Trimble Business Center: Under the Hood

Trimble Business Center: Under the Hood

As a user of most modern data platforms, I can easily use Trimble Business Center(TBC) to do most anything with ease. Being a non-AutoCAD program, the commands are different from CAD but achieve the same results. More on that later. First, I would like to discuss the advantages of the program as well as some of the tricks and tips I have learned along the way.

The Interface

As TBC matured, features and options have become easily available. The noun/verb selection and right click access have proven to be powerful.

Here is a list of options from a linestring right click:

  • Selection Explorer can help to group frequently selected items. It reduces the risk of not getting everything you need or too much.
  • Line Commands include Edit, Break Lines, Join Lines and Offset Line. They give immediate access to fixing issues related to the line(s) selected.
  • Variable Offset Line allows multiple instructions to a line and results new offsets. Think of a paving edge that can be made to form bottom and top of curb in one operation.
  • Add/Remove Surface Members is a way to take things in and out of a surface. I use this a lot for testing potential breaklines in problem areas.
  • Media Files are used to refer to an image of a point shot or relevant information that goes deeper than a line or node can.
  • Profile Viewer brings up a quick 3D of what the linestring is doing. It’s great for troubleshooting curb grades in a parking lot.

More Power

Trimble has reset icons to promote a left to right progression for a job. Countless others have created special toolbars and icon groups to deal with not missing a step. For years, I have had to work with clients that do not have a custom setup. I think it is unnecessary to go through these steps. Learn the commands and know their location and you will get what you need. Not every job needs all the commands. I see no big rush for producing these parlor tricks. My other issue is that commands are added and changed.

With my dismissal of workflow organization, how should you go about accomplishing a job? I think every job is different. Yes, there are threads that connect all work. 2D, 3D lines and points make up a TIN. The issue is getting there. CAD files come in different flavors and I may need to run down the rabbit hole in order to get a good-looking file to work with. Once I get things cleaned up, I can finish the data prep with the usual laundry list.

Biggest Advantage

I’m going to show this in a video, but the biggest advantage of TBC is the ability to try a breakline or surface change and update the model to see how things look. I have used a lot of different software and this has been a big game changer for the platform. Use it and leverage the power. This is a screenshot of the two windows open at the same time. Here the plan view and the 3D view show the new breakline and its effects on the surface. You can explore different results until you get what you want.

Interactive surface changes are a double edged sword. With power comes responsibility. Don’t get too cute – you might be messing with something the grader will blow through in a second. With that being said, when you need to get things changed in a hurry, accessing the 3D and plan view at the same time is important. The Surface Regeneration is usually set to auto. With big surfaces change that to “by user” to make a bunch of changes then regenerate the surface. You will save time and be able to see changes to an entire area without waiting for things to update.

The other thing I will do is add a bunch of breaklines to a job in plan view then use the Surface Members command to add or remove surface members to see what the lines are doing. Once you know what a breakline will do, remove some of them to reduce TIN density and make things cleaner.

File Transfer

The “get the file to the machine” process has always been a pain to me. Work orders and the rest are a lot of work but often necessary. I choose to do work orders when necessary for file creation. Meaning if I can make it in TBC commands, I will skip the process. With Earthworks, the process can get easier but it is still procedural.

With connected machines the work can get processed easily. We usually email files to the client’s office and they push them to the field as needed. Be careful with sending a lot of files out to operators. If you need to send one file a day, the file probably needs more work. The workers won’t know if what was done yesterday will be wrong today. An example would be a strip of pads in a subdivision. Somebody somewhere decided to raise that strip of pads by a couple of tenths. The grade checker goes out to verify the work done by the blade and finds things off. Make sure to document changes that affect the different types of work on the job with each new iteration. I use bullets and break out each trade, so you only need to pay attention to your work. Always use dates. Here is an example:

Site Changes 050120

Underground

  • Storm connection in NW corner has been updated to reflect surveyed elevations.
  • Waterline location changes in playground area.

Earthmoving

  • Model now reflects 2 foot back of curb blowup for curb machine.
  • NE retention has been redesigned.
  • Lot berms have been added where required.

This information will make things in the field flow easier. It takes a few minutes in the office but makes the work in the dirt that much better. I am a big proponent of making things as easy as possible for the field. I came from there and it is a pain to type information for the rest of the crews on a small keyboard in the rain.

Layer Groups

AutoCAD users have always had an easy layer solution. TBC has made things better with easy layer group selection and sorting. When you want to move a layer to a group, highlight it in the View Filter Manager and right click to bring up the menu. Go to layer manager and change the group. I’ll go over this in the video but it’s a big deal to be able to grab the layer you want and switch layers around with this level of ease.

More Layer Tips

In the Layer Manager Box you can do even more things to make your life easier.

  • Rename the Layer to something you use in your CAD standards.
  • Change the color.
  • People often ignore line style. This is a good way to see what’s on a layer. Be sure to uncheck the Show all Lines as Solid in the bottom tool bar. Things can get slow panning and zooming when this setting is off so be careful with big files.
  • Line weight is a good way to highlight a layer to see what you have.
  • Protect keeps the layer from being deleted. This is useful when you get a template file set up and may not have populated one of your named layers. When you go to delete all unused layers, it will prevent these from deletion.
  • Display Priority keeps the layer in front or back when it overlaps a crossing line. I don’t use this much but it does help with dense CAD files.
  • Turn Layer printing on or off.
  • Delete a layer that is not protected and is empty.

Flags

We all have our routine upon reviewing a model done by someone else. The flags pane is one way to get a good snapshot of surface quality in TBC. The issue may be a mess or nothing depending on settings. Let’s look at what I mean.

Within the Project Settings/Computations/Surface is the Minimum Warning Distance setting. This is the factory setting of 7-thousandths of a foot. This means a flag will be thrown if two crossing 3D lines are outside that tolerance. That means a lot of jobs will have flags. Maybe dumb down the amount. I’ll leave the exact number to you and if you get it around a couple hundredths, you will be on track.

Yes, everybody builds perfect models. I do not have time to chase non-essential data down a rabbit hole to reduce the number of flags. Build a good surface, set a reasonable tolerance and chase those flags. You can then dial up the difficulty and see what you have. Don’t despair. Some jobs will have none no matter how tight you go. Enjoy the moment. Other jobs will need a ton of work to get right at high numbers. Choose your battles.

Profitable Implementation of Civil Integrated Management

Profitable Implementation of Civil Integrated Management

The recent advances in technology for use in civil construction are impressive. The broad appeal of GPS, LIDAR, lasers, total stations and computers have provided the contractor with many opportunities. Contractors have embraced these advances but not without difficulty during the learning process. Many have made technology a profitable part of their business while others question the advantages.

This presentation will answer questions and provide a strategy for establishing, or streamlining, your use of technology.

Equipment

  • Brief overview of current equipment types: GPS, Total Stations, LIDAR and field computers.
  • Best use for each type of technology.
  • What to buy and when.

Training

  • What training options are available and their differences.
  • How to take full advantage of dealer, manufacturer and independent training.
  • How to identify key staffers for leading the technology push.
  • How to stay current with training as it relates to hardware and software upgrades.

Application

  • What to expect from the technology.
  • Implementation – gradual or all in?
  • Responsibility chain when using technology.
  • How the high-tech jobsite differs from traditional grading.
  • How the connected jobsite can help profitability.

Work Flow

  • How technology changes job dynamics.
  • How electronic data affects a site.
  • How to effectively manage data from the office to the field.
  • Meeting requirements for the use of technology.

I wrote the overview of CIM (Civil Integrated Management) over 10 years ago. Now is a good time to give an industry update and address the above bullet points. I created the CIM acronym to show how advanced technology that was creating BIM could be used in civil work. Happy to see it used and the idea embraced.

Equipment Overview

Close-range photogrammetry wasn’t mentioned at first. It wasn’t even on my radar. LIDAR has really seen a lot more use with prices becoming more realistic. Many contractors are using LIDAR where a drone was tried before. Limited flight areas near cities and airports are just one issue. Though still expensive, LIDAR is worth a look.

Drones fill a niche. I like to start a job with a good LIDAR scan then use the drone for interim topo’s. At the end of the job and when utilities are in, I like to scan again. A scan takes time, and processing can be tedious with all those points. A good drone flight will suffice for progress data.

Training Explained

We now have two big advantages: the equipment is easier to use and more operators have general experience that transfers to new equipment.

However, every company still needs a champion. We need to cultivate an office champion and a field champion. The full implementation of CIM takes coordination from the two areas. A good estimator/project manager needs to be comfortable with the following:

  • Web-based file management.
  • Advanced project management software, getting all the way to 5-D.
  • Ability to process field data from scanners, drones, GPS and total stations.
  • Send data to your field people as well as subs that can leverage information.
  • Create data rich requests and change orders to better optimize progress and profits.

The field role has expanded as well. I’ve listed some new duties.

  • Pre-job topo created by available technology.
  • Constant data collection from your equipment for interim payment topo’s and record keeping.
  • Shoot in pipes, structures and other utilities prior to covering.
  • Gather data for Requests for Information (RFI’s) and change orders.
  • Work with subs that have technology and help them be successful.

Application Descriptions

In a perfect world, you would acquire a new technology every month so you could learn, then add it to your workflow. Usually equipment gets purchased after the completion of a profitable job. The order of MY recommended process has been updated as well with the addition of more equipment.

  • GPS Rover. Get it, learn it. Everything else is easier when you know how to use it.
  • Machine Control. Nothing works better than a good model on a blade. Nothing is worse than a bad model. Get good data with your rover experience then put it on a machine
  • Cheap, reliable data collection that is easy to learn. Fast turnaround with web-based processing services.
  • Total Station. Precise layout and data collection as well as powerful control for a blade.
  • A scanner will add versatility. They are still expensive but if you can complete three scans a week it makes fiscal sense.

The transition from just a rover to a CIM job is easier than it used to be. Tools and experienced trainers make things easier. Make the move. Every dollar you spend will quickly bring a return on your investment.

Workflow Management Best Practices

The biggest improvement in CIM has been the ability to get things up and downloaded from the Cloud. I can go to a Dropbox folder on my phone and transfer new data to a rover or machine. Notifications of folder changes and just a simple text to let me know something new is amazing. But don’t think that you need 24/7 communication. I have seen this cripple jobs and turn off new adopters. I agree with them; there can be such a thing as too much information.

The biggest issue with having everybody in the loop is that can feel like drinking from a fire hose. I come to lay out curb and I get 1,000 messages about stuff that I don’t care about. Never fear, I have a solution. I’ll address it in the accompanying video but here is the process.

  • You need a gatekeeper. Assign an office person, project engineer or estimator to quickly plow through the unnecessary noise and give you just what you need.
  • From there, it goes to the office people for processing. Does this need a new model or just a note that gets transmitted to the field?
  • The flow from the field follows the same idea. Don’t let the office know everything. You will transmit daily topo’s and work done. They should key in on questions you need answers to.
  • The type of communication is important. You need to see what must be done and find a way to show it completed. Web-based project management software is good for this. Pick one, become proficient and stick with it.
The ABC’s of XYZ (Points)

The ABC’s of XYZ (Points)

At one time the only way to lay something out on a jobsite was to locate a point in 3-dimensions. With the advent of having real time/location elevations from a surface model, points have become less frequent on the jobsite.

There are three major uses for points on a job: layout, surface creation, and collection. I will cover these and their use in surface-based production.

Point Layout

There is nothing more precise than staking out a 3D point. Accuracy settings can be adjusted depending on the type of work being done. This screen capture shows the distance to the point I want to stake. When the point is eventually located, I will also have a record of the distance from the point for future reference. This is all related to what a surveyor does, the carryover to surface based layout may seem extreme.

This accuracy is best used by surveyors and is a bit fussy for grading in general, so why would we use that detail? I always enforce the seperation of field layout and actual staking done by a surveyor. Our layout of a point is only a snapshot of the surface and surrounding influences of other 3D data. This myopic focus will tend to take away the big picture view that is necessary for site work. Sometimes you just need to nail a spot and point layout gets you there. Here are some instances where spot layout is beneficial.

  • Confirm a building corner for sidewalk offset.
  • Bases for hardscape items and playground equipment.
  • For curb layout we will often provide 3-foot top back of curb offsets for layout as well as pc’s pt’s and radius points for curves.
  • Street and road details. Staking station and offset is quick with points.
  • Lightpoles and electrical stub-outs are easy as points. Electricians will not have the technology to make sure you won’t need to dig up the asphalt due to misplaced electrical.
  • Fire hydrants, bends and tees. This gets into as-builts which we will cover later.
  • We do a lot of 3D point layout for storm and sanitary on projects. Flow line excavation and locating is much easier with points.
  • Parking lot striping has been laid out with points with good results.

The list can get longer as users become comfortable with equipment and perform basic tasks quickly. If you want to do more, we have a list of things to do with point layout that can keep users as busy as they want to be.

Points in Surface Preparation

It’s obvious that points are going to end up being used in building a surface. What I want to cover here is what happens when you use a point that was not obvious. We get so wrapped up in what we use for a surface, take all the engineering data and build. I have seen users try all sorts of fixes to lines and contours when a simple point would make it all better.

Corridors

Let’s first talk about points for layout and points to control a surface generated during data prep. The best use of point data on plans placed to control a surface is storm rims. The image shows a manhole that has an elevation called out in the plans. There is also a curb inlet with similar properties. The issue is these elements are in a street that is governed by a vertical profile and templates. If a point is added, it would not be necessary as the street will be correct here. We add points for two reasons: we can verify the elevation is correct, and that point will be labeled and sent to the field for layout.

Job Sites

If that example was a parking lot, the rules would be different. With no overriding cross slope information, we need these to bring water down to the drain. Here we see a grate against a curb in a parking stall. The elevation along the bottom of curb is going to get picked up and paving will drop to make water flow. What is not seen here is layout points. We will talk about those later.

Spirited discussions over beer include how to make the surface look around these inlets. The image above shows a single point at the center of box along the face of curb. Other users feel it important to run points all around the box in order to show that as a flat surface. Here is my take: a small box like this (2 feet x 2 feet) only needs one point. If it gets over that, use points to make it flat. The image below is the same inlet with elevations included to make the entire structure flat. Things did not get messed up with the additional vertices, but it can happen so be careful. Remember, each of these triangles are flat. The first image shows nice flat planes leading to the drain. The additional points made more triangles and they slope in an asymmetrical pattern distorting the otherwise nice flow to the drain. Further exploration brings up some interesting points.

With little change to the surface for a small inlet, there is no need to complicate things. This is flat here so the additional triangles and breakover angles are not huge. If the approach to the inlet was over 2%, it could have become messy.

Another area that benefits from points is controlled site grading. That is (usually grass) areas that need to drain or have structures like a playground. I will use points to make water move where it needs to as well as placing supports for installed items. Something to note here is that points for foundations, or bases, are not usually part of a surface model. The grading around these areas are often below the concrete and would only distort the surface. These would be added to a list of layout points to be laid out when it came time to dig footings.

General Rules

I use points to “connect dots” and improve conditions. When a point is added, you increase the number of flat triangles thus reducing the breakover angle between each triangle. This also makes each one smaller and smooths out transitions. With each addition of data, you run the risk of screwing things up, be careful. Here are some situations I look for when cleaning up a surface.

Contour Grading

In this first image, there is a valley that reduces in depth until it hits a rounded retention. There are steps in the valley and the addition of a break line will improve this. The break line is not the addition of points but a 3D (or 2D) line that is a visual connection of points. The line is only there for your convenience, the TIN connects 3D points.

I ran break lines along the top and toe of the drainage swale. This cleaned things up and now water will flow better. Any time you add points by the addition of a break line, make sure it does what you want it to do. I’ve seen a lot of additions that are not needed for a good model. Surfaces are best when the minimum number of extras are added.

The basis of this article is what we call “named points.” A named point is a point you will most likely list and stake to at some point during construction. They also get included in surfaces as well as used for locating. Cleaning up of the ditch, as shown in the image, brings up an idea. This could be easily laid out as a surface. In this case, there is a concrete liner that gets placed in the swale, and points help to get things right. When the surface looks good, we will add layout points so the form carpenters can easily set the forms for the pour.

Now that the water works the way I want, the addition of points will make a good transition to the field. The image is an example of what I would send, end points as well as a point along line for the bottom of the vee. This represents the outside of the concrete so that becomes the edge of the form. It is better to throw in a point or two to clarify the intent of the plans. Remember, you are in the office in a controlled environment. In the field it’s not as easy to look at plans, specifications and details in cold, wind and rain.

 

Point Collection

When a point is shot, you are doing it for a specific purpose. That eventual use dictates the collection method employed. GPS is an accurate tool but that changes with conditions and collection settings. A topo point will take a second. When you are shooting top of pipe for as-builts a longer occupation is better for improved accuracy. GPS increases vertical accuracy with a longer occupation of a point. The x, y coordinates will not shift much with increased time.

When you first initialize a site, the time you cook on control points can be as long as three minutes to get a good result. That time would be a waste if you did that for all your as-builts. Know when less can be as effective for the work at hand. I have seen field people not take enough time to get a point collected correctly. Don’t use topo collection for critical locations that are going to be covered up and accessed in the future. That information will eventually end up on a GIS database somewhere and others will use it for planning and excavation. We are making a long-term investment in getting a workable map of our work to make things easier in the future.

Point Organization

I can’t take the high road here. I start as-built collection with correct P Codes (Point Codes) and somewhere along the line I forget to change the code and my great field to finish idea is gone.

  • Establish a company standard for point naming. This should be done for layout as well as collection.
  • Try to set codes in the field as you collect. If you mess it up, don’t abandon the idea, just get it right again and fix in the office.
  • Collect more points than you need and more points of random areas. They will help tell the story when in the office.
  • Set up field to finish codes with company standard point naming. This is fluid and will change/improve over time.

Yes, points are part of a surface, but using them to locate and collection later is something you need to do and get good at. I will address field to finish solutions in the future. For the time being, get set up with a smooth transfer of point information to and from the field.

GPS Use for Roadway Subgrade

GPS Use for Roadway Subgrade

When spring rolls around, road construction gets into full swing. Road contractors have been early adopters of technology and continue to drive the development of new applications and equipment. Among them are laser augmentation for vertical accuracy and the automation of paving and curb machines. To improve efficiency, contractors should use technology wherever possible. This includes preparation of dirt grades and the application of subgrade materials.

Standard Road Subgrades

When working with a site, it is easy to “dial down” the surface in order to grade to the top of dirt, compacted subgrade, and rock. This vertical offset works well, even though it just lowers the entire site to the set amount.

This drawing shows three (3) layers that can be installed using at vertical offset. With a well prepared subgrade, it is possible to pave using sonics and obtain good results in a basic parking lot.

For many road jobs, the subgrade is easily set with vertical offsets. A typical road design for urban rehabilitation work is one example. Here we see top of dirt and a prepared native subgrade that can be done with vertical offsets.

The subgrade extends beyond the road/curb finish. To make this easier to model, just the finished surface can be built. The equipment operator can run the blade down the road section and use sonic and cross slope, or a horizontal machine offset to pick up the additional two feet.

Extended Road Subgrades

Another layer of difficulty is added where side slopes are built into a roadway. The subgrade hinge represents the intersection of the side slope and the projection of the subgrade. It is shown in this drawing inside the red circle. Refer to the video for a better understanding. There are two ways to accomplish the production of the subgrade hinge, office calculations or field adjustment.

Office Calculated Subgrades Software programs can build the subgrade for roads with extended hinge points. It requires the data builder to build “another road”, adding time and complexity to the project. The result of this work is a new surface that represents the top of dirt grade where the subgrade and side slopes can be graded as one surface.

Often there is not enough time, or the data builder may not have learned the process. The field crews can establish the hinge point by the following method.

Build the road to finish grade. Establish the side slopes and begin grading them. At the same time, machines working the driving lanes can check the progress of the dirt grade. The machines on the driving lanes can dial down to the top of dirt, as long as they do not break over to the side slopes. Using horizontal offsets, the driving lane machines can work with those on the side slopes. The hinge point will result from their work. My YouTube video will clarify this.

Complex Road Subgrades

Often, roads are done in two complete stages; from actual bidding to execution. The earthwork is part of one contract, and base and finish is on another and comes later. We see this in areas that have limited work due to weather constraints. In these areas, subgrades may not follow the cross slope of the main lines in super elevated sections. We have seen tangent section subgrades that are different cross slopes than the paving. Conditions like these require a full office build of the subgrade, as it changes cross slopes at a different rate than the paving.

A complex road subgrade benefits from machine control. It also requires the production of at least one additional surface for the subgrade. The additional work is rewarded with a better product produced in a shorter amount of time.

Finding compacted hinge point location

When building a road subgrade model, we know the finished location of the hinge point in 3-dimensions. If you don’t make all subgrades in the model the hinge point, the surface you are working on may not be called out. I will cover a work around in detail.

When this information gets into the field, the dirt either needs to be laid flat to compact to grade or compacted high to trim. With expensive subgrade materials and expensive geo-textile mats, there is no room for error. Here are some methods we employ to make this work.

Trimming subgrade

When you get compaction on select fill in a subgrade planned for trimming, the trim amount is often not specified. We have seen times where you need to overbuild to 5-hundreths and trim, but this is the exception. Here is what we do:

  • Run tests with real world natural conditions, meaning the OG may compact more in some areas. Test compaction amounts of the select fill and adjust if the material spec changes. A close relationship with the supplier will help here. The biggest change we see is moisture. Some fills will respond to high moisture content poorly. Once everybody is happy with the testing, closely monitor the first few instances to confirm. Stringless trimming is the way to go here.
  • The road model is also what was used to produce the subgrade model. Trimming fill is cheaper than grinding concrete, so this is your first check of the roadway model. Any adjustments made in the field need to go back to the model builder so that the finished paving can reflect updates. We see this mostly around bridges, drainages, and tie ins.
  • A trimmer needs the same setup quality a paver does. I have seen trimming crews run a bit fast and loose with subgrades as the stakes are not as high. Watch closely.

Multiple Subgrades

It is possible to model all the subgrades in a road job. We have all seen, and marveled, at a well compiled model that allows us to quickly create a model of a surface. Material types change during a project as well as thicknesses. We want to keep up with the changes, but it is easier to dial down from finish and intercept the side slope.

Here we see a paving section where multiple materials intersect and even stop short of the side slope. The called out “Embankment Side Slope Area” is drawn differently than it will be graded. Most will run the subgrade and embankment to the side slope.

In building this model, there are multiple hinge points. The best way to address this is to get the side slope close to right and run the subgrades out to the hinge. There are some precautions that you need to be aware of:

  • The BIGGEST issue that needs to be addressed are correct slopes and daylight lines. Be sure you have a tight ground model to model. Only then can you rough cut the side slopes to get the hinges right with less material use.
  • Compaction of embankment will be a moving target. Watch compaction of different soil types.
  • Don’t think you’re wasting your time building different subgrades. They make sense for a lot of jobs.
  • When automating paving, we will build a track grade model that sometimes changes the hinge point during construction. A final model is used to get the slopes back in line after.
Working with Surveyors

Working with Surveyors

Many years ago, I proposed that machine control would change the surveyor’s role and made it a point to discuss this with many state surveying groups. As a rule, surveyors need to be exact. A circumstance could come up where one would have to defend their work in court. With the need for accuracy, surveyors were not happy with contractors bringing precision equipment onto a site. Some thought contractors were cutting costs by reducing survey crew trips to construction sites. However, the real reason was that a surveyor may have to go back and tell a contractor some of their work was done incorrectly. Every surveyor hates to return and re-pound stakes that got knocked over, so how do they make sure the contractor can perform great work independently?

Survey Builds Data

I have been involved in lively discussions to legal debates over the production of machine control data. Regardless of the state, the answer is always the same: data built by or on behalf of a contractor is not an issue. Once that got settled the question remained, “Who should build the surface you will grade to?”

Traditional Surveying

Survey is solely about points. Load calc points into a data collector and go out and place them on the ground. The contractor connects the dots and a surface is made from the points.

The image at the right shows what we were given in a set of plans. Points found on the plans are placed on the ground in three-dimensions with a stake. The cut/fill to the desired location was marked and the dirt was moved. When things got close, blue tops were placed with the top of the wood stake at finish. Other types have a staple in the top holding the whiskers, a good operator would “polish” the staple and get grade that precise. The difficulty in this method of staking/grading is what happens between the hubs, a low spot or incorrect drainage is easy to miss. Only when a lot was paved would the problems show up. No matter how much spot checking we did, sometimes a spot would get missed.

Data Models

When I started doing this work, the only frame of reference I had was how things were staked and cut in the field. Because first generation equipment was difficult to use and problematic, training and ongoing support were normal. I spent more time in the field than in the office. We would build the model and I would be in the field for days, to weeks, training crews and getting a better idea of how to leverage the data that I collected.

The knowledge I gained by working in the field allowed me to create workflows that are now commonplace. The other problem we faced was that nobody knew how to build a model, but surveyors felt they were the best option. This is a learned ability and with practice anyone can become proficient, like me for instance. I worked long and hard to figure out how a model works in the office and the field. Coupled with a good understanding of how the mouse clicks transferred to the ground, I began to connect those dots. One of the most frequently asked questions I get is who the best candidate for a data builder is. I find it easier to train a computer savvy field person than try to get a CAD expert to think in three-dimensions.

In time, more people learned how to create good data and software ran ahead to improve commands and performance. The future holds the key to 3D design and implementation of data into the field. BIM has taken the lead due to multiple trades trying to occupy the same physical space. Currently much of that design work is done with CAD technicians producing the 3D models suitable for construction.

The ability to design, (or produce 3D data from CAD and plans) is mature. We will discuss the integration of surveying and data.

Cross Training

As more contractors started to create their own files, surveyors were not building as much data but keeping busy doing the important job of positioning. It’s necessary to understand what a surveyor does, but not actually do it. Surveyors need to understand data but not necessarily know how to build surfaces. Here is what each needs to know about the other.

Somebody must make a model for the machines to work. With model in hand, it’s time to go to the field. Surveyors are critical to any job large or small. I have seen the start of too many jobs by well-meaning contractors placed in the wrong spot or incorrect elevation. The nuances of positioning are complicated, and it is the surveyor who can assist in correct site placement. The GPS lead on the jobsite needs to have some of this ability too. The most important thing is sensing an issue and when to contact survey for work to be done. I have a surveyor friend who ten years ago would build the model and give the contractor a rover with the data loaded. They would start the job and call when they needed something.

I need to be clear; office and field civil construction workers are not doing survey. We are laying out and grading to information the surveyor knows is in the right place and will perform as intended. That is the end point of data and survey working together, so how do we get there?

Data Prep

I’ll run through the process when we work with a client on a typical site job.

  • We build the initial model and do the following:
    • Fix obvious errors and note them.
    • Make grading changes to reflect proper water flow.
    • Verify dates and changes to the plans to confirm current versions.
    • Report these changes to the contact(s). Usually this is the contractor. As the jobs get larger, we are often asked to communicate directly with the engineers and surveyors and include the contractor in the discussions.
  • Responses are received regarding questions.
  • Data is updated and work continues.

The data needs to start out as a representation of the finished product. There may be changes pending but not so detailed that we must redo a lot of dirt work. This rough grade file will keep the schedule moving and let the engineers know how long we have until we run out of things to do. Hard deadlines go both ways, stakeholders need to know we are faster at moving dirt and need answers to questions.

Your surveyor is invaluable at this stage, coordinate values need to be correct, the best way to know this is to bring them in early. As hired guns, we communicate with survey crews on jobs all the time. Be sure to do this early and with all jobs.

The next step in confirming data is to bring in control and verify locations and accuracy. Now that things are in the right spot and the data is close to correct, we can send the data to involved parties and gather input. Don’t expect a lot of information, everybody is busy, and most don’t have the time to review your data. It’s more of a courtesy.

Survey Functions

I have often been involved in some very detailed discussions about survey’s role on a job. I am an expert witness regarding disputes that sometimes involve surveying. I am no surveyor but have a good grasp on the practice. It takes time to be good at this and I leave it to the professionals.

The surveyor needs a plan for what they will do on your site. This prevents duplication of effort as well as ensuring it is going correctly. Here is a list of things to get right.

  • Understand what a site calibration (localization) is and what the report means. These numbers are critical and you need to understand them. When the surveyor is using different equipment than you are, you will need to perform this on your own. Compare the results to theirs to verify.
  • Know the difference in collection times. Sometimes you can walk and click, and other times you set up the bipod and cook for a minute. This affects accuracy and a few more seconds on various point types will be rewarded.
  • Respect procedure. Don’t take phone calls or talk to people on site when you are involved in critical tasks. When the surveyor tells you not to bother them now, it’s not because they are a jerk. They are in the zone and don’t want to miss something. When you are laying out curb points for example, always do things the same way. For example; I always do PC, RP, PT. Pick your method and stick with it. Here is a simple curb layout. This is what I want to see when I’m laying out.
  • Perform daily check-ins. Know that when you start your day you are as correct as you were yesterday. Do this for rovers and machines.
  • Share and listen. The information needs to go to the surveyors and engineers for review and comment. Again, you will not hear much, it’s just good to let them know what things look like in the field. This is a big advantage on remote jobs.

To wrap things up, learn enough about the other person’s job for better communication and efficiency. None of us can do a job that we are not trained for, but an understanding of the roles around you will go a long way in making things run smoother.

Regarding Civil Site Takeoffs

Regarding Civil Site Takeoffs

The request for “a quick takeoff” means different things to different clients. When a client makes this request, I generally know exactly what they need. The quick dirt number I provide usually leads them to knowing how much Teflon tape they’ll need for the water pipe joints.

The procedural filters we use while doing a scope of work will change over time, coinciding with the different stages, to make our job easier and more productive. Clients each have different requirements for their takeoff, eventual bidding, and final production. To walk you through this process, I will begin with the basics and investigate advanced ideas while I progress.

During this offering, I will speak in the first person, like it is “our job,” acting as a consultant who will perform the takeoff and processing services for our clients and not perform the work ourselves.

Just a Takeoff

When we “old timers” used to receive a request for a takeoff, the rules were simple and worked well for years. With more technology introduced, the deliverables clients expect to receive are much more advanced. Acquiring additional information, in respect to a civil site takeoff, may help you get your numbers right. The data in hand is purely for bidding purposes, but clients often want more information than they need. It only wastes their money.

Takeoff to Project Management

Once a client has won a job, I am all for details and more information. Many of you know my old line, “if you’re using your takeoff for data, you are doing too good a takeoff.” The same holds true for takeoff detail. If your takeoff can instantly become a project management document, you’re wasting your time with a too detailed takeoff.

The difficulty comes from transitioning a file from takeoff to production. Many think that you need to start over in order to make things work for production. As an old timer, I would agree with this, but industry software has made this a non-issue. Here are some of the transitions we need to make when the job is won.

The Dirt Number

As an experienced estimator and large-scale project manager, I always keep some money safely tucked away in different scopes for the eventual rainy day. The dirt number was one way to do this. During the bid phase we might have listed the strata from bore logs, but often they are not available, or time won’t allow it. Now that the job is ours, I start the deep dive into the actual cost of dirt moving and investigate the following items:

  • I get our drone, or hire a local drone operator, to fly a pre-start topo. We all know once you mobilize to a site and put a tooth in the ground, all bets are off for another trip to the well for more money because the OG information supplied in the plans was incorrect.
    When we get the topo information, the takeoff is rerun. If we are better than before, I use the advantage in my rainy-day fund. If the numbers go bad, we call a meeting with the owner and renegotiate. Make sure this is all done before digging. When fast-tracking, you still have the date the topo was flown as well as images that show no disturbance. An email to let everyone know this is an issue will serve to keep the issue open until a change order is processed.
  • The different amounts of each type of dirt that needs to be moved is the next area I look at. If you had the bore logs and they were entered into the takeoff numbers, review them and start to look at actual costs for handling each material type. Many contractors know their areas well and will assign an average dirt number to the quantities at bid time and come back later for refining. You can now figure amounts much more closely with additional information.
  • For mass haul analysis, cut/fill and enter our average number for dirt moving works well for bidding. These quick numbers are a result of careful figuring based on prior work and should get you in the ballpark to win some of the hard-bid jobs you go after.
  • When you get the job, it’s time to start drilling down into the numbers and squeeze those few percentage points to make the boss some money. The amount of dirt getting moved at what distance on what quality surface is the breakdown. I will review a site mass haul in the video and go over what I look for in the reporting.
  • Many site jobs require going offsite to dispose or import material. This is another chance to make some calls, shorten distances and lower costs. During the bid, you might have used local numbers or made a quick call to plug in a price. Now is the time to get some savings from the averages used in the proposal.
  • Now that we have won the job and returned from the celebration, it’s time to be good to the owners, and help us a bit along the way. We all need to bid to the plans and specifications and consider the pricing on additions and alternates. There are too many variables to go over here, but each contractor knows that there are a lot of better ways to do certain parts of a job than what’s been drawn by the engineers. We see the biggest disparities in chain business when plans have been drawn out of state without intimate knowledge of the area. Others have some luck by having worked in the immediate area and are then able to recommend some changes that will enhance the job and save everyone some money.

To this point, I have used quick and basic takeoffs that drove the dirt numbers without having to redo anything. I just spent more time drilling down in the listed areas. I made a lot of owner’s good money by being diligent in the above areas except when back in my day we walked the topo, drones weren’t invented then.

You need to perform the above first. This ensures the original ground information is good, you understand conditions, as well as knowing how far you’ll need to go for material import or export. With this completed, it’s on to the next phase.

Project Management Process

A lot of time is wasted moving materials on a jobsite. It could be dirt that was set incorrectly. To pipe and other import items that always seem to be in the way. We now need to elevate the quality of our data from a takeoff to a performing site data model. The big question is whether to start over or improve the takeoff to data quality. Here is my process:

The Big Stuff

My first question is, did the overall footprint change? With the basic layout still intact, the improvement of the takeoff is my first choice for a data model. We already have the layers broken out and most of the COGO (Coordinate Geometry) is good.

Many times, there are changes to the plans after we have won the bid. Hopefully some of them are from our value engineering proposals to the owners and engineers. With that information in hand, a fresh look at the model will tell you if you should start over or improve things that were in the takeoff. With good layer naming and consolidation, it is not hard to add islands or redo a changed curb line. Resized retentions and other common areas are easy to remove and replace. I will go over a few of these points in a video regarding the use of layers and how to use them to your benefit.

The Details

When we do a takeoff, little attention is paid to making a parking lot look great. We elevate curb lines and possibly change bad spikes. I have done countless studies and presentations from a takeoff to data model quantities and the difference is miniscule. The price of a data model is about 3-times what a takeoff costs. It is not worth our client’s money to get crazy detailed with a takeoff. During the bidding phase, plans are often not approved by all agencies and will change before being issued with final approval. It is important to note the delta changes on the latest and greatest set. A word of advice; never trust clouds on the plans to indicate all the changes made to the job. I like Bluebeam sheet compare for this, I will do a video to explain.

With a final set of approved for construction plans in hand, we can get to work. Let’s elevate the takeoff data and prepare it for construction.

  • Drill down into the dirt as explained above. Get those numbers correct and detailed.
  • Break out the job the way you need for phasing and ordering. You have gross numbers, now you can meet with project managers and superintendents to organize things better.
  • Verify the data model is good, (at least for now) with current changes. During data building, we will find issues and submit questions. In the mean time, you can leave the data as-is for the rough grade phase. If the questions would affect the initial mass earthwork, leave the area blank in the model until you get guidance. Don’t move dirt twice to look busy.
  • Add numbers to the quantities. All current takeoff software can export to your spreadsheet estimating program or Excel for adding prices.
  • Go back to the takeoff and add any additional information you want to run through the process of measure, export, and price. We will do everything from count light poles, measure striping, breakout straight and curved curb, and place playground equipment bases. With the plans in front of you digitally, we find it good to even measure items that will be subbed out. It sure is nice to adjust a supplier’s estimate and save some money.
Paving Rehab Data

Paving Rehab Data

The U.S. Interstate Highway system is almost complete. Regional networks are mature, and the new right of way is geared for housing. Luckily, we still see new alignments and the percentage is increasing for repaving and full reconstruction. This increase has led us to become efficient with sometimes difficult road improvement jobs. Let me explain.

Types of Rehab

There are three basic types of road rehabilitation all requiring a different approach to the data. While I have defined the types for data purposes, there are projects that can be a combination requiring a change in the process.

Full Rehab

This is the easiest and currently the most popular type we perform. The road may move horizontally and/or vertically and none of the previous roadway elements are to remain. Paving, curbs, and driveways are all replaced. Ditches will usually be reworked, if there is an underground storm system, it may change as well.

With everything being new, it may not make sense to refer to this as rehab. The reason is at some point the work you are doing will need to connect to something that will not be moving. Driveways, buildings and off-right-of-way drainage are required to match-in with the least amount of disturbance possible.

Mill and Fill

Asphalt paving does not have a great life in many parts of the country. Freeze-thaw in the North, water and heat in the South, and brutal sun in the West define the finite life and eventual repair of the wear surface. When spot repair is no longer possible, the road surface will be milled, and a new full-depth mat will be laid on the freshly compacted base.

We will go into detail later, but the curbs are usually in good enough shape to keep. We are now required to respect the vertical and horizontal constraints of the existing road. In addition, there are required minimum and maximum coverage and lifts for the base and wear surface. This gets difficult to work with, as there are many constraints plus having little or no ability to try and fit everything in.

Widening

Right of way acquisition is usually done with the future in mind, especially with larger arterial roads. As traffic counts increase, lanes are added to accept the load. When confronted with a widening job, we are concerned with two major points. First, the condition of the edge we are joining to, and then the topography of the extension. I will detail these in a moment.

The Basics

When doing rehab work, we usually go the route of a road job. Alignments and templates are a good start to get things right and, most importantly, a way to easily adjust as things change. The single biggest issue with rehab projects is the dynamic nature of all the parts that need to come together. Here is an outline of what we like to see.

Horizontal Alignments

Ordinary COGO (Coordinate Geometry) will be provided when doing a new road. Sometimes in a rehab job, the plans call out for following the existing road center. Yes, this is a loaded statement from the designers. There may be a line on the plans that might be an old alignment, or something drawn for convenience. Alignments with good instructions are easy to get on your screen, but what about that mystery scratch in the near middle of the road? There are several alternatives.

If you can’t get a good centerline from the CAD, you need to decide on how to guide machines for the work. A best fit centerline takes the edges of pavement and averages the distance between them to give you something to steer to. Here is a set of shots that were taken along the existing edge of pavement along the slip formed curb/gutter.

There are many ways to get an alignment, in this case I am using Carlson’s Best-Fit Centerline. You can use points or lines. Here I drew lines through the points with arcs in order to give the program a smoother start to figuring out a centerline. The alignment is drawn through the upper line (shown above) and will offset to get it to the approximate center.

I often times will do this on the other side of the road as well. When this is necessary, you need to either make a new averaged centerline or create two different roads using one for each side. These cases are generally for older, small streets and roads where environmental conditions have caused heaving and erosion to move the curb. Logic says we will replace those sections so this is a rare exception, not the rule. Knowing that, you are now able to fix real issues.

The new centerline is shown here. It deviates from the edge by almost 3-feet in the worst spot. This is too much. Changing the parameters will tighten things up. This is shown in the video.

With a good alignment to steer to, we will now work on the vertical.

Vertical Alignments

With horizontal alignments we are trying to get a centerline close to actual. With a vertical alignment, the stakes are higher. When the vertical profile corresponds with the centerline, it must follow road speed rules regarding cross-slope and the finished job needs to look good.

The job depicted above has 3D shots along the edge of pavement, as well as, centerline shots that are turned off. With these 3-points acting as cross-sections, we can create a good existing road surface as cross-sections. Don’t be alarmed if a contoured surface looks bad, a cross-section look is the best way to generate a finished product.

I have used Carlson’s Road Rehabilitation Profile command with good results. You will need to get things in order, including some of the outlined steps I will reference. When the pieces are in place, you will have access to the options shown in the dialog box. Lots of power is provided to automate a sometimes-difficult task.

With the alignments done be assured you will be revisiting these to make things work better. We will generate cross-sections to verify the quality of the data.

The following is the Carlson section alignment dialog box. There are enough options to give you the results you are looking for. I am using these options for the job in this article.

With the section interval and special stations defined, I will now create sections of the existing road to give me an idea of what I’m looking at.

Gathering Existing Data

I need to mention a critical point. When we work with clients who build models, we insist the shots are taken with a total station. GPS accuracy is not reliable for the number of required shots and would take too long to get low residuals. A robot and one person can shoot quickly and with accuracy to make sure we are not wasting time. We accept GPS shots only to fully rebuild the job after receiving good data.

Section Review

The production of cross-sections will be the true test of what needs to be done next. I have spent a lot of hours getting things ready for production on rehab jobs. The constraints of the existing features that remain and the rules imposed by the parameters of the road design make the task difficult. It may be necessary to rebuild the job several times in order to make everything work.

Also be aware of the hierarchy of importance in case something must give. For example, we need to keep the curb but need to go less than the required 2% slope. That’s an easy one, but there may be situations where several rules need to be flexed for things to work.

Here is one such example. The road is straight and calls for a 1.5% cross-slope. The right side of the road is almost flat. We need to review up and down station to see how far this extends. The solution here was a 75-foot curb replacement due to heaving of the existing curb and gutter.

With requirements that are often out of the requested values, this type of work takes more time. Many rehab jobs just want to follow the existing road, mill the existing surface and come back with minimum cover. This type of job still needs data to work correctly.

Carlson has a tool I have used with great success. The Match Reference Section Slope command allows you to specify the desired slopes and the limits of deviation to it. Here we are trying to get a 2% cross-slope with a variance to try and make things fit better.

After filling out the dialog box, the command has listed the varying cross-slopes generated by the settings.

Adjusting the Parameters

There are two tools I use to verify a rehab design. The first is the actual material to be used. At some point there was a takeoff done, and I want to make sure we are in the ballpark.

This is just a portion of the report, but the totals are in line. To adjust things, go back to the Process Options dialogue box and check the Adjust Template Grade Table. The side not associated with the Profile Grade will adjust. This may push the slopes outside the design parameters and require a variance to get the volumes down.

I will then plot the sections to verify the profile is doing what I want it to. With a small road like this there is not a lot of room to move, but if the job is several miles long small tweaks can bring big savings.  This particular road is getting 8-inches of white paving. The red is the sub-base needed to bring this up to grade. Had this trend continued for several stations in both directions, I would revisit the vertical profile to try and pick up some material savings.

Summary

The task may sound daunting, but the job needs to be broken down into the individual parts that make up the job. I have tried what seemed to be quicker and easier methods, but changes are near impossible and always take longer.

Approach each part of the process as a separate task and the delineation makes things easier to imagine. With more of these jobs coming along every day, it pays to be proficient.

I have featured Carlson because I have experience using the commands for road rehab projects. Other software can accomplish the same tasks. The commands will be different, but the procedure remains the same.

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