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Our team of experts are available to answer your questions.

Twining’s team of experts are unparalleled in their knowledge and experience in the fields of concrete, welding, asphalt concrete, materials testing and inspection, and geotechnical engineering. Our experts are frequently called upon to provide support on issues such as thermal monitoring of massive concrete placements, inadequacies of concrete mix designs, unique field and laboratory testing requirements for concrete and structural steel elements, performance and interpretation of non-destructive testing of welds (including phased array evaluations), and value engineering of foundation and pavement designs that are suspected to be overdesigned.

We invite you to challenge our team of registered geotechnical and civil engineers, PhD’s, ASNT Level III professionals, and specialty testing experts with your specific questions on your current or future projects. We are confident that our team, with a combined 255 years serving as experts in their respective fields, will provide useful answers to your technical questions.

Twining Consulting

My project has a structural steel component to it. Am I required to have shop inspection?

As with almost all questions related to materials testing and inspection, the answer to this question will depend on the authority having jurisdiction over the project.  Per 1704.2.5 of the 2013 California Building Code (CBC) special inspection of structural load-bearing members and assemblies at the fabricator is required.  However, per the exception in 1704.2.5.1 if the fabricator is approved by the building official this requirement is waived.  Each jurisdiction has their own procedure/policy for approval of fabricators so you should verify with the jurisdiction and with your contractor if the fabricators that will be utilized for your project are approved.  In addition, should complete joint penetration welds be performed at the fabricator these will still need to be independently ultrasonically tested as the exception is only for inspection and does not also apply to any testing required.  Please also note that this exception is not present in Chapter 17A which governs DSA and OSHPD projects.

Twining Consulting

Is there a cheaper alternative to stabilize soft soils than using geosynthetics and layers of gravel?

Gravel and geosynthetic products are very expensive and large amounts are often needed to stabilize particularly soft soil.  Additionally, overexcavation and export of these soft and usually wet soil needs to be performed and this material generally needs to be disposed as it is not usually fill material.  In many cases, cement-treating the soft soils is a more practical and economic approach to stabilization.  If the area is relatively large, cement-treatment of the upper approximately 10 to 15 inches of soil will likely be less costly than overexcavating and placing geosynthetic products and layers of gravel.  This approach has been adopted frequently for troublesome roadway subgrades.  In addition to stabilizing the roadway subgrade, the cement treatment also provides structural support characteristics that can be calculated and accommodated in the design.  There a few specialty contractors that perform cement treatment and they are usually willing to provide free estimates so that you can judge whether your site is appropriate for this approach.

Twining Consulting

Is Cold in place recycling suitable for a neighborhood ?

Asked by: Adam

Cold In-Place Recycling (CIR) can be simply applied to neighborhoods as long as the CIR train can move around and can exit the project location. In this manner, the only locations that have proved difficult for CIR trains are cul-de-sacs and driveways. Also, CIR train cannot cover the top of the “T” intersections on the roadways, unless small cold planer are be utilized

Twining Consulting

I have a recycled base that passed LA Abrasion test (easily) but fails on Sulfate (significantly) any ideas?

Asked by: Curt Ingraham

To best answer this question, we would need to know the intended application of the base material.  Assuming that it will be used for a base course material below a Portland cement concrete pavement (hence the concern for sulfate), table of  ACI 318 prescribes the necessary water-cement ratio and compressive strength to mitigate the potential for damage of the concrete due to the presence of sulfates.


I would welcome the opportunity to discuss this with you further and provide you with a more tailored answer to your specific situation. I have provided my contact information below, and look forward to hearing from you.

Paul Soltis
Vice President, Geotechnical Engineering
562.426.3355 (office)

Twining Consulting

I am consulting engineer in the amusement industry. I may have a need to have some mountaineering dynamic rope tested. There are a series of tests defined in the standard BS EN892:2012. However, my question right now is; if you were to do just a pull test on the rope for breaking strength, how much rope would be necessary?
Ed Pribonic

Asked by: Ed Pribonic

Hi Eric,

We would suggest you carry out the tests in accordance with BS EN Standard 5.6 on three unused test samples with a minimum length of 5 m for single and half ropes, and 10 m for twin ropes, cut out of the available test sample.

Thanks for using Ask an Expert!

Twining Consulting

What are some ways to improve an asphalt mixture’s moisture damage resistance (higher tensile strength ratio per Lottman test) after it is already treated (1% lime DWA) while keeping aggregate source the same?

Asked by: Ed

Unfortunately, there aren’t many other options to improve the moisture susceptibility other than lime treatment. However, if the dry strength of the samples is good, increasing the asphalt film thickness and using coarser aggregate gradation will reduce the damage during the moisture treatment and will relatively improve the moisture damage resistance.

Please feel free to contact us, to discuss this matter further.

Twining Consulting

Hi, are you providing training for personnel in highway and geotechnical engineering? If yes, please message me back through thanks

Asked by: Mr. Sunday Onadiran


Hello Mr. Onadiran, Twining does provide some training in these fields.  Typically, we provide this as a service to clients and agencies for a specific topic or project.  Please email, so we can understand what you are specifically looking to accomplish with your training and we can more directly address your needs.

Twining Consulting

What are the steps to be able to join your crew into becoming an inspector myself?

Asked by: Michael

Hi Michael,

Assuming you are already an inspector, the first order of business would be to verify your certifications currently held to determine if we have a need for someone with your qualifications.  Secondly, membership in IUOE Local 12 is mandatory, so we would need to know if you are currently in Local 12, or would be willing to join Local 12.  Assuming you are a member or are willing to join, we would then speak with our Dispatch who would provide you with contact information for Local 12 so that you can get on the out of work list which would allow us the opportunity to request an inspector with the qualifications that we need.

Hope this helps, and thank you for asking!

Twining Consulting

Hi, does your lab run oil extractions using a solvent? And what type?

Asked by: Mario

Hi Mario,

Yes, if you are referring to asphalt binder chemical extraction, we use Trichloroethylene. Twining is capable of running chemical asphalt binder extractions following ASTIM D 2172, Method A and B.

Twining Consulting

Is there a Standard (Test Method) for using a thermal imaging camera to confirm grout and resteel installation in a CMU wall?

Asked by: Michael

We are not aware of any Standard test method utilizing thermal imaging cameras to confirm grout and reinforcing steel installation in a CMU wall.  However, Ground Penetrating Radar (GPR), is a non-destructive method that can be used to verify that cells are grouted and also to verify placement of reinforcing steel.