The Trinity River floodplain and the Eagle Mountain Lake basin create a mix of alluvial silts, clay-rich terraces, and sandy deposits across Arlington. These layers respond differently under load, which is why a proper differential settlement analysis is essential before pouring any foundation. When we evaluate a site, we combine soil borings with laboratory consolidation tests to predict how much each layer will compress. The variability in Arlington's geology means that two adjacent lots can settle at very different rates. We've seen cases where ignoring this step led to cracked slabs and misaligned utility connections. That's why our team always pairs the settlement study with a bearing capacity test to confirm the soil can support the design loads without excessive movement. It's a straightforward way to avoid expensive repairs later.
In Arlington's alluvial soils, ignoring differential settlement can crack a slab within two years. A consolidation test before construction is cheap insurance.
Methodology and scope
Our field crew brings a truck-mounted drill rig capable of reaching 25 meters in Arlington's alluvial soils. We extract undisturbed tube samples using thin-walled Shelby tubes, following ASTM D1586 for the SPT portion. Back at the lab, we run one-dimensional consolidation tests (ASTM D2435) on a minimum of three samples per boring to capture the settlement profile at different depths. The equipment measures the soil's compression index (Cc) and recompression index (Cr), which feed directly into the differential settlement calculation. We also check the preconsolidation stress to see if the ground has been preloaded by previous structures or natural overburden. For sensitive clays found near Lake Arlington, we run the Atterberg limits test to correlate plasticity with settlement potential. This data lets us model how much the foundation will move over time.
Technical reference image — Arlington
Local considerations
The difference between west Arlington near the lake and south Arlington along the floodplain is night and day. In the west, you find stiff clay over limestone, which settles less than 10 mm under a typical house load. But in the south, near the Trinity River, soft alluvial clays can settle 50 mm or more. A differential settlement analysis catches that contrast early. If you build on the south side without the study, you risk a slab that cracks along the living room wall while the garage stays level. The repair cost often exceeds the price of the original geotechnical work. Our lab has seen this pattern repeat on residential projects in the Cooper Street corridor and commercial sites near I-20.
We run one-dimensional consolidation tests on undisturbed samples to determine compression and recompression indices. Data is delivered in a report with settlement vs. time curves.
02
Bearing Capacity Evaluation
Using SPT blow counts and laboratory shear strength, we calculate the allowable bearing pressure for shallow and deep foundations. The analysis includes factor of safety.
03
Settlement Monitoring Plan
We design and install settlement plates or telltales on active construction sites. Our team reads the instruments weekly and alerts you if movement exceeds the predicted values.
Applicable standards
ASTM D2435 – One-Dimensional Consolidation Test, ASTM D1586 – Standard Penetration Test, ASCE 7 – Minimum Design Loads for Buildings, IBC Chapter 18 – Soils and Foundations
Frequently asked questions
What is the typical cost for a differential settlement analysis in Arlington?
For a standard residential lot with two borings and consolidation tests, the cost ranges from US$820 to US$1,750. Larger commercial sites with multiple borings and advanced modeling fall at the higher end. Contact us for a quote tailored to your project.
How long does it take to get results from the settlement study?
Field work takes one day for a typical lot. Laboratory consolidation tests run for 5 to 7 days because each load increment needs 24 hours. The final report is ready within 10 business days from the start of drilling.
What's the difference between total settlement and differential settlement?
Total settlement is how much the entire foundation sinks as a whole. Differential settlement is the difference in movement between two points of the same foundation. In Arlington's variable soils, a 30 mm total settlement might be acceptable, but a 15 mm difference across a 10-meter slab can crack drywall and doors.
Do I need a differential settlement analysis for a small residential addition?
Yes, especially if the addition connects to an existing structure. The new footing may settle differently than the old one, causing a step crack at the joint. In Arlington, where clay and alluvial soils shift with moisture, a quick analysis prevents a costly repair later.
Location and service area
We serve projects across Arlington and its metropolitan area.
