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LOAD RATING BY MANUAL CALCULATIONS. RC_ SLAB BRIDGE RATING Amjad Waheed, PE Ohio Department of Transportation. Agenda – Day 1. 8:00 am – 8:15 am Introductions and House Keeping 8:15 am – 8:45 am Session 1: Load Rating Basics 8:45 am – 9:30 am Session 2: Basic Load Rating Calculations
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LOAD RATING BY MANUAL CALCULATIONS RC_ SLAB BRIDGE RATING Amjad Waheed, PE Ohio Department of Transportation Load Rating
Agenda – Day 1 8:00 am – 8:15 am Introductions and House Keeping 8:15 am – 8:45 am Session 1: Load Rating Basics 8:45 am – 9:30 am Session 2: Basic Load Rating Calculations 9:30 am – 9:45 am Break 9:45 am – 11:45 am Session 3: Example – Load Rating Concrete Slab Bridge 11:45 am – 12:00 pm Questions 12:00 pm – 1:00 pm Lunch 1:00 pm – 2:30 pm Session 4: Example – Load Rating Steel Beam Bridges 2:30 pm – 2:45 pm Break 2:45 pm – 3:45 pm Session 4: Example – Load Rating Steel Beam Bridges (Con’t) 3:45 pm – 4:00 pm Questions Load Rating Seminar
What is Load Rating? The safe live load carrying capacity of a highway structure is called its load rating. How to calculate the rating factor (RF) A1 = Factor for dead loads A2 = Factor for live load C = Capacity of the bridge D = Dead loads I = Impact loads L = Live loads Capacity for (L+I) RF = Actual (L + I) C – A1 * D RF = A2 * (L + I) Load Rating
Factors for LFR Load Rating Ref: AASHTO Manual for Condition Evaluation of Bridges 1994 Load Rating
Rating Factor Equation Inventory Rating C – A1 * D R.F. = A1 = 1.3 A2 = 2.167 = 1.3 * 1.67 A2 * (L + I) C – 1.3 * D R.F. = 1.3 * 1.67 * (L + I) C/1.3 – D R.F. = 1.67 * (L + I) Load Rating Seminar
Rating Factor Equation Operating Rating C – A1 * D R.F. = A1 = 1.3 A2 = 1.3 A2 * (L + I) C – 1.3 * D R.F. = 1.3 * (L + I) C/1.3 – D R.F. = (L + I) Load Rating Seminar
Single-span slab bridge Load Rating
Live Load Distribution Factor AASHTO Standard Specification for Highway Bridges 3.24.3.2 CASE B – Main Reinforcement Parallel to Traffic Load Rating
Impact Load (Impact Factor) AASHTO Standard Specification for Highway Bridges 3.8.2 Impact Formula Load Rating
Summary of Rating Results POSTING NOT REQUIRED Load Rating Seminar
Material Strengths BMD - Figure 904 Load Rating Seminar
Material Strengths BMD - Figure 905 Load Rating Seminar
Learning Curve Load Rating
ODOT Rating Contact Information • Amjad Waheed, PE614.752.9972 (awaheed@dot.state.oh.us) • Shelton A. Howard, PE614.752.9975 (showard@dot.state.oh.us) • Richard C. Irwin, PE614.752.9977 (richard.irwin@dot.state.oh.us) • Cindy Wang, PE614.466.1973 (cindy.wang@dot.state.oh.us) Load Rating
That’s all folks Load Rating