2824 GRAND AVE NAUTICA CONDOMINIUMS 2018-01-02 MF Import

GEOTECHNICAL ENGINEERING STUDY Cascasia Pacific Properties, Ltd. July 15, 1999 E-8602 Page 10 As previously discussed, foundation support in the vicinity of the existing Burlington Northern tunnel alignment, can be derived by the use of conventional continuous and spread footings, or pile foundations. To limit foundation loading above the tunnel structure, conventional foundations should maintain a minimum distance of 1.58 from the edge of the tunnel, where "B" is the footing width. This minimum setback distance assumes at least two feet of soil over the tunnel structure will be removed as part of the mass excavation. Use of the above minimum footing setback, and removal of at least two feet of soil over the tunnel structure, will effectively result in a compensating condition in terms of loading over the tunnel. ECI should review the foundation plan and column loading to verify the footing setbacks, and to modify the setback recommendations if necessary. As stated previously, Burlington Northern should be contacted to discuss limitations on loading over the tunnel structure. Recommendations for conventional foundations and piling design are presented in the following sections of the report. Conventional Foundations For conventional foundations bearing on competent native soils or lean mix, an allowable soil bearing capacity of five thousand (5,000) psf can be used. Foundations bearing on structural fill should be designed using an ailowable soil bearing capacity of two thousand five hundred (2,500) psf. Continuous and individual spread footings should have minimum widths of eighteen (18) and twenty-four (24) inches, respectively. Loading of this magnitude would be provided with a th^oretical factor -of -safety in excess of three against actual shear failure. A one-third increase in the above allowable soil bearing capacities can be assumed for short-term wind and seismic loading conditions. Exterior foundations elements should be placed a minimum depth of eighteen (18) inches below final exterior grade. Interior spread foundations can be placed at a minimum depth of twelve (12) inches below the top of slab, except in unheated areas, where interior foundation elements should be founded at a minimum depth of eighteen (18) inches. Provided the foundations are installed in accordance with the recommendations contained in this report, we expect total settlements of approximately one inch and differential settlement of approximately one-half inch. Most of the anticipated settlements should occur during construction as dead loads are applied. Earth Consuhe,ttl, Inc.