# 5837-9 - to determine the corrected effective composite k...

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Application of AASHTO Pavement Design Guide for Rigid Pavements Recall design equation: Log W t18 = Z R S 0 + 7.35 Log (D + 1) – 0.06 + log [(4.5 – p t )/(4.5 – 1.5)] /[1 + 1.624 X 10 7 /(D+1) 8.46 ] + (4.22 – 0.32 p t )log [(S’ c C d / 215.63J) (D 0.75 – 1.132)/ (D 0.75 – 18.42/(E/k) 0.25 )] Determination of Effective Modulus of Subgrade Reaction (Continued) Determination of Composite k from Subbase and Subgrade Properties Use the numbers in Columns (2) & (3) to determine the composite k, which are entered in Column (4) Adjustment of subgrade k due to depth to bedrock Use numbers in Column (4) to determine the adjusted k due to bedrock. The results are entered in Column (5) Chart for estimation of relative damage based on slab thickness composite k Use numbers in Column (5) to find u r , which are entered in Column (6). Use the average u r to determine the average effective composite k.

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Correction of Effective k due to loss of subbase support Use the average effective composite k and the expected LS
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Unformatted text preview: to determine the corrected effective composite k from chart. Load Transfer Coefficient (J) for Various Pavement Types and Design Conditions Drainage Coefficient (C d ) for Rigid Pavements Rigid Pavement Design Example: Design for a plain jointed concrete pavement Dowel bars used at the joints. Solving for required D by means of nomograph Solution by nomograph (continued) Slab Thickness, inches Solution by nomograph: Required D = 10 in. Joint Spacing The joint spacing in feet should not exceed twice the slab thickness in inches. Typical joint spacing for plain concrete pavement is 16 to 20 feet. Use 16 feet joint spacing. Dowel Bar Design Dowel diameter should be equal to slab thickness multiplied by 1/8. Use bar diameter of (10 X 1/8 = ) 1 ¼ inches. Use length of 18 inches & spacing of 12 inches. Tie Bar Design Use 5/8 inch diameter bars with spacing of 48 inches. Design Chart for Dowel Bars Design Chart for Tie Bars...
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5837-9 - to determine the corrected effective composite k...

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