Rev. H Overview Rev. H Adoption Overview Effective January 1, - PowerPoint PPT Presentation

Rev. H Overview

Rev. H Adoption Overview • Effective January 1, 2018 • Referenced in 2018 IBC States with Rev. H Adopted States with County/City Adoption of Rev. H

Panel Introductions Bryan Lanier, P.E., S.E. Director, Broadcast Engineering American Tower Corporation Tyler Stevens, P.E. Manager Engineering Crown Castle Tyler.Stevens@crowncastle.com Mike Oglesby, P.E. Senior Engineering Manager Kimley-Horn Michael.Oglesby@kimley-Horn.com

Overview of Changes Capacity Capacity Topic Topic Effects Effects ▲ ▬ Allowable Capacities & Grandfathering Mount Analysis ▼ ▬ Anchor Rods & Grout Consideration Risk Category & Site Hardening ▲ ▼ Angle Strengths Rooftop Converging Wind ▬ ▲ Corrosion Control Standards Topographic Factor ▬ ▬ Drone Usage Verification Inspections ▲ ▬ Ground Elevation Factor Wind Direction Probability & Clean Poles ▲ ▲ Modification Factor / Reliability Factor Wind Speeds

Allowable Capacities / Grandfathering Code Location: Section 15 Criteria (one of following): How is it applied: 1. Baseline Analysis in Rev. H • Maximum Stress = 105% 2. Current Analysis in Rev. H • Current vs. Original Design ≤ 5% 3. Compare against one another to • Current vs. Structural Design ensure ≤ 5% deviation Upgrade ≤ 5% Increase Impact: 105% codified Limit upgrades to established structures T HOME

Angle Strengths Strength vs. KL/r 40 Code Location: Section 4.5.4.2 35 Criteria: 30 • Updated angle strength derivation • ASCE10-15 25 How is it applied: 20 • Replaces typical AISC equations 15 Impact: 10 • 11% increase for short members • 30% increase for intermediate members 5 • 27% increase for long members 0 0 20 40 60 80 100 120 140 160 180 200 220 240 B Rev. G Rev. H HOME

Anchor Rod & Grout Code Location: Section 4.9.9, Annex Q Criteria: How it is applied: • Assessment of anchor rods as • Anchor rods assessed considering load carrying member multiple loadings and rod projections • Not similar to a fastener • Grout impacts differently • Greater emphasis on threaded diameter and combined loading Impact: • Potential increase in anchor rod usages • Installation and grout details critical T HOME

Corrosion Control Code Location: Annexes A14.4 & H Criteria: How is it applied: • Steel in contact with soil • Owner controlled • Focus on guyed anchor rods • Site specific assessment Impact: • Awareness of anchor condition • Safety B HOME

Drones Code Location: Annex J How is it applied: Criteria: • Drone with camera or laser • Use of UAV to replace climbing tower technology and land survey • Data measured and processed • LIDAR (Light Detection and Ranging) • Desired information provided • Photogrammetry Impact: • Improved or limited data and consistency • Improved safety • Cost and availability M HOME

Ground Elevation Factor Code Location: Section 2.6.8 / Table 2-6 Criteria: How is it applied: • NEW Ground Elevation Factor (K e ) • Factor per below table used to reduce wind pressure • Based on tower base height above sea level Impact: • Some high level terrain towers (i.e. Denver) can receive > 15% additional capacity T HOME

Modification Factor / Reliability Factor Code Location: Annex S Criteria: How is it applied: • Risk Category II • 0.95 factor applied to wind loads • Less stringent loading • 0.85 factor applied to ice thickness • Mandatory inspections and repair • Not applicable to new structures Impact: • 5% demand reduction, MP and SST • 5 – 20% demand reduction, GT • Inspection planning • Maintenance remediation B HOME

Mounts Analysis Code Location: Section 16.0 Criteria: How is it applied: • New standardized mount analysis • All equipment additions on mount methods and procedures. require structural analysis unless: • Prescribed Loads Less than 5% increase from Original Design or • 250lbs / 500lbs at specific location Last Structural Modification • Rigging Plans -OR- Changed conditions are within documented capacity Impact: • More consistent analysis • Safer Structures M • Many new mounts / mount mods HOME

Risk Category Code Location: Section 2.2, Table 2-1 Criteria: • Structure Class → Risk Category • Matches IBC How is it applied: • Windspeed and Importance Factors increase/decrease design loads for wind, ice and seismic Impact: • Clarity between Categories • Hardened Network defined B HOME

Rooftop Converging Wind Code Location: Section 2.6.7 / Annex A.2.6.7 Criteria: How is it applied: • NEW Ground Elevation Factor (K s ) • Factor in wind pressure calculation • Accounts for wind speed up over isolated tall buildings (>50’ or >50’ of surrounding buildings) Impact: • Increase in demand of some rooftop structures for tall and/or isolated buildings • 5%-30% potential increase for qualifying structures M HOME

Topographic Factor Code Location: Section 2.6.6, Figure 2-1, A.2.2.6 Criteria: • Rev H contains (3) methods of Topographic evaluation: Method Type Notes 1 Simplified Similar to formal Rev. G method Adopts SEAW-RSM-03. What many engineers were already doing under Rev. G. 2 Rigorous Just made more formal. 3 Site-Specific Requires recognized published literature and/or research How is it applied: Impact: • More accurate analysis à Less Conservative T HOME

Verification Inspections Code Location: Annex N & Annex O Criteria: How is it applied: Engineering documents to have required Inspections & Observations before, checklists within per code which may include: during and after construction for: • Material Test Reports • New Site Builds • Weld Inspections • Tower Modifications • Foundation (rebar & concrete) Inspections • Anchor Rod Inspections & Pull Tests • Member Size Verification • Member Connection Verification • Climbing Facilities Inspection Impact: • Potential higher cost through construction for those currently not performing M • Safer structures with a higher integrity HOME

Wind Direction Probability Factor Code Location: Section 2.6.11 / Table 2-2 Criteria: How is it applied: • Existing factor (K d ) but with an • Factor in wind pressure calculation adjustment: Concealment Poles 0.95 in Rev. G à 1.0 in Rev. H Impact: Wind Direction Wind Direction • Reduces capacity of concealment poles by 5% Note: Canceled out by “drag factor” changes on clean poles T NEXT

Clean Poles – Drag Factors Code Location: Table 2-8b Criteria Impact: • Wind Force Coefficients (C f ) • “Bare” poles receive some potentially substantial additional capacity based • Table contains new values for upon shape: structures without linear appurtenances Pole Shape % Reduction Round 25 How is it applied: 18-Sided 3 • Applied to projected area 16-Sided 13 calculations à Reduces footprint 12-Sided 15 8-Sided 0 T HOME

Wind Speeds Code Location: Annex B How is it applied: Criteria: • Different windspeeds used at same • ASCE7-16 Wind Maps geographic location based on Risk • 300 / 700 / 1700 / 3000 year Category recurrence • Hurricane and thunderstorm updates Impact: • 90%+ of US receives wind speed reduction, up to 30% • Inland Florida wind speeds slight increase • Improved assessment of risk B HOME