Between the sandy bluffs of the Historic District and the marshy lowlands near the Vernon River, the subgrade beneath Savannah's streets changes radically within half a mile. A pavement section that works perfectly on the Pleistocene sand ridges east of Forsyth Park can fail within five years on the compressible clays downstream toward Thunderbolt. Rigid pavement design here is about managing that transition without letting the slabs crack at the boundary. The Port of Savannah is the third-busiest container port in the country, which means container trucks with legal axle loads up to 80,000 pounds are constantly rolling through industrial corridors. Our team correlates CBR road testing with the AASHTO 93 empirical equation to determine the required PCC thickness, adjusting the modulus of subgrade reaction for seasonal moisture swings that hit Savannah's water table hard between July thunderstorms and October dry spells. For industrial yards near the port, we also pull data from CPT testing to refine the k-value profile before finalizing the slab design.
A rigid pavement on Savannah's coastal clays lives or dies by the subbase drainage detail, because standing water at the slab interface will pump fines through the joints within three wet seasons.
Method and coverage
Regional considerations
AASHTO 93 Appendix LL warns that untreated fine-grained subgrades with k-values below 100 pci will pump and erode under repeated heavy axle loads. In Savannah, where the water table sits within three feet of the surface across much of Chatham County from August through October, that warning becomes a design constraint on every project. The biggest mistake we see is specifying a rigid pavement section based on soil borings taken in November when the ground is driest, then watching the slabs fault and crack after the first summer saturation cycle. Loss of support at the slab corner, combined with the thermal curling stresses that hit dark PCC surfaces under the south Georgia sun, can propagate a transverse crack across all four lanes of an arterial within weeks. For port terminal pavements, we now require in-situ permeability testing of the subbase material before placing the concrete, verifying that the coefficient of permeability exceeds 150 ft/day so that water doesn't pond beneath the slab.
Process video
Standards that apply
AASHTO Guide for Design of Pavement Structures (1993, with 1998 supplement), ASTM C78 / C78M: Standard Test Method for Flexural Strength of Concrete, ASTM D2487: Standard Practice for Classification of Soils (Unified Soil Classification System), PCA Design of Concrete Pavements for City Streets, ASTM D1883: Standard Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils
Complementary services
Port and Industrial Concrete Pavements
Heavy-duty PCC design for container yards, intermodal facilities, and warehouse access roads near the Port of Savannah. We use the AASHTO 93 empirical method with site-specific k-values from plate load tests and CPT data, accounting for the 80,000-lb axle loads and channelized traffic patterns that concentrate stress at the slab edges.
Municipal Street and Intersection Design
Joint layout and thickness design for Chatham County arterial roads, school bus routes, and signalized intersections where stopping trucks cause high static loads. We coordinate with the City of Savannah's standard details for curb-and-gutter integration and specify dowel baskets at all transverse contraction joints to maintain load transfer efficiency above 80 percent through the design life.
Subgrade Stabilization and Drainage
Chemical stabilization of Savannah's high-plasticity clays using lime or cement, combined with geotextile-wrapped open-graded subbase layers that intercept the seasonal groundwater rise. We verify the treated subgrade modulus through in-situ DCP testing and confirm the drainage coefficient meets the AASHTO 93 recommended range of 1.0 to 1.2 for coastal Georgia conditions.
Typical parameters
Q&A
What is the typical rigid pavement design life for a Savannah port access road?
We design port access roads and container yard pavements for a 20- to 30-year service life following AASHTO 93 procedures. The actual performance depends on the ESAL count, which on high-traffic corridors near the Port of Savannah can exceed 15 million over the design period. We factor in the terminal growth rate published by the Georgia Ports Authority and adjust the terminal serviceability index accordingly.
How does Savannah's high water table affect rigid pavement joints?
The water table in much of Chatham County sits at depths of two to four feet during the rainy months from June through September. Without a properly graded subbase and edge drains, water ponds beneath the slab and pumps fines out through the joints each time a heavy axle crosses. This erodes the subbase support and leads to faulting and corner breaks. We use AASHTO drainage coefficients and specify geotextile separators between the subgrade and subbase to prevent this mechanism.
What does rigid pavement design cost for a project in the Savannah area?
Design fees for a standalone rigid pavement engineering package in the Savannah area typically fall between US$1,920 and US$7,240, depending on the project's linear footage, the number of borings required, and the complexity of the joint layout. Projects that include subgrade stabilization design, drainage plans, and coordination with City of Savannah permitting fall toward the upper end of that range.
Which subgrade tests are required before designing rigid pavement in Savannah?
At minimum, we need Atterberg limits, grain-size distribution per ASTM D422, and the California Bearing Ratio (CBR) on the subgrade and subbase materials. For port pavements, we also recommend in-situ plate load tests or CPT soundings to determine the modulus of subgrade reaction directly. On Savannah's fat clays, we run moisture-density relationships to set the compaction specification and check for swell potential under the slab.