Description
This report examines the benefits of the design of concrete towers for land-based wind turbines with heights in excess of 325 ft (100 m), in comparison to those of round steel tubular towers. These benefits include reduced cost, increased stiffness, and superior service life performance. Construction alternatives, design criteria, design methodologies, and guidance for preliminary design of concrete towers are presented.
The report recognizes that final tower design requires close coordination with the turbine supplier. The report is intended for those involved in developing preliminary tower designs. Concrete towers designed for maximum wind forces can be satisfactory for preliminary design, but the final design requires checking for all loads, especially fatigue and dynamic effects from wind and turbine operations. Design of connections and their proportions require an understanding of fatigue requirements during preliminary design for the connection design to remain valid during final checks.
Keywords: concrete tower; full-height tower; hybrid tower; precast elements; prestressing; slipformed; spread footings; turbine; wind; wind farm.
Table of Contents
CHAPTER 1—INTRODUCTION
1.1—Introduction
1.2—Scope
CHAPTER 2—NOTATION AND DEFINITIONS
2.1—Notation
2.2—Definitions
CHAPTER 3—WIND FARM DEVELOPMENT AND TOWER SUPPLY CHAIN
3.1—Introduction
3.2—Certification and design
CHAPTER 4—CONCRETE TOWER TYPES
4.1—Hybrid concrete towers
4.2—Full-height concrete towers
4.3—Construction types
4.4—Construction considerations
4.5—Tolerances
4.6—Tower size and cost
CHAPTER 5—TOWER DESIGN
5.1—Tower frequency design
5.2—Service level design
5.3—Prestressing
5.4—Modeling
5.5—Fatigue
5.6—Preliminary design guidance
CHAPTER 6—DESIGN LOADS AND LOAD COMBINATIONS
6.1—Loads and load combinations
6.2—Load factors
CHAPTER 7—DESIGN LOADS
7.1—Basic weights and loads
7.2—Wind profile
7.3—Earthquake loads
7.4—Normal operating fatigue loads
7.5—Temperature loads
7.6—Abnormal operating conditions
CHAPTER 8—CONCRETE RESISTANCE
8.1—Strength design
8.2—Serviceability design
8.3—Joints and connections
CHAPTER 9—FOUNDATION DESIGN
9.1—Rock anchor foundations
9.2—Pier-type deep foundations
9.3—Spread footings
9.4—Termination of reinforcement and prestress
9.5—Tower-foundation structural integrity
CHAPTER 10—CONCLUSION AND RECOMMENDATIONS
CHAPTER 11—REFERENCES
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