Читать книгу Engineer's Report: Seismic Performance Evaluation and Tire Construction Analysis - Michael Reynolds - Страница 3

This engineering analysis is a compilation of studies and calculations conducted between 1990 and 1993 by Thomas E. Griepentrog P.E of Buckhorn-Geotech, Consulting Engineers and Geologists of Montrose Colorado and Kenneth D. DeLapp of DeLapp Engineering in Santa Fe, New Mexico. This report is a thorough analysis of all structural aspects of the Earth-rammed Tire Walls of the Earthship design by Architect Michael Reynolds.

This booklet also includes relevant parts of a F.E.M.A (Federal Emergency Management Agency) evaluation that researches many types of alternative building. Only the portion specific to Earthships is included here.

The F.E.M.A. discussion of foundations for earthen walls is included as a discussion of earthen building foundations which is relevant to the use of Earth-rammed buildings. The appendix C closes the booklet. This is pertinent information for an engineer.

The enclosed summary and calculations show the strength of the structural components of the standard Earthship Design. Charts, graphs and formulas are provided for the owner and the engineer to analyze the Earthship with site specific conditions. The information required for these calculations are: snow load and wind load, (available from a local building department) and frost depth and soil conditions (to be determined by a soils engineer on site).

The following information must be determined before construction in order to adapt each Earthship to its particular site:

1. Soil analysis: It is recommended that a licensed soil engineer be brought in to insure that your building site is suitable for construction of an Earthship. Minimum bearing capacity can be determined using the information found in Section II. This figure will vary based on the design snow load for your location. Actual bearing capacity at the site can be determined by the soils engineer. See section IV.

2. Earth cliffs: Some site conditions may require shorter earth cliffs than indicated on the Generic Earthship Construction Drawings. The stability of the earth cliff depends on the unit cohesive strength of the soil, the soils internal angle of friction, the total weight of the tire wall, and the potential failure plains. The formula and information necessary to determine the allowable height of the earth cliff is found in Section II.

Additional information must be provided by a soils engineer based on an inspection of your site. See section IV. This inspection is typically scheduled to coincide with the initial excavation.

3. Lateral loads:The tire walls will impart small loads to the roof diaphragm as a result of the Earth Berms. These loads can be determined by the soils engineer based on his/her calculation of soil pressure. See Appendix B. These results will determine if additional bracing will be required on the roof.