ETCULVERT EXAMPLE

ETCULVERT Design Process Project Data Update Reinforcing Design Mode Optimize Geometry & Matls Print / Review Loading Design Parameters Review / Optimize Switch to Analysis

STEP 1 – PROJECT DATA SCREEN 3-3 New Project AASHTO LRFD ASTM C1577 Select Culvert Type Rebar and Mesh are both allowed; User preference based on manufacturing requirements Single Cell Precast w/ 4 Sides. Per Section 6.5, the standard RCB designs provided in Table 1 are based on mesh with 4” maximum spacing of circumferentials. Sections 6.5 and 11.6 allow for Grade 60 rebar for longitudinal distribution reinforcement. Section 6.5 and 11.6 also allow the use of Grade 60 rebar provided the design values of Table have been increased accounting for yield strength, steel spacing, concrete cover and crack control.

Enter in Project or Job information and description into ET Culvert. STEP 1 – PROJECT DATA SCREEN 3-4 Enter in Project or Job information and description into ET Culvert.

Select LRFD Specification Select LRFD Specifications STEP 2 – DESIGN MODE SCREEN 3-5 Project Settings AASHTO LRFD ASTM C1577 Specifications Select LRFD Specification Select LRFD Specifications

State /Agency/Locality STEP 2 – DESIGN MODE SCREEN 3-5 Project Settings AASHTO LRFD ASTM C1577 State /Agency/Locality ------- -------- Allows the user to pre-define design criteria for specific agencies that have established criteria that differs from AASHTO LRFD or ASTM C1577.

STEP 2 – DESIGN MODE SCREEN 3-5 Always do the initial design in “DESIGN MODE”, then toggle over to “ANALYSIS MODE” to tweak the design

ASTM C1577 is a precast box culvert specification. STEP 2 – DESIGN MODE SCREEN 3-5 ASTM C1577 is a precast box culvert specification.

Select units based on project requirements. STEP 2 – DESIGN MODE SCREEN 3-5 Select units based on project requirements.

STEP 3 – GEOMETRY & MATLS SCREEN 3-6 Culvert Properties AASHTO LRFD ASTM C1577 No. Boxes: Project Specified Per 1.1, Single-celled RCB only. Clear Span, ft. Project Specified, Standard designs for even ft. increments. Clear Height, ft. Length, ft. Sections 4.6.2.10.4 & 12.11.2.1, RCB sections having a length less than 4 ft., edge beams required; User preference per mfg. equipment Not specified; User preference per mfg. equipment Fill Depth, ft. (Maximum) Project Specified. Standard designs provided for 20 ft. to 35 ft. depending on RCB size. Minimum Fill Depth, ft. Project Specified. Standard designs provided for 0 ft to 2 ft. of fill. Increment, ft. Project Specified. Standard designs for: 0’<2’; 2’<3’, 3’-5’, 10’, 15’, etc.

Slab and Wall Dimensions, in. Added Thickness for V-Bottom Slab STEP 3 – GEOMETRY & MATLS Slab and Wall Dimensions, in. AASHTO LRFD LRFD Table 2.5.2.6.3-1 ASTM C1577 Top Slab Min. = (S+10)/30 >/= 0.54 ft. & 4.6.2.10.4, Precast Box Culverts, Span : Slab Thickness = (s/t) </= 18. (Note: In-lieu of stated criteria, deflection analysis required.) See Tables for standard thickness. Special and Modified thickness allowed per Section 7.2. Bottom Slab ---- See Tables for standard thickness. Special and Modified thickness allowed per Section 7.2 Exterior Wall Added Thickness for V-Bottom Slab Top Haunch Bottom Haunch SCREEN 3-6

STEP 3 – GEOMETRY & MATLS

STEP 3 – GEOMETRY & MATLS SCREEN 3-6 Skew Angles, deg. AASHTO LRFD ASTM C1577 Culvert: Section 3.6.1.2.6 & 4.6.2.10 considers parallel and perpendicular applied LL. However, LL distribution need not be corrected for skew effects per 12.11.2.4. Per X1.2.3, If the live load travel is at an angle greater than 30 deg from parallel to the span and the fill height over the RCB is 5 feet and less, a separate skew analysis must be performed. All C1577 standard designs based on a 0 degree culvert skew angle. Left End: NA – For Cast In Place RCB Only. Right End SCREEN 3-6 Bottom Slab Support AASHTO LRFD ASTM C1577 Full Bottom Slab Section 12.11.1 applies to box culverts (cast in place & precast) and cast-in-place reinforced concrete arches. Section 1.1, applies only to single-cell precast reinforced concrete box sections (4 sided) cast monolithically. No Bottom Slab, Pinned Supports NA for four sided RCB No Bottom Slab, Fixed Supports

SKEW ANGLE IN ETCULVERT ONLY IMPACTS THE AASHTO DOES NOT DEFINE THE SKEW ANGLE, AASHTO ONLY CONSIDERS PARALLEL AND PERPENDICULAR APPLIED LIVE LOADS. PERP (>60) SKEW ANGLE IN ETCULVERT ONLY IMPACTS THE SKEWED PORTION OF A CULVERT WHERE THE EFFECTIVE SPAN LENGTH CHANGES 30 < CHECK BOTH < 60 PARALLEL (<30)

STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Concrete AASHTO LRFD ASTM C1577 Strength (f’c) Per Section 5.4.2.1 – 2.4 ksi to 10.0 ksi for normal weight concrete 5,000 psi minimum Density Per Table 3.5.1-1 & Comentary C3.5.1, Varies Linerly with concrete strength; 5.0<f'c</=15.0 ksi; Density = 0.140+.005+0.001(f'c) 150 pcf (min.) Elasticity, Ec LRFD-5.4.2.4-1; Varies as a function of concrete unit weight; Ec = 33,000(K1)Wc^1.5(f'c)^0.5 Per LRFD Concrete Type Per Table 3.5.1-1 - Normal weight concrete

STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Reinforcement Cover AASHTO LRFD LRFD 12.11.4.4 & 2013 Interim ASTM C1577 Exterior of Top Slab Per Specifications Table 5.12.3.1 - Top slabs used as a driving surface minimum reinforcement cover = 2.5"; top slabs with less than 2.0' of fill, minimum reinforcement cover = 2.0"; top slabs with under fills greater than 2.0' otherwise 1.0" ASTM C1577 - 2.00 inches of concrete cover for top slabs under fills of 0' to 2' in depth; 1.00 inch for slabs under fill greater than 2' Exterior of Bottom Slab 1.0” Exterior of Exterior Wall Interior of Top Slab Interior of Bottom Slab Interior of Exterior Wall

Reinforcement Diameter, in User input initial estimate STEP 3 – GEOMETRY & MATLS Reinforcement Steel AASHTO LRFD Section 5.4.3.1 ASTM C1577 Yield (fy) ksi Reinforcing bars, deformed wire, cold-drawn wire, welded plain wire fabric, and welded deformed wire fabric shall conform to the material standards as specified in Article 9.2 of the AASHTO LRFD Bridge Construction Specifications. The nominal yield strength shall be the minimum as specified for the grade of steel selected, except that yield strengths in excess of 75.0 ksi shall not be used for design purposes. Bars with yield strengths less than 60.0 ksi shall only be used with the approval of the owner. Per Section 12.4.2.7 – smooth WWF the yield strength may be taken at 65 ksi; for deformed the yield may be taken at 70 ksi. Standard Design Tables of ASTM C1577 based on reinforcement yield strength, fy = 65,000 psi Allow Stress, ksi NA - per C12.11.3 100% of yield stress Elasticity (Es) ksi 29,000 ksi per LRFD 5.4.3.2 --- Reinforcement Diameter, in User input initial estimate Shear Steel Yield, ksi Up to 100 ksi per LRFD 5.4.3.2 SCREEN 3-7

Industry standard is 120 pcf per ASTM C1577 STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Soil AASHTO LRFD LRFD 12.4.1.3 & 12.11.4.4 ASTM C1577 Density In the absence of precise project information, Table 3.5.1-1 may be used. Soil min. = 100 pcf. Industry standard is 120 pcf per ASTM C1577

STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Exposure Factor AASHTO LRFD ASTM C1577 Class 2 Exposure 0.75 for Class 2 exposure unless other wise specified. Select 0.75 for Class 2 exposure (see C5.7.3.4)

STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Soil Structure Interaction AASHTO LRFD LRFD 12.11.2.2.1 ASTM C1577 Compacted Fill Fe = 1 + 0.20 (H/Bc), however Fe shall not exceed 1.15 for installations with compacted fill along the RCB sides, LRFD 12.11.2.2.1 (Project specific-user input required) ASTM C1577, Table X1.1 assumes compacted side fill, Fe = 1 +0.20(H/Bc) Fe Max. = 1.15 Uncompacted Fill Fe = 1 + 0.20 (H/Bc), however Fe shall not exceed 1.40 for installations with uncompacted fill along the RCB sides LRFD 12.11.2.2.1 --- User Defined Per LRFD 12.11.2.2.1-Trench varies as a function of trench width; Installations other than embankment or trench based on previous experience, tests, or soil-structure interaction analysis.

Section X1.1.2, X1.3.3 & Table X1.1, granular soil, STEP 3 – GEOMETRY & MATLS SCREEN 3-7 Slope Factor AASHTO LRFD Table 3.6.1.2.6a-1 2013 Interim Spec ASTM C1577 Granular Soil – All culverts and buried structures, except concrete pipe 1.15 Section X1.1.2, X1.3.3 & Table X1.1, granular soil, LL Dist. = 1.15

STEP 4 – LOADING SCREEN 3-8 Live Load AASHTO LRFD ASTM C1577 Truck Per LRFD 3.6.1.1.1 to 3.6.1.1.2, 3.6.1.2.1 to 3.6.1.2.6, & 3.6.1.3 Design truck, design tandem and design lane load. These may be modified by a given jurisdiction when: legal loads are significantly greater than typcial HL93; roadway is expected to carry unusually high percentages of truck traffic; traffic flow controls are in place; Special industrial loads are common. HL93

SCREEN 3-9 Live Load AASHTO LRFD ASTM C1577 HL93 LRFD Figure 3.6.1.2.2-1 Figure X1.1 SCREEN 3-9

Box needs to be checked to include Tandem Load Live Load AASHTO LRFD ASTM C1577 HL93 Box needs to be checked to include Tandem Load SCREEN 3-9

Standard Designs do not include lane load Live Load AASHTO LRFD ASTM C1577 HL93 AASHTO LRFD does not require a lane load. However, some DOT agencies specify that lane load is to be applied Standard Designs do not include lane load SCREEN 3-9

SCREEN 3-9 Only Matters if Lane Load is Included Live Load AASHTO LRFD ASTM C1577 HL93 AASHTO LRFD requires that both the Truck and Tandem loads be checked. SCREEN 3-9 Only Matters if Lane Load is Included

(Project specific-user input required) STEP 4 – LOADING SCREEN 3-8 Live Load AASHTO LRFD ASTM C1577 Traffic Direction Per LRFD Section 4.6.2.10.2 Parallel & 4.6.2.10.3 Perpendicular to span (Project specific-user input required) Section X1.2.3 –Std. designs based on parallel to culvert span – perpendicular to span when The skew angle is greater than 30 degrees and the fill is less than 5 feet.

(Project specific-user input required) STEP 4 – LOADING SCREEN 3-8 Live Load AASHTO LRFD ASTM C1577 Max. Number of Lanes Per LRFD Section 3.6.1.1.1, in general are determined by taking the integer of w/12, where w = width of clear roadway. (Project specific-user input required) So long as the direction of traffic is parallel to main reinforcement, input the number of lanes = 1

STEP 4 – LOADING SCREEN 3-8 Live Load AASHTO LRFD ASTM C1577 Override MPF Section 3.6.1.1.2-1 Don’t override MPF Per Section X1.1 MPF = 1.2 for one lane Depth of LL Surcharge Table 3.11.6.4-1 <2‘ (enter depth of SC if different for agency) enter depth of SC if different for agency Apply LL Surcharge at Fill Depth Greater Than 2 Foot? Table 3.11.6.4-1 YES, Apply LL surcharge at fill depths greater than 2 feet (Check Box) Include Lane Load? Per LRFD Section 3.6.1.3.3, box culverts are exempted from lane loads regardless of span and regardless of span orientation (transverse or longitudinal) to the direction of traffic (Do not check box) See Section X1.2.2 Neglect LL for Fill Depths Greater Than 8 Feet and Greater Than Span Length Per LRFD Section 3.6.1.2.6, for single span culverts, the effects of live load may be neglected where the depth of fill is more than 8 feet. (User’s preference) C1577 considers live load for the full depth, Appendix X1.

STEP 4 – LOADING SCREEN 3-8 Dead Load AASHTO LRFD ASTM C1577 Additional Uniform DL, klf Per Section 3.5.1, Dead Loads, the dead load shall include the weight of all components of the structure, appurtenances and utilities attached thereto, earth cover, wearing surface, future overlays and planned widening. (Project specific-user input required) Earth Load Only Future Wearing Surface, klf For bituminous wearing surfaces, 0.140 kcf (Table 3.5.1-1)

(Project specific-user input required) STEP 4 – LOADING SCREEN 3-8 Concentrated Loads AASHTO LRFD 12.11.2.3 ASTM C1577 Loads 1 to 3 The width of the top slab strip used for distribution of concentrated wheel loads, specified in Article 12.11.2 shall also be used for the determination of moments, shears and thrusts in the side walls and the bottom slab. (Project specific-user input required)

STEP 4 – LOADING SCREEN 3-8 Lateral Soil Loads AASHTO LRFD 3.11.5.1; 3.11.5.5; 3.11.7 ASTM C1577 Soil Equivalent Fluid Pressure, pcf The equivalent-fluid method may be used where Rankine Earth Pressure Theory is applicable where the backfill is free-draining. (Project specific-user input required) User to Input: Max. = 60 Min. = 30

STEP 4 – LOADING SCREEN 3-8 Fluid Pressures AASHTO LRFD ASTM C1577 Consider Internal Water Pressure Include fluid weight contained in the box culvert. TYPICAL

Live Load Strength Factor STEP 5 – DESIGN PARAMETERS Load Factors AASHTO ASTM C1577 LRFD Table 3.4.1-2 Table X1.1 DC (max./min.) 1.25 / 0.9 “ DW (max./min.) 1.5 / 0.65 EV (max./min.) 1.3 / 0.9 EH (max./min.) 1.35 / 0.9 WA 1  Live Load Strength Factor LRFD Table 3.4.1-1 LL-Strength I 1.75 LL-Strength II 1.35 SCREEN 3-12

Operational Importance LRFD Section 1.3.5 & Section 12.5.4 STEP 5 – DESIGN PARAMETERS Load Modifiers AASHTO ASTM C1577 Ductility LRFD Section 1.3.3 & Section 12.5.4 1.00 for conventional design and details complying with LRFD specifications Redundancy LRFD Section 1.3.4 & Section 12.5.4 Non-redundant under earth fill = 1.05; Redundant under live load and dynamic load allowance = 1.0 Operational Importance LRFD Section 1.3.5 & Section 12.5.4 1.00 for typical bridges SCREEN 3-12

STEP 5 – DESIGN PARAMETERS Capacity Modifiers AASHTO ASTM C1577 Condition 1.00 for conventional design and details complying with LRFD specifications --- System Non-redundant under earth fill = 1.05; Redundant under live load and dynamic load allowance = 1.0 SCREEN 3-12

STEP 5 – DESIGN PARAMETERS Resistance Factors AASHTO  ASTM C1577 Shear 0.9 per LRFD Table 12.5.5-1 0.90 Moment 1.00 per LRFD Table 12.5.5-1 1.00 P-M Diagram   Compression Tension SCREEN 3-12

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Member Thickness AASHTO  ASTM C1577 Top Slab LRFD Table 2.5.2.6.3-1: Traditional Depths for Constant Depth Structures, Minimum Depth = (S+10)/30 >/= 0.54 ft. & Section 4.6.2.10.4, Precast Box Culverts, Span to Slab Thickness (s/t) </= 18. Fixed Bottom Slab --- Exterior Wall Interior Wall

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Live Load Analysis  AASHTO LRFD  ASTM C1577 Automatically Set Direction to Account for Skew Effects? No LRFD 12.11.2.4 Include Impact on Bottom Slab Yes, Per LRFD 12.11.2.3 the width of the top slab strip used for distribution of concentrated wheel loads, shall be used for the determination of moments, shears and thrusts in the side walls and bottom slab. Override DLA Dynamic Load Allowance? No Table 3.6.2.1-1 DLA Dynamic Load Allowance Per LRFD Section 3.6.2.2 Buried Components covered by Section 12, in percent, shall be taken as IM=33(1.0-0.125De)> 0%

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Live Load Analysis  AASHTO LRFD  ASTM C1577 Limit Distribution Width to Culvert Length for Fills Less Than 2 Feet? YES, per LRFD Section 3.6.1.2.6 – Interim Spec. Check Box Limit Distribution Width to Culvert Length for Fills Greater Than 2 Feet? NO, per LRFD Section 3.6.1.2.6 –Interim Spec. Do Not Check Box. Do Not Check Box. Combine Axle Overlaps for Fills Greater Than 2 Feet User – Check Box. Always Distribute Wheel load? ???????? Axle Increment for Analysis See ET Culvert User Manual ----

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Reinforcement  AASHTO LRFD   ASTM C1577 Individual Top and Bottom Slab Design? Yes  Yes Individual Interior and Exterior Wall Design?  NA NA Always Include Distribution Steel? Do not check Max. As Used in Vc Calcs,  

Miscellaneous Options STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Miscellaneous Options  AASHTO LRFD   ASTM C1577 Use Strength II Do Not Check Box

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Live Load Deflection Criteria  AASHTO LRFD ASTM C1577  1/800,1/1000, User Defined LRFD Section 2.5.2.6.2, Criteria for Deflection 1/800 – Non Pedestrian App. 1/1000 – Pedestrian App. (Project Specified) ----

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Slenderness  AASHTO LRFD ASTM C1577  Check Slenderness LRFD 5.7.4.3 ----

Bottom Left Node on Rollers STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Structural Modeling  AASHTO LRFD ASTM C1577  Use Haunches Yes – Check Box Bottom Left Node on Rollers User Preference

Extend Critical Sections Use Max Moment w/ Max Shear STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Critical Sections  AASHTO LRFD ASTM C1577  Consider Haunches Yes – Check Box Extend Critical Sections Use Max Moment w/ Max Shear User preference

STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Flexure  AASHTO LRFD ASTM C1577  Ignore Axial Thrust Do Not Check Box Use Pipe Equation

Always Check Iterative Beta STEP 5 – DESIGN PARAMETERS SCREEN 3-14 Shear  AASHTO LRFD ASTM C1577  Always Check Iterative Beta Do Not Check Box

STEP 5 – DESIGN PARAMETERS SCREEN 3-15

STEP 5 – DESIGN PARAMETERS SCREEN 3-17 Design Mode does not investigate shear reinforcement – concrete is assumed to provide only means of shear resistance. Shear reinforcement is only reviewed in Analysis Mode.

STEP 6 – REVIEW / OPTIMIZE Reduce the length of the text report: CLICK <<FILE>> CLICK <<OPTIONS>>

STEP 6 – REVIEW / OPTIMIZE Review Input Data

STEP 6 – REVIEW / OPTIMIZE Review Input Data – continued…..

STEP 6 – REVIEW / OPTIMIZE Review Input Data – continued…..

STEP 6 – REVIEW / OPTIMIZE Overall Design Results (slab thicknesses and reinforcing areas) Modify Spacing to 2” (plant standard) Adjust As, prv based on actual sizes

STEP 6 – REVIEW / OPTIMIZE Review Flexural Design Results @ each depth increment Consider reducing As1

STEP 6 – REVIEW / OPTIMIZE Review Shear Design Results @ each depth increment Could reduce slab thickness – but plant has 8” forms as a standard – could also reduce concrete strength required

STEP 7 – SWITCH TO ANALYSIS SCREEN 3-5

STEP 8 – UPDATE REINFORCING

OK @ 2’ – check other depths STEP 9 – OPTIMIZE Reduced As1 from 0.30 to 0.24 OK @ 2’ – check other depths

Change Steel Yield or Concrete Strength STEP 9 – OPTIMIZE Problem with Mcr check Change Steel Yield or Concrete Strength

STEP 9 – OPTIMIZE fc = 4.5ksi or fy = 65 ksi

Reduced Concrete Strength (lower MOR) STEP 9 – OPTIMIZE Reduced Concrete Strength (lower MOR)

Increased Steel Yield Strength STEP 9 – OPTIMIZE Increased Steel Yield Strength

STEP 10 – PRINT / REVIEW Switch back to Full Length Report: CLICK <<FILE>> CLICK <<OPTIONS>>

STEP 10 – PRINT / REVIEW

STEP 10 – PRINT / REVIEW

STEP 10 – PRINT / REVIEW

STEP 10 – PRINT / REVIEW