Mike Hernandez, Technical Director The Voice Newsletter August 2023

There are various new and developing technologies on the market that are of use to concrete contractors. ASCC technical staff and Associate Members can assist you with many of them. Members can also ask for feedback from the general membership in the ASCC Forum.

Total Station

The most accessible technology may be to invest in a Total Station for self-performed layout or verification of layout by others. They vary in cost from $3,500 to over $40,000 for a robotic machine capable of long-distance land survey. There are 5 arc seconds, 3 seconds and 1 second instruments on the market. If you are constructing a medium-size commercial building or smaller, a 5 second Total Station is probably just fine. Personally, I prefer the 2-man team with an instrument man and a rod man. They often act as a journeyman and apprentice team. The rod man is staking points and can someday be an instrument man himself. Also, a robotic Total Station was stolen in a grab and run operation too close to a busy Miami street years ago. Fortunately, the surveyor had written his name and our company name under the batteries with ultraviolet ink, so he was able to identify it at a pawn shop several weeks later with a UV flashlight, despite the serial numbers being scratched off. You will also need software, a data collector and training. I feel the expense is well worth the upgrade in quality vs traditional processes.

Laser Scanner

In the upcoming September issue of ACI’s Concrete International, there is an article by ASCC Member Leo Zhang with The Conco Companies regarding laser scanners. The article compares the performance of several competing scanners and provides guidance on their speed and accuracy at various distances. Absent from the article is the cost. The ones tested range in price from $23,000 to $104,000 plus the cost of the software and training.

Scanners are helpful in capturing existing conditions or performing as-builts. Having used scanners on projects for 17+ years and as a member of ACI 117 laser scanning subcommittee, they are a double-edged sword. They will find mistakes you did not realize were there which could be used against you or help you mitigate a dispute with minimal grinding, patching, and rescanning. Our team performed multiple rounds of grinding-patching-scanning of vertical shear walls to minimize the impact of a stucco sub wanting $100,000 to thicken the coatings on several 5-story shear walls back in 2007 with similar mitigation processes more recently.

Flatwork slab topographs or “heat maps” are the most common work products. It will find the high, intermediate, and low points in a slab. Be careful that the contour line spacing is reasonable if someone else performs the scans. Scans of elevated decks prior to--then after--shoring removal have made several disputes go away over the years because concrete contractors can’t control deflection, only the top surface (prior to shoring removal) is in their control.

Building Information Modeling (BIM)

If you are constructing a moderately complex structure or if the drawings seem incomplete, then consider using BIM to model the concrete frame for the project. The structure is constructed digitally before going to the field. The Mechanical-Electrical-Fire Protection-Plumbing trades are modeling their work regularly to cram their scopes into walls and ceilings using clash detection and coordination so this might be happening with the general contractor already. Some aspects of the final concrete are often not coordinated properly in the "For Construction" set of plans or additional information is added during shop drawing review.

The goal of the BIM modeling is to provide the field with a coordinated set of line drawings checked against architectural drawings, structural drawings, civils and includes block outs and embeds. The BIM coordinated concrete shop drawings become the single source of truth. This exercise should decrease risk, improve efficiency, and thus reduce cost. From this you can provide model-based layout to a total station, run schedule simulations (4D) or even use it to model the formwork and rebar. BIM can even be used with a virtual reality headset to digitally walk through the structure. The investment is substantial, so consider using a domestic or international 3rd party consultant until you are familiar with the processes enough to know which software to buy and have an enthusiastic modeler on staff.

Part of the issue with evaluating your return on investment is it will be impossible to accurately quantify actual savings of a well-coordinated set of drawings vs finding issues during concrete construction operations or worse, by a follow-on trade. I like to say, “It is hard to place a value on the bus you did not get hit by.” When a project goes smoothly, and the team meets the schedule and quality goals then moves to another project without rework, that is a good project!

Drones

The use case for drones is for progress photos and capturing post tensioning and rebar prior to concrete placement. As an FAA Licensed part 107 drone pilot, I have flown dozens of flights to capture progress photos. Having those progress photos was helpful in updating the master schedule and billing percent complete. Other projects have used a drone flying a programmed route like mowing a lawn to capture rebar, post tensioning and conduits prior to placing concrete. The series of images can be combined for a high resolution as-built composite image if a slab ever needs to be drilled. If you are going to use a drone on a commercial jobsite, go through the proper licensing and liability insurance procedures.

Artificial Intelligence (AI)

There are several AI tools available if you want to push the innovation envelope. One is a scheduling tool, which will run thousands of schedule “what if” scenarios based upon the sequence logic, durations, manpower and equipment constraints you input. It will generate the fastest solution to complete the project. The more complex the schedule, say 2500+ activities, the more likely it is to come up with a novel solution. A former employer was using this tool 6 years ago, and we tested our plan against it. Having managed projects with a best-case scenario master schedule it is a high-risk and high-reward setting. A few hiccups in manpower or formwork cycling and the ultra-fast plan is out the window with craft labor and general conditions consuming the perceived savings. Massive overtime and a difficult conversation with your client come next. The lesson learned was to under commit and over deliver as much as possible. Try this tool when the whole project team can get on board with your innovative AI plan to share the risk. If you would like additional details about AI leveraged project scheduling, please contact me.

A less risky use of AI is for language translation. With a predominantly Hispanic workforce in many companies, the more we can provide our workforce content in their native language, the more likely we are for them to internalize the text. AI can translate to hundreds of languages. I am still trying to determine if Google Translate or Chat GPT does a better job with concrete construction lingo. Your feedback is welcomed.   

As contractors, we must make buy-sell-lease decisions for the benefit of the long-term health of the organization. Fellow ASCC members and staff can help you recognize the pros and cons of technology investments. Take advantage of these resources as a benefit of ASCC membership.