Detailed meteorological analysis to help designers optimize fan comfort and minimize construction costs for an open-air stadium
SunTrust Park became the new home of the Atlanta Braves at the launch of the 2017 Major League Baseball (MLB) season. A 41,500-seat open-air ballpark with three decks of seating and a large shade canopy, the venue was constructed in conjunction with an adjacent entertainment district designed to attract patrons year-round.
Baseball season in Atlanta can include a wide range of weather conditions--from hot, humid day games in mid-summer to cool, windy evenings in April (or, if the Braves do well, late October). To promote spectator comfort, the ballpark’s design needed to incorporate features like sun shades and natural ventilation appropriate to local seasonal conditions.
Efficiency in design and construction were also priorities. SunTrust Park and its surrounding amenities demanded major investment: $1.1 billion in all. Controlling materials and construction costs while ensuring safety and comfort was critical.
We delivered detailed climate engineering analysis to help the project’s owners achieve two key objectives:
- promote game-time spectator comfort throughout the baseball season, and
- design the park’s structure and façade to handle local wind conditions safely and efficiently
Our team of meteorologists and climate engineers offered expert analysis and modeling of relevant meteorological data, ensuring that our clients got the most relevant, valuable insights possible from recorded weather records. Our work on SunTrust Park had four key elements:
Assessing the meteorological data for relevance to the building site
Two meteorological stations held data on local conditions; each had a strength and a weakness. Dobbins Air Reserve Base (MGE) was closer to the ballpark, but had less detailed records. Hartsfield-Jackson International Airport (ATL) had more comprehensive information but was 14 miles farther away from the park. Our in-house meteorology team performed a comparison of the two stations’ hourly data on wind speed and direction, temperature, humidity, and precipitation, and concluded that there was strong agreement between the two sets of climate statistics. This meant we could use the more complete records while remaining confident that our analyses would accurately reflect conditions at the ballpark. We complemented the weather station data with modeled solar radiation data for the area.
Zeroing in on game-time conditions
Equipped with data we had confidence in, we then analyzed variations in climatic and thermal comfort parameters at the ballpark across various seasons and times of day. In particular we focused on typical periods for day games (noon to 6pm) and evening games (7pm to midnight) during baseball season. We developed a statistical picture of the frequency and intensity of various conditions that might occur during these key windows.
To assess spectators’ comfort during game times, we used a unique RWDI approach to analyzing human comfort: we calculate a metric that provides an overall gauge of a spectator’s comfort, based on the integration of multiple calculated variables such as wind, shade, humidity, clothing and activity.
Everyone experiences how conditions can moderate or reinforce each other: a hot day can be fine in the shade and miserable in full sun, while a cool evening might be pleasant in a protected area but too chilly when a breeze comes up. Our unique measurement approach lets us account for the complex interplay between all the relevant variables and determine whether the overall result is comfortable or uncomfortable.
Combined with assessments of the frequency with which various combinations of conditions are likely to occur, our analysis gave the design team precise insights into the potential benefits of features such as shade structures. This helped them optimize the park’s design, making it as comfortable as possible for as many game-times as possible. Our analysis also helped the designers avoid the effort and expense of design adaptations that wouldn’t have made a meaningful difference to fans’ experience.
Finding savings in building design with a directional wind model
We also put the measured data from ATL to use as we developed a statistical model of extreme windstorms. By using this statistical model in combination with physical wind-tunnel testing of the park, we were able to help the park’s developers identify areas for savings in the building design. A detailed and accurate picture of the wind loads the park would experience allowed for the refinement of both the park’s structure and its cladding, resulting in a more efficient structure that was both safe and cost effective.
SunTrust Park opened in February 2017. Our team of wind and climate engineers as well as meteorologists supported a successful project outcome with precise, well-founded recommendations to the park’s design team. We helped minimize materials and construction costs while optimizing design elements that will promote spectator comfort in the baseball seasons ahead. The Atlanta Braves played their first regular-season home game at SunTrust Park on April 14th 2017, beating the San Diego Padres 5-2.