be controlled by the controls on the rod, which can make accurate measurements easily performed by one person. It removes the job of one person, but they're tens of thousands to purchase. During my career, it was one of those items I knew I would never see. It was far beyond what a small company could justify for what little use it would have. Mine required someone to hold the rod, and I was happy to have it.

Once a total station is set up, known coordinates are shot to determine the current location of the total station, the height of the total station above a point, or the ground, is entered, the station can be used to either record, or find locations. Elaborate software allows placing offsets, the points in a curve, and does so with accuracies within a fraction of an inch. Coordinates can be downloaded into the instrument, and when set up correctly with a good rodman, be more accurate than any measuring tape over long distances. Wood stakes, with nails, are used to set temporary controls. These are surrounded with lathes covered in barricade tape. Lathes, with information written with a sharpie, are used to show stations. These are holy objects on a construction site, and disturbing any is frowned upon; especially temporary benchmarks. 

Paint may show stationing, or known underground utilities. With stationing, the paint is a reference for a location. The stationing is a good reference for determining the big picture of the project, and for a quantity reference in the future. The stationing on the ground may show a discrepancy in the plans, or help with determining access to parts of the project. Regardless of how accurate plans can be, plans don't indicate ground condition, or the fact the local rancher has a little drive he uses daily. With ground conditions, the planned storing of materials in a boggy area is usually a bad idea. With the rancher, he probably owns half the county and hob nobs with state officials a few times each year. Both are problems that need to be handled before the crews arrive, and a good superintendent takes care of both contingencies way before that happens.

Paint for utility marking is color coded. White is for the contractor, orange for communication cables, red is for electrical, green is for sewer, blue is for water, yellow is for gas, and none can be assumed to be marked correctly. Some markings may match the plans, but others may indicate an underground utility missed by the initial survey, and cause problems. One of my worst situations was water line running right through the center of a large proposed junction box. We had paving to break, a large hole to excavate, and the project was shut down. My calls to the engineer I knew were wasted on voicemail messages, but I was lucky when a supervisor of the water utility happened to arrive on the site. With a few minutes conversation, and cutting off the water main, we broke the paving, excavated for access, and his crew relocated the main in a few hours. 

With enough surveying completed, and required items handled, the next part of the project is embankment, piling, or both. That requires another post.

The Four Weeks are Over

I had a ganglion cyst removed from my wrist four weeks ago. It was a simple surgery, which is probably never really simple. The surgery was removing the cyst, suturing the tendon that was leaking, and four weeks of wearing an arm brace. The arm brace was the hard part, since it is really a pain in the butt, but much better than a cast. At least I could remove it while showering. I tried a bath, but getting out of the tub was pretty much a lesson in futility using only one hand. Cautions about the glue they used mandated never submerging the wound in water. Flopping around the bathtub proved it was a strong possibility.

On my two week follow up, I asked the doctor if there was any chance of the cyst reappearing. He said if I follow his directions, it's less than one percent. That, and unless I had any problems, that was my last visit, and in two weeks, I could remove the wrist brace. 

So today was the day. I realized much of my movements were dictated by the brace, and found I was still trying to navigate the use of the arm as though the brace was still there. I did find some movements cause a sharp pain. I figure that's a little due to atrophy, and the need to slowly start using the hand again. Time will tell, but it's good to have the large, painful lump off my wrist. I reached the point I couldn't ignore it, and putting the surgery off was just procrastination.

The doctor that performed the surgery performed my two carpal tunnel releases. After those episodes, choosing a doctor for the surgery was a simple task. It's good to have a doctor you trust, and the fact he didn't seem the least bit concerned about Covid only made it better.

Winter Shenanigans

Yesterday, the power went off for about four hours. The high winds, and the colder air can cause problems with the power lines, and if it's a big enough problem, restoring power is a multi-step  process to keep the large breakers from throwing. Four hours is understandable, but a little inconvenient for my all electric home. 

Last night, at about 11:00, the power went out again. This time, the problem was from the big company power supplier, which turned out to be the original problem. The big difference was it was 16 hours before it came back on. 

So, the power is back on, the house is a toasty 67 degrees, and I had a chance to run my generator to keep it well maintained. Tomorrow I'll change the oil, put some fresh gasoline, cover it back up, and hope I won't have to use it again tonight. If I do, I won't wait long to fire it up. It's supposed to drop to about freezing, and the wind is still high.