Preliminary Design

This is a possible design of our green roof(Figure 1), we are still working on the layers and material of the roof. We discovered that the building's roof was enhanced for the landing of aircrafts in a time of emergency. Therefore part of the green roof will be serving as a air purifier as well as an emergency heliport! In our design, the roof will be covered by a layer of extensive green roof and pathways in between. Since the roof has been designed for the landing of aircrafts, it is enhanced with Alabama Limestone. Because of this, we know that the roof will be strong enough to hold a larger coverage of green roof. We also aim to develop the roof into a public area where people could stay and hang out.

Figure 1: Preliminary design of 30th green roof 

Research So Far

As of Week 3, we have decided to create an extensive green roof for 30th Street Station. The area over the main concourse, which we will be redesigning, covers an area of approximately 64,000 square feet.
Here are some of the basic layers of the green roof we will be designing:

• The growing medium supports plant growth and provides for storage of stormwater within voids. The storage capacity is a function of medium depth, surface area, and total void space.
• Filter or separation fabric, or geotextile, prevents migration of soil into the underlying drainage layer of the green roof.
• A drainage layer may incorporate measures to intercept and retain percolated rainfall as it moves through the green roof storage area. Examples include membranes with depressions to hold water and specialized fabrics or mats with high capillary indices.
• Moisture interception layers/root barriers are impermeable liners that protect the underlying roof deck from moisture and plant root intrusion. Some waterproofing materials are inherently root resistant, whereas others require an additional root barrier.
• Underlying roofing systems typically consist of a structural deck, its supporting structures, and a traditional overlying waterproofing system.

We are also going to take our research into the field, where we will look at other green roofs in Philadelphia, specifically the Free Library of Philadelphia and Cira Green Rooftop Park. 

Project Proposal

Cira Green, Philadelphia, PA
An example of a well furnished green rooftop
Completed by the Roofmeadow Studio

As a direct solution to participate in the Philadelphia’s Stormwater Management System and to reduce the negative effects that stormwater runoff brings, this project intends to create a systematic stormwater management program on the rooftop of the 30th Street Station using Green Stormwater Infrastructure (GSI). The motivation for this project is to update the station and lessen its negative impact on the environment. The goal is to decrease the impervious surface, which prohibits water from infiltrating the ground, on stormwater runoff within Philadelphia. The impervious areas lead to a greater problem, which causes increased stormwater runoff and higher stormwater peak flows. Therefore, located on Market Street, the 30th Street Station is chosen as the project site because of its encompassment of a large impervious surface -- 95% of its ground is impervious. The completion of the project aims to turn this area into an environmentally friendly surface which functions to minimize stormwater runoff, and to purify the air of Philadelphia. There are some major technical obstacles such as a steep learning curve for certain computer software and creating a physical model to scale. The major tasks of this project include: literature studies, calculation, computer programing, creating a physical model, and completing the final project report. To complete this project, a pragmatic project must be carried out, which includes a base plan, drainage area map, proposed design plan, sections & profiles of proposed systems, and GSI sizing & runoff calculations.