Soil-Structure Interaction Seminar - Foundation Performance ...

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General QUALITY CONTROL Construction monitoring and quality control tests should be planned to verify materials and placement in accordance with the project design documents and specifications. Earthwork observations on the house pad, pad thickness measurements, drilled footing installation monitoring, and concrete placement monitoring should be performed. Details of each of these items is described in the following paragraphs. Earthwork Observations The subgrade and fill soils under the floor slabs should be compacted to about 95 percent of maximum dry density (ASTM D 698). Furthermore, the fill soils should be non-e*Pansive. Atterberg limit tests should be performed on the fill soils, obtained from the borrow pit, to evaluate the suitability of these soils for use as structural fill and their shrink/swell potential. Expansive soils, of course, should not be used as structural fill. Field density tests should be conducted on the subgrade soils and any borrow fill materials in the floor slab and pavement areas. In the areas where expansive soils are present, about 18- to 36inches of structural fill is placed under the floor slab areas. Laboratory proctor tests will also be performed on the on-site soils as well as off-site borrow fill materials to evaluate the moisture-density relationship of these soils. Fill Thickness Verification Fill soils may have to be placed on the lots to raise the lot or to provide a buffer zone in between the on-site expansive soils and the floor slabs. We recommend that the required thickness of the fill be verified after the completion of the building pad. This task can be accomplished by drilling two borings to a depth of four-feet in the building pad area, examining and testing the soils to verify the fill thickness. Drilled Footing Inspection In the event that the structure is supported by drilled footings, we recommend that the installation of the footings be observed by a geotechnical technician. The technician will conduct hand penetrometer tests on the soil cuttings to estimate the bearing capacity of the soil at each footing location. He will make changes to the foundation depth and dimensions if obstacles or soft soils are encountered. Therefore, minimizing costly construction delays. In addition, the technician must verify the bell size by a bell measurement tool. One set of concrete cylinders (four cylinders) will be made for each day of pour. Two cylinders will be broken at seven days, and two cylinders at 28 days. GEOTECH ENGINEERING AND TESTING, INC. ____________ ... 17
Concrete Placement Monitoring The concrete sampling and testing in the floor slab and placement areas will be conducted in accordance with ASTM standards. A technician will monitor hatching and placing of the concrete. At least four concrete cylinders should be made for each floor slab pour. Two concrete cylinders are tested at seven days and two cylinders at 28 days. General HOMEOWNER MAINTENANCE PROGRAM <strong>Performance</strong> of residential structures depends not only on the proper design and construction, but also on the proper foundation maintenance program. Many residential foundations have experienced •major foundation problems as a result of owner's neglect or alterations to the initial design and landscaping. This has resulted in considerable financial loss to the homeowners, builders, and designers in the form of repairs and litigation. A properly designed and constructed foundation may still experience distress from vegetation and expansive soil which will undergo volume change when correct drainage is not established or incorrectly controlled water source becomes available. The purpose of this document is to present recommendations for maintenance of properly designed and constructed residential projects in Houston. It is recommended that the builder submit this document to his/her client at the time that the owner receives delivery of the house. Drainage The initial builder/developer site grading should be maintained during the useful life of the residence. In general, a civil engineer develops a drainage plan for the whole subdivision. Drainage sewers or other discharge channels are designed to accommodate the water runoff. These paths should be kept clear of debris such as leaves, gravel, and trash. In the areas where expansive soils are present, positive drainage should be provided away from the foundations. Changes in moisture content of expansive soils are the cause of both swelling and shrinking. Positive drainage is extremely important in minimizing soil-related foundation problems. Sometimes, the homeowners, mount the flowerbed areas, creating a dam, preventing the surface water from draining away from the structure. This condition may be visually appealing, but can cause significant foundation damage as a result of negative drainage. The most commonly used technique for grading is a positive drainage away from the structure to promote rapid runoff and to avoid collecting ponded water near the structure which could migrate down the soil/foundation interface. This slope should be about 3 to 5 percent within 10feet of the foundation. GEOTECH ENGINEERING AND TESTING, INC. -------------· 18
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SOIL STRUCTURE INTERACTION SEMINA
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FOUNDATION FAILURE DEFINED IN TERMS
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FOUNDATION FAILURE DEFINED IN TERMS
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FOUNDATION FAILURE IN THE HOUSTON A
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FOUNDATION FAILURES IN THE HOUSTON
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Inspections of the foundation had b
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J CASE NO. 10 - THE USE OF SPREAD F
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GARAGE 0" ·-0.2" -0.8 11 -0.3" •
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V) IJ.J u
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• +0.3" +0.5" • 0 10 I SCALE IN
Page 40 and 41: CURRENT PRACTICES FOR DESIGN OF TRA
Page 42 and 43: INTRODUCTION CURRENT PRACTICES FOR
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Page 47: 4.0 DESIGN PARAMETERS 4.1 General T
Page 62: I I. I I APPENDIX B TYPICAL GENERAL
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Page 72 and 73: GUIDLINES FOR GEOTECHNICAL DESIGN,
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Page 76 and 77: INTRODUCTION The variable subsoil c
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Page 85 and 86: Vegetation Control We recommend tre
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Page 95 and 96: Moisture Barriers Moisture barriers
Page 97: RECOMMENDED QUALITY CONTROL AND INS
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Page 110 and 111: PROFESSIONAL RESUME of DONALD E. LE
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Page 119: A P P E N D I X- DRAWINGS SAMPLE FO
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EXAMPLE OF HELICAL ANCHORS Pipe Typ
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RESIDENTIAL SOIL AND FOUNDATION REQ
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Section 6-52. Exceptions CITY OF WE
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Soil Structure Interaction Seminar
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July 21, 1994 Page3 corporation, as
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Residential Construction Liability
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July 21, 1994 Page 8 E. Defenses to
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The Texas Deceptive Trade Practices
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construction or design of the house
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(5) Arguably, implied warranties do
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(3) Includes any diminution in mark
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D. Who Is a Proper Plaintiff? 1. An
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a. claimant's damages are limited t
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a. May be based on hearsay (i.e., e
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d. The Broker (1) Absent specific a
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VI. More Honored in the Breach HORA
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