![]() (125 MPa/m)).Ģ3 Subbase Effects At the AASHO Road Test, concrete pavements with granular bases could carry about 30% more traffic. (80 MPa/m)) Cement treated/lean concrete subbase (k 500 psi/in. (40 MPa/m)), Asphalt treated subbase (k 300 psi/in. (25 MPa/m)), Granular subbase (k 150 psi/in. ![]() Need to know if pavement is on: Subgrade (k 100 psi/in. Subgradeġ9 Subgrade Properties Subgrade Soil Types and Approximate k Values Type of Soil Support k value range) Fine-grained soils in which silt and claysize particles predominate Sands and sandgravel mixtures with moderate amounts of silt and clay Sands and sandgravel mixtures relatively free of plastic fines Low Medium High pci (20-34 MPa/m) pci (35-49 MPa/m) pci (50-60 MPa/m)Ģ0 Subgrade Properties Resilient Modulus of the Subgrade Soil Type Support Resilient Modulus (MR), psi Fine-grained with high amounts of silt/clay Sand and sandgravel with moderate silt/clay Sand and sandgravel with little or no silt/clay Low Medium HighĢ1 Subgrade Properties Typical composite k-values for unbound granular, aggregate, or crushed stone subbase Subgrade k-value (pci) Thickness of Unbound Granular or Crushed Stone SubbaseĢ2 Subgrade and Subbases Design Summary Subgrade strength is not a critical element in the thickness design. ![]() Subbase Layer of material directly below the concrete pavement.ġ7 Design for Uniform Support Three Major Causes for Non-Uniform Support Expansive Soils Differential Frost Heave Pumping (loss of support)ġ8 Subgrade Properties Modulus of Subgrade Reaction, k-value k = Plate load on subgrade Plate deflection on subgrade Plate-Load Test Reaction Pressure Gage Stacked Plates k = 5.0 psi 0.5 in = 100 psi / in. PROFILE No curb Integral curb Separate curb NOT TO SCALEġ6 Municipal Pavement Design Subgrade Subgrades and Subbases Natural ground, graded, and compacted on which the pavement is built. PROFILE PROFILE No curb No curb Integral curb Separate curb Integral curb Separate curb NOT TO SCALEġ5 Three-Lane Section PLAN 34 to 42 wide L 1/3 width (typ.) min. ![]() ( mm)ġ1 Municipal Pavement Design Geometric Designġ2 Geometric Design Increase Edge Support Integral Curb Tied Curb & Gutter Widened Lanes (2 feet no parking) Parking Lanes Rural Areas Tied Concrete Shouldersġ3 Edge Support Concrete Shoulder Curb & Gutter Widened Lane separate or integralġ4 Basic Two-Lane Sections PLAN 25 to 28 wide PLAN 28 to 42 wide L L min. Two-way Average Daily Traffic (ADT) Two-way Average Daily Truck Traffic (ADTT) Typical Range of Slab Thickness Less than in. Truck and bus routes are primarily on these roads. Streets that serve traffic from major expressways and carry traffic through metropolitan areas. Streets that provide access to industrial areas or parks, and typically carry heavier trucks than the business class. Streets that provide access to shopping and urban central business districts. Streets that collect traffic from several residential subdivisions, and that may serve buses and trucks. Through-streets in subdivisions and similar residential areas that occasionally carry a heavy vehicle (truck or bus). 1 Municipal Pavement Design with StreetPave Software MaScott Haislip Senior VP Pavement EngineeringĢ Presentation Overview Background / history of the design procedure Concrete pavement design principles Discussion of the primary factors (inputs) affecting concrete pavement design Example using StreetPave design softwareģ Municipal Pavement Design Thickness Design BasicsĤ Streets and Local Roads Thickness Design Procedure Longitudinal joint Transverse joint Surface Texture Surface smoothness or rideability Thickness Design Concrete materials Tiebars Subgrade Subbase or base Dowel barsĥ Thickness Design Procedures Empirical Design Based on observed performance AASHO Road Test Mechanistic Design Based calculated pavement responses PCA Design Procedure (PCAPAV) StreetPave (ACPA Design Method) AASHO Test Road: Ottawa, Illinois (approximately 80 miles southwest of Chicago) between 19Ħ StreetPave Design Software Pavement design tool geared primarily for roads & streets Based on the PCA s pavement thickness design methodology Checks adequacy of concrete thickness using both fatigue and erosion criteriaħ Concrete Pavement Types Jointed Plain Undoweled Doweled Jointed Reinforced Continuously Reinforced Prestressedĩ SLR Pavement Design Street classification Traffic Geometric design Subgrade and subbase Concrete quality Thickness design Jointing Dowel Bar Recommendationsġ0 Street Classifications Street Class Light Residential Residential Collector Business Industrial Arterial Description Short streets in subdivisions and similar residential areas often not through-streets.
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