This half Ironman Build and Peak period plan was designed by Joe Friel using the principles of his books--The Triathletes Training Bible and Going Long. All higher-intensity bike workouts are described using power. You must have a power meter and be familiar with using it. You will also need power zones (based on the Coggan system). To establish goals go to http://tinyurl.com/29t3q6m and under Joe Friel's picture you will see a PDF titled 'Using Heart Rate, Power & Pace.' Download that and follow the instructions for setting your power zones.
This plan is best started 11 weeks prior to your A-priority, half Ironman race. If you have been training consistently you may start at any point in this plan and still do well.
This plan is intended for the experienced, intermediate to advanced under-age-50 triathlete. To start this plan you should have completed a Base training period and be able to swim 1 hour, bike 3 hours, and run 2 hours. Weekly volume is about 13 hours per week with 3-4 swims, 4 bikes, 4-5 runs and 1 strength session. The exceptions are the R&R weeks every fourth week with volume significantly reduced for 4 to 5 days and self-testing at the end of the week to measure progress. There are also fitness-building race-simulation bricks every week. The last 3 weeks of this plan taper and peak you for the race.
The plan uses common language to describe the workouts and is easy to follow. By the end of 11 weeks you will have excellent half Ironman race fitness.