MPC
Research Projects (2007-08)

Identifying Number

MPC-278

Project Title

Bus-Stop Shelters: Improved Safety, Year 2

University

Colorado State University

Project Investigators

Wayne A. Charlie, PhD, PE, Professor, Richard M. Gutkowski, PhD, PE, Professor, and Jeno Balogh, PhD, Affiliate Professor

Description of Project Abstract

Bus-stop shelters (school and public transit) typically provide, at best, only limited reduction to exposure to rain, snow, wind and direct sunlight. Most shelters provide little or no reduction in potential injury from severe storms (wind, wind generated missiles, or hail) or vehicle impacts. The proposed research will evaluate and physically test bus-stop shelter designs, including a timber based design, to evaluate and upgrade the impact resistance of bus-stop shelters.

Project Objectives

Research objectives are to design, construct and test a prototype timber bus-stop shelter capable of providing improved safety to occupants from vehicle impacts, hail, and windstorm and tornado generated debris. Year-one tested several prototype sub-assemblies using ASTM E 1886 and E 1996 test methods for impacts from hail and hurricane and tornado generated debris. During year-two, we will do impact tests on two-walls of a prototype full-scale shelter. The U.S.D.A. Forest Service's Healthy Forest Initiative (healthyforests.gov) is resulting in a large volume of timber products in rural areas. We propose to investigate multiple materials for bus-stop shelters, including timber. Based on these tests, we will evaluate the potential of recommending commercial development of the concept of "impact resistant bus-stop shelters".

Project Approach/Methods

The need exists to quantify the impact resistance of bus-stop shelters.

The main goals of this proposed 2nd year research are:

1. In year-2 we propose to complete a literature search started in year-1 to determine a) national and worldwide use of bus-stop shelters and existing specifications, designs and materials used for such shelters, b) impact strength of typical materials used for such shelters, c) existing designs to include impact resistance of structures, d) accidents related to hail and windstorm generated debris and automobile impacts of bus-stop shelters, and e) load-displacement characteristics of timber protective barriers to upgrade existing bus-stop shelters as a function of soil conditions, timber type and dimensions, and other variables.
2. During year-2, we propose to conduct ASTM impact tests on additional prototype sub-assemblies and conduct impact tests on two interconnected-walls of a full-scale prototype bus-stop shelter, conduct preliminary computer modeling, and compare physical test results with the computer modeling results. In year-1 we tested a prototype sub-assembly using ASTM test methods for impacts from tornado generated debris impacting at velocities of 100 mph. In Year-2 we will analyze the high-speed video of the tests conducted in Year-1 to determine the force-time impact loading and the resulting energy resisted by the sub-assemblies.

Contributions/Potential Applications of Research

Bus-stop shelters should harmonize with the local area and combine simplicity, functionality, good design, and safety. In addition, if these structures can offer safe refuge from hail or debris generated by windstorms and tornados, they would offer additional benefits. Improved structural modeling contributes to better understanding of response to these increasing loads and field conditions. The research proposed will lead to a better understanding of impact resistance of bus-stop shelters leading to more realistic assumptions of a bus-stop shelter's response to impact loading. This information should be of potential benefit to designing new and upgrading existing bus-stop shelters.

Technology Transfer Activities

Technology transfer will be via an MPC technical report and an MPC Research Seminar will be presented over the Transportation Learning Network telecommunications network after completion of the project. If warranted, a technical journal and/or conference paper will be prepared for submittal. Publicity about all of the MPC projects is available through the MPC website maintained at NDSU.

Colorado State University has an extensive database from its past research on windstorm, tornado and hurricane impact resistance of structures and similar research on blast load resistance of structures. Colorado State University also has an extensive database and computer modeling experience in modeling timber bridges and structures to static and dynamic loadings.

Time Duration

July 1, 2007 - June 30, 2008

Yearly and Total Project Cost

$90,818 Total $186,568

TRB Keywords

Bus-stop shelters, hail, impact resistance, tornado and hurricane debris, timber